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Introduction: High‐frequency low‐tidal‐volume (HFLTV) ventilation during radiofrequency catheter ablation (RFCA) for paroxysmal atrial fibrillation (PAF) has been shown to be superior to standard ventilation (SV) in terms of procedural efficiency, acute and long‐term clinical outcomes. Our study aimed to compare ablation lesions characteristics utilizing HFLTV ventilation versus SV during RFCA of PAF. Methods: A retrospective analysis was conducted on patients who underwent pulmonary vein isolation (PVI) for PAF between August 2022 and March 2023, using high‐power short‐duration ablation. Thirty‐five patients underwent RFCA with HFLTV ventilation and were matched with another cohort of 35 patients who underwent RFCA with SV. Parameters including ablation duration, contact force (CF), impedance drop, and ablation index were extracted from the CARTONET database for each ablation lesion. Results: A total of 70 patients were included (HFLTV = 35/2484 lesions, SV = 35/2830 lesions) in the analysis. There were no differences in baseline characteristics between the groups. While targeting the same ablation index, the HFLTV ventilation group demonstrated shorter average ablation duration per lesion (12.3 ± 5.0 vs. 15.4 ± 8.4 s, p <.001), higher average CF (17.0 ± 8.5 vs. 10.5 ± 4.6 g, p <.001), and greater impedance reduction (9.5 ± 4.6 vs. 7.7 ± 4.1 ohms, p <.001). HFLTV ventilation group also demonstrated shorter total procedural time (61.3 ± 25.5 vs. 90.8 ± 22.8 min, p <.001), ablation time (40.5 ± 18.6 vs. 65.8 ± 22.5 min, p <.001), and RF time (15.3 ± 4.8 vs. 22.9 ± 9.7 min, p <.001). Conclusion: HFLTV ventilation during PVI for PAF was associated with improved ablation lesion parameters and procedural efficiency compared to SV. [ABSTRACT FROM AUTHOR]

Introduction: Training in clinical cardiac electrophysiology (CCEP) involves the development of catheter handling skills to safely deliver effective treatment. Objective data from analysis of ablation data for evaluating trainee of CCEP procedures has not previously been possible. Using the artificial intelligence cloud‐based system (CARTONET), we assessed the impact of trainee progress through ablation procedural quality. Methods: Lesion‐ and procedure‐level data from all de novo atrial fibrillation (AF) and cavotricuspid isthmus (CTI) ablations involving first‐year (Y1) or second‐year (Y2) fellows across a full year of fellowship was curated within Cartonet. Lesions were automatically assigned to anatomic locations. Results: Lesion characteristics, including contact force, catheter stability, impedance drop, ablation index value, and interlesion time/distance were similar over each training year. Anatomic location and supervising operator significantly affected catheter stability. The proportion of lesion sets delivered independently and of lesions delivered by the trainee increased steadily from the first quartile of Y1 to the last quartile of Y2. Trainee perception of difficult regions did not correspond to objective measures. Conclusion: Objective ablation data from Cartonet showed that the progression of trainees through CCEP training does not impact lesion‐level measures of treatment efficacy (i.e., catheter stability, impedance drop). Data demonstrates increasing independence over a training fellowship. Analyses like these could be useful to inform individualized training programs and to track trainee's progress. It may also be a useful quality assurance tool for ensuring ongoing consistency of treatment delivered within training institutions. [ABSTRACT FROM AUTHOR]

The article comments on a research which found fewer incidence of repeats, shorter procedures and lower rate of major complications or adverse events among Medicare beneficiaries as trends in atrial fibrillation (AF) ablation. Factors to improved success and efficiency of AF ablation to mapping technology, jet ventilation, pacing strategy to improve catheter stability and high power short duration settings. Study limitations include underestimation of failure rates using time to redo ablation.

