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[Circadian variability of rhythm disorders]
1Division de cardiologie, Centre hospitalier universitaire vaudois (CHUV), Lausanne.
Insights
Cardiac arrhythmias show daily rhythms, particularly dangerous ventricular tachycardia and sudden cardiac death. Morning adrenergic surges are a key trigger, but beta blockers can significantly reduce this risk.
Area of Science:
- Cardiology
- Chronobiology
- Pharmacology
Context:
- Cardiac arrhythmias, including sustained ventricular tachycardia and sudden cardiac death, display significant circadian variability.
- Physiological adrenergic stimulation during morning hours, marking the transition from nocturnal to diurnal activity, is a recognized arrhythmogenic factor.
Purpose:
- To investigate the circadian patterns of cardiac arrhythmias.
- To evaluate the efficacy of beta-blocking agents in mitigating arrhythmia risk during high-incidence periods.
Summary:
- Circadian variability is prominent in cardiac arrhythmias, with increased risk observed during morning hours due to adrenergic stimulation.
- The Beta-Blocker Heart Attack Trial (BHAT) demonstrated that beta-blocking agents substantially reduce the risk of sudden cardiac death during these morning hours.
Impact:
- Findings suggest that the timing of beta-blocker administration should be considered in managing patients at risk for cardiac arrhythmias.
- This highlights the importance of chronotherapy in cardiovascular medicine for optimizing patient outcomes.
Abstract:
Cardiac arrhythmias exhibit also a circadian variability. It is impressingly apparent in sustained ventricular tachycardia and sudden cardiac death. Adrenergic stimulation during morning hours, a physiologic event for the transition from nocturnal to diurnal activity, appears to be an important arrhythmogenic factor (25). The results of the BHAT-study show that beta blocking agents may substantially reduce the risk for sudden cardiac death during morning hours. This notion should thus be considered in treating patients at risk.