Approaching a decade of cryo catheter ablation for type 1 atrial flutter-a meta-analysis and systematic review

Despite increasingly widespread use of cryo catheter ablation (CCA) in clinical practice, current ACC/AHA/ESC guidelines for management of supraventricular arrhythmias cite only radiofrequency catheter ablation (RFCA) as first-line treatment for type 1 atrial flutter (AFL). We performed a meta-analysis of efficacy and procedure outcomes from randomized controlled clinical trials comparing CCA with RFCA for type 1 AFL. A systematic review of non-randomized, single-arm clinical studies of CCA for type 1 AFL was also done.

An English language search of Medline, Cochrane, Embase, and an extensive bibliography search from January 2000 to May 2010 was conducted. Inclusion/exclusion criteria were met by six randomized clinical trials for meta-analysis (n = 341) and 13 non-randomized, single-arm clinical studies for systematic review (n = 763). Four primary outcomes were analyzed, namely, percent of patients with bidirectional conduction block (BCB) at procedure, proportion of patients who were asymptomatic during follow-up, procedure time, and fluoroscopy time.

Random effect analyses for CCA versus RFCA favored the latter ablation modality for percent of patients with BCB at procedure (84.3% vs. 93.3%; OR = 0.51; p = 0.14). A similar proportion of patients were asymptomatic during follow-up (85.5% vs. 87.3%; OR = 0.68; p = 0.53). A significantly longer procedure time was determined for CCA (171.7 min vs. 134.5 min; Std diff means = 0.57; p < 0.001), but fluoroscopy time was similar for both (27.5 vs. 27.3 min; Std diff means = 0.12; p = 0.28). Sensitivity analyses revealed a shift in favor of CCA with large tip size catheters only versus RFCA for long-term effectiveness (OR = 1.5; p = 0.09).

Results from this meta-analysis and systematic review do not generally favor one ablation modality over another for treatment of type 1 AFL. Indeed, there is higher percent BCB at procedure and shorter procedure time with RFCA. However, chronic success and fluoroscopy time were similar for both ablation modalities. Ultimately, investigator experience, catheter costs, and patient preference may sway device selection in clinical practice.