Response by Zhao et al to Letter Regarding Article, "Tachycardia-Induced Cardiomyopathy in a 43-Year-Old Man".

A 43-year-old man with a 5-year history of palpitation and dyspnea was referred to our hospital for further evaluation and management of persistent tachycardia. Before his referral, pharmacological therapy with metoprolol and digoxin failed to alleviate his symptoms. He reported no other significant medical history. On presentation, he had an irregular heart rate of 109 beats/min. A12-lead ECG and 24-hour Holter ECG were obtained and are shown in Figures 1 and 2. The N-terminal pro-brain natriuretic peptide level was 1875 pg/mL, and a chest x-ray showed cardiac enlargement. Transthoracic echocardiography revealed a left ventricular end-diastolic diameter of 67 mm, a left ventricular ejection fraction of 23% with global hypokinesis, confirming the diagnosis of dilated cardiomyopathy. Tachycardia-Induced Cardiomyopathy in a 43-Year-Old Man