Ventricular tachyarrhythmias are an important mode of sudden death in patients with cardiomyopathy. Animal studies suggest that abnormal ventricular repolarization can lead to ventricular arrhythmias. In humans, the relevance of cardiac repolarization as a substrate for arrhythmogenesis is not well understood. Our laboratory is characterizing the spatiotemporal distribution of ventricular repolarization in patients with cardiomyopathy and defining the dynamic range of repolarization in response to physiologic stress that can trigger ventricular arrhythmias. The experiments involve body surface and intracardiac recordings of repolarization under varying physiological conditions. Using linear and nonlinear dynamics, several aspects of cardiac repolarization are quantified including spatiotemporal heterogeneity, restitution, memory and alternans. The knowledge gained from our experiments will provide better understanding of the pathogenesis of lethal ventricular arrhythmias in cardiomyopathic patients which may lead to the development of novel antiarrhythmic therapies.
J Interv Card Electrophysiol. 2014 Jun;40(1):93-8
Procainamide infusion in the evaluation of unexplained cardiac arrest: from the Cardiac Arrest Survivors with Preserved Ejection Fraction Registry (CASPER).
Heart Rhythm. 2014 Jun;11(6):1047-54
Bipolar ablation for deep intra-myocardial circuits: human ex vivo development and in vivo experience.
Europace. 2014 Nov;16(11):1684-8
The prevalence and risk factors for atrioesophageal fistula after percutaneous radiofrequency catheter ablation for atrial fibrillation: the Canadian experience.
J Interv Card Electrophysiol. 2014 Mar;39(2):139-44
Evolution of clinical diagnosis in patients presenting with unexplained cardiac arrest or syncope due to polymorphic ventricular tachycardia.
Heart Rhythm. 2014 Feb;11(2):274-81
J Cardiovasc Electrophysiol. 2013 Nov;24(11):1308-10
Conf Proc IEEE Eng Med Biol Soc. 2012;2012:6361-4
High-resolution 3D scar imaging using a novel late iodine enhancement multidetector CT protocol to guide ventricular tachycardia catheter ablation.
J Cardiovasc Electrophysiol. 2013 Jun;24(6):708-10
Relationship of bipolar and unipolar electrogram voltage to scar transmurality and composition derived by magnetic resonance imaging in patients with nonischemic cardiomyopathy undergoing VT ablation.
Heart Rhythm. 2012 Nov;9(11):1837-46
J Cardiovasc Electrophysiol. 2013 Jan;24(1):105-7
Scientist, Toronto General Hospital Research Institute (TGHRI)
Associate Professor, Department of Physiology, University of Toronto