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Background: Visualizing the specific regions where atrial fibrillation (AF) is maintained is crucial for effective treatment, but it remains challenging in clinical practice. We aimed to address this challenge by developing a mapping approach focused on the cycle length (CL) and its gradient (CL‐gradient). Methods: In 105 patients undergoing initial ablation for persistent AF, pre‐ablation CARTOFINDER data were utilized to create maps based on three indicators: (1) CL, the atrial frequency during AF calculated using CARTOFINDER; (2) Short CL, encompassing CLs within 5 ms of the minimum CL; and (3) CL‐gradient, the CL range within a 6 mm radius. We evaluated the association between the AF termination through ablation and the measured values and patterns in each map. Results: AF termination occurred in 17 patients. The AF termination group exhibited the significant large maximum CL‐gradient (48.8 ms [interquartile range, 38.6–66.3], p <.001) and the short distance between the minimum CL site and the maximum CL‐gradient site (15.8 mm, [interquartile range, 6.0–23.2], p =.029). Of the 17 AF termination cases, 13 exhibited a CL distribution pattern characterized by a steep CL‐gradient near the minimum CL site (SG‐MCL), defined as the distance of less than 23.2 mm and the maximum CL‐gradient greater than 33.1 ms. In these AF termination cases, SG‐MCL was also correlated with the ablation area. Conclusions: The minimum CL area accompanied by significant CL gradients in the immediate vicinity may play a crucial role in sustaining AF. [ABSTRACT FROM AUTHOR]

Background: Patients with subcutaneous implantable cardioverter‐defibrillators (S‐ICDs) experience an oversensing episode (OS) more frequently than those with transvenous ICDs. However, no established electrocardiography (ECG) parameters can accurately detect an OS. This study aimed to evaluate the incidence of an OS in real‐world clinical practice and the association of synthesized 18‐lead ECG (syn18‐ECG) parameters with an OS. Methods: We retrospectively included 21 consecutive patients who underwent S‐ICD implantation and collected syn18‐ECG parameters. We placed the generator in a deep posterior position and defined an OS as an inappropriate charging episode caused by cardiac or noncardiac signals. A SMART pass filter and two tachyarrhythmia zones were programed. Results: The most frequent underlying heart disease was Brugada/J wave syndrome (n = 7). During a median follow‐up period of 1188 days, an OS was observed in six patients (28.6%). The QRS amplitude in synthesized V7 lead (synV7) was significantly lower in the OS group than in the non‐OS group (0.59 ± 0.17 vs. 0.91 ± 0.35 mV, p = 0.019). The optimal cutoff value of synV7 QRS amplitude was 0.61 mV, with a sensitivity of 80.0% and a specificity of 83.7% for predicting an OS. Univariate logistic analysis showed that a synV7 QRS amplitude of <0.61 mV was only associated with an OS (odd ratio, 20.0; 95% confidence interval, 1.66–241.72; p = 0.018). Conclusions: In patients with S‐ICDs, an OS was not a rare complication during long‐term follow‐up. A low synV7 QRS amplitude was associated with a high OS incidence. [ABSTRACT FROM AUTHOR]

Background: The fibrosis‐5 (FIB‐5) index is a noninvasive marker for assessing the progression of liver fibrosis and predictor in patients with heart failure (HF). This study investigated the association between the FIB‐5 index and response to cardiac resynchronization therapy (CRT) and evaluated its predictive value for prognosis. Methods: In total, 203 patients who underwent CRT/CRT‐defibrillator (CRT‐D) implantation were retrospectively included. The FIB‐5 index was calculated using blood samples obtained before and after CRT/CRT‐D. Response to CRT was defined as a relative reduction in left ventricular end‐systolic volume of ≥15% 6 months after CRT/CRT‐D. We compared the prognosis after CRT/CRT‐D between the groups according to the FIB‐5 index. Results: One hundred and twenty‐three patients (61%) responded to CRT. The responder group demonstrated a significantly higher FIB‐5 index than the nonresponder group (−2.76 ± 3.85 vs. −4.67 ± 3.29, p < 0.001). Receiver‐operating characteristic analysis demonstrated that the area under the curve of the FIB‐5 index was 0.660 with a cutoff value of −4.00 for responders. In multivariate analysis, FIB‐5 index ≥ −4.00 was an independent predictor for CRT response (odds ratio: 3.665, p = 0.003), in addition to QRS duration ≥ 150 ms and echocardiographic dysynchrony. The FIB‐5 index increased significantly after 6 months in the responder group but not in the nonresponder group. The FIB‐5 index ≥ −4.00 group showed a significantly better prognosis for cardiac death, HF hospitalization, and composite endpoint than the FIB‐5 index < −4.00 group. Conclusion: The FIB‐5 index in addition to classical predictors may be a useful marker for predicting response to CRT. [ABSTRACT FROM AUTHOR]

Introduction: The underlying risks of asymptomatic embolization during high‐power short‐duration (HPSD) ablation for atrial fibrillation remain unclear. We aimed to evaluate microembolic signals (MESs) during HPSD ablation with power settings of 50 and 90 W in comparison with those during cryoballoon (CB) ablation using a novel carotid ultrasound‐Doppler system that classifies solid and air bubble signals using real‐time monitoring. Methods and Results: Forty‐seven patients underwent HPSD ablation using radiofrequency (RF), and 13 underwent CB ablation. MESs were evaluated using a novel pastable soft ultrasound probe equipped with a carotid ultrasound during pulmonary vein isolation. We compared the detailed MESs and their timing between RF and CB ablations. The number of MESs and solid signals were significantly higher in the RF group than in CB group (209 ± 229 vs. 79 ± 32, p =.047, and 83 ± 89 vs. 28 ± 17, p =.032, respectively). In RF ablation, the number of MESs, solid, and bubble signals per ablation point, or per second, was significantly higher at 90 W than at 50 W ablation. The MESs, solid, and bubble signals were detected more frequently in the bottom and anterior walls of the left pulmonary vein (LPV) ablation. In contrast, many MESs were observed before the first CB application and decreased chronologically as the procedure progressed. Signals were more prevalent during the CB interval rather than during the freezing time. Among the 28 patients, 4 exhibited a high‐intensity area on postbrain magnetic resonance imaging (MRI). The MRI‐positive group showed a trend of larger signal sizes than did the MRI‐negative group. Conclusion: The number of MESs was higher in the HPSD RF group than in the CB group, with this risk being more pronounced in the 90 W ablation group. The primary detection site was the anterior wall of the LPV in RF and the first interval in CB ablation. [ABSTRACT FROM AUTHOR]

