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Background: Accurate measurements of intracardiac electrograms (EGMs) remain a clinical challenge because of the suboptimal attenuation of far-field potentials. Multielectrode mapping catheters provide an opportunity to construct multipolar instead of bipolar EGMs for rejecting common far-field potentials recorded from a multivectorial space., Objectives: The purpose of this study was to develop a multipolar EGM and compare its characteristics to those of bipolar EGMs METHODS: Using a 36-electrode array catheter (Optrell-36, Biosense Webster), a far-field component was mathematically constructed from clusters of electrodes surrounding each inspected electrode. This component was subtracted from the unipolar waveform to produce a local unipolar, referred to as a "multipolar EGM." The performance of multipolar EGMs was evaluated in 7 swine with healed anteroseptal infarction., Results: Multipolar EGMs proved superior in attenuating far-field potentials in infarct border zones, increasing the near-field to far-field ratio from 0.92 ± 0.2 to 2.25 ± 0.3 (P < 0.001). Removal of far-field components reduced the voltage amplitude (P < 0.001) and enlarged the infarct surface area (P = 0.02), aligning more closely with histological findings. Of 379 EGMs with ≥20 ms activation time difference between bipolar and multipolar EGMs, 95.3% (361 of 379) were accurately annotated using multipolar EGMs, while annotation based on bipolar EGM was predominantly made on far-field components., Conclusions: Multielectrode array catheters provide a unique platform for constructing multipolar EGMs. This new EGM may be beneficial for "purifying" local potentials within a complex electrical field, resulting in more accurate voltage and activation maps., Competing Interests: Funding Support and Author Disclosures This research was partially funded by Biosense Webster through a research grant. Dr Anter has received research grants and speaking honoraria from Biosense Webster, Boston Scientific, and Medtronic; and is a previous stockholder in Affera Inc Dr Barkagan has received consulting fees from Biosense Webster and Cardiodet. Dr Greenbaum, Mr Bubar, and Mr Yarnitsky are employees of Biosense Webster. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: In patients with persistent atrial fibrillation (PerAF), antiarrhythmic drugs (AADs) are considered a first-line rhythm-control strategy, whereas catheter ablation is a reasonable alternative., Objectives: This study sought to examine the prevalence, patient characteristics, and clinical outcomes of patients with PerAF who underwent catheter ablation as a first or second-line strategy., Methods: This multicenter observational study included consecutive patients with PerAF who underwent first-time ablation between January 2020 and September 2021 in 9 medical centers in the United States. Patients were divided into those who underwent ablation as first-line therapy and those who had ablation as second-line therapy. Patient characteristics and clinical outcomes were compared between the groups., Results: A total of 2,083 patients underwent first-time ablation for PerAF. Of these, 1,086 (52%) underwent ablation as a first-line rhythm-control treatment. Compared with patients treated with AADs as first-line therapy, these patients were predominantly male (72.6% vs 68.1%; P = 0.03), with a lower frequency of hypertension (64.0% vs 73.4%; P < 0.001) and heart failure (19.1% vs 30.5%; P < 0.001). During a mean follow-up of 325.9 ± 81.6 days, arrhythmia-free survival was similar between the groups (HR: 1.13; 95% CI: 0.92-1.41); however, patients in the second-line ablation strategy were more likely to continue receiving AAD therapy (41.5% vs 15.9%; P < 0.001)., Conclusions: A first-line ablation strategy for PerAF is prevalent in the United States, particularly in men with fewer comorbidities. More data are needed to identify patients with PerAF who derive benefit from an early intervention strategy., Competing Interests: Funding Support and Author Disclosures Dr Barkagan has received consulting fees from Biosense Webster and Cardiodet. Dr Gerstenfeld has received research grants and speaking honoraria from Abbott Medical; has served on the advisory board of Biosense Webster; and has served on the data safety monitoring board of Abbott Medical. Dr Narayan has served as a consultant for Abbott, LifeSignals, and TDK. Dr Tzou has served as a consultant for Abbott, Biosense Webster, Boston Scientific, and Medtronic. Dr Siddiqui has received consulting fees from Abbott, Biosense Webster, Boston Scientific, Medtronic, and Stereotaxis. Dr Natale has served as a consultant for Abbott, Baylis, Biosense Webster, Biotronik, Boston Scientific, and Medtronic. Dr Anter has received research grants and speaking honoraria from Biosense Webster and Boston Scientific; and has previously held stock in Affera Inc. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Ablation index (AI) is used for guiding therapy during pulmonary vein isolation. However, its potential utility in ventricular myocardium is unknown., Objectives: This study sought to examine the correlation between AI and lesion dimensions in healthy and infarcted ventricles., Methods: In ex vivo experiments using healthy swine ventricles, the correlation between AI (400-1,200) and lesion dimensions was examined at fixed power (30 W) and contact force (CF) (15 g). To examine the accuracy of AI in predicting lesion dimensions created by different combinations of ablation parameters, applications with a similar prespecified AI value created using different power (30 vs 40 W), CF (15 vs 25 g) or impedance (130-170 Ω) were created. In in vivo experiments, the correlation between AI and lesion dimensions was examined in healthy and infarcted myocardium., Results: Ex vivo experiments (247 lesions, 36 hearts) showed good correlation between AI and lesion depth (R = 0.93; P < 0.001). However, in vivo experiments (9 healthy swine and 10 infarcted swine) showed moderate correlation in healthy myocardium (R = 0.64; P < 0.01) and poor correlation in infarcted myocardium (R = 0.23; P = 0.61). AI values achieved using different combinations of power, CF, and baseline impedance resulted in different lesion depths: Ablation at 30 W produced deeper lesions compared with 40 W, ablation with CF of 15 g produced deeper lesions compared with CF of 25 g, and ablation at lower impedance produced larger lesions at similar prespecified AI values (P < 0.01 for all)., Conclusions: AI has limited value for guiding ablation in ventricular myocardium, particularly scar. This may be related to small proportional significance of application duration and complex tissue architecture., Competing Interests: Funding Support and Author Disclosures Dr Anter has received research grants and speaking honoraria from Biosense Webster and Boston Scientific; and is a previous stockholder in Affera. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Aims: To test the hypothesis that the dispersive patch (DP) location does not significantly affect the current distribution around the catheter tip during radiofrequency catheter ablation (RFCA) but may affect lesions size through differences in impedance due to factors far from the catheter tip., Methods: An in silico model of RFCA in the posterior left atrium and anterior right ventricle was created using anatomic measurements from patient thoracic computed tomography scans and tested the effect of anterior vs. posterior DP locations on baseline impedance, myocardial power delivery, radiofrequency current path, and predicted lesion size., Results: For posterior left atrium ablation, the baseline impedance, total current delivered, current distribution, and proportion of power delivered to the myocardium were all similar with both anterior and posterior DP locations, resulting in similar RFCA lesion sizes (< 0.2 mm difference). For anterior right ventricular (RV) ablation, an anterior DP location resulted in slightly higher proportion of power delivered to the myocardium and lower baseline impedance leading to slightly larger RFCA lesions (0.6 mm deeper and 0.8 mm wider)., Conclusions: An anterior vs. posterior DP location will not meaningfully affect RFCA for posterior left atrial ablation, and the slightly larger lesions predicted with anterior DP location for anterior RV ablation are of unclear clinical significance., Competing Interests: Conflict of interest: None declared., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: Endocardial bipolar voltage amplitude is largely derived from endocardial and subendocardial wall layers. This may result in situations of low bipolar voltage amplitude despite the presence of mid-myocardial including epicardial (ie, intramural-epicardial) viable myocardium. This study examined the utility of endocardial unipolar voltage mapping for detection of viable intramural-epicardial atrial myocardium., Methods: In 15 swine, an atrial intercaval ablation line with an intentional gap was created. Animals survived for 6 to 8 weeks before electroanatomical mapping followed by sacrifice. Gaps were determined by the presence of electrical conduction and classified based on the histopathologiclly layer(s) of viable myocardium into the following: (1) transmural, (2) endocardial, and (3) intramural-epicardial. Voltage data from healthy, scar, and gap points were exported into excel. The sensitivity and specificity of bipolar and unipolar voltage amplitude to detect intramural-epicardial gaps were compared using receiver operating characteristic analysis., Results: In 9 of 15 (60%) swine, a focal ablation gap was detected in the intercaval line, while in the remainder 6 of 15 (40%), the line was complete without gaps. Gaps were classified into transmural (n=3), endocardial (n=3), or intramural-epicardial (n=3). Intramural-epicardial gaps were characterized by very low bipolar voltage amplitude that was similar to areas with transmural scar ( P =0.91). In comparison, unipolar voltage amplitude in intramural-epicardial gaps was significantly higher compared to transmural scar ( P <0.001). Unipolar voltage amplitude had higher sensitivity (93% versus 14%, respectively) and similar specificity (95% versus 98%, respectively) to bipolar voltage for detection of intramural-epicardial gaps., Conclusions: Atrial unipolar voltage mapping may be a useful technique for identifying viable intramural-epicardial myocardium in patients with endocardial scar.

