Right ventricular fibrosis and conduction delay in a patient with clinical signs of Brugada syndrome: a combined electrophysiological, genetic, histopathologic, and computational study

Circulation. 2005 Nov 1;112(18):2769-77. doi: 10.1161/CIRCULATIONAHA.105.532614.

Abstract

Background: The mechanism of ECG changes and arrhythmogenesis in Brugada syndrome (BS) patients is unknown.

Methods and results: A BS patient without clinically detected cardiac structural abnormalities underwent cardiac transplantation for intolerable numbers of implantable cardioverter/defibrillator discharges. The patient's explanted heart was studied electrophysiologically and histopathologically. Whole-cell currents were measured in HEK293 cells expressing wild-type or mutated sodium channels from the patient. The right ventricular outflow tract (RVOT) endocardium showed activation slowing and was the origin of ventricular fibrillation without a transmural repolarization gradient. Conduction restitution was abnormal in the RVOT but normal in the left ventricle. Right ventricular hypertrophy and fibrosis with epicardial fatty infiltration were present. HEK293 cells expressing a G1935S mutation in the gene encoding the cardiac sodium channel exhibited enhanced slow inactivation compared with wild-type channels. Computer simulations demonstrated that conduction slowing in the RVOT might have been the cause of the ECG changes.

Conclusions: In this patient with BS, conduction slowing based on interstitial fibrosis, but not transmural repolarization differences, caused the ECG signs and was the origin of ventricular fibrillation.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Amino Acid Substitution
  • Cell Line
  • Electric Stimulation
  • Humans
  • Kidney
  • Male
  • Reference Values
  • Sodium Channels / genetics
  • Sodium Channels / physiology
  • Syndrome
  • Ventricular Fibrillation / genetics
  • Ventricular Fibrillation / pathology
  • Ventricular Fibrillation / physiopathology*

Substances

  • Sodium Channels