Mid-term outcomes of delivery catheter-based and stylet-based right ventricular septal pacing: Follow-up results from a multicenter, prospective, randomized study.

Background: The Mt FUJI study was a multicenter, prospective, randomized, single-blind, controlled trial comparing delivery catheter-based and stylet-based right ventricular (RV) lead placement at the RV septum. This study extended the follow-up duration to 1 year after implantation. Methods: Seventy patients with pacemaker indications for atrioventricular block were randomly assigned to the delivery catheter and stylet groups. We compared the mid-term efficacy and safety between the two groups at 1 year after implantation. The primary outcome was the change in the left ventricular ejection fraction (LVEF), and the secondary outcomes were changes in brain natriuretic peptide (BNP) levels, lead parameters, paced QRS duration, and the incidence of adverse events. Results: At the 1-year follow-up, no significant differences were observed in the changes in the LVEF (+1.0% ± 8.6% vs. +3.1% ± 8.1%, p = .332), BNP levels (+8.0 [-11.1, 26.5] pg/mL vs. -8.7 [-15.3, 13.2] pg/mL, p = .193), or lead performance between the delivery catheter and stylet groups. The QRS duration was significantly shorter in the delivery catheter group than in the stylet group (128 ± 23 ms vs. 146 ± 17 ms, p < .001). All-cause death, hospitalization for heart failure, new development of atrial fibrillation, and pacing-induced cardiomyopathy occurred in seven patients in the delivery catheter group and five in the stylet group. Conclusion: The delivery catheter system was similarly useful and safe compared to the stylet system in the mid-term follow-up from the Mt FUJI trial. Further long-term evaluations are warranted.

Delivery catheter system carries more physiological right ventricular septal pacing than stylet system.

INTRODUCTION: The Mt. FUJI multicenter trial demonstrated that a delivery catheter system had a higher rate of successful right ventricular (RV) lead deployment on the RV septum (RVS) than a conventional stylet system. In this subanalysis of the Mt. FUJI trial, we assessed the differences in electrocardiogram (ECG) parameters during RV pacing between a delivery catheter system and a stylet system and their associations with the lead tip positions. METHODS: Among 70 patients enrolled in the Mt FUJI trial, ECG parameters, RV lead tip positions, and lead depth inside the septum assessed by computed tomography were compared between the catheter group (n = 36) and stylet group (n = 34). RESULTS: The paced QRS duration (QRS-d), corrected paced QT (QTc), and JT interval (JTc) were significantly shorter in the catheter group than in the stylet group (QRS-d: 130 ± 19 vs. 142 ± 15 ms, p = .004; QTc: 476 ± 25 vs. 514 ± 20 ms, p < .001; JTc: 347 ± 24 vs. 372 ± 17 ms, p < .001). This superiority of the catheter group was maintained in a subgroup analysis of patients with an RV lead tip position at the septum. The lead depth inside the septum was greater in the catheter group than in the stylet group, and there was a significant negative correlation between the paced QRS-d and the lead depth. CONCLUSION: Using a delivery catheter system carries more physiological depolarization and repolarization during RVS pacing and deeper screw penetration in the septum in comparison to conventional stylet system. The lead depth could have a more impact on the ECG parameters rather than the type of pacing lead.

Usefulness of delivery catheter on accurate right ventricular septal pacing: Mt FUJI trial.

AIMS: Although the delivery catheter system for pacemaker-lead implantation is a new alternative to the stylet system, no randomized controlled trial has addressed the difference in right ventricular (RV) lead placement accuracy to the septum between the stylet and the delivery catheter systems. This multicentre prospective randomized controlled trial aimed to prove the efficacy of the delivery catheter system for accurate delivery of RV lead to the septum. METHODS AND RESULTS: In this trial, 70 patients (mean age 78 ± 11 years; 30 men) with pacemaker indications of atrioventricular block were randomized to the delivery catheter or the stylet groups. Right ventricular lead tip positions were assessed using cardiac computed tomography within 4 weeks of pacemaker implantation. Lead tip positions were classified into RV septum, anterior/posterior edge of the RV septal wall, and RV free wall. The primary endpoint was the success rate of RV lead tip placement to the RV septum. RESULTS: Right ventricular leads were implanted as per allocation in all patients. The delivery catheter group had higher success rate of RV lead deployment to the septum (78 vs. 50%; P = 0.024) and narrower paced QRS width (130 ± 19 vs. 142 ± 15 ms P = 0.004) than those in the stylet group. However, there was no significant difference in procedure time [91 (IQR 68-119) vs. 85 (59-118) min; P = 0.488] or the incidence of RV lead dislodgment (0 vs. 3%; P = 0.486). CONCLUSION: The delivery catheter system can achieve a higher success rate of RV lead placement to the RV septum and narrower paced QRS width than the stylet system. TRIAL REGISTRATION NUMBER: jRCTs042200014 (https://jrct.niph.go.jp/en-latest-detail/jRCTs042200014).