Introduction: Intrinsic antitachycardia pacing (iATP) is a novel automated antitachycardia pacing (ATP) that provides individual treatment to terminate ventricular tachycardia (VT). However, the clinical efficacy of iATP in comparison with conventional ATP is unknown. We aim to compare the termination rate of VT between iATP and conventional ATP in patients with implantable cardioverter‐defibrillators using a unique setting of different sequential orders of both ATP algorisms. Methods: Patients with the iATP algorithm were assigned to iATP‐first and conventional ATP‐first groups sequentially. In the iATP‐first group, a maximum of seven iATP sequences were delivered, followed by conventional burst and ramp pacing. In contrast, in the conventional ATP‐first group, two bursts and ramp pacing were initially programmed, followed by iATP sequences. We compared the success rates of VT termination in the first and secondary programmed ATP zones between the two groups. Results: Fifty‐eight and 56 patients were enrolled in the iATP‐first and conventional ATP‐first groups, and 67 and 44 VTs were analyzed in each group, respectively. At the first single ATP therapy, success rates were 64% and 70% in the iATP and conventional groups, respectively. At the end of the first iATP treatment zone, the success rate increased from 64% to 85%. Moreover, secondary iATP therapy following the failure of conventional ATPs increased the success rate from 80% to 93%. There was a significant benefit of alternative iATP for VT termination compared to secondary conventional ATP (100% vs. 33%, p =.028). Conclusions: iATP may be beneficial as a secondary therapy after failure of conventional ATP to terminate VT. [ABSTRACT FROM AUTHOR]

Introduction: The clinical outcomes and mechanisms of delayed responses to cardiac resynchronization therapy (CRT) remain unclear. We aimed to investigate the differences in outcomes and gain insight into the mechanisms of early and delayed responses to CRT. Methods: This retrospective study included 110 patients who underwent CRT implantation. Positive response to CRT was defined as ≥15% reduction of left ventricular (LV) end‐systolic volume on echocardiography at 1 year (early phase) and 3 years (delayed phase) after implantation. The latest mechanical activation site (LMAS) of the LV was identified using two‐dimensional speckle‐tracking radial strain analysis. Results: Seventy‐eight (71%) patients exhibited an early response 1 year after CRT implantation. Of 32 non‐responders in the early phase, 12 (38%) demonstrated a delayed response, and 20 (62%) were classified as non‐responders after 3 years. During the follow‐up time of 10.3 ± 0.5 years, the delayed and early responders had a similar prognosis of mortality and heart failure (HF) hospitalization. In contrast, non‐responders had a worse prognosis. Multivariate analysis revealed that a longer duration (months) between initial HF hospitalization and CRT (odds ratio [OR]: 1.126; 95% confidence interval [CI]: 1.036–1.222; p =.005), non‐exact concordance of LV lead location with LMAS (OR: 32.744; 95% CI: 1.101–973.518; p =.044), and pre‐QRS duration (OR: 0.901; 95% CI: 0.827–0.981; p =.016) were independent predictors of delayed response to CRT compared with early response. Conclusion: The prognoses were similar regardless of the response time after CRT. A longer history of HF, suboptimal LV lead position, and shorter pre‐QRS duration were related to delayed response than early response. [ABSTRACT FROM AUTHOR]

Deep septal ventricular pacing is a recently developed physiological pacing modality with good efficacy; however, it has a potential risk of unusual complications. Here, we report a patient with pacing failure and spontaneous, complete lead dislodgement after >2 years of deep septal pacing, possibly caused by systemic bacterial infection and specific lead behavior in the septal myocardium. This case report may implicate a hidden risk of unusual complications in deep septal pacing. [ABSTRACT FROM AUTHOR]

Introduction: Diagnosis of outflow tract ventricular arrhythmia (OTVA) localization by an electrocardiographic complex is key to successful catheter ablation for OTVA. However, diagnosing the origin of OTVA with a precordial transition in lead V3 (V3TZ) is challenging. This study aimed to create the best practical electrocardiogram algorithm to differentiate the left ventricular outflow tract (LVOT) from the right ventricular outflow tract (RVOT) of OTVA origin with V3TZ using machine learning. Methods: Of 498 consecutive patients undergoing catheter ablation for OTVA, we included 104 patients who underwent ablation for OTVA with V3TZ and identified the origin of LVOT (n = 62) and RVOT (n = 42) from the results. We analyzed the standard 12‐lead electrocardiogram preoperatively and measured 128 elements in each case. The study population was randomly divided into training group (70%) and testing group (30%), and decision tree analysis was performed using the measured elements as features. The performance of the algorithm created in the training group was verified in the testing group. Results: Four measurements were identified as important features: the aVF/II R‐wave ratio, the V2S/V3R index, the QRS amplitude in lead V3, and the R‐wave deflection slope in lead V3. Among them, the aVF/II R‐wave ratio and the V2S/V3R index had a particularly strong influence on the algorithm. The performance of this algorithm was extremely high, with an accuracy of 94.4%, precision of 91.5%, recall of 100%, and an F1‐score of 0.96. Conclusions: The novel algorithm created using machine learning is useful in diagnosing the origin of OTVA with V3TZ. [ABSTRACT FROM AUTHOR]

A 69‐year‐old man presented bradycardia with a constant blocked atrial bigeminy and heart failure. Successful catheter ablation of blocked atrial bigeminy with bradycardia resulted in myocardial reverse remodeling and restoration of the normal sinus rhythm from the ectopic atrial rhythm. [ABSTRACT FROM AUTHOR]

Introduction: Data are limited regarding outcomes of cryoballoon ablation for atrial fibrillation (AF) in patients with heart failure (HF). This large‐scale multicenter study aimed to evaluate the prognosis of patients with HF after cryoballoon ablation for AF. Methods: Among 3655 patients undergoing cryoballoon ablation at 17 institutions, 549 patients (15%) (391 with paroxysmal AF and 158 with persistent AF) diagnosed with HF preoperatively were analyzed. Clinical endpoints were recurrence, mortality, and HF hospitalization after ablation. Results: Most patients had a preserved left ventricular ejection fraction (LVEF) ≥ 50%. During a mean follow‐up period of 25.7 months, recurrence, all‐cause death, and HF hospitalization occurred in 29%, 4.0%, and 4.8%, respectively. Cardiac function on echocardiography and B‐type natriuretic peptide (BNP) levels significantly improved postoperatively, and the effect was more pronounced in the nonrecurrence group. Major complications occurred in 33 patients (6.0%), but most complications were phrenic nerve palsy (3.6%). Although death and HF hospitalization occurred more frequently in patients with LVEF ≤ 40% (n = 73) and New York Heart Association (NYHA) class III–IV (n = 19) than other subgroups, the BNP levels, and LVEF significantly improved after ablation in all LVEF and NYHA class subgroups. High BNP levels, NHYA class, CHADS2 score, and structural heart disease, but not postablation recurrence, independently predicted death, and HF hospitalization on multivariate analysis. The patients with tachycardia‐induced cardiomyopathy had better recovery of BNP levels and LVEF after ablation than those with structural heart disease. Conclusions: Cryoballoon ablation for AF in HF patients is feasible and leads to significantly improved cardiac function. [ABSTRACT FROM AUTHOR]

Septal coronary artery fistula is a rare but concerning complication of left bundle branch area pacing (LBBAP). We report the case of an 82‐year‐old man who was indicated for cardiac resynchronization therapy and underwent LBBAP. The patient had no chest symptoms during or after implantation. Postoperative echocardiography demonstrated a new abnormal tunnel inside the interventricular septum (IVS) and shunt flow from the IVS toward the right ventricle. Coronary angiography confirmed a septal coronary artery fistula, which might have been formed by failed deep screw attempts. Since the shunt volume assessed by the Qp/Qs was small, the patient was treated conservatively. [ABSTRACT FROM AUTHOR]

