Summary

We report the case of a 58-year-old Caucasian woman with severe symptoms attributable to hypertrophic obstructive cardiomyopathy (HOCM). When supine there was no significant left ventricular outflow tract (LVOT) gradient on echocardiography or cardiac catheter measurements—despite provocation with supine leg exercise and right ventricular pacing. However, semi-supine bicycle exercise induced a marked increase in the LVOT gradient, which helped guide successful percutaneous alcohol septal ablation. This case report demonstrates the usefulness of bicycle exercise echocardiography in diagnosing HOCM with latent LVOT obstruction.