Convergence of Epicardial and Endocardial RF Ablation for the Treatment of Symptomatic Persistent AF (CONVERGE Trial): Rationale and design.

Atrial fibrillation is the most common sustained arrhythmia affecting over 33 million people worldwide. Approximately 70% of AF patients have non-paroxysmal AF. As AF progresses from paroxysmal to non-paroxysmal forms, the prevalence of comorbidities increases. The efficacy of catheter ablation for persistent and long standing persistent (LSP) AF is <40%, often requiring multiple ablation procedures with greater cost and potentially more complications. There is an unmet need to effectively treat such patients. METHODS: CONVERGE is an investigational device exempt, prospective, multi-center, open label 2:1 randomized controlled pivotal study to evaluate the overall success of the Convergent hybrid procedure compared to endocardial catheter ablation for the treatment of symptomatic persistent AF refractory or intolerant to at least one Class I and /or III anti-arrhythmic drug (AAD). A total of 153 subjects at 27 centers are treated in the study. The CONVERGE study is differentiated from other studies currently being conducted on the persistent AF population, because a) there is no time restriction on the duration of diagnosed AF in the patients being studied and b) the trial allows patients with left atrial sizes up to 6 centimeters. The ongoing trials are limited to either 6 months, 12 months or 3-years of continuous AF making CONVERGE the only ablation trial thus far to include a substantial portion of patients with longstanding persistent AF. The convergent procedure involves combination of minimally invasive pericardioscopic epicardial ablation with endocardial left atrial ablation. The primary endpoint is freedom from AF/AFL/AF absent class I/III AAD, except for a previously failed class I/ III AAD with no increase in dosage following 3-months through 12-months. The primary safety endpoint is the incidence of major adverse events from the procedure through 30-days post procedure. CONCLUSION: CONVERGE AF compares the overall success of the Convergent hybrid procedure to endocardial catheter ablation for the treatment of persistent and longstanding persistent AF. By providing objective comparative data, the study aims to provide guidance on the treatment of such patients.

Clinical evaluation of a novel 12-hole irrigated tip catheter ablation system for the treatment of typical atrial flutter-results from the Duo FLAIR clinical study.

INTRODUCTION: Higher current density at the proximal end of a six-hole catheter is not irrigated and thus could lead to uneven heating and possibly coagulum and charring. This study tested a novel 12-hole irrigated catheter with six additional holes at the proximal end that provides more uniform cooling during atrial flutter (AFL) ablation. METHODS: A total of 188 patients (28 females, 66 ± 11 years) were treated for typical AFL at 22 sites in the USA and Canada using Cool Path Duo at 50 W and 45 °C at an irrigation rate of 13 ml/min. The results were compared to historical data from an AFL study which used a six-hole catheter with similar design. RESULTS: A total of 2,725 RF lesions were applied in 188 patients with a mean RF duration of 18.2 ± 11.7 min per procedure. Procedural success was achieved in 96.3 % (181 of 188) acutely and 98.3 % (173 of 176) patients at 3 months. Steam pops occurred in 0.6 % of lesions (15 of 2,725) without coagulum or charring… Compared to the six-hole irrigated tip catheter, the Cool Path Duo catheter delivered more power (33.8 ± 5.9 vs. 29.7 ± 5.2 W, p < 0.0001) at a lower average tip temperature (34.7 ± 1.5 vs. 37.2 ± 2.1 °C, p < 0.0001) with no statistical differences in either 3-month AFL recurrence or complications. CONCLUSION: Cool Path Duo™ irrigated tip catheter is safe and effective in treating typical AFL. When compared to a six-hole irrigated tip catheter, the Cool Path Duo catheter delivers more power at a lower temperature.