The Empirical Evidence in the Successful Anatomical Ablation of Idiopathic LV Summit Ventricular Arrhythmias: Lessons from Endocardial Mapping (JCEP April 2026)-Article: The Empirical Evidence in the Successful Anatomical Ablation of Idiopathic LV Summit Ventricular Arrhythmias: Lessons from Endocardial Mapping

Article: The Empirical Evidence in the Successful Anatomical Ablation of Idiopathic LV Summit Ventricular Arrhythmias: Lessons from Endocardial Mapping

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This retrospective two-center study examined 40 patients with idiopathic left ventricular summit (LVS) ventricular arrhythmias who underwent successful anatomical radiofrequency catheter ablation with complete endocardial mapping. The main question was whether operators should target the endocardial site closest to the epicardial earliest activation site in the great cardiac vein (GCV), or instead target the endocardial earliest activation site itself.<br /><br />The study found that the earliest activation in the endocardium was often only slightly before QRS onset, while the GCV activation was much earlier. Endocardial ablation was successful in 93% of patients when it targeted the endocardial earliest activation site or a nearby site, rather than simply the anatomically closest site to the epicardial GCV activation. In many patients, the initially chosen “closest” site failed, and success was achieved only after moving to the true endocardial earliest activation site, often in the left coronary cusp, left ventricular outflow tract, aorto-mitral continuity, or the junction between the left and right coronary cusps.<br /><br />Two activation patterns emerged. Type I arrhythmias behaved as expected, with successful ablation at the site closest to the epicardial activation. Type II arrhythmias showed an “eccentric” activation pattern, where the epicardial GCV activation appeared earlier than the endocardial breakout, even though the true origin was better targeted by the endocardial earliest activation site. This pattern likely reflects preferential epicardial conduction and slower intramural spread to the endocardium.<br /><br />The authors conclude that for anatomical ablation of LVS arrhythmias, operators should first seek the endocardial earliest activation site, not simply the site closest to the epicardial earliest activation in the GCV. This approach may improve success and avoid unnecessary ablation.

Meta Tag

Concept Left Ventricular Summit

Concept Catheter Ablation

Concept Retrograde Atrial Activation Site

Concept Endocardial Earliest Activation Site

Concept Idiopathic Ventricular Arrhythmia

Keywords

idiopathic left ventricular summit

ventricular arrhythmias

radiofrequency catheter ablation

endocardial mapping

great cardiac vein

earliest activation site

epicardial activation

left ventricular outflow tract

left coronary cusp

intramural conduction

Left Ventricular Summit

Catheter Ablation

Retrograde Atrial Activation Site

Endocardial Earliest Activation Site

Idiopathic Ventricular Arrhythmia