[Activation of the right atrioventricular valve in the avian heart]

Using intramural needle electrode, in situ determinations have been made of the moment of activation of the right muscular atrioventricular valve during electrical systole of the heart. In the hen, Gallus domesticus, the electrical activation of the valve was observed 8.8 +/- 1.4 ms (mean QRS duration 25 ms) whereas in the pigeon Columba livia--5 +/- 1 ms (QRS duration 17 ms) after the beginning of ventricular depolarization, i.e. during excitation of the main bulk of the myocardium of the free wall of the right ventricle.