Background: Baseline impedance, radiofrequency current, and impedance drop during radiofrequency catheter ablation are thought to predict effective lesion formation. However, quantifying the contributions of local versus remote impedances provides insights into the limitations of indices using those parameters. Methods: An in silico model of left atrial radiofrequency catheter ablation was used based on human thoracic measurements and solved for (1) initial impedance (Z), (2) percentage of radiofrequency power delivered to the myocardium and blood (3) total radiofrequency current, (4) impedance drop during heating, and (5) lesion size after a 25 W−30 s ablation. Remote impedance was modeled by varying the mixing ratio between skeletal muscle and fat. Local impedance was modeled by varying insertion depth of the electrode (ID). Results: Increasing the remote impedance led to increased baseline impedance, lower system current delivery, and reduced lesion size. For ID = 0.5 mm, Z ranged from 115 to 132 Ω when fat percentage varied from 20 to 80%, resulting in a decrease in the RF current from 472 to 347 mA and a slight decrease in lesion size from 5.6 to 5.1 mm in depth, and from 9.2 to 8.0 mm in maximum width. In contrast, increasing the local impedance led to lower system current but larger lesions. For a 50% fat−muscle mixture, Z ranged from 118 to 138 Ω when ID varied from 0.3 to 1.9 mm, resulting in a decrease in the RF current from 463 to 443 mA and an increase in lesion size, from 5.2 up to 7.5 mm in depth, and from 8.4 up to 11.6 mm in maximum width. In cases of nearly identical Z but different contributions of local and remote impedance, markedly different lesions sizes were observed despite only small differences in RF current. Impedance drop better predicted lesion size (R2 > 0.93) than RF current (R2 < 0.1). Conclusions: Identical baseline impedances and observed RF currents can lead to markedly different lesion sizes with different relative contributions of local and remote impedances to the electrical circuit. These results provide mechanistic insights into the advantage of measuring local impedance and identifies potential limitations of indices incorporating baseline impedance or current to predict lesion quality.

