The auricular rhythm in patients with the Morgagni-Adams-Stokes syndrome before and after electrical cardiac stimulation

Summary

Observations were made on 17 patients with complete or incomplete atrioventricular block complicated by attacks of the Morgagni-Adams-Stokes syndrome. In ten cases the attacks were recorded electrocardiographically. In two patients an enhanced rate of auricular contraction was observed to occur before the attack. During the attacks, in which ventricular asystole lasting for 25 sec or more occurred, the auricular contraction rate was at first increased, and then decreased and arrhythmic. The Erlanger-Blackman phenomenon was found in six patients in which the automatism was initiated in the atrioventricular node.

When the rate of electrical stimulation of the ventricles was increased to above the spontaneous rhythm the frequency of the auricular contractions was reduced. In our opinion these changes are reflex. The fact we have described, that a change of sinus autornatism may be induced by electrical stimulation of the ventricles, may help in the choice of the optimal stimulus rhythm.