Abstract: Introduction: Atrial fibrillation (AF) ablation is increasingly common, but is associated with potential major complications. Technology, experience, and protocols have evolved significantly in recent times, and may have impacted procedural safety. We sought to compare AF ablation safety profiles, including complication rates and fluoroscopy times in a “modern” versus “historical” cohort. Methods and results: We evaluated consecutive patients undergoing AF ablation from a modern cohort (MC) from 2014 to 2015 and a historic cohort (HC) from 2009 to 2011 for complications. Major complications were categorized according to Heart Rhythm Society guidelines. We included 1,425 patients, 726 in the HC and 699 in the MC. The MC was older, had more OSA and less valvular AF. Fifty‐two (3.5%) procedures suffered major complications across the cohorts, with significantly fewer in the MC (5.0% vs. 2.3%, P  =  0.007). The largest reductions were seen in vascular, hemorrhagic, ischemic stroke, and perforation/tamponade related complications. Periprocedural antiplatelets drugs (aHR 2.1 [95 CI 1.1–3.9], P  =  0.02) and force‐sensing catheters (aHR 0.4 [95 CI 0.2–0.9], P  =  0.03) were independently related to major complication rates. Direct oral anticoagulants and uninterrupted anticoagulation were not associated with complications. There was a decrease in both fluoroscopy (–17.4 minutes [95 CI 19.2–15.6], P < 0.0001) and radiofrequency ablation times (−561 seconds [95CI −750 to −371], P < 0.0001). Conclusions: The safety profile of AF ablation has improved significantly in less than a decade. [ABSTRACT FROM AUTHOR]

Background Patients on rivaroxaban have variable international normalized ratios (INRs) but it is uncertain if INR impacts procedural heparin requirement during left atrial ablation. We sought to examine the determinants of heparin dosing in this patient population. Methods We reviewed consecutive patients who received rivaroxaban within 24 hours of left atrial ablation and compared them to patients on uninterrupted warfarin. The determinants of heparin requirement were evaluated using regression analysis. We then tested a weight-based heparin dose prospectively in rivaroxaban patients. Results There were 258 patients on rivaroxaban and 213 on warfarin. The mean INR was 1.4 in the rivaroxaban group and 2.3 in the warfarin group (P < 0.01). To achieve an activated clotting time (ACT) >350 seconds, rivaroxaban patients required significantly more heparin (166.9 vs. 78.3 units/kg, P < 0.001). In the rivaroxaban group, body weight was the strongest predictor of heparin dose (r = 0.52), while INR was weakly correlated (r = −0.21). In the prospective group, 25 patients were given an initial heparin dose of 120 units/kg with 22/25 (88%) achieving an ACT > 300 seconds. There were seven and three cases of pericardial effusion in rivaroxaban and warfarin patients, respectively (P = 0.41). The average volume drained in the rivaroxaban group was elevated (988.6 vs. 275.0 mL, P = 0.21). Conclusions Body weight is the strongest predictor of procedural heparin requirement during left atrial ablation in patients on uninterrupted rivaroxaban, even in those with an elevated INR. A heparin dose of 120 units/kg achieves an ACT > 300 seconds in the majority of patients. In cases of pericardial effusion, bleeding may be prolonged. [ABSTRACT FROM AUTHOR]