Objectives: This study sought to examine the effect of the return electrode's surface area on bipolar RFA lesion size., Background: Bipolar radiofrequency ablation (RFA) is typically performed between 2 3.5-mm tip catheters serving as active and return electrodes. We hypothesized that increasing the surface area of the return electrode would increase lesion dimensions by reducing the circuit impedance, thus increasing the current into a larger tissue volume enclosed between the electrodes., Methods: In step 1, ex vivo bipolar RFA was performed between 3.5-mm and custom-made return electrodes with increasing surface areas (20, 80, 180 mm 2 ). In step 2, ex vivo bipolar RFA was performed between 3.5-mm and 3.5-mm or 8-mm electrode catheters positioned perpendicular or parallel to the tissue. In step 3, in vivo bipolar RFA was performed between 3.5-mm and either 3.5-mm or 8-mm parallel electrode at the: 1) left ventricular summit; 2) interventricular septum; and 3) healed anterior infarction., Results: In step 1, increasing the surface area of the return electrode resulted in lower circuit impedance (R = -0.65; P < 0.001), higher current (R = +0.80; P < 0.001), and larger lesion volume (R = +0.88; P < 0.001). In step 2, an 8-mm return electrode parallel to tissue produced larger and deeper lesions compared with a 3.5-mm return electrode (P = 0.014 and P = 0.02). Similarly, in step 3, compared with a 3.5-mm, bipolar RFA with an 8-mm return electrode produced larger (volume: 1,525 ± 871 mm 3 vs 306 ± 310 mm 3 , respectively; P < 0.001) and more transmural lesions (88% vs 0%; P < 0.001)., Conclusions: Bipolar RFA using an 8-mm return electrode positioned parallel to the tissue produces larger lesions in comparison with a 3.5-mm return electrode., Competing Interests: Funding Support and Author Disclosures Mr Bubar is an employee of Biosense Webster. Dr Tarakji receives consultation fees from AliveCor, Medtronic, Janssen, and Pfizer. Dr Anter has received research grants and speaking honoraria from Biosense Webster, Boston Scientific, Affera Inc, and Itamar Medical; and holds stock options in Affera Inc. Dr Koruth has received research grants from Affera Inc, Farapulse, Cardiofocus, Biosense, Acutus, Kardium; has equity in Affera Inc; and serves as a consultant to Farapulse and Abbott. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2022 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to investigate the sensitivity of electroanatomical mapping (EAM) to detect scar as identified by late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR)., Background: Previous studies have shown correlation between low voltage electrogram amplitude and myocardial scar. However, voltage amplitude is influenced by the distance between the scar and the mapping surface and its extent. The aim of this study is to examine the reliability of low voltage EAM as a surrogate for myocardial scar using LGE-derived scar as the reference., Methods: Twelve swine underwent anterior wall infarction by occlusion of the left anterior descending artery (LAD) (n = 6) or inferior wall infarction by occlusion of the left circumflex artery (LCx) (n = 6). Subsequently, animals underwent CMR and EAM using a multielectrode mapping catheter. CMR characteristics, including wall thickness, LGE location and extent, and EAM maps, were independently analyzed, and concordance between voltage maps and CMR characteristics was assessed., Results: LGE volume was similar between the LCx and LAD groups (8.5 ± 2.2 ml vs. 8.3 ± 2.5 ml, respectively; p = 0.852). LGE scarring in the LAD group was more subendocardial, affected a larger surface area, and resulted in significant wall thinning (4.88 ± 0.43 mm). LGE scarring in the LCx group extended from the endocardium to the epicardium with minimal reduction in wall thickness (scarred: 5.4 ± 0.67 mm vs. remote: 6.75 ± 0.38 mm). In all the animals in the LAD group, areas of low voltage corresponded with LGE and wall thinning, whereas only 2 of 6 animals in the LCx group had low voltage areas on EAM. Bipolar and unipolar voltage amplitudes were higher in thick inferior walls in the LCx group than in thin anterior walls in the LAD group, despite a similar LGE volume., Conclusions: Discordances between LGE-detected scar areas and low voltage areas by EAM highlighted the limitations of the current EAM system to detect scar in thick myocardial wall regions., (Copyright © 2020 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: The goal of this study was to compare lesion durability between high-power short-duration (HP-SD) and moderate-power moderate-duration (MP-MD) ablation strategies., Background: HP-SD radiofrequency ablation (RFA) was developed to improve pulmonary vein isolation (PVI) by reducing the effect of catheter instability inherent to MP-MD ablation strategies. However, its long-term effect on lesion durability for the treatment of atrial fibrillation is unknown., Methods: Patients with atrial fibrillation (n = 112) underwent PVI using HP-SD ablation (45 to 50 W, 8 to 15 s) with contact force-sensing open irrigated catheter. Cavotricuspid isthmus, mitral annular, and roof lines were permitted. A control group (n = 112) underwent ablation using MP-MD ablation (20 to 40 W, 20 to 30 s) with similar technology. Chronic PV reconnection was examined in patients who required a redo procedure (HP-SD ablation, n = 18; MP-MD ablation, n = 23)., Results: The rate of PVI at the completion of the initial encirclement was similar between the HP-SD and MP-MD ablation strategies (90.2% vs. 83.0%; p = 0.006). The HP-SD strategy required shorter RFA time (17.2 ± 3.4 min vs. 31.1 ± 5.6 min; p < 0.001). The incidence of chronic PV reconnection was lower with HP-SD ablation (16.6% vs. 52.2%; p = 0.03). Areas of chronic reconnection were associated with catheter motion ≥1 mm for ≥50% application duration. In a higher proportion of HP-SD applications, catheter motion was <1 mm during ≥50% duration (88.6% vs. 72.8%; p < 0.001), allowing energy delivery with greater stability. Both ablation strategies were effective for cavotricuspid isthmus; however, the HP-SD strategy was less effective for mitral annular lines, requiring ablation at lower power for longer duration to avoid steam pops., Conclusions: HP-SD ablation may improve PVI durability, and it shortens RFA time. However, ablation in thicker myocardium often requires lower power applied for longer duration, allowing deeper lesions without tissue overheating., (Copyright © 2020 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Pulsed field ablation (PFA) is a nonthermal energy that may provide safety advantages over radiofrequency ablation (RFA). One-shot PFA catheters have been developed for pulmonary vein isolation, but they do not permit flexible lesion sets. This study investigated a novel lattice-tip catheter designed for focal RFA or PFA ablation., Methods: The effects of PFA (biphasic, 24 amperes) were investigated in 25 swine using a lattice-tip catheter and system (Affera Inc). Step 1 (n=14) examined the feasibility to create atrial line of block and described its acute effects on the phrenic nerve and esophagus. Step 2 (n=7) examined the subacute effects of PFA on block durability, phrenic nerve, and esophagus ≥2 weeks. Step 3 compared the effects of PFA and RFA on the esophagus using a mechanical deviation model approximating the esophagus to the right atrium (n=4) and by direct ablation within its lumen (n=4). The effects of endocardial PFA and RFA on the phrenic nerve were also compared (n=10). Histological analysis was performed., Results: PFA produced acute block in 100% of lines, achieved with 2.1 (1.3-3.2) applications/cm line. Histological analysis following (35 [18-37]) days showed 100% transmurality (thickness range 0.4-3.4 mm) with a lesion width of 19.4 (10.9-27.4 mm). PFA selectively affected cardiomyocytes but spared blood vessels and nervous tissue. PFA applied from the posterior atria (23 [21-25] applications) to the approximated esophagus (6 [4.5-14] mm) produced transmural lesions without esophageal injury. PFA (16.5 [15-18] applications) applied inside the esophageal lumen produced mild edema compared with RFA (13 [12-14] applications) which produced epithelial ulcerations. PFA resulted in no or transient stunning of the phrenic nerve (<5 minutes) without histological changes while RFA produced paralysis., Conclusions: PFA using a lattice-tip ablation catheter for focal ablation produced durable atrial lesions and showed lower vulnerability to esophageal or phrenic nerve damage compared with RFA.

Aims: Multielectrode mapping catheters can be advantageous for identifying surviving myocardial bundles in scar. This study aimed to evaluate the utility of a new multielectrode catheter with increased number of small and closely spaced electrodes for mapping ventricles with healed infarction., Methods and Results: In 12 swine (four healthy and eight with infarction), the left ventricle was mapped with investigational (OctarayTM) and standard (PentarayTM) multielectrode mapping catheters. The investigational catheter has more electrodes (48 vs. 20), each with a smaller surface area (0.9 vs. 2.0 mm2) and spacing is fixed at 2 mm (vs. 2-6-2 mm). Electrogram (EGM) characteristics, mapping efficiency and scar description were compared between the catheters and late gadolinium enhancement (LGE). Electrogram acquisition rate was faster with the investigational catheter (814 ± 126 vs. 148 ± 58 EGM/min, P = 0.02) resulting in higher density maps (38 ± 10.3 vs. 10.1 ± 10.4 EGM/cm2, P = 0.02). Bipolar voltage amplitude was similar between the catheters in normal and infarcted myocardium (P = 0.265 and P = 0.44) and the infarct surface area was similar between the catheters (P = 0.12) and corresponded to subendocardial LGE. The investigational catheter identified a higher proportion of near-field local abnormal ventricular activities within the low-voltage area (53 ± 16% vs. 34 ± 16%, P = 0.03) that were considered far-field EGMs by the standard catheter. The investigational catheter was also advantageous for mapping haemodymically non-tolerated ventricular tachycardias due to its higher acquisition rate (P < 0.001)., Conclusion: A novel multielectrode mapping catheter with higher number of small, and closely spaced electrodes increases the mapping speed, EGM density and the ability to recognize low amplitude near-field EGMs in ventricles with healed infarction., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2020. For permissions, please email: journals.permissions@oup.com.)

