Energy Sources for Ablation in the Pericardial Space.

Catheter ablation has been widely used for the management of cardiac arrhythmias. Transvenous endocardial catheter ablation successfully eliminates or modifies the critical substrate for most arrhythmias. Most arrhythmias can be eliminated with conventional endocardial mapping and radiofrequency energy delivery, but some critical arrhythmic substrates are not accessible via endocardial access and this has led to epicardial mapping and ablation in addition to traditional endocardial mapping techniques. This article reviews current approaches to epicardial ablation and discusses the specialized tools that increase ablation efficacy and safety.

A nationwide survey on the prevalence of atrioesophageal fistula after left atrial radiofrequency catheter ablation.

BACKGROUND: There are limited data on the prevalence of atrioesophageal fistula (AEF) after left atrial radiofrequency catheter ablation for atrial fibrillation (AF). The purpose of this study was to determine the prevalence and factors associated with AEF using a nationwide anonymous survey. METHODS AND RESULTS: The information solicited included the practice setting, number of left atrial ablations performed for AF, prevalence of AEF, clinical presentation and outcome of these patients, ablation strategy, type of ablation catheter, and energy settings used to deliver radiofrequency energy. The survey was mailed to 1,874 members of the Heart Rhythm Society within the US and 585 physicians responded (31%). AEF was reported in six of the 20,425 patients who underwent a left atrial ablation procedure (0.03%). All six patients suffered from major cerebrovascular events. Five of the six patients died (83%). The patient who survived had residual hemiparesis. There was no association between the risk of AEF and the case volume. In five patients, wide area circumferential ablation was performed. In the remaining patient, pulmonary vein isolation by ostial ablation was employed. In all cases an 8-mm tip ablation catheter was used. The power in patients who did and did not develop AEF were 58 +/- 13 and 41 +/- 9 W, respectively (P = 0.03). In one patient AEF occurred despite <1 degrees C rise recorded from an esophageal temperature probe. In the remaining patients no specific method was used to visualize the location of the esophagus. CONCLUSIONS: Based on the responses to the survey, the risk of AEF appears to be <1%. However, AEF is associated major cerebrovascular events and leads to death in >80% of the patients.