Bundle branch reentry: A novel mechanism for sustained ventricular tachycardia in Chagas heart disease

Figures

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  Figure 1. A: Twelve-lead electrocardiogram (ECG) showing sinus rhythm with prolonged PR interval (240 ms) and intraventricular conduction delay resembling left bundle branch block with left axis deviation. B: Baseline intracardiac recordings showing a normal atrial-His (AH) interval of 110 ms, a prolonged His-ventricular (HV) interval of 80 ms, and QRS duration of 130 ms. Displayed from top to bottom are ECG leads and intracardiac recordings from the right atrium (RA) and His-bundle proximal (His p) and distal (His d).

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  Figure 2. A: Twelve-lead electrocardiogram of the induced sustained ventricular tachycardia (VT) with a rate of 190 beats/min (bpm) and left bundle branch block morphology, similar to QRS configuration as in sinus rhythm. Dissociated P waves are also seen during VT, especially in the precordial lead V1. B: Intracardiac recordings during induced sustained bundle branch reentrant VT. His bundle potential precedes each QRS complex with HV interval of 95 ms and early activation of the right ventricular apex (RVA) during VT; some irregularity of VT cycle length is seen, and changes in H-H intervals precede changes in V-V intervals, indicating that His-Purkinje activation drives the VT. Abbreviations as in Figure 1.

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  Figure 3. A: Baseline intracardiac recordings before right bundle branch (RBB) ablation showed HV interval of 80 ms and radiofrequency (RF) ablation catheter positioned at proximal RBB showed RBB-V interval of 65 ms. B, C: RF delivery at proximal RBB resulted in development of right bundle branch block pattern on surface electrocardiogram with prolongation of QRS to 150 ms, increase of basal HV interval to 95 ms, and disappearance of the RBB potential at the ablation site. Abbreviations as in Figure 1.