A case of hypertrophic obstructive cardiomyopathy in which left ventricular remodeling and reverse remodeling were seen with pacing on and off

A 77-year-old woman with hypertrophic obstructive cardiomyopathy was admitted to the hospital in March 2005 with a chief complaint of chest discomfort, and a left ventricular outflow tract (LVOT) gradient was seen. After starting apical dual chamber (DDD) pacing and oral cibenzoline 300 mg/day to relieve the stenosis, the pressure gradient and subjective symptoms disappeared. The patient was then followed as an outpatient. In January 2008, cibenzoline was discontinued because the patient experienced a hypoglycemic attack. Plain chest radiographs showed an increased cardiothoracic ratio from May 2009 and ventricular remodeling was suspected, although there were no changes in chest symptoms. Therefore, pacing off was considered. Acute changes in the LVOT gradient were evaluated with echocardiography before and after pacing on–off, but no changes were seen, so the course was observed in the pacing-off state. The LVOT gradient gradually increased again from 7 months after pacing off, and the pressure gradient decreased again after pacing was restarted. On the electrocardiogram, a deep negative T wave was seen in V4–6 immediately after pacing off, but with time, it became positive, similar to before an implantable cardioverter defibrillator was inserted. Reverse remodeling was judged to occur after pacing off, and pacing therapy was restarted. The patient is currently under observation