Left ventricular outflow tract obstruction masked by severe aortic stenosis

An 81-year-old woman developed severe hemolytic anemia after aortic valve replacement. The anemia was not caused by paravalvular leakage, as in most cases. Instead, it occurred secondary to left ventricular outflow tract obstruction that had not been seen preoperatively and was induced by afterload reduction following aortic valve replacement. The hemolytic anemia was drug-refractory and finally treated with dual-chamber pacing, as for hypertrophic cardiomyopathy.