2021 Volume 41 Issue 2 Pages 57-63
Catheter ablation of idiopathic ventricular arrhythmias（VAs）originating from the summit of the left ventricle（LV summit）can be challenging. There may be the communicating vein between the great cardiac vein and small cardiac vein which is located in close association with the LV summit（summit-CV）. We mapped the LV summit using a 2-Fr microcatheter introduced into the summit-CV. The site of origin was confirmed to be the LV summit near the summit-CV when the mapping catheter positioned in the summit-CV showed the earliest activation time during VAs with an excellent matching pacemap obtained by pacing at the location. The QRS morphology was characterized as an inferior axis with monomorphic R pattern in all inferior leads（taller R wave in leadIIIthan leadII）, a negative polarity in leadI, a QS pattern in leads aVR and aVL, and nonspecific bundle branch block morphology with an R/S ratio in lead V1 of 0.67±0.33. The ablation attempt was performed from the right/left ventricular outflow tract, aortic cusps, or great cardiac vein, whichever is earliest and/or closest to the microcatheter in the summit-CV. Overall, 10 patients（71％）were free from recurrent VAs during follow-up after their ablation procedure. A detailed mapping inside the summit-CV has the potential to localize the precise site of origin of LV summit VAs, which may serve as a landmark of the ablation target and facilitate ablation through adjacent structures.
