Gender differences in the electrophysiological properties of rabbit a trio ventricular node

ABSTRACT

There are gender differences in the electrocardiographic parameters and in the prevalence of arrhythmias. Women have faster heart rale, longer QT interval, shorter PR interval and shorter atrioventricular node [AVN] effective refractory period as compared to men. These changes may be due to gender differences in ion channel expression and thereby in currents responsible for the electrophysiological function of the AVN, Gender differences in the electrophysiological function in the AVN have been investigated using extracellular potential recording from isolated spontaneously beating A VN preparations from adult male and female New Zealand White rabbits under control conditions and after the application of ion channel b lockers. Cycle length of isolated A VN preparations was significantly longer in adult female as compared to adult male. 2 mMCs, an Ifblocker, significantly increased the cycle length of adult male [i.e. slowed the spontaneous activity of the AVN; by 120%] and tended to increase the cycle length in adult female by 28%. Hundred nM TTX, a b locker of TTX sensitive neuronal l[na] tended to increase the cycle length of both adult male and female. In conclusion, If and TTX-sensitive currents may be partly responsible for the difference in AVN cycle length and thereby in the AVN rate/ pacemaking between adult male and female