Idiopathic basal crux ventricular arrhythmias with left bundle branch block and superior axis: A comparison with inferior‐septal valvular arrhythmias

Abstract

Introduction Left bundle branch block (LBBB) with superior axis is common in patients with idiopathic‐ventricular arrhythmia (VA) originating from the tricuspid annulus (TA) and rarely from the cardiac basal crux and mitral annulus (MA). We described the electrocardiography and electrophysiological findings of idiopathic‐VA presenting with LBBB and superior axis. Methods and Results We described 42 idiopathic‐VA patients who had an LBBB and superior axis; 15 basal crux‐VA, 17 TA‐VA, and 10 MA‐VA. No patient had a structural heart disease. Among patients with idiopathic‐VA referred for ablation, we investigated the electrocardiogram and clinical characteristics of basal crux‐VA as compared with other LBBB and superior axis‐VA. The left ventricular ejection fraction with MA‐VA was significantly lower in comparison with basal crux‐VA (P = .01). All patients had a positive R wave in lead I and aVL. The maximum deflection index with basal crux‐VA was significantly higher in comparison with TA‐VA or MA‐VA (P = .01). Patients with basal crux‐VA presented with QS wave in lead II more frequently as compared with TA‐VA or MA‐VA (P = .001). All MA‐VA patients had Rs wave in V6, and basal crux‐VA, and TA‐VA patients had a monophasic R wave or Rs wave in V6. Basal crux‐VA patients underwent ablation in the middle cardiac vein (MCV) or coronary sinus (success rate: 94%, recurrence rate: 6%). Conclusions We could distinguish basal crux‐VA, TA‐VA, and MA‐VA, using a combination of clinical and electrocardiographic findings. These findings might be useful for counseling patients about an ablation strategy. Ablation via the MCV is effective for eliminating basal crux‐VA.

Electrocardiographic Characteristics of Ventricular Arrhythmias Originating from Different Areas Adjacent to the Mitral Annulus

“…Previous studies have reported the ECG characteristics of MA-VAs in patients without structural heart disease as the following: right bundle branch block pattern (RBBB), S or s waves in lead V6, and an early precordial transitional zone < V2 [ 7 , 8 ]. After that, many studies focused on ECG characteristics and RFCA of VAs originating from specific areas adjacent to the MA [ 9 , 10 , 11 , 12 , 13 , 14 ]. However, few have systematically analyzed VA’s ECG characteristics originating from both epicardial and endocardial areas adjacent to the MA.…”