Wide Complex Tachycardia: An Enigmatic Sequence.

BACKGROUND

Differentiating perpetuated aberrant conduction from ventricular tachycardia in atrial fibrillation (AF) is challenging and may lead to inappropriate therapies.

CASE SUMMARY: A 64-year-old man with ischemic cardiomyopathy and AF presented with decompensated heart failure. Admission electrocardiogram showed a wide-complex tachycardia with runs of up to 10 consecutive aberrant QRS complexes mimicking nonsustained ventricular tachycardia (VT). Careful analysis revealed perpetuated Ashman-type aberrancy best explained by concealed transseptal conduction. Abrupt normalization despite a subsequent long-short sequence most likely reflected transient resolution of functional right bundle branch fatigue.

DISCUSSION: This case demonstrates an unusually long run of perpetuated Ashman-type aberrancy in AF, a rare diagnostic challenge that mimics nonsustained VT and carries risk of inappropriate treatment.

TAKE-HOME MESSAGES: Long runs of wide QRS complexes in AF may reflect perpetuated aberrancy rather than VT. Accurate recognition of this phenomenon is essential to avoid unnecessary and potentially harmful therapies.