Background: The current study aimed to evaluate changes in electrical depolarization and repolarization parameters after His-bundle pacing (HBP) compared with right ventricular pacing (RVP) and its association with ventricular arrhythmia (VA).Methods: Forty-one patients (13 with HBP, 14 with RVP, and 14 controls [AAI mode]) were evaluated. After continuous pacing algorithm, QRS duration, QT interval, QTc, JT interval, T-peak to T-end (Tpe), and Tpe/QT ratio were measured on electrocardiography at baseline and 1 week, 1 month, and 6 months postoperatively. We investigated VA occurrence and adverse events after implantation.Results: At 6 months, QRS duration was significantly shorter in the HBP (121.6 ± 15.6 ms) than in the RVP (150.1 ± 14.9 ms) group. The QT intervals were lower in the HBP (424.0 ± 40.9 ms) and control (405.9 ± 23.0 ms) groups than in the RVP (453.0 ± 40.2 ms) group. The Tpe and Tpe/QT ratios at 6 months differed significantly between the HBP and RVP groups (Tpe, 69.8 ± 19.7 ms vs 87.4 ± 11.9 ms and Tpe/QT, 0.16 ± 0.03 vs 0.19 ± 0.02, respectively). The Tpe and Tpe/QT ratios were similarly shortened in the HBP and control groups. VA occurred less frequently in the HBP (15%) and control (7.1%) groups than in the RVP (50%) group (p = 0.020). The non-RVP group showed significantly lower rates of VA and major adverse events than the RVP group. Patients with VA demonstrated significantly longer QRS duration, QT interval, Tpe, and Tpe/QT at 6 months than those without VA.Conclusion: HBP showed better depolarization and repolarization stability than RVP. [ABSTRACT FROM AUTHOR]

Introduction: Reactive atrial‐based antitachycardia pacing (rATP) in patients with cardiac implantable electronic devices (CIEDs) suppresses the progression of atrial fibrillation (AF) to the persistent form. However, the clinical factors associated with successful reactive atrial‐based antitachycardia pacing (rATP) treatment are unknown. This study aimed to examine the predictors of high rATP efficacy in patients with CIEDs. Methods: The data of 101,325 rATP‐treated atrial tachyarrhythmia (AT/AF) episodes in 51 patients, obtained through remote monitoring and device interrogation, were analyzed. The study population was divided into the high and low efficacy groups based on the overall median success rate of rATP. Clinical characteristics were compared between the two groups. Results: During a follow‐up period of 28.6 ± 8.6 months, the median success rate was 43.7% (31.5%–64.9%). The prevalence of a history of catheter ablation of AF was significantly higher in the high efficacy group than in the low efficacy group (73.0% vs. 44.0%, p =.048) and was the only independent predictor of high rATP efficacy (odds ratio, 3.45; p =.038). The rATP success rate in patients with (n = 30) and without (n = 21) a history of catheter ablation was 53.9% (40.0%–67.5%) and 36.4% (22.2%–47.7%), respectively (p =.012). The effect of rATP after ablation was more pronounced in patients with long cycle length episodes (≥75% of AT/AF sequences having a cycle length of 200–449 ms) (67.3% [46.0%–73.6%] vs. 30.6% [18.1%–60.3%], p =.027). The high efficacy group had a significantly lower incidence of AT/AF lasting ≥1, ≥7, and ≥30 days than the low efficacy group. Conclusion: rATP combined with catheter ablation therapy is effective in suppressing AT/AF. [ABSTRACT FROM AUTHOR]

Background: Permanent His‐bundle pacing (HBP) is effective and safe; however, the success rate of HBP is low, especially in patients with infranodal block. This study aimed to assess the efficacy and feasibility of HBP implantation using an electrophysiological guided approach targeting a distal His‐bundle electrogram (HBE) in patients with atrioventricular block (AVB). Methods: Thirty‐four consecutive patients with AVB (infranodal block in 28 patients) who underwent HBP were enrolled. During implantation, we attempted to target the distal part of the HBE (distal HBE) beyond the block site based on unipolar mapping. The His‐capture threshold was evaluated for 1 year after implantation. Results: HBP was achieved in 26 patients and in 21 patients (75%) with infranodal block. Detection of distal HBE was significantly higher in the successful HBP group than in the HBP failure group (65.4% vs. 0%, p =.001). Among 15 patients with intra‐Hisian block, 14 patients (93%) successfully achieved HBP with distal HBE detection. During the 1‐year follow‐up period, an increase in His‐capture threshold by ≥1.0 V at 1.0 ms occurred in five (19.2%) of 26 patients. The increased His‐capture threshold group exhibited significantly less detection of distal HBE (20% vs. 76.2%; odds ratio 0.078, 95% confidence interval 0.07–0.87, p =.038) and a higher His‐capture threshold at implantation (2.0 ± 1.1 V vs. 1.1 ± 0.9 V; odds ratio 1.702, 95% confidence interval 1.025–2.825, p = 0.04) than the non‐increased His‐capture threshold group. Conclusion: HBP implantation guided by distal HBE approach may be feasible with subsequent stable pacing in patients with intra‐Hisian and atrioventricular nodal block. [ABSTRACT FROM AUTHOR]

Introduction: With regard to short‐term outcome in atrial fibrillation (AF), the benefit of cryoballoon ablation (CBA) by pressing a balloon against the earliest pulmonary vein (PV) potential site during PV isolation (earliest potential [EP]‐guided CBA) has been previously demonstrated. The present study aimed to evaluate the long‐term outcome of the EP‐guided CBA. Methods and Results: This study included 136 patients from two randomized studies, who underwent CBA for paroxysmal AF for the first time. Patients were randomly assigned to the EP‐guided and conventional CBA groups in each study. In the EP‐guided CBA group, we pressed a balloon against the EP site when the time‐to‐isolation (TTI) after cryoapplication exceeded 60 and 45 s in the first and second studies, respectively. We compared the clinical outcomes for 1 year after the procedure between the EP‐guided CBA group (68 patients) and the conventional CBA group (68 patients). The primary endpoint was the recurrence of atrial arrhythmia after ablation. No significant differences in baseline characteristics were observed between the two groups. Compared with the conventional CBA group, the EP‐guided CBA group had a significantly higher success rate at TTI ≤ 90 s (98.5% vs. 90.0%, p <.001); lower touch‐up rate and total cryoapplication; and shorter procedure time, and fluoroscopy time. The recurrence at 1 year after ablation was significantly lower in the EP‐guided CBA group than in the conventional CBA group (6.0% vs. 19.4%; p =.019). Conclusions: The EP‐guided CBA approach can facilitate the ablation procedure and achieve low recurrence at 1 year after ablation. [ABSTRACT FROM AUTHOR]

Background: Many studies have reported the predictors of atrial fibrillation (AF) recurrence after persistent AF (peAF) ablation. However, the correlation between the atrial defibrillation threshold (DFT) for internal cardioversion (IC) and AF recurrence rate is unknown. Here we investigated the relationship between the DFT prior to catheter ablation for peAF and AF recurrence. Hypothesis: DFT prior to ablation was the predictive factor for AF recurrence after peAF ablation. Methods: From June 2016 to May 2019, we enrolled 82 consecutive patients (mean age, 65.0 ± 12.4 years), including 45 with peAF and 37 with long‐standing peAF, at Hamamatsu Medical Center. To assess the DFT, we performed IC with gradually increasing energy prior to radiofrequency application. Results: Forty‐nine and 33 patients showed DFT values less than or equal to 10 J (group A) and greater than 10 J or unsuccessful defibrillation (group B). During the mean follow‐up duration of 20.5 ± 13.1 months, patients in group B showed significantly higher AF recurrence rates than those in group A after the ablation procedure (p =.017). Multivariate analysis revealed that DFT was the only predictive factor for AF recurrence (odds ratio, 1.07; 95% CI, 1.00–1.13, p =.047). Conclusions: The DFT for IC was among the strongest prognostic factors in the peAF ablation procedure. [ABSTRACT FROM AUTHOR]

