We describe a case of a 59-year-old woman with
hypertrophic cardiomyopathy who remained with
right ventricular outflow tract obstruction after the pressure gradient in the left midventricle was resolved by a
drug with a negative inotropic effect. The patient was diagnosed with
hypertrophic cardiomyopathy 30 years previously and was only on low-dose beta-blocker
therapy. She presented at our hospital with suspected exacerbation of
heart failure because of the development and exacerbation of
dyspnea and chest tightness. Transthoracic echocardiography showed an accelerated blood flow of 3 m/s in the middle of the left ventricle; thus, she was started on
cibenzoline, a
drug with a negative inotropic effect. After admission, intracardiac pressure measurement showed no pressure gradient in the left chamber. However, there was a pressure gradient of 18 mmHg between the apex of the right ventricle and the right ventricular outflow tract, and
right ventricular outflow tract obstruction was confirmed on cardiac magnetic resonance imaging. We decided to reinforce the negative inotropic effect by adding
bisoprolol, and the subjective symptoms and auscultatory
systolic murmur were eliminated 2 months later.
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