What Precedes Atrial Ectopy: An Analysis in Healthy Sleeping Children

JURA AUGUSTINAVICIUS; GUIDO SIMONELLI; COLIN SHAPIRO; DANIEL E. VIGO; DAVID NEWMAN

Congreso; Canadian Cardiovascular Congress 2013; 2013

Background: Absolute magnitude of spontaneous atrial ectopy in healthy young people has not been established, but is thought to occur more often during sleep. The occurrence of atrial ectopy may presage atrial arrhythmia. We sought to assess the magnitude of atrial ectopy in healthy children and adolescents without any structural heart disease or cardiac symptoms. We hypothesized that autonomic modulating factors may have a role in determining the occurrence of atrial ectopy. Methods: Children and adolescents between 7 and 18 years were recruited for the study. Holter monitors were worn for 24-­hours. Day and night segments were identified per participant from a device that has been validated for sleep and wake assessment based on locomotor activity (Actigraphy). Time and frequency domain heart rate variability (HRV) measures were analyzed over 24-­hours. Instantaneous peak ectopy during the night was identified and HRV measures were assessed in the 5-­minute bin immediately preceding the peak in a time frame that had no ectopic beats. HRV parameters were also measured in a 5-­minute bin immediately preceding a period with no ectopy. Results: The total sample included 20 young people (7 males/13 females) with a mean age of 13.5 ± 2.97 years;8 children (≤ 12 years) and 12 adolescents (≥ 13 years). Children and adolescents had an average total of 117 ± 339 and 143 ± 300 ectopic beats over 24 hours, respectively. The mean RR interval was not different between the period preceding ectopy and the period without ectopy. The standard deviation of RR intervals (SDNN) was greater immediately preceding ectopy (100.1 ± 42.7ms) compared to a period without ectopy (67.4 ± 27.83ms), p = .01. The standardized effect size index, d, was 0.91 indicating a large effect. In those 12 years or younger, the root mean square successive difference of RR intervals (RMSSD) was greater prior to ectopy (62.6 ± 19.34ms) when compared to a no ectopy period (41.5 ± 15.41ms), p = .02. There were no differences in any other HRV measures. Conclusion: Independent of heart rate, nocturnal atrial ectopy in young healthy individuals is related to an increase in HRV indexes related to parasympathetic activity.