title: Dependency of premature ventricular contractions on heart rate and circadian rhythms during childhood.
abstract: The aim of the present study was to identify and quantify the rate dependence of premature ventricular contractions (PVC) during childhood. A 24-hour Holter recording was performed in 16 consecutive children, aged 22 days to 11 years (mean age 5.6 years), with frequent (>5,000/day), isolated monomorphic PVC. Those PVC were identified and the length of the preceding sinus cycle was measured. The values were ordered into 50-ms class intervals, and the percentage of PVC for each class was calculated and then analyzed by linear regression analysis. On the basis of the significance of the p value, and the positive or negative value of the slope, we identified a tachycardia-enhanced, a bradycardia-enhanced, and an indifferent pattern. Chronobiologic analysis was made by the cosinor method. All the patients had upper and lower limits of cycle length beyond which PVC disappeared. A tachycardia-enhanced pattern was present in 7 patients and an indifferent one in 9 patients. In the latter a second-degree polynomial correlation was systematically found. Children but not infants had a significant circadian variation in the frequency of PVC with a very variable time of highest incidence. In conclusion, it is possible to identify a circadian rhythm of PVC and a spontaneous trend between their incidence and the length of the preceding cardiac cycle in children.
authors.affiliation: Division of Pediatric Cardiology, CHR Citadelle, University of Liège, Belgium. martial.massin@chrcitadelle.be
authors.forename: M M
authors.initials: MM
authors.lastname: Massin
authors.forename: K
authors.initials: K
authors.lastname: Maeyns
authors.forename: N
authors.initials: N
authors.lastname: Withofs
authors.forename: P
authors.initials: P
authors.lastname: Gérard
mesh_terms: D002648:Child; D002675:Child, Preschool; D002940:Circadian Rhythm / Q000502:physiology*; D015716:Electrocardiography, Ambulatory; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009200:Myocardial Contraction / Q000502:physiology*; D018879:Ventricular Premature Complexes / Q000503:physiopathology*