Studies of arrhythmias by 24-hour polygraphic recordings: relationship between atrioventricular block and sleep states.

The relationship between AV conduction disturbances and sleep states was investigated using continuous polygraphic recordings for one full night. The results were as follows: (1) In the case of first-degree AV block, the phasic shortening of the PQ interval was observed during rapid eye movement (REM) sleep. (2) In the case of second-degree AV block (Wenckebach type), the conduction ratio increased transiently during REM sleep and significant relationships were observed between the number of nonconducted P waves and the mean heart rate in each sleep stage. (3) In the case of advanced AV block, complete AV block was observed less frequently during REM sleep and the period of falling asleep. Since the reproducibility of these results from night to night has not yet been investigated, additional evaluation is required.