Researchers at University of Sherbrooke, Medical Department publish new data on arrhythmia.

According to recent research from Sherbrooke, Canada, "Women have a higher incidence of long QT-related arrhythmias, whereas men exhibit a higher incidence of Brugada syndrome (BrS). The cardiac sodium current (I-Na) is associated with arrhythmias in BrS and long QT-syndrome (LQTS) and conduction disease."

"Although a great deal of work has been performed to explain how heterogeneous distribution of repolarizing currents triggers arrhythmias, the transmural distribution of I-Na within the cardiac ventricle and its contribution to generate the arrhythmogenic substrate remain unknown. We undertook to determine whether I-Na was heterogeneously distributed within the ventricular wall of canine heart, an animal model close to humans. Using patch-clamp and molecular biology techniques, we tested whether gender differences exist in the ventricular distribution and amplitude of I-Na in the canine heart model. Our results show that the I-Na amplitude is smaller in the female epicardial and endocardial layers of the left ventricle, but similar to male in the mid-myocardium. Exposure of female cardiomyocytes to testosterone increased the amplitude of I-Na to levels similar to male in epicardium, but had no effects in mid-myocardial and endocardial cells. Castrated male dogs displayed I-Na amplitudes similar to what was found in female hearts. The larger dispersion of I-Na ...