Slow and Discontinuous Conduction Conspire in Brugada Syndrome
- 1 December 2008
- journal article
- research article
- Published by Wolters Kluwer Health in Circulation: Arrhythmia and Electrophysiology
- Vol. 1 (5) , 379-386
Abstract
Brugada syndrome (BrS) is associated with lethal arrhythmias, which are linked to specific ST-segment changes (type-1 BrS-ECG) and the right ventricle (RV). The pathophysiological basis of the arrhythmias and type-1 BrS-ECG is unresolved. We studied the electrophysiological characteristics of the RV endocardium in BrS. RV endocardial electroanatomical mapping and stimulation studies were performed in controls (n=12) and BrS patients with a type-1 (BrS-1, n=10) or type-2 BrS-ECG (BrS-2, n=12) during the studies. BrS-1 patients had prominent impairment of RV endocardial impulse propagation when compared with controls, as represented by: (1) prolonged activation-duration during sinus rhythm (86+/-4 versus 65+/-3 ms), (2) increased electrogram fractionation (1.36+/-0.04 versus 1.15+/-0.01 deflections per electrogram), (3) longer electrogram duration (83+/-3 versus 63+/-2 ms), (4) activation delays on premature stimulation (longitudinal: 160+/-26 versus 86+/-9 ms; transversal: 112+/-5 versus 58+/-6 ms), and (5) abnormal transversal conduction velocity restitution (42+/-8 versus 18+/-2 ms increase in delay at shortest coupling intervals). Wider and more fractionated electrograms were also found in BrS-2 patients. Repolarization was not different between groups. BrS-1 and BrS-2 patients are characterized by wide and fractionated electrograms at the RV endocardium. BrS-1 patients display additional conduction slowing during sinus rhythm and premature stimulation along with abnormal transversal conduction velocity restitution. These patients may thus exhibit a substrate for slow and discontinuous conduction caused by abnormal active membrane processes and electric coupling. Our findings support the emerging notion that BrS is not solely attributable to abnormal electrophysiological properties but requires the conspiring effects of conduction slowing and tissue discontinuities.Keywords
This publication has 53 references indexed in Scilit:
- Longer Repolarization in the Epicardium at the Right Ventricular Outflow Tract Causes Type 1 Electrocardiogram in Patients With Brugada SyndromeJACC, 2008
- Monophasic action potentials and activation recovery intervals as measures of ventricular action potential duration: Experimental evidence to resolve some controversiesHeart Rhythm, 2006
- Dynamics and Cardiac ArrhythmiasJournal of Cardiovascular Electrophysiology, 2006
- Cardiac Histological Substrate in Patients With Clinical Phenotype of Brugada SyndromeCirculation, 2005
- Right Ventricular Fibrosis and Conduction Delay in a Patient With Clinical Signs of Brugada SyndromeCirculation, 2005
- Delay in Right Ventricular Activation Contributes to Brugada SyndromeCirculation, 2004
- Tissue Discontinuities Affect Conduction Velocity RestitutionCirculation, 2003
- Sudden Death in Noncoronary Heart Disease Is Associated With Delayed Paced Ventricular ActivationCirculation, 2003
- Anisotropic Conduction Properties in Canine Atria Analyzed by High-Resolution Optical MappingCirculation, 2002
- Familial cardiomyopathy underlies syndrome of right bundle branch block, ST segment elevation and sudden deathJACC, 1996