Aims: Catheter ablation can be lifesaving in ventricular tachycardia (VT) storm, but the underlying substrate in patients with storm is not well characterized. We sought to compare the clinical factors, substrate, and outcomes differences in patients with sustained monomorphic VT who present for catheter ablation with VT storm versus those with a nonstorm presentation. Methods: Consecutive ischemic (ICM; n = 554) or nonischemic cardiomyopathy patients (NICM; n = 369) with a storm versus nonstorm presentation were studied (ICM storm 186; NICM storm 101). Results: In ICM, storm compared with nonstorm patients had significantly lower left ventricular (LV) ejection fraction (EF), greater number of antiarrhythmic drug (AAD) failures, slower VTs, greater number of scarred LV segments, higher incidence of anterior, septal, and apical endocardial LV scar (all P < 0.05). However, outcomes in follow-up were similar (12-month ventricular arrhythmia [VA]-free survival: 51% vs. 52%, P = 0.6; survival free of death/transplant 75% vs. 87%, P = 0.7). In addition to the above differences, NICM storm patients were also older; however, the extent and distribution of scar was similar except for a higher incidence of lateral endocardial scar in storm patients (P = 0.05). VA-free survival (36% vs. 47%, P = 0.004) and survival free of death/transplant, however, were worse in NICM storm than nonstorm patients (72% vs. 88%, P = 0.001). NICM storm patients had worse VA-free survival than ICM storm patients. Conclusion: There are differences in clinical factors and scar patterns in patients undergoing VT ablation who present with VT storm versus thosewith a nonstorm presentation. Clinical outcomes areworse in NICM storm patients. [ABSTRACT FROM AUTHOR]

Background To exposure in patients undergoing cardiac electrophysiology (EP) ablation. This included the use of a 'very low' dose protocol, and the impact of angulations and patient body mass index (BMI) on radiation dose as a mean to reduce exposure. Methods A total of 212 retrospective patient data sets were collected during EP ablation procedures on a biplane fluoroscopy system. Dose metrics were computed based on dose-area product (DAP) measured by the system for each x-ray acquisition. Results Dose baselines of different ablation procedures were established as DAP and DAP per hour, with respect to patient BMI. The use of a 'very low dose' protocol reduced exposure by 62% while providing adequate image quality. With approximate left anterior oblique (LAO) 50° and right anterior oblique (RAO) 30°, DAP and DAP rate were significantly higher in LAO compared to RAO (11.2 [4.8-25.3] Gy·cm2 vs 5.28 [2.9-11.1] Gy·cm2 and 74.0 [38.2-136.1] Gy·cm2/h vs 25.0 [16.4-44.1] Gy·cm2/h, respectively; P < 0.001). DAP and DAP rate were also significantly higher in patients with BMI > 30 vs BMI ≤ 30 (34.2 [22.3-58.7] Gy·cm2 vs 12.4 [6.0-26.9] Gy·cm2 and 84.9 [68.1-120.4] Gy·cm2/h vs 34.2 [21.7-52.9] Gy·cm2/h, respectively; P < 0.001). Conclusion Protocol setting, system angulation, and BMI, in particular, wider angulation in LAO compared to RAO plane, exposes patients to significant higher radiation doses. Obese patients in standard LAO plane receive six times the radiation dose of nonobese patients in RAO. [ABSTRACT FROM AUTHOR]

Catheter Ablation of Atrial Arrhythmias Background Management of atrial arrhythmias (AA) in orthotopic heart transplant (OHT) patients is challenging. Objective The purpose of this study was to define the mechanisms of these arrhythmias and to evaluate the role of ablation. Methods Patients with OHT referred for ablation of AA from 1999 to 2011 were included (n = 15). Entrainment and anatomic 3-D mapping were utilized to identify AA mechanism and guide ablation. Results The median time from OHT to ablation was 8 years (range: 1 month-16 years). AA types included 1 (7%) AVNRT, 5 (33%) cavotricuspid isthmus (CTI) dependent donor atrial flutter (AFl), 3 (20%) non-CTI-dependent donor AFL (n = 3), focal atrial tachycardia (AT) (n = 2) and in 4 (27%) recipient to donor atria conduction (RDC) that involved the right atrial anastomosis in 3 and left atrial anastamosis in 1 patient. In RDC tachycardia, ablation was performed at the site of earliest donor atrial activation on the suture line. AA in the recipient atria were not targeted. This resulted in acute success in all cases. In most patients 12/15 (80%) only right atrial ablation was necessary. Regardless of surgical technique (bicaval vs biatrial) right-sided AA was most common. Acute success occurred in 14/15 (93%) patients and 3/15 (20%) required repeat Abl for recurrence. There were no major complications. Conclusion AA after OHT are most commonly due to atrial macroreentry, but focal arrhythmias and RDC atrial conduction also occur. Ablation of organized AA is usually successful with low risk, warranting early consideration in preference to medical treatment. [ABSTRACT FROM AUTHOR]

