Right and Left Ventricular Outflow Tract Obstruction in Hypertrophic Cardiomyopathy
Hypertrophic obstructive cardiomyopathy (HOCM) affecting both the right and left ventricular (RV and LV) outflow tracts is rare, and the mechanism of obstruction is different in each ventricle. A 21-year-old man with a family history of HOCM and sudden death was referred with breathlessness (New York Heart Association grade II) and occasional presyncope. There had been no discharges of an implantable defibrillator inserted 2 years earlier, and the sole medication was a β-blocker. A transthoracic echocardiogram revealed marked, bilateral ventricular hypertrophy. Doppler revealed a 70 mm Hg LV outflow gradient and obstruction of the right outflow tract at rest. Right and left heart catheterization, with simultaneous central aortic and LV pressure recording, revealed a 100 mm Hg subaortic gradient (Figure, a) and a 75 mm Hg subpulmonic gradient at rest (Figure, b and c). Ventriculography confirmed that the obstruction of the LV outflow was due to systolic anterior mitral valve movement (Figure, d and e), whereas RV outflow obstruction was due to massive hypertrophy of the crista supraventricularis (Figure, f).
The editor of Images in Cardiovascular Medicine is Hugh A. McAllister, Jr, MD, Chief, Department of Pathology, St Luke’s Episcopal Hospital and Texas Heart Institute, and Clinical Professor of Pathology, University of Texas Medical School and Baylor College of Medicine.
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