Gender differences in the electrophysiological properties of rabbit atrioventricular node

Abstract EN

There are gender differences in the electrocardiographic parameters and in the prevalence of arrhythmias.

Women have faster heart rate, 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 AVN preparations from adult male and female New Zealand White rabbits under control conditions and after the application of ion channel blockers.

Cycle length of isolated AVN preparations was significantly longer in adult female as compared to adult male.

2 mM Cs+, an If blocker, significantly increased the cycle length of adult male (i.e.

slowed the spontaneous ac vity of the AVN; by 120%) and tended to increase the cycle length in adult female by 28%.

Hundred nM TTX, a blocker of TTX sensitive neuronal INa, 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..