[BRADY-ARRHYTHMIAS IN THE OBSTRUCTIVE SLEEP APNEA SYNDROME: DANGEROUS COMPLICATION OR DEFENSE MECHANISM?].

Sleep is characterized by cycling and consecutive alternation of different phases and stages, each of them featuring intrinsic changes of vegetative regulation with oscillations of heartbeat rate that may cause development of cardiac rhythm disorders especially under presence of concomitant somatic diseases. This paper deals with the problems of interrelationships between disturbances of heart conduction and obstruc- tive sleep apnea. It is shown that some mechanisms of the occurrence of brady-arrhythmias (first of all, features of vegetative regulation with increasing parasympathetic tone) under sleep arrests are inherent to human divers as well as to mammals conducting water or near-water way of living associated with forced breathing delays at diving and prolonged staying under water. These mechanisms may carry out defense function.