Objectives: The goal of this study was to examine the safety and efficacy of radiofrequency ablation (RFA) with irrigated catheters operated in a temperature-controlled mode for ventricular ablation., Background: Techniques to increase RFA dimensions are associated with higher risk for steam-pops. A novel irrigated catheter with circumferential thermocouples embedded in its ablation surface provides real-time surface temperature data. This study hypothesized that RFA operated in a temperature-controlled mode may allow maximizing lesion dimensions while reducing the occurrence of steam-pops., Methods: RFA with an irrigated catheter incorporating surface thermocouples was examined in 6 swine thigh muscle preparations and 15 beating ventricles at higher (50 W/60 s, T max 50 o C) and lower (50 W/60 s, T max 45 o C) temperature limits. Biophysical properties, lesion dimensions, and steam-pop occurrence were compared versus RFA with a standard catheter operated in power-control mode at higher (50 W/60 s) and lower (40W/60 s) power, and additionally at high power with half-normal saline (50 W/60 s)., Results: In the thigh muscle preparation, lesion depth and width were similar between all groups (p = 0.90 and p = 0.17, respectively). Steam-pops were most frequent with power-controlled ablation at 50 W/60 s (82%) and least frequent with temperature-controlled ablation at 50 W/60 s, T max 45 o C (0%; p < 0.001). In the beating ventricle, lesion depth was comparable between all RFA settings (p = 0.09). Steam-pops were most frequent using power-controlled ablation at 50 W/60 s (37%) and least frequent with temperature-controlled ablation at 50 W/60 s, T max 45 o C (7%; p < 0.001). Half-normal saline had no incremental effect on lesion dimensions at 50 W in either the thigh muscle or the beating heart., Conclusions: RFA using a novel irrigated catheter with surface thermocouples operated in a temperature-controlled mode can maximize lesion dimensions while reducing the risk for steam-pops., (Copyright © 2020 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Ventricular tachycardia ablation is often limited by insufficient lesion creation. A novel radiofrequency catheter with an expandable lattice electrode has a larger surface area capable of delivering higher currents at a lower density to potentially increase lesion dimensions without overheating., Methods: This 8F bidirectional irrigated catheter (Sphere-9, Affera Inc) has a 9 mm spherical lattice tip ("lattice") with an effective surface area 10-fold larger than standard linear catheters. Nine surface thermocouples provide temperature feedback to a proprietary high-current generator operating in a temperature-controlled mode. Ex vivo phase: in 11 bovine hearts, unipolar ablation at 30, 60, and 120 seconds was compared between the lattice (Tmax60°C) and a standard linear irrigated-tip catheter (40 W) at contact force of 10 g. In 5 porcine hearts, bipolar ablation was compared between the catheters (Tmax60°C versus 40 W; 60 seconds). In vivo phase: in 9 swine, ventricular ablation at Tmax60°C versus 40 W was performed for 60 seconds. In addition, direct tissue temperature at 3- and 7-mm tissue depth was measured in a thigh muscle preparation., Results: Ex vivo: lattice produced deeper lesions at 30, 60, and 120 seconds application duration (6.7±1.3 versus 4.8±1.2 mm; 8.3±1.4 versus 5.4±0.8 mm; 10.0±1.6 versus 6.1±1.6 mm, respectively, P ≤0.001 for all). Bipolar lesions were deeper (15.8±4.1 versus 10.5±1.4 mm, P <0.001) and more likely to be transmural (80% versus 0%, P =0.002). In vivo: lattice produced deeper lesions (10.5±1.4 versus 6.5±0.8 mm, P ≤0.001). Tissue temperature at 7 mm was higher with the lattice (+15.1±2.4°C; P <0.001). The steam-pop occurrence was lower with the lattice (total: 4% versus 18%, P =0.02; in vivo 0% versus 14.2%, P =0.13)., Conclusions: This novel radiofrequency system produces larger ventricular lesions compared with standard irrigated catheters and at a lower risk of tissue overheating. This may improve the efficacy of ventricular tachycardia ablation procedures while reducing the number of applications and procedural duration.

Background: In infarct-related ventricular tachycardia (VT), the circuit often corresponds to a location characterized by activation slowing during sinus rhythm (SR). However, the relationship between activation slowing during SR and vulnerability for reentry and correlation to components of the VT circuit are unknown. This study examined the relationship between activation slowing during SR and vulnerability for reentry and correlated these areas with components of the circuit., Methods: In a porcine model of healed infarction, the spatial distribution of endocardial activation velocity was compared between SR and VT. Isthmus sites were defined using activation and entrainment mapping as areas exhibiting diastolic activity within the circuit while bystanders were defined as areas displaying diastolic activity outside the circuit., Results: Of 15 swine, 9 had inducible VT (5.2±3.0 per animal) while in 6 swine VT could not be induced despite stimulation from 4 RV and LV sites at 2 drive trains with 6 extra-stimuli down to refractoriness. Infarcts with VT had a greater magnitude of activation slowing during SR. A minimal endocardial activation velocity cutoff ≤0.1 m/s differentiated inducible from noninducible infarctions ( P =0.015). Regions of maximal endocardial slowing during SR corresponded to the VT isthmus (area under curve=0.84 95% CI, 0.78-0.90) while bystander sites exhibited near-normal activation during SR. VT circuits were complex with 41.7% exhibiting discontinuous propagation with intramural bridges of slow conduction and delayed quasi-simultaneous endocardial activation. Regions forming the VT isthmus borders had faster activation during SR while regions forming the inner isthmus were activated faster during VT., Conclusions: Endocardial activation slowing during SR may differentiate infarctions vulnerable for VT from those less vulnerable for VT. Sites of slow activation during SR correspond to sites forming the VT isthmus but not to bystander sites.

Objectives: This study sought to characterize the histopathological features of radiofrequency ablation (RFA) in heterogeneous ventricular scar in comparison to those in healthy myocardium., Background: The histopathological features of RFA have been studied largely in normal myocardium. However, its effect on clinically relevant heterogeneous scar is not well understood., Methods: Five swine with chronic infarction underwent RFA using 35-W, 45-s, 10-20 g (Biosense Webster, Irwindale, California) in heterogenous scar tissue (voltage ≤1.5 mV) and healthy myocardium (≥3.0 mV). The location of each application was marked using the electroanatomical mapping system. Histological sections at intervals of 0.5 mm with hematoxylin and eosin and Masson's trichrome stained intervals were created. A pathologist blinded to the myocardium type characterized the extent of RF injury in cellular, extracellular, and vascular structures., Results: In healthy myocardium, 23 of 23 lesions (100%) were well demarcated and could be precisely measured (width: 11.3 ± 3.3 mm; depth: 7.3 ± 2.0 mm). In scar tissue, only 3 of 30 lesions (10%) were identified, and none could be measured due to a lack of defined borders. Lesions in healthy myocardium had a distinctive architecture showing a coagulative necrosis core surrounded by an outer rim of contraction band necrosis. Lesions in scar had ill-defined tissue injury without a distinct architecture. In all ablated regions, viable myocytes remained interspersed between necrotic myocytes exhibiting characteristics of both coagulative and contraction band necrosis. Connective tissue was more resistant to thermal injury in comparison to cardiomyocytes., Conclusions: RFA in scarred myocardium results in irregular tissue injury and unpredictable effect on surviving cardiomyocytes. This may be related to biophysical differences between healthy and scarred myocardium., (Copyright © 2019 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background Radiofrequency ablation of intramural ventricular substrate is often limited by insufficient tissue penetration despite high energy settings. As lesion dimensions have a direct and negative relationship to impedance, reducing the baseline impedance may increase the ablation effect on deep ventricular tissue. Methods This study included 16 patients with ventricular tachycardia or frequent ventricular premature complexes refractory to ablation with irrigated catheters. After a failed response to radiofrequency ablation, impedance was modulated by adding or repositioning return patches in an attempt to decrease the circuit impedance. Ablation was repeated at a similar location and power settings, and the effect on arrhythmia suppression and adverse effects were evaluated. Results Six patients with idiopathic ventricular premature complexes originating from the left ventricular summit (n=4) or papillary muscles (n=2), 6 patients with noninfarct related ventricular tachycardia and 4 patients with infarct-related ventricular tachycardia had unsuccessful response to radiofrequency ablation at critical sites (number of applications: 10.4±3.1, power: 42.3±2.9 W, duration: 55.3±25.5 seconds, impedance reduction: 14.6±3.5 Ω, low-ionic solution was used in 81.25%). Modulating the return patches resulted in reduced baseline impedance (111.7±8.2 versus 134.7±6.6 Ω, P<0.0001), increased current output (0.6±0.02 versus 0.56±0.02 Amp; P<0.0001) and greater impedance drop (16.8±3.0 Ω, P<0.001). Repeat ablation at similar locations had a successful effect in 12 out of 16 (75.0%) patients. During a follow-up duration of 13±5 months, 10 out of 12 (83.3%) patients remained free of arrhythmia recurrence. The frequency of steam pops was similar between the higher and lower baseline impedance settings (7.1 versus 8.2%; P=0.74). Conclusions In patients with deep ventricular substrate, reducing the baseline impedance is a simple, safe, and effective technique for increasing the effect of radiofrequency ablation. However, its combination with low-ionic solutions may increase the risk for steam pops and neurological events.

