A man in his 60s with a history of chronic kidney disease and long-term peritoneal dialysis presented to the emergency department with heart palpitations and severe weakness of the upper and lower limbs. The patient’s medical history also included an inferior wall myocardial infarction in 2011, but unexplained syncope was denied, and he reported no family history of sudden cardiac death. On admission, the patient’s blood pressure was 160/80 mm Hg; heart rate, 102 beats per minute; and respiratory rate, of 20 breaths per minute. Examination of the limbs showed symmetrical weakness in the extremities. Cardiopulmonary examination showed no notable findings. The result of high-sensitivity cardiac troponin level testing was 0.03 ng/mL (reference, <0.02 ng/mL; to convert to μg/L, multiply by 1.0). A 12-lead electrocardiogram (ECG) was obtained on admission (Figure, A).