Dr. Massumi was an interventional cardiologist and electrophysiologist specializing in cardiac rhythm disorders, radiofrequency catheter ablation of cardiac arrhythmias, defibrillators, pacemakers, coronary interventions, and mitral valve balloon valvuloplasty. He was the Director of the Center for Cardiac Arrhythmias and Electrophysiology, St. Luke’s Episcopal Hospital Houston, Texas. He is a Clinical Professor of Medicine at Baylor College of Medicine, Houston, Texas, and was the Program Director, Clinical Cardiac Electrophysiology, St. Luke’s Episcopal Hospital.