OBJECTIVES: We sought to clarify the prevalence and characteristics of idiopathic ventricular tachycardia or premature ventricular contraction originating from the mitral annulus(MAVT/PVC). BACKGROUND: Recent case reports have presented patients with MAVT/PVC. METHODS: Electrocardiographic(ECG) characteristics and the results of electrophysiologic investigation and radiofrequency catheter ablation(RFCA) were analyzed in 352 patients with symptomatic idiopathic ventricular tachycardia(IVT)/premature ventricular contraction(PVC). RESULTS: Nineteen cases of IVT/PVC(5%) represented MAVT/PVC. Of these, 11(58%)originated from the anterolateral portion of the mitral annulus(AL-MAVT/PVC), and 2(11%) arose fromthe posterior portion(Pos-MAVT/PVC). The remaining six cases of MAVT/PVC(31%) had posteroseptal origin(PS-MAVT/PVC). In all patients, an S-wave was present in lead V6. The QRS polarity in inferior leads and leads I and aVL was useful for differentiating AL-MAVT/PVC from Pos-MAVT/PVC or PS-MAVT/PVC. The Pos-MAVT/PVC had an Rs pattern in lead I and an R pattern in lead V1, whereas PS-MAVT/PVC invariably had an R pattern in lead I and a negative QRS component in lead V1. The AL-MAVT/PVC and Pos-MAVT/PVC showed a longer QRS duration than the PS-MAVT/PVC(p< 0.001), and all had late-phase “notching”of the QRS complex in inferior leads. In all patients, RFCA liminated MAVT/PVC,with no recurrences during follow-up for 21±15 months. CONCLUSIONS:Mitral annular VT/PVC is a rare but distinct subgroup of IVT/PVC. MAVT/PVC origin could be determined by ECG analysis. The AL and PS sites of the MA were preferential.
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