Comparison of the Efficacy of Empiric Thoracic Vein Isolation for the Treatment of Paroxysmal and Persistent Atrial Fibrillation in Patients Without Structural Heart Disease.

INTRODUCTION: The guidelines suggest that an adjuvant substrate modification in addition to pulmonary vein isolation (PVI) may be needed for persistent atrial fibrillation (PerAF) assuming that catheter ablation is less successful for PerAF than paroxysmal AF (PAF). To revisit the above assumption, we compared the outcome of the same catheter ablation strategy between PAF and PerAF. METHODS AND RESULTS: Two hundred and thirty-three consecutive patients (mean age 60 ± 10 years, 53 PerAF and 8 long-lasting PerAF) without structural heart disease underwent catheter ablation of AF by the same strategy using an empiric thoracic vein isolation (a wide circumferential PVI plus empiric superior vena cava isolation) as a major part of the strategy without any adjuvant substrate modification. The duration of AF in the patients with PerAF was 6 ± 4 months. During 25 ± 10 months of follow-up after single procedures, 71 (30%) patients had atrial tachyarrhythmia recurrences without antiarrhythmic drugs. A Kaplan-Meier analysis of the recurrence-free survival rate after a single procedure and after repeat procedures revealed no significant difference between the patients with PAF and those with PerAF (log-rank, P = 0.38 and P = 0.27, respectively). A Cox regression multivariate analysis of the variables including the age, gender, PerAF, body mass index, left ventricular ejection fraction, and left atrial volume index demonstrated that none of the variables were an independent predictor of an atrial tachyarrhythmia recurrence after a single ablation procedure. CONCLUSION: In patients without underlying heart disease, the procedural outcome of an empiric thoracic vein isolation is comparable for PAF and PerAF.

Long-Term Efficacy of Implantable Cardioverter Defibrillator in Repaired Tetralogy of Fallot　- Role of Anti-tachycardia Pacing.

BACKGROUND: Tetralogy of Fallot (TOF) is one of the common congenital heart diseases (CHD) in implantable cardioverter defibrillator (ICD) recipients, but few studies have reported the long-term outcomes of and the anti-tachycardia pacing (ATP) efficacy in repaired TOF.Methods and Results:Twenty-one repaired TOF patients with an ICD implanted between April 2003 and March 2015 were investigated retrospectively. ICD therapy and clinical outcome were analyzed. Mean patient age was 39±11 years; 62% were male; and mean age at repair surgery was 9.4±6.8 years. During a median follow-up of 5.6 years (range, 2.6-8.4 years), no patients died. Appropriate ATP were delivered in 11 patients (52%), with appropriate shocks in 5 patients (24%) and inappropriate shocks in 5 patients (24%). The success rate of ATP was 98% for fast ventricular tachycardia (VT; cycle length ≤320 ms) and 98% for slow VT (cycle length >320 ms). ATP effectiveness increased from 81.5% with the first ATP attempt to 93.7% with the second ATP attempt, to 97.5% with the third ATP attempt, and to 98.6% with the fourth or successive ATP attempt (P<0.0001, Cochran-Armitage trend test). CONCLUSIONS: ATP was highly effective in repaired TOF regardless of VT cycle length. Multiple ATP attempts could have an important role in VT termination, and the novel subcutaneous ICD without ATP capability should be used carefully.

Interatrial Conduction Time Can Predict New-Onset Atrial Fibrillation After Radiofrequency Ablation of Isolated, Typical Atrial Flutter.