Cardiovascular implantable electronic devices (CIEDs) are frequently utilized for management of cardiac dysrhythmias in patients with chronic kidney disease or end-stage renal disease receiving hemodialysis. The survival benefit from use of implantable cardioverter defibrillators in patients with CKD or ESRD is not as clear as in the general population, particularly when used for primary prevention of sudden cardiac death. Transvenous CIED leads are associated with central vein stenosis resulting in significant adverse consequences for existing or future arteriovenous access. Venous hypertension from CIED lead-related central vein stenosis is a challenging clinical problem and may require repeated percutaneous interventions, replacement of the CIED, or creation of alternative arteriovenous access. Infections associated with transvenous CIED leads are more frequent and associated with worse outcomes in patients with renal disease. Epicardial CIED leads or other nontransvenous devices may reduce complications of both central venous stenosis and endovascular infection in these vulnerable patients. Consensus recommendations are offered for avoidance and management of complications arising from the use of CIEDs and arteriovenous hemodialysis access. [ABSTRACT FROM AUTHOR]

Long-Term Follow-Up in Patients with Brugada Syndrome. Introduction: Risk stratification for patients with suspected Brugada syndrome (BS) remains difficult. Implantation of cardioverter-defibrillators (ICDs) in high-risk patients provides continuous long-term arrhythmia protection. Methods: Data of 33 consecutive patients undergoing ICD implantation after BS evaluation between 1995 and 2008 were reviewed. Results: There were 30 (91%) men and 3 (9%) women (46.4 ± 11.7 years). Type I Brugada was noted in 18 (54.5%), type II in 12 (36.4%) patients, and ST elevation after drug challenge in 3 patients (9.1%). Three patients had prior cardiac arrest; 70% a history of syncope; and 56% ventricular arrhythmias at the electrophysiology study. During 7.9 ± 3.6 years of follow-up, 2 patients with prior arrest received appropriate ICD shocks. None of the 30 patients without prior arrest had a sustained arrhythmia detected. ICD-related adverse effects occurred in 11 (33%) patients, including inappropriate shocks in 5 (15%). Eight patients (24%) developed 11 major device-related complications including subclavian vein thrombosis (1), pericardial effusion (1), lead fracture (2), and infection (2); in 4 patients the only complication was premature battery depletion that required early ICD replacement; however, some of these complications such as lead fractures and early battery depletion may not be specific for this patient cohort and may not repeat in the future. Conclusion: Risk stratification for patients with BS for primary prevention remains challenging. The low risk of arrhythmic events that is exceeded by ICD-related adverse effects should inform discussions with patients who do not have a prior history of cardiac arrest. (J Cardiovasc Electrophysiol, Vol. 22, pp. 1115-1119, October 2011) [ABSTRACT FROM AUTHOR]

Background: Atrial fibrillation (AF) can have a significant effect on quality of life (QoL). Other chronic diseases are known to not only affect the patient but to also impact the QoL of persons living with them. Scant data exist on the QoL effect of AF in spouses/significant others (SOs). Methods: An anonymous survey regarding the perceived effect of AF on QoL was designed and distributed to both patients and spouses/SOs during an educational symposium about living with AF. Both were asked to fill out the survey independently according to how their life was affected by either their AF or their partner’s AF. Questions included demographics, perceived impairment of overall QoL on a 5-point scale, as well as effect on subcategories of QoL, namely daily activity, work life, sex life, physical activity, psychological well-being, and social activity. Results: Five hundred and sixty-eight subjects completed the survey of which 411 were AF patients and 129 were spouses/SOs. The perceived effect of AF on overall QoL (N = 527) was similar in patients and spouses (AF patients: mild 42.0%, moderate 26.0%, severe 32.0% vs. spouses: 44.1%, 25.2%, 31.7%; P = 0.917). This result did not change when adjusted for age and gender. There was also no significant difference between patients and spouses in the subcategories of QoL with the exception of the perceived effect on work life, which was greater in patients than spouses (P = 0.041). Conclusions: AF has a similar perceived impact on the QoL of spouses and patients. QoL improvement strategies for patients with AF should take spouses into account. [ABSTRACT FROM AUTHOR]