Introduction: Multielectrode mapping catheters improve the ability to map within the heterogeneous scar. A novel Octaray catheter with eight spines and 48 electrodes may further improve the speed and resolution of atrial mapping. The aims of this study were to (1) establish the Octaray's baseline mapping performance and electrogram (EGM) characteristics in healthy atria and to (2) determine its utility for identifying gaps in a swine model of atrial ablation lines., Methods and Results: The right atria of eight healthy swine were mapped with Octaray and Pentaray catheters (Biosense Webster, Irvine, CA) before and after the creation of ablation lines with intentional gaps. Baseline mapping characteristics including EGM amplitude, duration, number of EGMs, and mapping time were compared. Postablation maps were created and EGM characteristics of continuous lines and gaps were correlated with pathology. Compared with Pentaray, the Octaray collected more EGMs per map (2178 ± 637 vs 1046 ± 238; P < 0.001) at a shorter mapping duration (3.2 ± 0.79 vs 6.9 ± 2.67 minutes; P < 0.001). In healthy atria, the Octaray recorded lower bipolar voltage amplitude (1.96 ± 1.83 mV vs 2.41 ± 1.92 mV; P < 0.001) while ablation gaps were characterized by higher voltage amplitude (1.24 ± 1.12 mV vs 1.04 ± 1.27 mV; P < 0.001). Ablation gaps were similarly identified by both catheters (P = 1.0). The frequency of "false gaps," defined as intact ablation lines with increased voltage amplitude was more common with Pentaray (6 vs 2) and resulted from erroneous annotation of far-field EGMs., Conclusion: The Octaray increases the mapping speed and density compared with the Pentaray catheter. It is as sensitive for identifying ablation gaps and more specific for mapping intact ablation lines., (© 2019 Wiley Periodicals, Inc.)

Background: High-current short-duration radiofrequency energy delivery has potential advantages for cardiac ablation. However, this strategy is limited by high current density and narrow safety-to-efficacy window. The objective of this study was to examine a novel strategy for radiofrequency energy delivery using a new electrode design capable of delivering high power at a low current density to increase the therapeutic range of radiofrequency ablation., Methods: The Sphere9 is an expandable spheroid-shaped lattice electrode design with an effective surface area 10-fold larger than standard irrigated electrodes (lattice catheter). It incorporates 9 surface temperature sensors with ablation performed in a temperature-controlled mode. Phase I: in 6 thigh muscle preparations, 2 energy settings for atrial ablation were compared between the lattice and irrigated-tip catheters (low-energy: T max 75°C/5 s versus 25 W/20 s; high-energy: T max 75°C/7 s versus 30 W/20 s). Phase II: in 8 swine, right atrial lines were created in the posterior and lateral walls using low- and high-energy settings, respectively. Phase III: the safety, efficacy, and durability at 30 days were evaluated by electroanatomical mapping and histopathologic analysis., Results: In the thigh model, the lattice catheter resulted in wider lesions at both low- and high-energy settings (18.7±3.3 versus 12.2±1.7 mm, P<0.0001; 19.4±2.4 versus 12.3±1.7 mm, P<0.0001). Atrial lines created with the lattice were wider (posterior: 14.7±3.4 versus 9.2±4.0 mm, P<0.0001; lateral: 15.8±4.2 versus 5.7±4.2 mm, P<0.0001) and required 85% shorter ablation time (12.4 versus 79.8 s/cm-line). While current squared (I 2 ) was higher with Sphere9 (7.0±0.04 versus 0.2±0.002 A 2 ; P<0.0001), the current density was lower (9.6±0.9 versus 16.9±0.09 mA/mm 2 ; P<0.0001). At 30 days, 100% of ablation lines created with the lattice catheter remained contiguous compared with only 14.3% lines created with a standard irrigated catheter. This was achieved without steam pops or collateral tissue damage., Conclusions: In this preclinical model, a novel, high-current low-density radiofrequency ablation strategy created contiguous and durable ablation lines in significantly less ablation time and a comparable safety profile.

Background: The mitral isthmus is the critical element of perimitral reentrant tachycardias. Prolongation in transisthmus conduction time and differential pacing techniques are commonly used to determine block. However, these may not distinguish block from slow conduction or conduction via epicardial bridging connections. The aim of this study was to examine these standard criteria for mitral line block with endocardial and epicardial activation mapping., Methods: In 56 patients, posterior mitral line was performed using radiofrequency ablation. Conduction block was defined as transisthmus time (≥100 ms) and reversal of coronary sinus activation during pacing from the left atrial appendage. These results were compared with high-resolution activation mapping (Rhythmia) of the endocardium and epicardium via the coronary sinus., Results: Mitral block determined by pacing was achieved in 51 out of 56 (91%) patients. In 11 out of 51 (21.6%), activation mapping demonstrated residual endocardial (3/11; 27.2%) or epicardial (8/11; 72.7%) connections. Epicardial bridging connections were distant from the line (2.4±1.6 cm), inserting laterally at the proximal-middle coronary sinus and septally at the left atrial ridge. Patients with residual conduction were prone to complex circuits involving the epicardium (7/11; 63.6%). Mitral line block was achieved in 75% by targeting these insertion site(s). The transisthmus conduction time had limited predictive value for distinguishing block from pseudoblock., Conclusions: Standard criteria for posterior mitral line block may not distinguish block from pseudoblock. In particular, epicardial bridging connections can result in prolonged transisthmus conduction time and reversal in coronary sinus activation to falsely suggest block. These connections are a frequent cause for complex circuits, and their insertion site(s) can be targeted for ablation.

Visualization of the complex 3D architecture of myocardial scar could improve guidance of radio-frequency ablation in the treatment of ventricular tachycardia (VT). In this study, we sought to develop a framework for 3D holographic visualization of myocardial scar, imaged using late gadolinium enhancement (LGE), on the augmented reality HoloLens. 3D holographic LGE model was built using the high-resolution 3D LGE image. Smooth endo/epicardial surface meshes were generated using Poisson surface reconstruction. For voxel-wise 3D scar model, every scarred voxel was rendered into a cube which carries the actual resolution of the LGE sequence. For surface scar model, scar information was projected on the endocardial surface mesh. Rendered layers were blended with different transparency and color, and visualized on HoloLens. A pilot animal study was performed where 3D holographic visualization of the scar was performed in 5 swines who underwent controlled infarction and electroanatomic mapping to identify VT substrate. 3D holographic visualization enabled assessment of the complex 3D scar architecture with touchless interaction in a sterile environment. Endoscopic view allowed visualization of scar from the ventricular chambers. Upon completion of the animal study, operator and mapping specialist independently completed the perceived usefulness questionnaire in the six-item usefulness scale. Operator and mapping specialist found it useful (usefulness rating: operator, 5.8; mapping specialist, 5.5; 1-7 scale) to have scar information during the intervention. HoloLens 3D LGE provides a true 3D perception of the complex scar architecture with immersive experience to visualize scar in an interactive and interpretable 3D approach, which may facilitate MR-guided VT ablation., Competing Interests: The authors have declared that no competing interests exist.

