The circadian variation of premature XXXX .

@entity11706 @entity955
AIMS: The aim of the study was to assess a possible circadian variation of premature @entity11706 (PACs) in a community-based population and to determine if the daily variation could be used to assess a more vulnerable period of PACs in predicting later incidence of @entity955 ( @entity955 ). METHODS AND RESULTS: We studied 638 subjects between the ages of 55 and 75 years from the Copenhagen Holter Study who underwent up to 48 h electrocardiogram recording. Follow-up on cardiovascular endpoints was performed in 2013 with a median follow-up time of 14.4 years. According to previous studies, two subgroups were studied based on a cut-off point of >= 720 PACs/day termed frequent PACs (n = 66) and not frequent PACs with <720 PACs/day (n = 572). Based on median values, a circadian rhythm could not be demonstrated in the population as a whole and the group without frequent PACs. However, a circadian variation was observed in the group with frequent PACs, who had the fewest PACs/h during the night with a nadir at 6 am and then reaching a peak value in the afternoon at 3 pm. Runs of PACs in all subjects showed a similar circadian variation. Both PACs/h and runs of PACs seemed to follow the daily variation in heart rate. After adjusting for relevant risk factors, the risk of @entity955 was equal in all time intervals throughout the day. CONCLUSION: Premature @entity11706 showed a circadian variation in subjects with frequent PACs. No specific time interval of the day was more predictive of @entity955 than others.
