Improvement of Refractory Heart Failure Using CRT in a Patient With QRS Duration Less Than 120 ms: A Case Report

A 50-year-old woman who had a cardiomegaly and low left ventricular ejection fraction, left ventricular end diastolic volume 231 mL, left ventricular end systolic volume 181 mL, LVEF 18%, BNP 488 pg/dL, NYHA class 4 was diagnosed heart failure. She has dyspnea on effort and orthopnea for a couple of months. She had a sinus rhythm and did not have a coronary artery disease. Although she was given optimal medical therapies, her symptoms were not getting better. She was in stage C heart failure and we decided to do cardiac resynchronization therapy. Her QRS duration was 114 m sec and she did not have a typical echocardiographic findings of dyssynchrony. Two weeks after implantation, she could discharged from hospital and six months later, she had no symptoms of heart failure. Her left ventricle became smaller and dramatically improved ejection fraction, left ventricular end diastolic volume 184 mL, left ventricular end systolic volume 98 mL, LVEF 47%, BNP 5.4 pg/dL, NYHA class 2. In this case, correction of the intraventricular dyssynchrony may not be the key to improve heart failure. Before CRT implantation, apical circumferential strain was relatively preserved. After CRT implantation, circumferential strain and longitudinal strain of apical long axis view and 4ch view were improved. The propriety of apical contraction might be related to the myocardial response to electrical stimulation.