Where is the exact origin of narrow premature ventricular contractions manifesting qR in inferior wall leads?

The Terminal End of Retro-aortic root branch ------An unrecognized Origin for " Proximal Left Anterior Fascicle" Premature Ventricular Complexes with narrow QRS duration

BACKGROUND

Premature ventricular complexes (PVCs) with narrow QRS duration, inferior frontal plane QRS axis and right bundle branch block(RBBB) pattern generally originate from the proximal segment of the left anterior fascicle(LAF).

OBJECTIVE

This study aimed to investigate the exact origin of this category of PVCs.

METHODS

22 patients with assumed proximal LAF-PVCs were enrolled in the present study. Detailed mapping of fascicular potentials (FPs) was performed during sinus rhythm (SR) and PVCs.

RESULTS

During SR, a cluster of FPs could be found at the most superior portion of the left ventricle (LV). These FPs represented the terminal end of a discrete branch of the left fascicular system which we named the "retro-aortic root branch"(RARB). The shortest distance between the proximal LAF and the terminal end of RARB was 13.5±4.2mm. The earliest activation site of PVCs in all patients were confirmed at the terminal end of RARB, where the FP-V interval was 35.1±4.3 ms during PVCs. The shortest distance from the RCC to the EAS was 5.3±3.5mm. PVCs could be eliminated by ablation from the RCC in 45.5%(10/22) cases, in the remaining cases, ablation at the EAS in the LV endocardium successfully abolished PVCs.

CONCLUSIONS

The terminal end of the retro-aortic root branch was the actual origin site for PVCs with inferior frontal plane axis, RBBB pattern and narrow QRS duration. Ablation in the right coronary cusp or at the earliest activation site in the LV could both eliminate PVCs safely with high efficacy.

Ablation at Right Coronary Cusp as an Alternative and Favorable Approach to Eliminate Premature Ventricular Complexes Originating From the Proximal Left Anterior Fascicle

BACKGROUND

Premature ventricular complex (PVC) with narrow QRS duration originating from proximal left anterior fascicle (LAF) is challenging for ablation. This study was performed to evaluate the safety and feasibility of ablation from right coronary cusp (RCC) for proximal LAF-PVC and to investigate this PVC's characteristics.

METHODS

Mapping at RCC and left ventricle and ECG analysis were performed in 20 patients with LAF-PVC.

RESULTS

The earliest activation site (EAS), with Purkinje potential during both PVC and sinus rhythm, was localized at proximal LAF in 8 patients (proximal group) and at nonproximal LAF in 12 patients (nonproximal group). The Purkinje potential preceding PVC-QRS at the EAS in proximal group (32.6±2.5 ms) was significantly earlier than that in nonproximal group (28.3±4.5 ms, P=0.025). Similar difference in the Purkinje potentials preceding sinus rhythm QRS at the EAS was also observed between proximal and nonproximal groups (35.1±4.7 versus 25.2±5.0 ms, P<0.001). In proximal group, the distance between the EAS to left His bundle and to RCC was shorter than that of nonproximal group (12.3±2.8 versus 19.7±5.0 mm, P=0.002, and 3.9±0.8 versus 15.7±7.8 mm, P<0.001, respectively). No difference in the distance from RCC to proximal LAF was identified between the 2 groups. PVCs were successfully eliminated from RCC for all proximal groups but at left ventricular EAS for nonproximal groups. The radiofrequency application times, ablation time, and procedure time of nonproximal group were longer than that of proximal group. Electrocardiographic analysis showed that, when compared with nonproximal group, the PVCs of proximal group had narrower QRS duration; smaller S wave in leads I, V₅, and V₆; lower R wave in leads I, aVR, aVL, V₁, V₂, and V₄; and smaller q wave in leads III and aVF. The QRS duration difference (PVC-QRS and sinus rhythm QRS) <15 ms predicted the proximal LAF origin with high sensitivity and specificity.

CONCLUSIONS

PVCs originating from proximal LAF, with unique electrocardiographic characteristics, could be eliminated safely from RCC.

Approach selection of radiofrequency catheter ablation for ventricular arrhythmias originating from the left ventricular summit: potential relevance of Pseudo Delta wave, Intrinsicoid deflection time, maximal deflection index

BACKGROUND

Ventricular arrhythmias (VAs) originating from the left ventricular summit is a challenge for radiofrequency catheter ablation (RFCA). The present study aimed to investigate the appropriate RFCA strategy for VAs originating from the left ventricular summit.

METHODS

Forty-five consecutive patients with VAs arising from the left ventricular summit were successfully ablated at our cardiac electrophysiology center and reviewed in the study.

RESULTS

Thirty-two cases of VAs were eliminated in the left ventricular endocardium by retrograde transaortic (n = 22, 22/45, 48.9%) or antegrade transseptal (n = 10, 10/45, 22.2%) approaches, the other 13 cases were eliminated in the left ventricular epicardium by distal great cardiac vein (DGCV) approach (n = 13, 13/45, 28.9%). Though these VAs were similar in electrocardiographic (ECG) morphology, the pseudo delta waves (PDW), intrinsicoid deflection time (IDT), maximal deflection index (MDI) differed among them, PDW >53 ms, IDT > 74 ms, MDI > 0.45 strongly indicated that ablating left ventricular summit VAs by DGCV approach. During mean follow-up of 19.5 ± 13.2 (range, 3-60) months, 2 (4.4%) patients experienced VAs recurrence.

CONCLUSION

This retrospective study showed that VAs of left ventricular summit origin can be effectively cured with RFCA. For these VAs, prolonged PdW, IDT, MDI indicating RFCA by DGCV approach can be attempted firstly.