Intraoperative diagnosis of hypertrophic obstructive cardiomyopathy

A thickened interventricular septum, a decrease in the size of the left ventricular outflow tract, and systolic anterior motion of the anterior leaflet of the mitral valve characterize hypertrophic cardiomyopathy (HCM). These changes may cause left ventricular outflow obstruction, giving origin to the term hypertrophic obstructive cardiomyopathy (HOCM) or, in older terminology, idopathic hypertrophic subaortic stenosis or asymmetric septal hypertrophy. Once thought to be rare, HOCM may occur relatively commonly, especially in elderly women. HOCM respresents a potential problems during anesthesia because positive inotropic drugs, decreased venous return, or decreased systemic vascular resistance may increase dynamic ventricular outflow obstruction. In our case, intraoperative diagnosis of previously unrecognized HOCM facilitated the care of this patient.