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Holter monitoring showed variable atrioventricular (AV) block. (A) 2:1 AV block. (B) 3:1 AV block. (C) Complete AV block. Intracardiac electrocardiogram showed infra-His block (D). Arrow, P wave; asterisk, QRS wave; A, atrial electrogram; H, His recording; V, ventricular electrogram.
