Provokable left ventricular outflow tract obstruction in a patient without hypertrophy.

A 61-year-old man presented with shortness of breath and chest pain on exertion. He had been diagnosed as having hiatus hernia 2 years previously and was taking proton-pump inhibitors as necessary. He had a family history of ischemic heart disease and subarachnoid hemorrhage. Physical examination, electrocardiography, echocardiography, cardiopulmonary exercise testing, coronary angiography, transoesophageal echocardiography, stress echocardiography. Provokable left ventricular outflow tract obstruction without electrocardiographic abnormalities or left ventricular hypertrophy on echocardiography. Pharmacological therapy (atenolol 50 mg daily, disopyramide 250 mg twice daily), dual-chamber pacemaker implantation.