Wide QRS Tachycardias With Syncope: Two for One?

BACKGROUND

The differential diagnosis of wide complex tachycardias can be challenging but is essential for correct diagnosis and treatment.

CASE SUMMARY: We describe the case of a patient presenting with 2 wide complex tachycardias, both with left bundle branch block-like morphology, left superior axis, and slurred onset. The diagnosis of pre-excited atrial flutter with 1:1, respectively, 2:1 conduction was made after careful analysis of the tracings. Electrocardiogram in sinus rhythm showed short PR but inapparent pre-excitation. An invasive electrophysiological study confirmed an anterograde-conducting right postero-septal pathway, and radiofrequency ablation was performed successfully.

DISCUSSION: Pre-excited atrial flutter may mimic ventricular tachycardia and represents an important diagnostic challenge with significant therapeutic implications.

TAKE-HOME MESSAGES: This case highlights the importance of correct differential diagnosis of wide complex tachycardias, as management strategies differ substantially. Careful electrocardiogram analysis is essential, as pre-excitation may be inapparent in sinus rhythm even for high-risk accessory pathways.