Background: Catheter ablation improves physical activity in patients with atrial fibrillation (AF). However, continuous daily evaluation and time course of improvement in physical activity after ablation have not been fully assessed. This prospective study was conducted to evaluate the daily physical activities and changes in the physical performance in patients undergoing catheter ablation for AF by continuous monitoring of a portable accelerometer. Methods: Ten patients scheduled for catheter ablation for AF were fitted with a uniaxial accelerometer prior to and 6 months after the procedure. This study evaluated changes in daily steps, activity intensity, and activity duration. We also evaluated changes in activity intensity using a short version of the International Physical Activity Questionnaire (IPAQ). Results: The maximum daily steps significantly increased from baseline to postablation (baseline, 9,232 [6,716–11,485]; after 1–3 months, 11,605 [8,285–14,802]; and after 4–6 months, 11,412 [8,939–13,808], p =.020). Similarly, Δ maximum‐mean daily steps increased significantly (baseline, 2,431 [1,199–6,181]; after 1–3 months, 4,674 [4,164–6,474]; and after 4–6 months, 4,871 [3,657–6,117], p =.014). These improvements were more pronounced in patients with paroxysmal and symptomatic AF. The total IPAQ score significantly improved from baseline to after 6 months ablation (from 1,170 [693–3,930] to 4,312 [1,865–6,569], p =.037). All patients were recurrence‐free from AF after ablation. Conclusions: The physical activity improved significantly even in the early phase following catheter ablation. The effect of suppressing AF on activity levels was apparent soon after the procedure. [ABSTRACT FROM AUTHOR]

A first‐line cryoablation for para‐Hisian VAs using a strict cryomapping protocol is useful and safe, even if the His bundle potential is recorded on the ablation catheter. [ABSTRACT FROM AUTHOR]

Evaluations of His bundle pacing (HBP) lead location at autopsy examination have been rarely reported. We report an autopsy case of a 98‐year‐old man who underwent HBP implantation due to atrioventricular block and heart failure. Although selective HBP was achieved with an acceptable threshold, the stimulus‐to‐QRS interval was relatively longer without correction of the right bundle‐branch block. A macroscopic examination revealed that the HBP lead was inserted on the ventricular side passing through the anteroseptal commissure of the tricuspid valve. Transthyretin cardiac amyloidosis may affect the distal conduction system resulting in a long stimulus‐to‐QRS interval during selective HBP. [ABSTRACT FROM AUTHOR]

Background: The mechanisms involved in changes in P wave following catheter ablation for atrial fibrillation (AF) are uncertain. This study aimed to assess the relationship between changes in P-wave morphology and pulmonary vein (PV) reconnection following ablation by the assessment of 12-lead surface electrocardiogram and signal-averaged electrocardiogram.Methods: This retrospective study included 115 consecutive patients with paroxysmal AF that underwent repeat ablation for recurrence following initial ablation. We investigated changes in P-wave morphology between baseline and repeat procedure in patients with and without PV reconnection. The study also included as validation group without recurrence (n = 67) following initial ablation.Results: The maximum P-wave duration (PWD) was significantly decreased from baseline to just after the procedure in all groups. However, for the PV reconnection group (n = 100), the maximum PWD was significantly increased again at the repeat procedure. In contrast, the maximum PWD was significantly reduced between baseline and repeat procedure in the non-PV reconnection group (n = 15). The signal-averaged PWD was significantly decreased from baseline to repeat procedure in the non-PV reconnection group, but, conversely, was increased in the PV reconnection group. In the non-PV reconnection group, the disappearance of notched P wave was detected in 8 of 15 patients (53%), which was significantly higher than in other groups (p = .001). A new or delayed notched P wave was identified in the PV reconnection group only. These results were confirmed in the validation group.Conclusions: The reverse dynamics of PWD after initial shortening directly following ablation were significantly associated with PV reconnection. [ABSTRACT FROM AUTHOR]

Background: His bundle pacing (HBP) is a recently developed pacing technique that can achieve an ideal physiological pattern of ventricular activation via stimulation of the native His‐Purkinje system. Despite the widespread introduction of HBP in clinical practice, its appropriate indications are yet to be determined clearly. Moreover, the efficacy and safety of HBP and long‐term prognosis of patients undergoing such are unknown. Methods: We conducted a multicenter observational prospective study in patients undergoing HBP in Japan. Patients with atrioventricular block or conduction delay and estimated ventricular pacing of ≥ 40% scheduled for HBP implantation are included. All patients are followed up until 3 years after the implantation. The primary endpoints are all‐cause death, heart failure‐related hospitalization, and upgrade to cardiac resynchronization therapy. The secondary endpoint is changes in cardiac function based on echocardiographic findings and laboratory data after the implantation. Results: The results are currently under investigation. Conclusions: This multicenter observational study evaluates the long‐term prognosis and changes in cardiac function of patients undergoing HBP implantation in a clinical setting. Considering the large number of patients included, the cumulative results would be helpful in establishing evidence on HBP application in this area and consequently allow accurate management and treatment of patients undergoing HBP. [ABSTRACT FROM AUTHOR]

Introduction: Cardiac memory is recognized as altered T‐waves when the sinus rhythm resumes after an abnormal myocardial activation period that recovers slowly over several weeks. The T‐wave changes after ablation of frequent premature ventricular contractions (PVCs) as cardiac memory was not known. Objective: This study identified whether cardiac memory exists after successful ablation of PVCs from the right ventricular outflow tract (RVOT). Methods: We investigated 45 patients who underwent successful ablation of PVCs from RVOT and 10 patients who underwent unsuccessful ablation. We analyzed the amplitude of the T‐wave, QT intervals, and QRST time‐integral values of a 12‐lead electrocardiogram before ablation and 1 day, 3 days, and 1 month after ablation. Results: In the successful ablation group, the amplitude of the T‐wave and QRST time‐integral values of lead II, III, aVR, aVL, and aVF significantly changed after ablation and gradually normalized within 1 month. In addition, if the number of pre‐ablation PVCs was small, then the corresponding impact was also small. However, the greater the number of pre‐ablation PVCs, the more prominent the changes. Significant changes were not observed in the unsuccessful ablation group. Conclusion: When ablation of PVCs from RVOT was successful, primary T‐wave changes because of cardiac memory and the gradual normalization of the amplitude of the T‐wave were observed. No significant T‐wave changes were detected after unsuccessful ablation. [ABSTRACT FROM AUTHOR]