INTRODUCTION: Many patients with successful atrial flutter (AFL) ablation will develop atrial fibrillation (AF) during follow-up. This study aimed to determine whether prolonged interatrial conduction time (IACT) is associated with risk for new-onset AF after ablation of isolated, typical AFL. METHODS: Participants were 80 consecutive patients who underwent successful radiofrequency ablation of isolated, typical AFL from 2004 to 2012. Patients with any history of AF prior to AFL ablation were excluded. IACT was defined as the interval from the earliest onset of the P-wave on the ECG to the latest activation in the coronary sinus catheter during sinus rhythm measured after AFL ablation. New-onset AF was identified from 12-lead ECGs, 24-hour ambulatory monitoring, and device interrogations. RESULTS: During a mean follow-up of 4.1 ± 2.5 years after successful AFL ablation, 22 patients (27.5%) developed new-onset AF. Cox regression multivariate analysis demonstrated that IACT was the independent predictor of new-onset AF after AFL ablation (hazard ratio: 1.03; 95% confidence interval: 1.00-1.06; P = 0.02). IACT was accurate in predicting new-onset AF (AUC = 0.70). The optimal cut-off point of IACT for predicting new-onset AF was 120 milliseconds (sensitivity 47.6%, specificity 89.8%). Kaplan-Meier curves showed that new-onset AF after AFL ablation was significantly higher in patients with IACT ≥120 milliseconds than in patients with IACT< 120 milliseconds (P = 0.0016). CONCLUSION: Prolonged IACT predicted new-onset AF after ablation of isolated AFL. This finding may contribute to guiding decisions regarding the maintenance of anticoagulation after AFL ablation.

Catheter ablation of atrial fibrillation in patients with severely impaired left ventricular systolic function.

Little is known about the outcome of catheter ablation of atrial fibrillation (AF) in patients with heart failure (HF) and a severely reduced left ventricular ejection fraction (LVEF). We aimed to clarify the effectiveness of catheter ablation of AF in patients with a severely low LVEF. This retrospective study included 18 consecutive patients with HF and an LVEF of ≤ 35 % who underwent catheter ablation of AF. We investigated the clinical parameters, echocardiographic parameters and the incidence of hospitalizations for HF. During a median follow-up of 21 months (IQR, 13-40) after the final procedure (9 with repeat procedures), 11 patients (61 %) maintained sinus rhythm (SR) (6 with amiodarone). The LVEF and NYHA class significantly improved at 6 months after the CA in 12 patients (67 %) who were in SR or had recurrent paroxysmal AF (from 25.8 ± 6.3 to 37.0 ± 11.7 %, P = 0.02, and from 2.3 ± 0.5 to 1.5 ± 0.7, P < 0.01, respectively) but not in patients who experienced recurrent persistent AF. The patients with SR or recurrent paroxysmal AF had significantly fewer hospitalizations for HF than those with recurrent persistent AF after the AF ablation (log-rank test; P < 0.01). Catheter ablation of AF improved the clinical status in patients with an LVEF of ≤ 35 %. A repeat ablation procedure and amiodarone were often necessary to obtain a favorable outcome.

Impact of an Empiric Isolation of the Superior Vena Cava in Addition to Circumferential Pulmonary Vein Isolation on the Outcome of Paroxysmal Atrial Fibrillation Ablation.

The safety and efficacy of an empiric superior vena cava isolation (SVCI) in addition to circumferential pulmonary vein isolation (CPVI) in patients with paroxysmal atrial fibrillation (PAF) have not been clarified. A total of 186 consecutive patients who underwent catheter ablation of PAF were included. All patients underwent a CPVI. Patients in the first half underwent an additional SVCI only if SVC-triggered AF or rapid SVC activity was observed during the procedure (n = 93, as-needed SVCI, group I), and those in the second half underwent an empirical SVCI after the CPVI (n = 93, empiric SVCI, group II). The CPVI was successfully performed in all patients. An SVCI was performed in 8 of 93 patients (9%) in group I and 81 of the 93 patients (87%) in group II. In the remaining 12 patients in group II, an SVCI was not performed because of the lack of SVC potentials. During a mean follow-up of 27 ± 12 months, the atrial tachyarrhythmia recurrence rate after a single ablation procedure in the patients in group II was lower than that in group I (44% vs 23%, p = 0.035). A Cox regression multivariate analysis demonstrated that an empiric SVCI was an independent predictor of an atrial tachyarrhythmia recurrence after a single ablation procedure (odds ratio: 0.57, 95% confidence interval 0.31 to 0.999; p = 0.049). Neither sinus node injury nor any injury to the phrenic nerve was observed. In conclusion, an empiric SVCI in addition to the CPVI improved the outcome of AF ablation in patients with PAF without any additional adverse effects.