Bum-Rak Choi, PhD
Assistant Professor of Medicine, Rhode Island Hospital and Brown University
Dr. Bum-Rak Choi aims to understand mechanisms of initiation and maintenance of cardiac arrhythmias, specifically, how mutations in ion channels and/or abnormal calcium handling cause chaotic rhythm. Our current understanding of abnormal Ca2+ handling is limited to mostly single cell preparation and the exact mechanisms of initiation and maintenance of cardiac arrhythmias are not clearly understood. Dr. Choi developed a dual imaging system which allows simultaneous recordings of membrane potential (Vm) and Ca2+ from intact heart using fluorescence probes and high speed cameras. Using these tools, he investigates their relationship in various pathological conditions such as ischemia or reperfusion induced arrhythmias, atrial and ventricular fibrillation, as well as heart failure. In addition, he also focuses on neuronal mechanisms that trigger ventricular arrhythmias in transgenic animal model of long QT syndrome. This project includes recordings of action potentials and Ca2+ transients from novel innervated heart preparation with intact sympathetic and vagal nerves. Dr. Choi also investigates the conduction system including the structure of the AV node and the role of Purkinje fiber network in arrhythmogenesis.
Tea Yun Kim
T-32 Postdoctoral Fellow
Rhode Island Hospital