Related Experiment Videos
[The circadian profile of ventricular extrasystole]
1Serviço de Cardiologia, Hospital Distrital de Angra do Heroismo.
Insights
This study found significant circadian variability in ventricular premature beats (VPBs), with higher occurrences in the morning and a strong correlation with heart rate variability. These patterns persisted across patient subgroups, including those on antiarrhythmic therapy.
Area of Science:
- Cardiology
- Chronobiology
- Electrophysiology
Background:
- Circadian variability (CV) in cardiac arrhythmias is increasingly recognized.
- Ventricular premature beats (VPBs) are common arrhythmias whose temporal patterns require further investigation.
- Understanding the diurnal patterns of VPBs may inform therapeutic strategies.
Purpose of the Study:
- To determine the circadian variability of single ventricular premature beats (VPBs).
- To investigate the relationship between VPB circadian variability and heart rate variation.
- To compare VPB patterns in patients with and without antiarrhythmic therapy and with or without ischemic cardiopathy.
Main Methods:
- A retrospective analysis of Holter monitoring data from 147 patients.
- Analysis of VPB circadian variability using single and two-harmonic regression models.
- Comparison of patient subgroups based on antiarrhythmic drug use and presence of ischemic cardiopathy.
Main Results:
- Significant circadian variability of VPBs was observed, with peak occurrences in the morning and minimums during the night.
- A strong positive correlation (r = 0.95) was found between VPBs and heart rate variability.
- Subgroups, including those on antiarrhythmic drugs, showed similar CV patterns, with a notable morning increase in the antiarrhythmic group.
Conclusions:
- A significant, often bi-modal, circadian variability exists for single VPBs.
- This variability is strongly correlated with heart rate variability.
- The observed patterns are consistent across various patient subgroups, suggesting a fundamental chronobiological influence on VPB occurrence.
Study Objective:
to determine the existence of circadian variability (CV) of single ventricular premature beats (VPBs) and study its relationship with the heart rate variation; to compare sub-groups of patients (Pts) with and without antiarrhythmic therapy and with ischemic cardiopathy versus a free structural cardiopathy group.
Design:
retrospective study.
Patients And Methods:
the CV of VPBs was analyzed by Holter monitoring in 147 Pts, 93 male and 54 female with a mean age of 59 +/- 14.6. Seventy seven Pts were not taking antiarrhythmic drugs while 70 were doing it: Amiodarone 23, Propafenone 30, B-Blockers 9, Quinidine and Disopyramide 7, Flecainide 1. Sixty five Pts had ischemic cardiopathy and 37 were free of any structural abnormality. The selection criteria consisted in: 1--more than 100 VPBs/24h; 2--distribution over more than 12 hours; 3--absence of any hour with more than 35% of the total VPBs in the recording. Data were presented in a percentage form and the results evaluation was made by using single and two-harmonic regression models.
Main Results:
a CV was found to the single VPBs, with minimum values during the nocturnal period and maximum values in the morning, with a significant adjustment to the two-harmonic regression model, defined by the equation y = 4.2 - Q,559 sen (2 pi T/24) - 0.604 cos (2 pi T/24) - 0.417 sen (4 pi T/24) + 0,272 cos (4 pi T/24) (p < 0.001). A strong positive correlation was observed between VPBs and heart rate variability (r = 0.95; p < 0.001). The sub-groups of Pts, whether taking antiarrhythmic drugs or not, also showed a CV with a statistically significant two-harmonic regression pattern, with a major morning increase of VPBs in the antiarrhythmic group. The free structural cardiopathy sub-group displayed a best adjustment to the single harmonic regression model while the ischemic group exhibited a two-harmonic regression pattern.
Conclusions:
a significant circadian variability of VPBs with a bi-modality expression was determined. The majority of the analyzed sub-groups showed the same kind of variation. A strong positive correlation with the heart rate variability was observed.