While surgical epicardial lead placement is performed in a subset of cardiac resynchronization therapy patients, data comparing survival following surgical versus transvenous lead placement are limited. We hypothesized that surgical procedures would be associated with increased mortality risk. Long-term event-free survival was assessed for 480 consecutive patients undergoing surgical (48) or percutaneous (432) left ventricle (LV) lead placement at our institution from January 2000 to September 2008. Baseline clinical and demographic characteristics were similar between groups. While there was no statistically significant difference in overall event-free survival (P = 0.13), when analysis was restricted to surgical patients with isolated surgical lead placement (n = 28), event-free survival was significantly lower in surgical patients (P = 0.015). There appeared to be an early risk (first approximately 3 months postimplantation) with surgical lead placement, primarily in LV lead-only patients. Event rates were significantly higher in LV lead-only surgical patients than in transvenous patients in the first 3 months (P = 0.006). In proportional hazards analysis comparing isolated surgical LV lead placement to transvenous lead placement, adjusted hazard ratios were 1.8 ([1.1,2.7] P = 0.02) and 1.3 ([1.0,1.7] P = 0.07) for the first 3 months and for the full duration of follow-up, respectively. Isolated surgical LV lead placement appears to carry a small but significant upfront mortality cost, with risk extending beyond the immediate postoperative period. Long-term survival is similar, suggesting those surviving beyond this period of early risk derive the same benefit as coronary sinus lead recipients. Further work is needed to identify risk factors associated with early mortality following surgical lead placement. (PACE 2011; 34:490-500) [ABSTRACT FROM AUTHOR]

Background: Ablation of atrial fibrillation (AF) with international normalized ratio (INR) ≥ 2.0 is safe and may reduce thromboembolic complications. Heparin is administered during the procedure, but the effect of elevated INR on heparin requirements and target activation clotting times (ACT) ≥ 350 seconds during ablation is unknown. Objectives: To study the effect of INR on intraprocedural anticoagulation during ablation of AF. Methods: We retrospectively studied 427 consecutive patients over an 18-month period when we were transitioning to continuation of warfarin for AF ablation. Baseline INR, procedural ACT measurements, heparin doses and major complications were analyzed according to Group 1 with INR < 2.0 (n = 246) and Group 2 with INR ≥ 2.0 (n = 181). Results: In Group 1, the mean INR was lower (1.3 ± 0.3 s vs 2.4 ± 0.3; P < 0.001), and the mean heparin dose was greater (106.82 ± 40.01 vs 77.03 ± 18.5 U/kg; P < 0.001). A single heparin bolus achieved ACT ≥ 350 seconds throughout the procedure in 51 patients (20.7%) in Group 1 compared to 108 patients (59.7%) in Group 2 (P < 0.01). Mean ACT values were higher in Group 2. Symptomatic pericardial effusions were similar (2.4% in Group 1 and 2.2% in Group 2). There were 3 thromboembolic cerebrovascular events in Group 1 and none in Group 2. Femoral hematomas occurred more frequently in Group 1 (8.1%) than in Group 2 (3.3%) (P = 0.007). Conclusions: AF ablation with INR ≥ 2.0 provides a consistent anticoagulant milieu during the procedure, with lower heparin requirements that are important to anticipate. (J Cardiovasc Electrophysiol, Vol. 22, pp. 248-254, March 2011) [ABSTRACT FROM AUTHOR]

