Decreasing the Pressure Gradient of the Left Ventricular Outflow Tract by Single-lead VDD Pacing in a Patient with Hypertrophic Obstructive Cardiomyopathy

admitted to our hospital for exertional dyspnea and previ-ous syncope. Cardiac catheterization showed a prominent left-ventricular outflow tract (LVOT) pressure gradient, and hypertrophic obstructive cardiomyopathy (HOCM) was diagnosed. To reduce LVOT obstruction, we implanted a single-lead VDD-mode pacemaker. Cardiac catheterization after the implantation revealed a remarkable decrease in the LVOT pressure gradient with short atrioventricular delay, 80 msec, and her symptoms disappeared. A single-lead VDD pacemaker is also a useful treatment for an HOCM patient due to the relative ease with which it can be implanted. valve replacement'-'), or atrioventricular sequential pacing10"5. But surgery frequently fails to reduce LVOT obstruction and leads to a 2-11 % possibility o