A randomized sham-controlled study of pulmonary vein isolation in symptomatic atrial fibrillation (The SHAM-PVI study): Study design and rationale.

INTRODUCTION: Pulmonary vein (PV) isolation has been shown to reduce atrial fibrillation (AF) burden and symptoms in patients. However, to date previous studies have been unblinded raising the possibility of a placebo effect to account for differences in outcomes. HYPOTHESIS & METHODS: The objective of this study is to compare PV isolation to a sham procedure in patients with symptomatic AF. The SHAM-PVI study is a double blind randomized controlled clinical trial. 140 patients with symptomatic paroxysmal or persistent AF will be randomized to either PV isolation (with cryoballoon ablation) or a sham procedure (with phrenic nerve pacing). All patients will receive an implantable loop recorder. The primary outcome is total AF burden at 6 months postrandomisation (excluding the 3 month blanking period). Key secondary outcomes include (1) time to symptomatic and asymptomatic atrial tachyarrhythmia (2) total atrial tachyarrhythmia episodes and (3) patient reported outcome measures. RESULTS: Enrollment was initiated in January 2020. Through April 2023 119 patients have been recruited. Results are expected to be disseminated in 2024. CONCLUSION: This study compares PV isolation using cryoablation to a sham procedure. The study will estimate the effect of PV isolation on AF burden.

A randomized comparison of retrograde left-sided versus anterograde right-sided ablation of the atrioventricular junction.

BACKGROUND: Catheter ablation of the atrioventricular node (AVN) is an effective treatment for patients with symptomatic atrial fibrillation. This study compares the success rate, procedure time, radiation time, and complication rates of retrograde left-sided (LSA) and anterograde right-sided (RSA) AVN ablation in a randomised controlled trial. METHODS: Thirty-one patients undergoing AVN ablation were randomized to either LSA (15 patients) or RSA (16 patients). Crossover occurred after six unsuccessful radiofrequency (RF) applications. RESULTS: The LSA cohort had a mean age of 77.00 ± 5.17 and the RSA cohort was 79.44 ± 6.08 (p = .0240). There were five crossovers from LSA to RSA and there was one crossover from RSA to LSA. There was no significant difference in ablation time between LSA and RSA (210.40 ± 179.77 vs. 192.19 ± 130.29 seconds, p = .748). There was no significant difference in procedure time, fluoroscopy time, radiation dose, or number of RF applications between the two groups. There was 1 (6.67%) serious adverse event in the LSA group and 1 (6.25%) in the RSA group due to femoral hematomas requiring blood transfusion or intervention. There was no significant difference in patient-reported discomfort between LSA and RSA (16.43 ± 20.67 vs. 17.87 ± 28.08, p = .877). The study was stopped before full recruitment due to futility. CONCLUSIONS: Retrograde LSA of the AVN does not reduce RF applications, procedure time, or radiation exposure compared with conventional RSA and cannot be recommended as a first-line clinical approach.

The effect of second-generation cryoablation without electrical mapping in persistent AF using continuous monitoring.

BACKGROUND: Second-generation cryoballoon ablation is safe and effective in patients with persistent atrial fibrillation (AF). The aim of this study is to report the real long-term AF burden and freedom from AF post-cryoablation using continuous monitoring, and to assess whether intraoperative confirmation of pulmonary vein isolation using electrical mapping is necessary. METHODS: A total of 33 patients (mean age 75.7 ± 5.6 years, 16 men) with persistent AF who underwent second-generation cryoablation without electrical mapping were reviewed. All patients had a cardiac implantable device and were followed up for a mean of 755 ± 170 days. RESULTS: AF burden significantly decreased from 67.51% ± 34.90% to 18.28% ± 26.65% at 1-year follow-up, and this reduction was maintained at final follow-up (18.26% ± 23.70%, p < 0.001). Continuous monitoring revealed a freedom from AF rate of 33% and 24% at 1-year and full follow-up, respectively. Patients who remained in persistent AF at final follow-up had a trend towards higher pre-ablation AF burden (81.6% ± 29.7% vs 57.3% ± 36.4%, p = 0.08). CONCLUSION: Second-generation cryoablation without confirming pulmonary vein isolation using electrical mapping is effective leading to significant reductions in AF burden based on continuous beat-to-beat monitoring at 1-year and long-term follow-up.

The efficacy of intraoperative atrial radiofrequency ablation for atrial fibrillation during concomitant cardiac surgery-the Surgical Atrial Fibrillation Suppression (SAFS) Study.

INTRODUCTION: Studies assessing radiofrequency ablation (RFA) for atrial fibrillation (AF) performed at the time of concomitant cardiac surgery have reported high success rates. The efficacy of this treatment has primarily been determined by a single electrocardiogram (ECG) or 24-h Holter monitor at follow-up. We sought to assess the true efficacy of this procedure using prolonged cardiac rhythm monitoring. METHODS: One hundred patients with paroxysmal (n = 47) and persistent AF (n = 53) requiring cardiac surgery were enrolled. Patients were clinically reviewed 6 weeks post-operatively and were monitored with 7-day Holter with full disclosure, 6 months post-surgery. A cohort of 50 patients also underwent 7 day Holter monitoring preoperatively. AF recurrence was defined as >30 s of AF. RESULTS: At 6 months, 75% of patients were in sinus rhythm according to a single ECG. However, only 62% of patients were free from AF on 7-day Holter; all AF episodes in these patients were asymptomatic. The procedure resulted in a significant decrease in AF burden from 56.2% at baseline to 27.5% at 6 months follow-up, (p < 0.001). Predictors of AF recurrence were (1) pre-operative AF duration; (2) persistent compared with paroxysmal AF; (3) increasing left atrial diameter and (4) requirement for mitral valve surgery. CONCLUSIONS: Surgical RFA for the treatment of AF, during concomitant cardiac surgery, is a successful procedure and significantly reduces AF burden. However, 13% of patients have asymptomatic AF episodes only identified with continuous monitoring. This has important implications for post-operative anti-arrhythmic and anticoagulant management and for the definition of surgical AF ablation success.