Background: Radiofrequency ablation using irrigated catheters is performed using a power-controlled mode. However, lesion size is dependent on current delivery at a particular impedance, such that a power value alone may not reflect actual energy delivery, resulting in lesion size variability at similar power settings. We hypothesized that modulating baseline impedance at fixed power settings affects ablation lesion dimensions., Methods: In 20 ex vivo swine hearts, radiofrequency ablation was performed using an irrigated catheter at a fixed power setting of 30 W per 20 seconds and a multistepped impedance load (100-210Ω). In 4 in vivo thigh muscle preparations and right atria, ablation was performed using similar power settings at 3 baseline impedances: low (90-130Ω), intermediate (131-180Ω), and high (181-224Ω). The relationship between baseline impedance, current, and lesion dimensions was examined., Results: Baseline impedance had a strong negative correlation with current squared ( I 2 ) for all experimental models: ex vivo (R=-0.94; P<0.0001), thigh muscle (R=-0.93; P<0.0001), and right atria (R=-0.94; P<0.0001). Lesion dimensions at similar power settings were highly variable and directly related to I 2 (width [R=0.853], depth [R=0.814]). In the thigh muscle, lesion depth was 8.2±0.7, 6.5±0.8, and 4.2±0.5 mm for low, intermediate, and high impedance, respectively ( P<0.0001). In right atria lines, low baseline impedance resulted in wider lines (7.2±1.4 mm) relative to intermediate (5.8±1.8 mm) and high impedance (4.7±1.7 mm; P<0.0001)., Conclusions: Radiofrequency ablation in a power control mode results in variable lesion dimensions that are partially related to differences in baseline impedance and current output. Ablation at a lower baseline impedance results in increased current output and lesion dimensions.

Introduction: PV reconnection is often the result of catheter instability and tissue edema. High-power short-duration (HP-SD) ablation strategies have been shown to improve atrial linear continuity in acute pre-clinical models. This study compares the safety, efficacy, and long-term durability of HP-SD ablation with conventional ablation., Methods and Results: In 6 swine, 2 ablation lines were performed anterior and posterior to the crista terminalis, in the smooth and trabeculated right atrium, respectively; and the right superior PV was isolated. In 3 swine, ablation was performed using conventional parameters (Thermocool-Smarttouch ® SF; 30 W/30 seconds) and in 3 other swine using HP-SD parameters (QDOT-MICRO™, 90 W/4 seconds). After 30 days, linear integrity was examined by voltage mapping and pacing, and the heart and surrounding tissues were examined by histopathology. Acute line integrity was achieved with both ablation strategies; however, HP-SD ablation required 80% less RF time compared with conventional ablation (P ≤ 0.01 for all lines). Chronic line integrity was higher with HP-SD ablation: all 3 posterior lines were continuous and transmural compared to only 1 line created by conventional ablation. In the trabeculated tissue, HP-SD ablation lesions were wider and of similar depth with 1 of 3 lines being continuous compared to 0 of 3 using conventional ablation. Chronic PVI without stenosis was evident in both groups. There were no steam-pops. Pleural markings were present in both strategies, but parenchymal lung injury was only evident with conventional ablation., Conclusions: HP-SD ablation strategy results in improved linear continuity, shorter ablation time, and a safety profile comparable to conventional ablation., (© 2018 Wiley Periodicals, Inc.)

Objectives: In this study, the scientific objective was to characterize the electrophysiological substrate of the ventricular tachycardia (VT) isthmus during sinus rhythm., Background: The authors have recently described the electrophysiological characteristics of the VT isthmus using a novel in vivo high-resolution mapping technology., Methods: Sixteen swine with healed infarction were studied using high-resolution mapping technology (Rhythmia, Boston Scientific, Cambridge, Massachusetts) in a closed-chest model. The left ventricle was mapped during sinus rhythm and analyzed for activation, conduction velocity, electrogram shape, and amplitude. Twenty-four VTs allowed detailed mapping of the common-channel "isthmus," including the "critical zone." This was defined as the zone of maximal conduction velocity slowing in the circuit, often occurring at entrance and exit from the isthmus caused by rapid angular change in activation vectors., Results: The VT isthmus corresponded to sites displaying steep activation gradient (SAG) during sinus rhythm with conduction velocity slowing of 58.5 ± 22.4% (positive predictive value [PPV] 60%). The VT critical zone displayed SAG with greater conduction velocity slowing of 68.6 ± 18.2% (PPV 70%). Critical-zone sites were consistently localized in areas with bipolar voltage ≤0.55 mV, whereas isthmus sites were localized in areas with variable voltage amplitude (1.05 ± 0.80 mV [0.03 to 2.88 mV]). Importantly, critical zones served as common-site "anchors" for multiple VT configurations and cycle lengths. Isthmus and critical-zone sites occupied only 18.0 ± 7.0% of the low-voltage area (≤1.50 mV). Isolated late potentials were present in both isthmus and nonisthmus sites, including dead-end pathways (PPV 36%; 95% confidence interval: 34.2% to 39.6%)., Conclusions: The VT critical zone corresponds to a location characterized by SAG and very low voltage amplitude during sinus rhythm. Thus, it allows identification of a re-entry anchor with high sensitivity and specificity. By contrast, voltage and electrogram characteristics during sinus rhythm have limited specificity for identifying the VT isthmus., (Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to examine the biophysical properties of high-power and short-duration (HP-SD) radiofrequency ablation for pulmonary vein isolation., Background: Pulmonary vein isolation is the cornerstone of atrial fibrillation ablation. However, pulmonary vein reconnection is frequent and is often the result of catheter instability, tissue edema, and a reversible nontransmural injury. We postulated that HP-SD ablation increases lesion-to-lesion uniformity and transmurality., Methods: This study included 20 swine and a novel open-irrigated ablation catheter with a thermocouple system able to record temperature at the catheter-tissue interface (QDOT Micro Catheter). Step 1 compared 3 HP-SD ablation settings: 90 W/4 s, 90 W/6 s, and 70 W/8 s in a thigh muscle preparation. Ablation at 90 W/4 s was identified as the best compromise between lesion size and safety parameters, with no steam-pop or char. In step 2, a total of 174 single ablation applications were performed in the beating heart and resulted in 3 (1.7%) steam-pops, all occurring at catheter-tissue interface temperature ≥85°C. Additional 233 applications at 90 W/4 s and temperature limit of 65°C were applied without steam-pop. Step 3 compared the presence of gaps and lesion transmurality in atrial lines and pulmonary vein isolation between HP-SD (90 W/4 s, T ≤65°C) and standard (25 W/20 s) ablation., Results: HP-SD ablation resulted in 100% contiguous lines with all transmural lesions, whereas standard ablation had linear gaps in 25% and partial thickness lesions in 29%. Ablation with HP-SD produced wider lesions (6.02 ± 0.2 mm vs. 4.43 ± 1.0 mm; p = 0.003) at similar depth (3.58 ± 0.3 mm vs. 3.53 ± 0.6 mm; p = 0.81) and improved lesion-to-lesion uniformity with comparable safety end points., Conclusions: In a preclinical model, HP-SD ablation (90 W/4 s, T ≤65°C) produced an improved lesion-to-lesion uniformity, linear contiguity, and transmurality at a similar safety profile of conventional ablation., (Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Metabolic syndrome (MetS) was shown to be related to a variety of diseases. High level of vigilance for the diagnosis of MetS is expected among health providers. We evaluated the level of awareness to MetS among physician and nurses working in a central hospital., Methods and Results: A specially designed anonymous questionnaire was used, including both open and multiple choice questions set to evaluate the participant's awareness to MetS. The study included 126 participants, 71% physicians and 29% nurses. Mean age was 36.2±3.8 years. Among physicians, 68.5% were residents and 45.5% were internists. 98% of the participants stated that they were familiar with the term MetS and that they treat MetS patients regularly. Most participants knew the correct number of criteria included in MetS definition and the number of criteria needed for MetS diagnosis (84% and 90%, respectively). However, only 12% were able to discriminate correctly all MetS cases from non-MetS ones. Physicians performed better than nurses (15.6% and 3.1%, respectively, P=0.003). Neither, field of practice nor seniority was found to have a significant influence on the results. The frequency of recommendation for MetS risk factor modulation in the discharge files was also analyzed. Such recommendations were scarcely given, with cardiology department being the exception (80% of discharge files from cardiology department compared with less than 20% in other departments)., Conclusion: Though hospital workers showed high level of awareness to the existence of MetS, they failed to differentiate correctly MetS cases from non-MetS ones., (Copyright © 2016 Diabetes India. Published by Elsevier Ltd. All rights reserved.)

