Left lateral pathway AVRT causing overdrive suppression of SA node and reversible cardiomyopathy: A case report.

The SA node is protected from the overdrive suppression by the other tissues or tachyarrhythmias by means of atrio-sinus entrance block. A 57-year-old woman presented with symptomatic tachy-brady syndrome and severe LV dysfunction. Electrophysiological study revealed presence of left lateral accessory pathway. After ablation of the accessory pathway, tachycardia could no longer be induced. Her LV systolic function significantly improved on follow up and an external loop recorder showed no episodes of bradycardia. Therefore, we conclude that the bradycardia was due to overdrive suppression of SA node caused by AVRT, and the reversible cardiomyopathy was also due to high tachycardia burden.