Percutaneous Epicardial Access. Introduction: There is a paucity of data on the success rates of achieving percutaneous epicardial access in different groups of patients. Methods and Results: Percutaneous epicardial access was attempted in 137 patients having 149 procedures; 19 patients had supraventricular tachycardia (SVT), 25 patients had idiopathic VT and 93 patients had scar-related ventricular tachycardia (VT). Ten patients had prior cardiac surgery. Successful epicardial access was achieved in 133 of 149 (89.3%) procedures. Access was achieved in 17 of 19 (89.5%) patients with SVT, all patients with idiopathic VT, 80 of 93 (86.0%) patients with scar-related VT and in 2 (20%) patients with prior cardiac surgery. Attempted access failed in 16 patients; 8 had prior cardiac surgery and 3 had prior pericarditis. After an initial procedure, repeat access was attempted in 15 patients, 5.1 ± 5.4 months after initial epicardial mapping and ablation. Access was successful in 13 (86.7%) and failed in 2 patients who had pericarditis after their first procedure. Only 4 patients were given intrapericardial glucocorticoid at their first epicardial procedure. Prior cardiac surgery and a history of pericarditis predicted unsuccessful access (P < 0.01). Complications (9 patients) included pericardial bleeding (80–250 mL) and intraabdominal bleeding. Conclusions: In patients without prior cardiac surgery, percutaneous epicardial access can be obtained in the majority of patients. Prior cardiac surgery precludes access in the most patients and when possible adhesions may limit catheter movement. Repeat access is possible in the majority of patients without the installation of intrapericardial glucocorticoid at the first procedure. (J Cardiovasc Electrophysiol, Vol. 21, pp. 406–411, April 2010) [ABSTRACT FROM AUTHOR]

Background: An automatic capture (AC) algorithm adjusts ventricular pacing output to capture the ventricle while optimizing output to 0.5 V above threshold. AC maintains this output and confirms capture on a beat-to-beat basis in bipolar and unipolar pacing and sensing. Objective: To assess the AC algorithm and its impact on device longevity. Methods: Patients implanted with a pacemaker were randomized 1:1 to have the AC feature on or off for 12 months. Two threshold tests were conducted at each visit— automatic threshold and manual threshold. Average ventricular voltage output and projected device longevity were compared between AC on and off using nonparametric tests. Results: Nine hundred ten patients were enrolled and underwent device implantation. Average ventricular voltage output was 1.6 V for the AC on arm (n = 444) and 3.1 V for the AC off arm (n = 446) (P < 0.001). Projected device longevity was 10.3 years for AC on and 8.9 years for AC off (P < 0.0001), or a 16% increase in longevity for AC on. The proportion of patients in whom there was a difference between automatic threshold and manual threshold of ≤0.5 V through follow-up was 99.0% (95% CI: 98.6, 99.3). The average difference between automatic threshold and manual threshold was 0.07 V (P = 0.002). Conclusions: This study showed that automatic threshold testing at follow-up provided comparable information to manually measured threshold testing. AC provided a significant increase in projected device longevity compared to standard programing. [ABSTRACT FROM AUTHOR]

Background: Adaptive rate sensors used in permanent pacemakers incorporate an accelerometer (XL) to increase heart rate with activity. Limited data exists regarding the relative benefit of a blended sensor (BS) (XL and minute ventilation) versus XL alone in restoring chronotropic response (CR) in chronotropically incompetent (CI) patients. Methods: One thousand five hundred thirty-eight patients from the limiting chronotropic incompetence for pacemaker recipients (LIFE) study were implanted with a pacemaker and 1,256 patients had data collected at 1 month. Patients performed a treadmill test 1-month postimplant while programed in nonrate responsive mode (DDD-60) to determine CI. Only patients who completed at least three exercise stages and achieved a peak perceived exertion ≥16 were included in the analyses. The metabolic chronotropic relationship (MCR) slope was used to evaluate CR in 547 patients. Patients were randomized to XL or BS with a conservative fixed rate response factor (XL = 8, MV = 4). CI patients performed a follow-up 6-month treadmill test. Results: CI prevalence in this patient population (n = 547) was 34%. No differences in baseline characteristics existed between groups. Although both groups showed significant within-group improvements in MCR slope from 1 to 6 months (both P < 0.001), the BS group had a significantly higher MCR slope at 6 months compared to the XL group (P = 0.011). Improvement in quality of life (QOL) did not differ between groups . Conclusions: In this general pacemaker population with CI, a BS programed empirically restores CR more favorably than an XL sensor programed nominally. Further studies are needed to determine if individual sensor optimization would lead to improvement in functional capacity, higher MCR slopes, and QOL. [ABSTRACT FROM AUTHOR]

