First- and Second-Degree A-V Heart Block with Rapid Eye Movement Sleep

A 56-year-old man with acute congestive heart failure was noted to have episodes of heart block in sleep that were associated with dreaming. He was studied with simultaneous electroencephalographs, electrooculographic, electrocardiographic, and respiratory measurements for a period of 52 consecutive hours. There was a statistically significant relationship between the REM (rapid eye movement) stage of sleep and brief episodes of first- and second (2:1) degree A-V heart block but none with other forms of observed arrhythmias (premature atrial and ventricular contractions). Periods of arousal from REM sleep, but not from non-REM sleep, were also significantly related to heart block. A follow-up study 7 months later showed no cardiac arrhythmias during sleep or wakefulness.