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.
Outcome of Apparently Unexplained Cardiac Arrest: Results From Investigation and Follow-Up of the Prospective Cardiac Arrest Survivors With Preserved Ejection Fraction Registry.
Circ Arrhythm Electrophysiol. 2016 Jan;9(1)
Temporal-Component Analysis of Diastolic Electrograms in Ventricular Tachycardia Differentiates Non-Vulnerable Regions of the Circuit.
Heart Rhythm. 2015 May 8;
Evaluation of Genes Encoding for the Transient Outward Current (Ito) Identifies the KCND2 Gene as a Cause of J Wave Syndrome Associated with Sudden Cardiac Death.
Circ Cardiovasc Genet. 2014 Sep 11;
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
Scientist, Toronto General Hospital Research Institute (TGHRI)
Associate Professor, Department of Physiology, University of Toronto