Background: Cardiac resynchronization therapy (CRT) improves the morbidity and mortality rate in patients with left bundle‐branch block (LBBB); however, some LBBB patients are non‐responders for CRT. Previous studies have shown that a transmural functional line block alters the left ventricular (LV) activation sequence, and that the presence of a line block is predictive for responders. We investigated whether responders could be predicted in patients with LBBB by 2‐dimensional (2‐D) speckle tracking strain imaging. Methods: We enrolled 54 patients with LBBB, who underwent echocardiography before and 6 months after CRT implantation. A responder was defined by a decrease in the LV end‐systolic volume >15% at the 6‐month follow‐up. We calculated a difference in the time from QRS onset to maximum strain between adjacent segments and defined the Tmax‐diff as the maximum difference among six intersegments. We compared the Tmax‐diff between responders and non‐responders. Results: Among 54 patients, 37 patients were identified as responders. The Tmax‐diff of the responders was significantly longer than that of the non‐responders (309.6 ± 168.6 ms vs 181.5 ± 138.4 ms, P = .009). Furthermore, Tmax‐diff ≥ 195 ms was higher in the septal and the anterior area. And patients with a Tmax‐diff ≥ 195 ms tended to be responders (P = .02). Conclusion: The present study showed that discontinuous contraction of the LV could be detected in CRT responders by 2‐D speckle tracking strain imaging, which may be a useful tool to identify the contraction pattern of patients with LBBB and predict CRT responders. [ABSTRACT FROM AUTHOR]

Introduction: Patients with advanced heart failure and dyssynchrony can benefit from cardiac resynchronization therapy (CRT). To predict the response to CRT, myocardial viability and improved dyssynchrony are suggested to be important. Methods: We retrospectively investigated 93 patients who underwent CRT implantation in Nagoya University Hospital. We assessed QRS narrowing the day after implantation to measure the improvement in dyssynchrony and measured the left ventricular pacing threshold (LVPT) to determine the local myocardial viability in all patients. Responders to CRT were defined as those having a greater than or equal to 15% decrease in left ventricular end‐systolic volume by echocardiography at their 6‐month follow‐up. Results: Sixty‐two patients (67%) were classified as responders. The QRS width before CRT implantation, QRS narrowing after implantation, left atrial diameter, septal‐to‐posterior wall motion delay, left ventricular end‐diastolic diameter, radial strain, and LVPT were significantly different between the responder and nonresponder groups. On multivariate analysis, QRS narrowing (odds ratio [OR], 1.03; 95% confidence interval [CI], 1.01‐1.05; P = 0.005) and LVPT (OR, 0.42; 95% CI, 0.22‐0.82; P = 0.011) were independent predictors of a response to CRT. We calculated the cutoff values from the receiver operating characteristic curves as 22.5 milliseconds of QRS narrowing and 1.55 V of LVPT. The response rates in patients with both predictive factors (QRS narrowing ≥ 22.5 milliseconds and LVPT ≤ 1.55 V), one factor, and no factors were 91%, 61%, and 25%, respectively (P < 0.001). Conclusion: Both myocardial viability and improved electrical dyssynchrony may be essential to predict a good response to CRT. [ABSTRACT FROM AUTHOR]

Abstract: Background: There are limited data on uninterrupted anticoagulation with direct oral anticoagulants during catheter ablation for atrial fibrillation (AF), particularly in Japan. We planned a subgroup analysis of the RE‐CIRCUIT study, comparing the use of uninterrupted dabigatran therapy with warfarin therapy during catheter ablation among the Japanese subgroup and with that in the total population. Methods: The RE‐CIRCUIT study utilized a prospective, randomized, open‐label, blinded endpoint design, and the primary endpoint was the incidence of major bleeding events (MBEs). Patients were randomized to uninterrupted dabigatran 150 mg twice daily or warfarin. In this study, we analyzed the results in Japanese patients. Results: Of 704 enrolled patients in the study, 112 Japanese patients were randomized to dabigatran (n = 65) or warfarin (n = 47). MBEs were experienced by two patients: one in the dabigatran group (1.6%, cardiac tamponade) and one in the warfarin group (2.2%, groin hematoma) (risk difference vs warfarin −0.6%; 95% CI −5.8, 4.7). Within the Japanese subgroup, there were no thromboembolic events in both groups. Conclusion: While not designed to show statistical difference between two treatment groups, our results from the Japanese subgroup supported those from the overall population. Furthermore, this study provided clinical information regarding MBE, especially cardiac tamponade, in Japanese patients. [ABSTRACT FROM AUTHOR]

Abstract: Background: Cryoballoon (CB) applications to pulmonary veins (PVs) can cause stenosis just as radiofrequency (RF) energy deliveries. The goal of the present study was to clarify whether or not there was any difference in the extent of acute or chronic PV narrowing after PV isolation between the two different energy sources. Methods: Consecutive patients with paroxysmal atrial fibrillation who were scheduled to undergo a PV isolation were randomized 1:1 to receive CB or RF ablation. The endpoints were any acute PV narrowing assessed with the use of intracardiac ultrasound during the procedure and PV stenosis measured with cardiac computed tomography at the 3‐month follow‐up. Results: An acute reduction in the luminal area of the left superior PV (mean ± standard deviation, –6.8 ± 8.7 vs –19.9 ± 14.7%; P < 0.001) and left inferior PV (–5.1 ± 20.2 vs –15.3 ± 11.6%; P = 0.03) was significantly smaller in the CB arm (N = 25) than the RF arm (N = 25). There was no difference in the extent of PV stenosis 3 months after the ablation between the arms (0–25% stenosis, 90% vs 88%, 25–50% stenosis, 10% vs 12%, >50% stenosis, both 0%; P = 0.82). A greater acute PV narrowing was likely to lead to chronic stenosis in the RF arm (P = 0.004). Conclusions: CB ablation may reduce the acute narrowing of the left‐sided PVs as compared to RF ablation. [ABSTRACT FROM AUTHOR]

Background Mechanism and effects of vagal response (VR) during cryoballoon ablation procedure on the cardiac autonomic nervous system (ANS) are unclear. The present study aimed to evaluate the relationship between VR during cryoballoon catheter ablation for atrial fibrillation and ANS modulation by evaluating epicardial adipose tissue (EAT) locations and heart rate variability (HRV) analysis. Methods Forty-one patients with paroxysmal atrial fibrillation (11 with VR during the procedure and 30 without VR) who underwent second-generation cryoballoon ablation were included. EAT locations and changes in HRV parameters were compared between the VR and non-VR groups, using Holter monitoring before ablation, immediately after ablation and one month after ablation. Results The total EAT volume surrounding the left atrium (LA) in the VR and non-VR groups was 29.0±18.4 cm 3 vs 27.7±19.7 cm 3 , respectively ( p =0.847). The VR group exhibited greater EAT volume overlaying the LA-left superior pulmonary vein (PV) junction (6.1±3.6 cm 3 vs 3.6±3.3 cm 3 , p =0.039) than the non-VR group. HRV parameters similarly changed following ablation in both the groups. EAT volume overlaying LA-right superior PV junction was significantly correlated with the relative changes in root-mean-square successive differences ( r =−0.317, p =0.043) and high frequency ( r =−0.331, p =0.034), immediately after the ablation. Conclusions Changes in HRV parameters following ablation were similarly observed in both the groups. EAT volume on the LA-PV junction is helpful for interpretation of VR occurrence and ANS modulation. [ABSTRACT FROM AUTHOR]

The article presents a case of a 76-year-old female who underwent pacemaker implantation for His bundle pacing and experienced palpitation following the procedure. She is suffering from frequent syncope because of temporal complete atrioventricular (AV) block. Her electrocardiography showed accelerated junctional rhythm. After one month, her accelerated junctional rhythm dissipated and her palpitation was suppressed.