Background: In the event of infection, erosion, or failure, fibrosis of a defibrillation lead can make extraction difficult. In the ENDOTAK RELIANCE G defibrillation lead, coils are covered with expanded polytetrafluoroethylene (ePTFE) to prevent tissue ingrowth. Objective: The objective of the REFLEx Study was to evaluate if RELIANCE G defibrillation leads with ePTFE-covered coils are as good as comparative defibrillation leads with respect to electrical performance and termination of spontaneous tachyarrhythmias. Methods: Patients were randomized to type of defibrillation lead—Guidant RELIANCE G lead or a non-ePTFE-covered lead of choice. Electrical performance success was defined as meeting all minimum standards in the respective manufacturer's manual for amplitude, threshold, and impedance. A noninferiority margin of 5% was prespecified. Results: Electrical performance success at 12 months was 93.0% (280/301) for RELIANCE G and 94.5% (291/308) for comparative leads. The performance success rate for RELIANCE G did not differ significantly from study comparative (P = 0.04, noninferiority). For spontaneous episodes, first shock conversion success rate was 90% for RELIANCE G and 95% for study comparative (P = 0.89, noninferiority). Implant conversion testing was successful in 96.7% (524/542) of RELIANCE G patients and 94.3% (512/543) of comparative patients (chi-square P-value = 0.0784). About 55% (609/1115) of patients completed follow-up through month 12. Conclusion: Data from the REFLEx study indicate that ePTFE-covered leads are not inferior to comparative leads with respect to electrical performance and implant conversion testing. We cannot conclude that the first shock conversion efficacy of ePTFE covered leads was statistically noninferior to comparative leads. [ABSTRACT FROM AUTHOR]

SAPP, J.L., et al.: Deep Myocardial Ablation Lesions Can Be Created with a Retractable Needle-Tipped Catheter. RF catheter ablation of ventricular tachycardia is sometimes limited by inadequate lesion depth. This study investigated the use of a retractable needle-tipped catheter to create deep RF lesions in vivo in porcine myocardium. An 8 Fr electrode catheter with an extendable 27-gauge needle at the tip was modified for RF ablation by embedding a thermocouple and attaching a pin connector. In three swine (32–58 kg) the left ventricle was entered via the femoral artery and endocardial contact was made. The needle was advanced 10 mm and 13 RF applications were made under a controlled temperature (90°C × 120 s). Nine control lesions were made using a standard 4-mm tip catheter (60°C × 120 s). The lesions were fixed, serially sectioned from the endocardium, digitally imaged, and quantified. Needle ablation lesions were deeper (10.15 ± 0.77 vs 5.67 ± 0.37 mm, P < 0.001) and more likely to be transmural (77 vs 11%, P = 0.008) than control lesions. The volume of control lesions, however, was larger (358.4 ± 56.2 vs 174.7 ± 18.6 mm3, P = 0.002) due to a significantly larger cross-sectional area at the endocardium (0.548 ± 0.04 vs 0.151 ± 0.01 cm2, P < 0.001). At depths > 6 mm, the needle electrode lesions had a greater cross-sectional area (0.136 ± 0.01 vs 0.005 ± 0.004 cm2, P < 0.001). Catheter-based needle ablation is feasible and allows creation of deeper lesions that can be transmural. Although deep, the lesions had a small cross-sectional area such that precise targeting would be required for success. (PACE 2004; 27:594–599) [ABSTRACT FROM AUTHOR]

