Demonstration of Ventricular Myocardial Extensions into the Pulmonary Artery and Aorta Beyond the Ventriculo‐Arterial Junction

Abstract

VMEs into the PA and Ao beyond the VAJ are relatively common. It seems that their mere presence does not predispose to OT VTs. There are probably intrinsic arrhythmogenic properties in tissues specific to these regions in those patients who develop OT VTs.

Catheter Ablation of Idiopathic Ventricular Arrhythmias Arising From the Cardiac Outflow Tracts – Recent Insights and Techniques for the Successful Treatment of Common and Challenging Cases –

“…Less common than RVOT-and LVOT-VAs, those originating from the PA are most likely induced by abnormal automaticity or triggered activity by myocardial tissue extending into the PA. [25][26][27] VAs originating from the PA have been previously described as targets of RFCA with low complications and high success rates. 7, 21 The following ECG characteristics have been described: because the VA origin site within the PA is in a very high position compared with the RVOT, the R-wave amplitudes of the inferior leads and the R/S ratio on lead V2 have been described as significantly larger.…”

Characteristics of idiopathic ventricular tachycardia originating above the pulmonary valve

“…In addition to a sharp potential, Timmermans et al also observed a fragmented electrogram at the successful ablation site above pulmonary valve in one out of 6 patients. [3] This observation and the histological evidence of inhomogeneous distribution of VME [23] suggest that myocardial activation above pulmonary valve may be delayed in association with increase in excitation frequency.…”

“…[23] Fibrosis and fatty tissue between the layers of VME was observed with high incidence (about 70%), thereby implicating the possible arrhythmogenic substrate with conduction disturbance. However, these results were obtained from subjects without any history of cardiac disease or symptoms.…”

Supravalvular Arrhythmia

“…4,5 The myocardial sleeve typically extends circumferentially around the pulmonic valve between and above all 3 cusps. 7 However, with the aortic valve, the myocardial extensions are asymmetrical, with sleeves routinely being found along the …”