Figure 1. Examinations which were conducted prior to electrophysiological study. Cerebral magnetic resonance imaging in April 2020 (A). Documented paroxysmal atrial fibrillation in July 2020 (B). Electrocardiogram in March 2021. The red square showed PR interval 240 ms (C).

aVF = augmented vector foot; aVL = augmented vector left; aVR = augmented vector right.