Background Although several prognostic factors of atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI) have been investigated, the accurate prediction of AF recurrence remains difficult. We propose an electrocardiogram (ECG) index, the P-wave force (PWF), which is the product of the amplitude of the negative terminal phase of the P wave in the V1 electrode and the filtered P-wave duration, obtained by a signal-averaged P-wave analysis. This study was conducted to evaluate the impact of the PWF on the recurrence of AF after PVI. Methods We retrospectively evaluated 79 paroxysmal AF patients (64 ± 9 years, 56 males) who underwent PVI by cryoballoon ablation. Standard 12-lead ECG and a P-wave signal-averaged electrocardiogram (SAECG) were recorded the day before and 1 month after the PVI procedure. Results During the mean follow-up of 10.2 months, AF recurred in 11 (14%) patients. The PWF 1 month after ablation was significantly higher in the recurrence group compared to that in the nonrecurrence group (8.8 ± 3.1 mVms vs 6.5 ± 2.9 mVms, P = 0.017). The patients with a PWF value ≥9.3 mVms had a significantly greater risk of recurrence after the ablation compared to the patients with a PWF value <9.3 mVms (log-rank test, P < 0.001). Conclusion Higher PWF after cryoballoon ablation was associated with poor prognosis during follow-up. The PWF may be a useful and noninvasive marker to predict the recurrence of AF. [ABSTRACT FROM AUTHOR]

Background Little is known about the association between B-type natriuretic peptide (BNP) levels and catheter ablation of atrial fibrillation (AF) in patients with heart failure. This study aimed to examine the impact of elimination of AF by catheter ablation on BNP levels in patients with left ventricular systolic dysfunction. Methods Fifty-four AF patients with left ventricular ejection fraction (LVEF) ≤ 50%, who underwent radiofrequency catheter ablation therapy of AF, were included. BNP sampling was performed at baseline, 3 days, and 1 month after ablation. Results After a follow-up period of 6 months, the BNP levels decreased significantly in the nonrecurrence group (n = 35; median 126.3 [interquartile 57.2-206.5] pg/mL, 63.5 [23.9-180.2] pg/mL, and 45.9 [21.9-160.3] pg/mL, P < 0.001, respectively), but not in the recurrence group (n = 19; 144.7 [87.1-217.3] pg/mL, 88.8 [12.9-213.2] pg/mL, and 118.5 [51.6-298.2] pg/mL, P = 0.368, respectively). The patients in the nonrecurrence group had a higher percentage relative reduction in BNP levels from baseline to 1 month after ablation than those in the recurrence group (56.5 [−9.0-77.4]% vs −2.4 [−47.1-60.9]%, P = 0.027). Additionally, a relative reduction in BNP levels significantly correlated with an increase in LVEF after ablation (r = 0.486, P < 0.001). Conclusions Plasma BNP levels decreased significantly with successful catheter ablation of AF in patients with impaired LVEF. The decrease in BNP levels might be associated with early recovery of cardiac function and subsequent maintenance of sinus rhythm at follow-up. [ABSTRACT FROM AUTHOR]

Introduction Apixaban, a factor Xa (FXa) inhibitor, is a new oral anticoagulant for stroke prevention in atrial fibrillation (AF). However, little is known about its efficacy and safety as a periprocedural anticoagulant therapy for patients who had undergone catheter ablation (CA) for AF. Methods and Results We evaluated 342 consecutive patients who underwent CA for AF between April 2013 and March 2014 and received apixaban (n = 105) and warfarin (n = 237) for uninterrupted periprocedural anticoagulation. We retrospectively investigated the occurrence of bleeding and thromboembolic complications during the procedural period and compared them between the apixaban group (AG) and warfarin group (WG). Thromboembolic complications occurred in one (0.4%) patient in the WG. Major and minor bleeding complications occurred in one (1%) and four (4%) patients in the AG, and three (1%) and 12 (5%) patients in the WG. No significant difference in complications was observed between the AG and WG. Of importance, adverse event rates did not differ between the two groups after adjusting by a propensity score analysis. In preoperative tests of blood coagulation, there were significant differences in the prothrombin time, activated partial thromboplastin time, FXa activity, and prothrombin fragment 1 + 2 (F1+2) levels between the AG and WG. Conclusion The use of apixaban during the periprocedural period of AF ablation seemed as efficacious and safe as warfarin. [ABSTRACT FROM AUTHOR]

Background Several algorithms for localizing accessory pathways (APs) are based on the delta wave morphology, R/S ratio, and QRS polarity. However, they are somewhat complicated, and an accurate determination of the delta wave morphology is occasionally difficult. The aims of this study were to develop a simple algorithm for localizing APs using only the R/S ratio, and to test the accuracy of the algorithm prospectively. Methods We studied 142 patients with a single anterogradely conducting AP on a 12-lead ECG. R/S ratios were analyzed in leads V1, V2, and aVF (R/S-V1, R/S-V2, and R/S-aVF). AP locations were divided into five regions based on fluoroscopic anatomy. Results A new algorithm was developed by correlating R/S-V1, R/S-V2, and R/S-aVF with successful ablation sites in 88 initial consecutive patients. All 55 patients with left free wall APs showed R/S-V1 ≥0.5, and 47 (98%) of 48 patients with left anterior or lateral APs showed R/S-aVF ≥1. In contrast, all seven patients with left posterolateral or posterior APs showed R/S-aVF <1. All nine patients with right-and-left midseptal or posteroseptal APs showed R/S-V1 <0.5 and R/S-V2 ≥0.5. Of 12 patients with right anterior, lateral or anteroseptal APs, 10 (83%) showed R/S-V1 <0.5, R/S-V2 <0.5 and R/S-aVF ≥1. Finally, nine (75%) of 12 patients with right posterolateral or posterior APs showed R/S-V1 <0.5, R/S-V2 <0.5, and R/S-aVF <1. Then this algorithm was tested prospectively in 54 patients. Overall, the sensitivity was 94%, and the specificity was 98%. Conclusions This ECG algorithm provides a simple and accurate way to identify the AP localization. [ABSTRACT FROM AUTHOR]

Background Patients with greater improvement of cardiac function after cardiac resynchronization therapy (CRT) implantation are identified as 'super-responders.' However, it remains unclear which kind of preimplant assessments could accurately predict outcomes after CRT. Thus, we aimed to examine the essential predicting factors for super-response to CRT, and to construct an accurate predictable model. Methods We retrospectively analyzed the CRT patients who underwent implantation at Nagoya University Hospital. Super-responders are defined as those who show a relative reduction in left ventricular end-systolic volume ≥30% after 6 months of CRT. Results Eighty patients (mean age, 67.8 ± 10.2 years) were included. Twenty-two patients received upgrading procedure to CRT implantation. Six months after the implantation, 29 patients (36%) were super-responders. Multiple logistic regression analysis shows that consistent right ventricular pacing with a previous device (odds ratio [OR] 7.28, 95% confidence interval [CI] 1.52-34.9; P = 0.013), lack of prior history of ventricular arrhythmia (OR 5.32, 95% CI 1.52-18.6; P = 0.009), and smaller left atrial diameter (LAD) (OR 0.92, 95% CI 0.86-0.98; P = 0.014) are independent predictors for CRT super-responders. The use of a combination of these predictive factors could increase the certainty with which a greater response to CRT is predicted and the presence of such a combination could improve prognosis. Conclusion Greater response to biventricular pacing occurs more frequently in patients with consistent right ventricular pacing, lack of prior history of ventricular arrhythmia, and smaller LAD. An association between patient background characteristics and a super-response to CRT was also identified. [ABSTRACT FROM AUTHOR]