Epicardial-Endocardial Approach to IST Ablation. A combined epicardial-endocardial approach to ablation of inappropriate sinus tachycardia in a highly symptomatic patient who failed to respond to medical therapy and endocardial ablation is described. The anatomy and physiology of the sinus node is discussed, providing a basis for performing this procedure. This case provides an additional therapeutic option for a condition that often is difficult to manage. (J Cardiovasc Electrophysiol, Vol. 15, pp. 237-240, February 2004) [ABSTRACT FROM AUTHOR]

Purkinje Tachycardias. Introduction: Ventricular tachycardia (VT) with involvement of the His-Purkinje system (HPS) can be difficult to recognize in patients with heart disease, but it may be particularly susceptible to ablation targeting the HPS. This study defines the incidence and types of HPS involvement in VT. Methods and Results: Involvement of the HPS was sought during electrophysiologic study with catheter mapping in 234 consecutive patients referred for catheter ablation of recurrent VT associated with heart disease. HPS VT was observed in 20 (8.5%) patients (mean ejection fraction 29%± 17%); in 9 (11%) of 81 patients with nonischemic heart disease and 11 (7.1%) of 153 patients with coronary artery disease (P = NS). Three types of HPS VT were observed: 16 patients (group 1) had typical bundle branch reentry, 2 patients (group 2) had bundle branch reentry and interfascicular reentry, and 2 patients (group 3) had VT consistent with a focal origin in the distal HPS. In all three groups, the VT QRS had morphologic similarity to the sinus rhythm QRS. Ablation of HPS VT was successful in all patients in whom it was attempted but produced high-degree AV block in 6 (30%). In 12 patients (60%), other VTs due to reentry through scar also were inducible. Conclusion: Involvement of the HPS in VT associated with heart disease has three distinct clinical forms, all of which are susceptible to ablation. Ablation often is not sufficient as the sole therapy due to other induced VT's and conduction abnormalities, requiring pacemaker and/or defibrillator implantation. (J Cardiovasc Electrophysiol, Vol. 15, pp. 52-58, January 2004) [ABSTRACT FROM AUTHOR]

Eyal Nof et al. respond to a letter to the editor which was submitted in response to their article "Catheter Ablation of Atrial Arrhythmias After Cardiac Transplantation: Findings at EP Study Utility of 3-D Mapping and Outcomes".

Background: Acute end points of catheter ablation for ventricular tachycardia (VT) remain incompletely defined. The aim of this study is to identify causes for failure in patients with structural heart disease and to assess the relation of this acute outcome to longer-term management and outcomes., Methods and Results: From 2002 to 2010, 518 consecutive patients (84% male, 62 ± 14 years) with structural heart disease underwent a first ablation procedure for sustained VT at our institution. Acute ablation failure was defined as persistent inducibility of a clinical VT. Acute ablation failure was seen in 52 (10%) patients. Causes for failure were: intramural free wall VT in 13 (25%), deep septal VT in 9 (17%), decision not to ablate due to proximity to the bundle of His, left phrenic nerve, or a coronary artery in 3 (6%), and endocardial ablation failure with inability or decision not to attempt to access the epicardium in 27 (52%) patients. In multivariable analysis, ablation failure was an independent predictor of mortality (hazard ratio 2.010, 95% CI 1.147 to 3.239, P=0.004) and VT recurrence (hazard ratio 2.385, 95% CI 1.642 to 3.466, P<0.001)., Conclusions: With endocardial or epicardial ablation, or both, acute ablation failure was seen in 10% of patients, largely due to anatomic factors. Persistence of a clinical VT is associated with recurrence and comparatively higher mortality.