Epicardial Ventricular Arrhythmias | Journal Scan

Study Questions:

What are the outcomes among patients undergoing epicardial ablation of ventricular arrhythmias (VA)s originating from the left ventricular (LV) summit?


The study group consisted of 23 patients who were referred for an epicardial ablation procedure. These patients had failed a conventional procedure, which included mapping/ablation of the LV/right ventricular (RV) sites, and the coronary sinus. The LV summit corresponds to a triangular region of the epicardial portion of the LV outflow tract, the apex of which is formed by the junction of the left anterior descending and circumflex arteries. The base is formed by an imaginary line from the first septal perforator to the circumflex artery.


The clinical arrhythmia was sustained in seven (30%), or nonsustained ventricular tachycardia in five patients (22%), and premature ventricular complexes in 11 patients (48%). LV function was impaired in five patients (22%). Preprocedure imaging revealed areas of delayed enhancement in the region of the LV summit in about one-third of the patients; however, mapping failed to reveal areas of low voltage/scar. Radiofrequency (RF) eliminated VAs in only five patients (22%). In the remaining, RF ablation was not attempted due to proximity of the target site to the coronary arteries (<5 mm) or ineffective due to epicardial fat. Certain electrocardiography (ECG) findings (e.g., Q-wave ratio of >1.8 in aVL/aVR, a R/S ratio of >2 in V1, and absence of q waves in lead V1) were more likely to be present in patients with successful ablation.


Epicardial ablation of VAs from the LV summit is frequently limited by presence of coronary arteries and epicardial fat. Specific ECG findings may aid in optimal patient selection.


VAs from the LV summit are a subgroup of outflow tract arrhythmias. These VAs may be ablated from endocardial LV and RV sites, coronary cusps, and the coronary sinus venous system. Epicardial mapping is a reasonable option in symptomatic patients who have not responded to a conventional procedure. These ECG characteristics may be helpful in identifying optimal candidates for an epicardial approach.

Clinical Topics: Arrhythmias and Clinical EP, Implantable Devices, EP Basic Science, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias

Keywords: Arrhythmias, Cardiac, Coronary Sinus, Coronary Vessels, Electrocardiography, Epicardial Mapping, Heart Conduction System, Heart Ventricles, Patient Selection, Tachycardia, Ventricular, Ventricular Premature Complexes

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