Nonreentrant proximal fascicular ventricular tachycardia, with normal QRS duration and normal axis, originating from a region remote from the His bundle

Electrophysiological features of repetitive focal Purkinje ventricular arrhythmias originating from the proximal cardiac conduction system

Background

Focal Purkinje ventricular arrhythmias (VAs) might originate from the vicinity of the proximal portion of the cardiac conducting system. This study aimed to clarify the features associated with focal Purkinje VAs originating from the proximal conduction system.

Methods

A total of 18 patients with focal Purkinje VAs undergoing radiofrequency catheter ablation (RFCA) were retrospectively examined and divided into the proximal type or the non-proximal type. The proximal type was defined as having the origin at the proximal half of the interventricular septum, or the proximal half and the septal side of the anterior wall. The 12-lead electrocardiogram and electrophysiological findings were investigated.

Results

Seven patients met criteria for proximal type of focal Purkinje VA. Out of the 7, 4 patients with proximal VAs had multiple QRS morphologies of VAs clinically, whereas out of 11 patients with non-proximal VAs, only 1 had multiple morphologies (p = .047). VA QRS duration was shorter in the proximal type than in the non-proximal type (111.2 ± 19.8 ms vs. 135.7 ± 17.7 ms; p = .003). The absolute axis difference between sinus rhythm and VA was smaller in the proximal type (80.4 ± 46.1°vs. 138.8 ± 59.6°; p = .014). The absolute axis difference ≤134° was useful in distinguishing the two types. Recurrence of VA was recorded in 3 proximal type patients and 3 non-proximal type patients. No procedure-related conduction block was observed.

Conclusion

A VA of absolute axis difference ≤134°, and multiple QRS morphologies of clinical VAs indicate a proximal origin. Focal Purkinje VAs from proximal origins can be suppressed by RFCA without severe conduction disturbance.

The clinical and electrophysiological characteristics of nonsustained repetitive monomorphic ventricular tachycardia from the left His-Purkinje system

BACKGROUND

Repetitive monomorphic ventricular tachycardia (RMVT) arising from the left His-Purkinje system can occasionally be encountered during clinical practice. We describe eight cases as a unique entity in this study to characterize the clinical and electrophysiological features of the patients.

METHODS

Eight patients with frequent palpitation (five men with median age of 28 years) were included in the study from January 2003 to July 2018. Twelve-lead ECG (Electrocardiogram), Holter, and echocardiographic tests were performed after medical history interrogations and physical examinations. Antiarrhythmic drug therapy was essential to all patients, and catheter ablation was attempted if the patients could not tolerate or were not responsive to drug therapy.

RESULTS

No patients had a history of syncope and a family history of sudden cardiac death. ECGrecording was characterized by frequent ventricular extrasystoles, ventricular couplets, and salvos of nonsustained VT competitive with sinus rhythm. The QRS morphology of ectopic beats was in the right bundle branch block pattern with severe left axis deviation. The width of the QRS complex from ECG was 135 ms (120-140) during ventricular tachycardia. Verapamil had no effect on all VT individuals. Enlargement of the left ventricle was found in two patients. Four out of six cases were successful with catheter ablation treatment.

CONCLUSION

RMVT arising from the left His-Purkinje system is a special arrhythmic and nonverapamil-sensitive entity. The electrophysiological mechanism of this treatment appears to be focal firing, which is amendable to catheter ablation in symptomatic and high-burden patients.