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.

Study of Cardiac Rate and Rhythm Patterns in Ambulatory and Hospitalized Children

“…Differences between recordings of ambulatory and hospitalized children are unlikely because rhythmic events occur mainly during sleep, such as minimal heart rate, marked sinus arrhythmia or conduction disorders. On the other hand, differences may be observed in the heart rate distribution, which depends on the physical activity, and also in the incidence of arrhythmias, which depends on the autonomic balance, physical activity, emotional stress, circadian rhythms or heart rate itself [10]. The pathophysiological mechanisms underlying the genesis of arrhythmia remain substantially unknown.…”

“…The pathophysiological mechanisms underlying the genesis of arrhythmia remain substantially unknown. The dependency of ventricular arrhythmia on circadian rhythms during childhood has been demonstrated [10]. Moreover, it is possible to identify a spontaneous trend between their incidence and the length of the preceding cardiac cycle [10].…”

“…The dependency of ventricular arrhythmia on circadian rhythms during childhood has been demonstrated [10]. Moreover, it is possible to identify a spontaneous trend between their incidence and the length of the preceding cardiac cycle [10]. In children, there is usually a tachycardia-enhanced relationship: the shorter the cycle length, the higher the incidence of ventricular arrhythmia.…”

“…In children, there is usually a tachycardia-enhanced relationship: the shorter the cycle length, the higher the incidence of ventricular arrhythmia. The phenomenon is also characterized by the existence of a window of heart rate above and below which arrhythmia disappears [10]. One can speculate that upper limits are influenced by sympathetic activities and lower limits by vagal activities.…”

Advancements in the diagnosis and management of premature ventricular contractions in pediatric patients

“…In older children and young adults, the incidence increases, although exact numbers are unknown since most patients are asymptomatic ( 14 ). Pediatric PVCs exhibit variability in terms of frequency, complexity, and configuration, which can change over time and may be influenced by factors such as age, autonomic tone, and myocardial substrate ( 15 ). Holter monitoring studies have demonstrated a higher prevalence, detecting PVCs in up to 41% of children over a 24-hour period, suggesting that intermittent PVCs may be a common and transient occurrence in this demographic ( 16 ).…”