Electroconvulsive therapy (ECT) is the treatment of choice for patients with a major depression disorder who have failed antidepressant therapy. Patients with hypertrophic cardiomyopathy (HCM) may have dynamic obstruction to left ventricular (LV) outflow. The effects on myocardial function during ECT and pretreatment with antihypertensive agents in patients with HCM and LV outflow tract obstruction gradients are unknown. We report the first use of continuous transthoracic echocardiography during ECT in a patient with HCM. We confirmed an outflow tract obstruction and showed a decrease in LV outflow tract gradients. Continuous transthoracic echocardiography monitoring using Doppler echocardiography during ECT is feasible.