A case of midventricular obstructive hypertrophic cardiomyopathy in which optimal pacing therapy could be introduced by monitoring hemodynamics with echocardiography

Abstract

An 83-year-old man was diagnosed with midventricular obstructive hypertrophic cardiomyopathy (MVOHCM) 8 years previously but had no symptoms. Onset of ventricular tachycardia (VT) caused him to lose consciousness 6 months previously, after which an implantable cardioverter defibrillator (ICD) was implanted. However, he continued to experience loss of consciousness due to fever, but there was no evidence of arrhythmia. Therefore, we considered left ventricular obstruction to be the cause of the symptoms and decided to perform echocardiography. The left ventricular pressure gradient (LVPG) was 16mmHg at rest, but it increased to 47mmHg with provocation with nitroglycerin loading. Right ventricular apex pacing decreased the LVPG to 9 mmHg. To optimize the atrioventricular (AV) delay, we evaluated hemodynamics while changing the setting time, and decided the optimal time was 100 msec because hemodynamics improved best at that time. Monitoring hemodynamics using echocardiography was useful for clarifying the efficacy of pacing therapy for MVOHCM and to optimize AV delay.