The epicardial outflow tract can be a site of origin of idiopathic ventricular arrhythmias. These arrhythmias are most commonly perivalvular and can be targeted from within the coronary venous system or from other adjacent structures, such as the right ventricular and left ventricular outflow tracts or the coronary cusp region. The authors report a case of an epicardial idiopathic outflow tract premature ventricular contraction originating from the midseptal epicardial left ventricle. In this case, direct epicardial access was crucial to identify early local activation and achieve successful catheter ablation.

BACKGROUND: Pneumopericardium is a rare complication of epicardial ablation after dry pericardiocentesis to treat ventricular arrhythmia (VA); its exact clinical effects on patients are still unclear. The purpose of this study was to evaluate the clinical effects of pneumopericardium during epicardial ablation on patients with VA.
METHODS: Patients with VA who underwent epicardial catheter ablation under local anesthesia at West China Hospital of Sichuan University from August 2012 to January 2022 were enrolled in this study. The incidence of pneumopericardium was investigated. The occurrence of major adverse cardiovascular events (MACEs) was evaluated 1 year after the operation.
RESULTS: A total of 86 VA patients were included in the study. Twenty-two cases had pneumopericardium, with an incidence rate of 25.6%, and 12 (54.55%) patients complained of dyspnea during the procedure with an average occurrence time of 5.4 ± 3.2 min after pericardiocentesis. The blood pressure (BP) decreased significantly, with the mean BP dropping from 119.8/73.2 to 103.5/64.9 mmHg (p < 0.001). None of the cases progressed to tension pneumopericardium. Postoperative follow-up with a median period of 411 days showed that the incidence rate of major adverse cardiovascular events (MACEs), including the composite endpoints of all-cause death, rehospitalization for heart failure, and tachyarrhythmia events, was 36.4% (n = 8) in the pneumopericardium group and 35.5% (n = 23) in the non-pneumopericardium group. The Kaplan-Meier survival analysis showed that there was no statistically significant difference in the incidence of MACEs between the two groups (p = 0.28).
CONCLUSIONS: The incidence of pneumopericardium during epicardial ablation was relatively high. However, if recognized early and managed properly, it is unlikely to progress to tension pneumopericardium. The occurrence of pneumopericardium during the procedure may not significantly affect the long-term prognosis of patients.

Catheter ablation (CA) is effective for recurrent episodes of ventricular fibrillation (VF) in Brugada syndrome (BrS). VF development in BrS is associated with several electrocardiogram (ECG) abnormalities. This study investigated changes in ECG parameters in high-risk BrS patients who underwent epicardial CA.Methods and Results:In all, 27 BrS patients were implanted with an implantable cardioverter-defibrillator (ICD). Patients were divided into 2 groups: (1) an ablation group (n=11) that underwent epicardial CA because of VF recurrence; and (2) a primary prevention (PP) group (n=16) with ICD implantation only. ECG parameters were evaluated before and 12 months after CA and compared with ECG parameters in the PP group. The T wave peak-to-end interval was significantly longer and the number of abnormal spikes in leads V1-V3 at the second, third, and fourth intercostal spaces was greater in the ablation than PP group. After ablation, ST levels and the sum of abnormal spikes in leads V1-V3 were significantly decreased. The mean (±SD) number of ICD shocks decreased markedly during a mean follow-up period of 42.0 months (from 3.8±3.7 to 0.2±0.4/year). Four patients had an ICD shock following the ablation procedure. Greater reductions in ST-segment elevation and abnormal spikes were observed in the group without than with VF recurrence.
Improvements in surface ECG parameters appear to be associated with successful ablation in high-risk BrS patients.

A 63-year-old man with a history of remote inferior myocardial infarction and coronary artery bypass grafting (CABG) underwent catheter ablation of ventricular tachycardia (VT). Epicardial catheter ablation of the VT was successful at the crux of the heart despite limited mapping within the pericardial space due to pericardial adhesion. Percutaneous subxiphoidal pericardial approach is usually impossible in patients with a history of open heart surgery due to pericardial adhesions. This report suggested that epicardial VT arising from the crux of the heart could be successfully treated by catheter ablation via subxiphoidal pericardial approach despite pericardial adhesions complicated by prior CABG.