Mesor-hypertension: hints by chronobiologists

Area of Science:

• Cardiology
• Chronobiology
• Physiology

Background:

• Circadian and ultradian rhythms are crucial in cardiovascular pathophysiology.
• Key cardiovascular parameters like heart rate and blood pressure exhibit daily patterns.
• Accurate blood pressure assessment requires prolonged monitoring, not single measurements.

Purpose of the Study:

• To investigate the effect of the beta-blocker penbutolol on circadian rhythms of cardiovascular parameters.
• To determine if penbutolol administration eliminates physiological circadian variations in blood pressure and heart rate.
• To assess the impact of penbutolol on cardiovascular rhythms using continuous monitoring.

Main Methods:

• Utilized automatic and continuous monitoring of cardiovascular parameters over extended periods (at least 48 hours).
• Analyzed circadian and ultradian rhythms in heart rate, arterial pressure, and other relevant metrics.
• Quantified cardiovascular parameter variations and identified potential phase shifts or amplitude changes.

Main Results:

• Penbutolol administration did not eliminate the physiological circadian variations in cardiovascular parameters.
• Continuous monitoring showed prominent amplitudes in cardiovascular rhythms during penbutolol treatment.
• A significant phase shift (approx. 100 degrees delay) in heart rate was observed in one patient.

Conclusions:

• The beta-blocker penbutolol preserves normal circadian variations in cardiovascular function.
• Continuous monitoring is essential for understanding the impact of medications on cardiovascular rhythms.
• Elimination of circadian rhythms is not observed with penbutolol, suggesting preserved physiological regulation.