Background Cardiac resynchronization therapy (CRT) improves cardiac function, but CRT recipients with advanced heart failure (HF) do not always respond well. Because the best parameters for the prediction of CRT response are not established, we investigated whether improvement of invasive left ventricular (LV) hemodynamic diastolic parameters could identify CRT responders. Methods A total of 34 consecutive patients (age, 69 ± 9 years; 70% men) who received CRT devices for HF were assessed as to whether acute invasive hemodynamic parameters with and without CRT function could predict LV volume responders. Results These patients demonstrated an improvement in LV dP/dtmax (11.1 ± 11.7%), LV dP/dtmin (4.6 ± 12.1%), and tau (3.7 ± 11.6%) by biventricular pacing. Nineteen patients (55%) were classified as CRT responders, which was defined by a >15% decrease in LV end-systolic volume (ESV) at the 6-month follow-up evaluation. The area under the receiver operator characteristic curve to detect CRT volume response was 0.93 for the shortening of tau, which was superior to any other hemodynamic parameter. The multivariate analysis revealed that this improvement in tau was the strongest predictive factor for identifying CRT volume responders. Of note, the magnitude of tau shortening during biventricular pacing was significantly correlated with the reduction in LVESV at the 6-month follow-up evaluation. Conclusions The extent of acute improvement in LV isovolumic relaxation time, as assessed by tau, was associated with favorable response to CRT. The assessment of invasive diastolic function could provide valuable information about CRT volume response. [ABSTRACT FROM AUTHOR]

V2S/V3R Index Distinguishes LVOT from RVOT Origins Introduction Although several ECG criteria have been proposed for differentiating between left and right origins of idiopathic ventricular arrhythmias (VA) originating from the outflow tract (OT-VA), their accuracy and usefulness remain limited. This study was undertaken to develop a more accurate and useful ECG criterion for differentiating between left and right OT-VA origins. Methods and Results We studied OT-VAs with a left bundle branch block pattern and inferior axis QRS morphology in 207 patients who underwent successful catheter ablation in the right (RVOT; n = 154) or left ventricular outflow tract (LVOT; n = 53). The surface ECGs during the OT-VAs and during sinus beats were analyzed with an electronic caliper. The V2S/V3R index was defined as the S-wave amplitude in lead V2 divided by the R-wave amplitude in lead V3 during the OT-VA. The V2S/V3R index was significantly smaller for LVOT origins than RVOT origins (P < 0.001). The area under the curve (AUC) for the V2S/V3R index by a receiver operating characteristic analysis was 0.964, with a cut-off value of ≤1.5 predicting an LVOT origin with an 89% sensitivity and 94% specificity. In the AUC and accuracy, the V2S/V3R index was superior to any previously proposed ECG criteria in an analysis of all OT-VAs. This advantage of the V2S/V3R index over the V2 transition ratio and other indices also held true for a subanalysis of 77 OT-VAs with a lead V3 precordial transition. Conclusion The V2S/V3R index outperformed other ECG criteria to differentiate left from right OT-VA origins independent of the site of the precordial transition. [ABSTRACT FROM AUTHOR]

Background We aimed to evaluate the feasibility of an oral direct thrombin inhibitor, dabigatran, as a periprocedural anticoagulant for use with ablation of atrial fibrillation (AF). Methods Consecutive patients scheduled to undergo an AF ablation were randomly assigned to receive dabigatran (n = 45) or warfarin (n = 45) to compare their clinical feasibility. Both of those oral anticoagulants were discontinued the day before the ablation and were resumed after confirming hemostasis of the venipuncture site. A bridging therapy with heparin was not used in either of the patient groups. Results Dabigatran was switched to warfarin before the ablation because of dyspepsia in three patients. An occurrence of rebleeding from the venipuncture site was less common in dabigatran-allocated patients than in warfarin-allocated patients (20% vs 44%; P = 0.013). The reduction in the D-dimer level after the initiation of oral anticoagulants was greater in the dabigatran-allocated patients than in the warfarin-allocated patients. The time from the initiation of the anticoagulants to the ablation was significantly shorter in the dabigatran-allocated patients than in the warfarin-allocated patients (43 ± 7 vs 63 ± 13 days; P < 0.0001). There was only one fatal periprocedural complication in a patient receiving warfarin, who had a mesenteric arterial thrombosis after the ablation. Conclusions An anticoagulation strategy with dabigatran may surpass that with warfarin in reducing both the periprocedural risk of minor bleeding and a hypercoagulable state, and the time to ablation in patients undergoing ablation of AF. [ABSTRACT FROM AUTHOR]

Background: The pacing lead system is electrically evaluated by a pacing system analyzer (PSA) during device implantation. However, it remains unknown whether measured data vary according to the PSA or the implantable device. We estimated differences in lead impedance measured by different PSAs and devices using a laboratory model. Methods: Five pacing and 3 defibrillation leads were used. We fixed the lead tip to a piece of meat immersed in physiologic saline and measured lead impedance using 4 PSA and 13 implantable device models. Results: The mean impedance of the 5 pacing leads as measured by PSAs was 735 to 611 ohms and the difference between the maximum and minimum values was 126 ohm. The maximum difference according to PSAs was 222 ohm. The mean impedance of the 5 pacing leads as measured by the implantable generators was 770 to 606 ohms, the difference was 175 ohms and the maximum difference was 309 ohms. The 3 defibrillation lead impedances varied from 427 to 1091 ohms and the mean impedance was 706 to 557 ohms. The differences were 149 ohm as measured by the PSAs and 157 ohms by the implantable cardioverter defibrillator (ICD) generators. The maximum differences were 241 ohms by the PSAs and 281 ohms by the ICD generators. Conclusion: Lead impedance varied according to analyzing systems. [Copyright &y& Elsevier]

