Exercise-Induced Tachycardia-Dependent Atrioventricular Block with Narrow QRS Complexes: A Case Report and Review of Literature.

Exercise-induced tachycardia-dependent atrioventricular block with a normal electrocardiogram at rest is rare. Herein, we present a case of a 65-year-old woman with exercise-related chest suppression and treadmill exercise test-induced second- and third-degree atrioventricular blocks with narrow QRS wave and normal resting electrocardiogram. High atrioventricular block leads to tissue and organ insufficiency, resulting in exercise intolerance, dyspnea, dizziness, and syncope. Ths diagnosis was exercise-induced high-degree atrioventricular block. For lack of effective medicines, the patient received a permanent dual chamber pacemaker to ensure atrioventricular sequential pacing during exercise. No exercise-related discomfort occurred during follow up.