Circadian variation of short-lasting asymptomatic paroxysmal supraventricular tachycardia.

This study determines the circadian variation of transient asymptomatic paroxysmal supraventricular tachycardia (PSVT). A total of 416 asymptomatic PSVT episodes (> or = 10 consecutive supraventricular beats) recorded in 62 patients were obtained from Holter monitoring. The incidence of the onset of PSVT was counted at the 1-hour interval. The duration (beats) and rate (beats/min) of PSVT and the preceding heart rate were also evaluated. The circadian variations of the onset, duration, and rate of PSVT were analyzed by the single cosinor method. The incidence of the onset of PSVT showed a significant circadian variation (P = .001); with high incidence in the daytime and low at nighttime. The rate and duration of PSVT also showed significant circadian variation (P = .02), faster and longer in daytime and slower and shorter at night, respectively. The rate (r = .45, P < .001) and duration (r = .22, P < .001) of PSVT correlated significantly with the preceding heart rate. Our findings suggest that the onset and persistence of short-lasting asymptomatic PSVT exhibit a circadian pattern and that autonomic tone might play an important role in the genesis of this form of PSVT.