Aims: Conduction abnormalities following transcatheter aortic valve replacement (TAVR) are caused by damage of the aortoventricular conduction tissue during positioning of the valve. Therefore, our aim was to assess whether a higher difference between the long and short diameters of the elliptic aortoventricular annulus will possess higher forces on the annulus, and thus will be a predictor of pacemaker need following TAVR., Methods: We retrospectively analyzed 123 patients who had the aortoventricular annulus measured by computed tomography angiography. The difference between maximal (Dmax) and minimal (Dmin) diameters of the annulus was considered the elliptic factor (ELFA), which was analyzed using t test to evaluate whether it differs between the group who received a pacemaker and the group without the need for a pacemaker. Then, using univariate and multivariate models adjusted for other confounders predicting the need for a pacemaker, we sought to evaluate whether a higher ELFA is a predictor of pacemaker implantation., Results: Mean age was 82.2 ± 6.4 years, and 62.6% were women. Average Dmax, Dmin and ELFA were 25.8, 20.8 and 5 mm, respectively. Fourteen patients (11.4%) underwent pacemaker implantation. Those patients had an ELFA of 5.9 mm compared with 4.9 mm in those who did not receive a pacemaker (P < 0.01). In multivariate analysis, a higher ELFA remained a statistically significant and independent predictor for the need of a pacemaker (P = 0.046)., Conclusion: A high ELFA is an independent and significant predictor of the need for pacemaker implantation after TAVR and suggests further investigation whether it should be considered as a factor in managing TAVR patients.

Background: Limited data is present regarding long-term outcomes in chronic kidney disease (CKD) patients presenting with stent thrombosis (ST). We evaluated the possible implications of CKD on long-term mortality in patients presenting with ST-segment elevation myocardial infarction (STEMI) and treated with primary percutaneous coronary intervention (PCI), and its interaction with the presence of ST., Methods: We retrospectively studied 1,722 STEMI patients treated with primary PCI. Baseline CKD was categorized as an estimated glomerular filtration rate <60 mL/min/1.73 m 2 at presentation. The presence of ST was determined using the Academic Research Consortium definitions. Patients were evaluated for the presence of CKD and ST, as well as for long-term mortality., Results: A total of 448/1,722 (26%) patients had baseline CKD. Patients with CKD were older and had more comorbidities and a higher rate of ST (4 vs. 7%, respectively, p < 0.001). In a univariate analysis, long-term mortality was significantly higher among those with CKD compared to those without CKD (17.6 vs. 2.7%, p < 0.001). The presence of ST did not alter long-term mortality in both CKD and no-CKD patients. In a Cox regression model, CKD was an independent predictor of long-term mortality (hazard ratio 2.04, 95% confidence interval 1.17-3.56, p = 0.01), while ST as a covariate was not significantly associated with long-term mortality., Conclusion: Among STEMI patients, CKD, but not ST, is a predictor of long-term mortality.

New generation of the most widely used devices for transcatheter aortic valve implantation have been recently introduced into practice. We compare the short-term outcomes of transcatheter aortic valve implantation with the Edwards SAPIEN S3 and the Medtronic Evolut-R. We performed a retrospective analysis from a single high-volume tertiary center. Valve Academic Research Consortium-2 criteria were used to define composite end points of device success and safety at 30 days. Study population included 232 patients implanted with the SAPIEN S3 (n = 124) and Evolut-R (n = 108). Device success reached 91.9% and 95.4% in the SAPIEN S3 and Evolut-R groups, respectively (p = 0.289). Postprocedural echocardiography showed greater aortic valve gradients (22.8 ± 7 vs 16 ± 9 mm Hg, p <0.001) among SAPIEN S3 group. Paravalvular leak of ≥ moderate severity was observed in 2.4% and 0% in the SAPIEN S3 and Evolut-R groups, respectively (p = 0.251). Similar rates of in-hospital complications, including major bleedings, vascular complications, and pacemaker implantations were recorded in both groups. At 30-day follow-up, the combined safety end point was reached in 5.6% and in 6.5% of patients in the SAPIEN S3 and Evolut-R groups, respectively (p = 0.790). During follow-up of 237 ± 138 days, all-cause mortality was higher in patients implanted with Evolut-R compared with SAPIEN S3 (7 vs 1 cases, respectively, p = 0.006), however, cardiovascular mortality was not significantly different between groups. In conclusions, in a single-center comparative analysis, comparable rate of device success as well as safety profile and long-term cardiovascular mortality were observed with the SAPIEN S3 and Evolut-R valves., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Objectives: Previous reports showed inconsistencies in the outcomes and prognosis of stent thrombosis (ST) when stratified according to the timing of its occurrence. We evaluated the incidence and possible prognostic implications of early and late ST presenting as ST-segment elevation myocardial infarction (STEMI) in a large cohort of consecutive patients undergoing a primary percutaneous coronary intervention., Materials and Methods: We retrospectively studied 1722 STEMI patients treated by primary percutaneous coronary intervention. The presence of ST was determined using the Academic Research Consortium definitions. Patients were evaluated for the time of ST (early, late) and for in-hospital outcomes as well as long-term mortality., Results: A total of 83/1722 (4.8%) patients showed definite ST, 35 (42%) of whom had early ST and 48 (58%) had late ST. Patients with early ST had more adverse events during hospitalization as well as higher 30-day mortality compared with patients with late or no ST (11 vs. 0 vs. 2%, P<0.001). In a multivariate logistic regression model, early ST was an independent predictor of 30-day mortality (odds ratio 6.6, 95% confidence interval 1.1-38, P=0.033). No significant difference was observed in long-term mortality between patients presenting with early, late ST, or no ST., Conclusion: Early ST manifested as STEMI is associated independently with a higher 30-day mortality rate in comparison with STEMI because of late ST or de-novo coronary thrombosis.

