CIRCADIAN PATTERN AND RELATIONSHIP WITH HEART RATE VARIABILITY OF FREQUENT VENTRICULAR PREMATURE BEATS IN PATIENTS WITHOUT STRUCTURAL HEART DISEASE
In the daily practice management of frequent ventricular premature beats (VPB) could be difficult in thesetting of patients without significant heart disease. In our work, keeping in mind the potential impact on therapy, we studied the circadian distribution of VPB and their relationship with statistical parameters of heart rate variability (HRV).Methods.The 24 hours Holter recordings (Labtech EC-3H) of 20 symptomatic (palpitations) patients (9 women, 11 men, mean age 58.9 years) free of structural heart disease were processed for the study. All the patients have 1500 VPB on the Holter recording. The VPB were expressed in absolute and relative (% of total beats) hourly numbers. The circadian pattern was studied using t-test, the day being divided in three time-periods (16:00-22:00, 22:00-06:00, 06:00-16:00). We also studied the correlation between the ln transformed values of average hourly number and the relative number of VPBand the average hourly values of global and vagal HRV parameters (meanNN, SDNN and rMSSD) using Pearson`s correlation.Results. There was no significant (p>0,3 for each comparation) tendency for circadian distribution of VPB. The number of VPB showed a significant correlation with rMSSD (r=0,51 and p=0,02 for the relative number), which became even stronger when the number of VPB was >8000/day (r=0,65 and p=0,04 for both the absolute and relative number).
Conclusions. In patients without structural heart disease does not exist a specific circadian distribution pattern of VPB. The significant correlation with the vagally mediated parameter rMSSD underlines the triggering/permitting effect of parasympathetic tone, which suggests that initiation of betablocker treatment could not be a routine therapeutic approach.