Aims Idiopathic epicardial ventricular arrhythmias (VAs) are clustered in the areas of the summit and crux. This study was to report a group of idiopathic epicardial VAs remote from the summit and crux areas. Methods In total, 9 patients (6 males, mean age 32±13 years) were enrolled. The locations were identified by epicardial mapping and ablation. The electrocardiographic and electrophysiological characteristics were compared to those of 9 patients who had VAs ablated at the opposite endocardial site. Results VAs were identified at the epicardium, with 4 patients had VAs located at the inferior wall, one at the anterior wall, one at the apex and 3 patients had VAs at the lateral wall. A “QS” type at the location-related leads was the only identified surface electrocardiogram indication suggesting epicardial origin (compared to that of the controls, 100% vs 0%, p<0.001). Endocardial and epicardial mapping revealed pre-maturities of -11±4 ms and -25±8 ms, respectively (VS. -28±8 ms revealed by endocardial mapping in control patients, p<0.001 and p=0.389, respectively). All of the study cases demonstrated an “rS” pattern in the endocardial unipolar electrogram. Acute and long-term successful ablation (a median of 11 months of follow-up) was achieved in all patients without complications. Conclusion A distinct group of idiopathic VAs remote from the summit and crux areas warranting ablation by a subxiphoid approach were identified. Morphological ECG features of a “QS” type among the location-related grouped leads combined with the mapping findings helped in the identification of the epicardial site of origin.

Background: Combination of endocardial and epicardial approach has improved the overall success rate of ventricular tachycardia (VT) ablation in patients with cardiomyopathy. However, the origins of some VTs are truly intramural or close to coronary arteries, which make this combined strategy either prone to failure or too risky. Objectives: This observational study aimed to explore the feasibility and efficacy of direct epicardial ablation combined with intramural ethanol injection via surgical approach for such VTs. Methods: Six consecutive patients with recurrent sustained VT refractory to combined endocardial and epicardial radiofrequency ablation were included. Direct epicardial access was achieved through limited left thoracotomy in 3 patients and median sternotomy in other 3 patients. Ablation was performed using irrigation catheter guided by electroanatomic mapping. Ethanol was injected in all patients to reinforce transmural lesions. The primary outcome was freedom of sustained VT determined by device interrogation and periodical 24h-holter recordings subsequently. Results: Over a median follow-up of 22 months (range, 6~65), all patients remained free of sustained VT. One patient died of pulmonary infection one year after the procedure. Conclusions: A hybrid strategy of surgical ablation combined with intramural ethanol injection is feasible and effective in patients with multiple failed percutaneous ablation attempts.

Biatrial macro-reentrant tachycardia (Bi-MAT) is a relatively uncommon arrhythmia. Sometimes, it can be produced by the left atrial (LA) anterior or septal-anterior linear ablation. However, data concerning the proarrhythmic role of this ablation lesions are lacking. Here, we reported a case of a single-loop Bi-MAT developing after the LA anterior ablation line performed in one patient with persistent atrial fibrillation.