Atrial Tachycardia and Bundle Branch Re-Entry Ventricular Tachycardia With Similar QRS Complex Morphology.

BACKGROUND

Wide-QRS-complex tachycardia with QRS complex morphology identical to sinus rhythm has been described in bundle branch re-entry ventricular tachycardia (BBR-VT). However, the coexistence of supraventricular and ventricular tachycardias with identical electrocardiographic (ECG) morphology has not been well described.

CASE SUMMARY: A 56-year-old woman exhibited 2 sustained tachycardias with nearly identical right bundle branch block-type QRS complex morphology. One was atrial tachycardia (AT), and the other was malignant reverse-type BBR-VT, confirmed by invasive electrophysiology. Radiofrequency catheter ablation targeting the crista terminalis and coronary sinus eliminated AT, and radiofrequency ablation at the right bundle branch rendered BBR-VT noninducible. Despite similar ECG appearance, mechanisms, prognosis, and management differed significantly.

DISCUSSION: AT and BBR-VT may share common features in ECG QRS complex indistinguishable from sinus rhythm in patients with advanced His-Purkinje conduction disease.

TAKE-HOME MESSAGES: AT and malignant BBR-VT may coexist and produce nearly identical surface ECGs. Surface ECG QRS complex morphology alone may be misleading, and electrophysiologic evaluation is mandatory when wide-QRS-complex tachycardia occurs in patients with septal conduction disease.