Bigeminy Related to REM Sleep

To the Editor.—  A variety of autonomic changes occur during rapid eye movememt (REM) sleep. Of these, changes in the cardiovascular functions are perhaps of the greatest clinical interest dating from MacWilliam's¹ pioneering observation of cardiovascular disorders associated with "disturbed" sleep. The statement is commonly made that cardiac arrhythmias are frequently found in REM. The work of Nowlin et al² is usually cited. These authors described ST-T wave changes and angina in four patients during REM sleep, but no actual arrhythmias. Similar changes and changes in heart rate have been frequently reported.However, reports of REM-related arrhythmias are quite rare. Fahrion³ described a patient with paroxysmal atrial tachycardia with "heart rate variability" during dreams. Rosen-blatt et al⁴ reported an increase in premature ventricular contractions in 11 subjects in all stages of sleep, but more so in REM. However, this phenomenon appeared to be related more to