Background: A few series of focal atrial tachycardia (AT) originating from the noncoronary sinus of Valsalva (NCSV) have been reported in the literature during the last decade., Methods and Results: Of 147 patients with AT referred for radiofrequency ablation (RFA), we identified nine (6%) originating in the vicinity of the NCSV. Clinical AT was induced during electrophysiological study in all patients without (n = 6) and with (n = 3) isoproterenol infusion. Mean cycle length of the induced tachycardia was 399 ± 85 ms. Mapping of the right atrium and of the left atrium (LA) was initially performed in all nine patients and in four patients, respectively. Earliest tachycardia activation occurred at the His bundle area in all cases. Earliest activations in the LA were at the low paraseptal regions. In two patients with antegrade dual atrioventricular (AV) node physiology that rendered difficult accurate distinction between atrial and ventricular activation, slow pathway ablation was necessary. A retrograde aortic approach was used for mapping the aortic cusps. The earliest local atrial activation in the NCSV preceded the atrial activation in the His area in all patients by 27 ± 8 ms. RFA was performed in all nine patients and was acutely successful in eight. Two patients required radiofrequency (RF) energy outputs of 50 W in order to terminate the arrhythmia. In one patient, successful AT ablation was associated with complete AV block requiring implantation of permanent pacemaker., Conclusions: Focal AT can be successfully mapped and ablated in the NCSV. Higher than usual RF energy levels are sometimes required. Complete AV block is a possible complication., (© 2016 Wiley Periodicals, Inc.)

Background: Accurate risk stratification is pivotal for appropriate selection of patients with severe symptomatic aortic stenosis for either surgical or transcatheter aortic valve replacement (TAVR). We sought to determine whether recent risk prediction models developed specifically in TAVR patients enhance prognostication in comparison with previous surgical scores used in clinical practice (EuroScore I, EuroScore II, STS)., Methods: The Israeli TAVR Registry Risk Model Accuracy Assessment (IRRMA) study utilized a multicenter prospective TAVR database (n=1327) to perform a quantitative comparison between previous risk scores developed in either surgical or TAVR populations, with the present registry serving as an independent external validation set., Results: In the IRRMA population, 4 variables (NYHA functional class IV, chronic obstructive pulmonary disease, systolic pulmonary artery pressure ≥60mmHg, vascular access other than by the femoral route) identified by cross-validation and leave-one-out analyses provided the most discriminative model (C-statistic=0.63) for predicting 30-day mortality. Previous scores developed in surgical (EuroScores I and II, STS), TAVR (FRANCE-2, OBSERVANT), or mixed (German AV score) populations were applied to the IRRMA cohort. Resultant C-statistics ranged between 0.52-0.71 (for the German AV and FRANCE-2 scores, respectively) and did not differ significantly (p=0.07 for the comparison between the lowest and highest C-statistics). The observed C-statistic for 5 of these 6 scores was lower than originally reported when applied to the IRRMA population., Conclusion: Available TAVR risk scores showed limited accuracy when applied to an independent validation set and did not enhance prognostication in comparison to previous surgical scores., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Various physical, emotional, and extrinsic triggers have been attributed to acute coronary syndrome. Whether a correlation can be drawn between identifiable ischemic triggers and the nature of coronary artery disease (CAD) still remains unclear. In the present study, we evaluated the correlation between triggered versus nontriggered ischemic symptoms and the extent of CAD in patients with ST-segment elevation myocardial infarction (STEMI). We conducted a retrospective, single-center observational study including 1,345 consecutive patients with STEMI, treated with primary percutaneous coronary intervention. Acute physical and emotional triggers were identified in patients' historical data. Independent predictors of multivessel CAD were determined using a logistic regression model. A potential trigger was identified in 37% of patients. Physical exertion was found to be the most dominant trigger (65%) followed by psychological stress (16%) and acute illness (12%). Patients with nontriggered STEMI tended to be older and more likely to have co-morbidities. Patients with nontriggered STEMI showed a higher rate of multivessel CAD (73% vs 30%, p <0.001). In a multivariate regression model, nontriggered symptoms emerged as an independent predictor of multivessel CAD (odds ratio 8.33, 95% CI 5.74 to 12.5, p = 0.001). No specific trigger was found to predict independently the extent of CAD. In conclusion, symptoms onset without a recognizable trigger is associated with multivessel CAD in STEMI. Further studies will be required to elucidate the putative mechanisms underlying ischemic triggering., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Background: The efficacy and safety of thrombectomy as an adjunct to primary percutaneous intervention (PCI) in the management of acute myocardial infarction (AMI) are debated. We performed a meta-analysis of randomized trials comparing primary PCI performed with versus without routine aspiration thrombectomy (AT)., Methods: A meta-analysis of randomized AT trials reporting clinical outcomes was done in accordance with the PRISMA guidelines. Trials reporting only non-clinical endpoints and those of technologies other than manual devices were excluded. The primary endpoint of this meta-analysis was mortality (either all-cause or cardiovascular). Secondary endpoints were reinfarction, stent thrombosis, and stroke., Results: Seventeen randomized trials, involving 20,853 patients were included. Weighted mean follow-up was 9.3 ± 3.3 months. The rates of all-cause mortality (reported in 14 trials, n = 10,430) and cardiovascular mortality (reported in 6 trials, n = 11,810) did not differ significantly between patients treated with or without AT (4.6% vs. 5.3%, RR = 0.88 [95%CI = 0.75-1.04]; and, 3.0% vs. 3.7%, RR = 0.83 [95%CI = 0.68-1.01]; respectively). The rates of reinfarction and stent thrombosis were also similar in patients treated with versus those treated without AT (2.1% vs. 2.2%; RR = 0.96 [95%CI = 0.80-1.15]; and, 1.2% vs. 1.4%; RR = 0.84 [95%CI = 0.65-1.07], respectively). However, stroke rates were increased with AT (0.84% vs. 0.52%, RR = 1.56 [95%CI = 1.09-2.25])., Conclusions: Routine AT as an adjunct to primary PCI does not reduce the rates of death, reinfarction, or stent thrombosis, but is associated with increased stroke risk., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Surgical aortic valve replacement (SAVR) is associated with an increased mortality risk in elderly or high-risk patients. Transcatheter aortic valve implantation (TAVI) is an alternative to surgery in patients with symptomatic severe aortic stenosis who are inoperable or at high operative risk. The impact of diabetes mellitus (DM) on patients referred to TAVI merits further investigation. The aim of our study was to evaluate the clinical characteristics and the impact of DM status on the updated Valve Academic Research Consortium 2-defined outcomes of TAVI and to stratify patient outcomes according to their initial glycated hemoglobin (HbA1c) levels. We enrolled and stratified patients who underwent TAVI at our institution according to DM status. A total of 586 patients were enrolled: 348 (59%) without DM and 238 (41%) with DM. There were no significant differences in 30-day mortality patients with diabetes compared to patients without diabetes (3.3% vs 2.9%, p = 0.974). Insulin-treated DM was not associated with adverse outcome in comparison to orally treated DM. To delineate the prognostic power of HbA1C in these patients, the cohort was divided into 3 groups according to HbA1C levels (<5.7%, 5.7% to 6.49%, and ≥6.5%). Patients with HbA1C ≥6.5% were at increased risk for mortality during follow-up (hazard ratio 2.571, 95% confidence interval 1.077 to 6.136, p = 0.033) compared to patients with HbA1C <5.7%. In conclusion, unlike SAVR, DM is not associated with an increased mortality risk after TAVI, nor is it associated with increased complications rates. A more poorly controlled disease, as manifested by elevated HbA1c levels, may be associated with increased mortality during long-term follow-up., (Copyright © 2015 Elsevier Inc. All rights reserved.)