IVT Arising Adjacent to the Left Sinus of Valsalva. Background: Idiopathic ventricular arrhythmias (VAs) may be amenable to catheter ablation within or adjacent to the left sinus of Valsalva (LSOV). However, features that discriminate these sites have not been defined. The purpose of this study was to determine the electrocardiographic and electrophysiological features of VAs originating within or adjacent to the LSOV. Methods and Results: We studied 48 consecutive patients undergoing successful catheter ablation of idiopathic VAs originating from the left coronary cusp (LCC, n = 29), aortomitral continuity (AMC, n = 10) and great cardiac vein or anterior interventricular cardiac vein (Epi, n = 9). A small r wave, or rarely an R wave, was typically observed in lead I during the VAs and pacing in these regions. An S wave in lead V5 or V6 occurred significantly more often during both the VAs and pacing from the AMC than during that from the LCC and Epi (p < 0.05 to 0.0001). For discriminating whether VA origins can be ablated endocardially or epicardially, the maximum deflection index (MDI = the shortest time to the maximum deflection in any precordial lead/QRS duration) was reliable for VAs arising from the AMC (100%), but was less reliable for LCC (73%) and Epi (67%) VAs. In 3 (33%) of the Epi VAs, the site of an excellent pace map was located transmurally opposite to the successful ablation site (LCC = 1 and AMC = 2). Conclusions: The MDI has limited value for discriminating endocardial from epicardial VA origins in sites adjacent to the LSOV probably due to preferential conduction, intramural VA origins or myocardium in contact with the LCC. (J Cardiovasc Electrophysiol, Vol. 21, pp. 170-176, February 2010) [ABSTRACT FROM AUTHOR]

A 65-year-old man with frequent premature ventricular contractions (PVCs) underwent electrophysiological testing. Although an excellent pace map was obtained from the right coronary cusp (RCC), radiofrequency ablation at that site interrupted the PVCs transiently. Successful ablation was achieved in the left coronary cusp with earlier local ventricular activation during the PVCs than that in the RCC. These findings suggest that preferential conduction within the aortic root may exist and cause ventricular arrhythmias (VAs) arising from this region to exhibit variable electrocardiographic features, thereby limiting the reliability of electrocardiographic algorithms and pace mapping to predict the site of the VA origin. (PACE 2010; e10–e13) [ABSTRACT FROM AUTHOR]

Idiopathic VAs Originating from the LV Papillary Muscles. Introduction: Idiopathic ventricular arrhythmias (VAs) can originate from the left ventricular (LV) papillary muscles (PAMs). This study investigated the prevalence, electrocardiographic and electrophysiological characteristics, and results of catheter ablation of these VAs, and compared them with other LV VAs. Methods and Results: We studied 71 patients with VAs originating from the LV anterolateral and posteroseptal regions among 159 patients undergoing successful catheter ablation of idiopathic LV VAs. PAM VAs were uncommon, rare in a sustained form, and more common from the posterior papillary muscle (PPM) than anterior papillary muscle (APM). A younger age was a good predictor for differentiating left posterior fascicular VAs from PPM VAs. There were several electrocardiographic features that accurately differentiated PAM and LV fascicular VAs from mitral annular VAs. However, an R/S ratio ≤1 in lead V6 in the LV anterolateral region and a QRS duration >160 ms in the LV posteroseptal region were the only reliable predictors for differentiating PAM VAs from LV fascicular VAs. A sharp ventricular prepotential was recorded at the successful ablation site during 42% of the PAM VAs. Radiofrequency current with an irrigated or conventional 8-mm tip ablation catheter was required to achieve a lasting ablation of the PAM VA origins whereas that with a nonirrigated 4-mm tip ablation catheter produced excellent results in LV fascicular and mitral annular VAs. Conclusions: There are differences in the electrocardiographic and electrophysiological features among VAs originating from these regions that are helpful for their diagnosis and effective catheter ablation. (J Cardiovasc Electrophysiol, Vol. 21, pp. 62–69, January 2010) [ABSTRACT FROM AUTHOR]

Introduction: Focal ventricular arrhythmias (VAs) have been reported to arise from the posterior papillary muscle in the left ventricle (LV). We report a distinct subgroup of idiopathic VAs arising from the anterior papillary muscle (APM) in the LV. Methods and Results: We studied 432 consecutive patients undergoing catheter ablation for VAs based on a focal mechanism. Six patients were identified with ventricular tachycardia (VT, n = 1) or premature ventricular contractions (PVCs, n = 5) with the earliest site of ventricular activation localized to the base (n = 3) or middle portion (n = 3) of the LV APM. No Purkinje potentials were recorded at the ablation site during sinus rhythm or the VAs. All patients had a normal baseline electrocardiogram and normal LV systolic function. The VAs exhibited a right bundle branch block (RBBB) and right inferior axis (RIA) QRS morphology in all patients. Oral verapamil and/or Na+ channel blockers failed to control the VAs in 4 patients. VT was not inducible by programmed electrical stimulation in any of the patients. In 4 patients, radiofrequency current with an irrigated or conventional 8-mm-tip ablation catheter was required to achieve a lasting success. Two patients had recurrent PVCs after a conventional radiofrequency ablation with a 4-mm-tip ablation catheter had initially suppressed the arrhythmia. Conclusions: VAs may arise from the base or middle portion of the APM and are characterized by an RBBB and RIA QRS morphology and focal mechanism. Catheter ablation of APM VAs is typically challenging, and creation of a deep radiofrequency lesion may be necessary for long-term success. [ABSTRACT FROM AUTHOR]

Background: Pulmonary vein (PV) isolation (PVI) has been demonstrated to be an effective technique for curing atrial fibrillation (AF). AF foci that cannot be isolated by PVI (non-PV foci) can become the cause of AF recurrence. The purpose of this study was to investigate the characteristics of non-PV AF foci. Methods and Results: Two hundred consecutive patients with symptomatic AF underwent electrophysiologic studies. In all patients, successful ostial or antral PVI was achieved with a multielectrode basket catheter (MBC). In 45 patients, spontaneous AF was induced even after PVI. In 23 of those patients, 30 AF foci were found in the left atrium (LA) (12 in the PV antrum, and 18 in the LA wall). Twenty-six of those foci were eliminated by focal ablation guided by an MBC. Five of those foci (four in the PV antrum and one in the LA posterior wall) were speculated to be located epicardially because a small potential preceding the LA potential was recorded from the MBC electrodes during AF initiation at the successful ablation site where single large potentials were recorded during sinus rhythm and a longer duration of radiofrequency energy delivery was needed to eliminate them. Conclusions: MBC mapping with induction of spontaneous AF may be useful for identifying non-PV AF foci in the LA after PVI. In some of those non-PV foci, mainly around the PVI lesions, a few electrophysiologic findings suggesting an epicardial location were observed. This may be a rationale for the efficacy of extensive PV ablation [ABSTRACT FROM AUTHOR]

Electrical isolation of the pulmonary veins (PV) has become a curative treatment for patients with atrial fibrillation (AF). Recently, there have been many reports that circumferential PV isolation (CPI) on the atrial side has a better outcome than segmental ostial PV isolation (SOPI). However, reports on the combination of CPI using electoroanatomic mapping and SOPI using a circular mapping catheter have been few. The aim of the present study was to investigate the efficacy and safety of a combined therapy using CPI and supplemental SOPI for the treatment of AF. We performed CPI in 120 patients with drugrefractory AF. In 27 of those patients CPI resulted in a disconnection between the left atrium (LA) and PVs. In the remaining patients, supplemental SOPI completed the LA-PV disconnection. After an average follow-up period of 10.4 months, 81.7%, 90.5% and 71.4% of the patients with paroxysmal, persistent and chronic AF, respectively, have been free of AF. In 14.1% of the patients with paroxysmal AF, a greatly reduced frequency and/or duration of the episodes of AF were observed after the ablation. No fatal complications were encountered. The present results suggest that the combination of CPI and supplemental SOPI is efficient and safe for the treatment of AF. [Copyright &y& Elsevier]