Related Experiment Video
Updated: Aug 2, 2026
Assessing Cerebral Autoregulation via Oscillatory Lower Body Negative Pressure and Projection Pursuit Regression
Published on: December 10, 2014
Circadian heart rate variability in patients with primary arterial hypertension
Władysława Kolasińska-Kloch1, Agata Furgała, Tomasz Banach
1II Klinika Kardiologii Instytutu Kardiologii, Collegium Medicum Uniwersytet Jagielloński, Kraków.
Insights
Antihypertensive treatment with angiotensin-converting enzyme inhibitors (ACEI) did not improve cardiac autonomic function in hypertensive patients. Long-term ACEI therapy did not alter circadian heart rate variability, suggesting persistent autonomic dysfunction.
Area of Science:
- Cardiology
- Autonomic Nervous System Function
- Hypertension Research
Background:
- Autonomic nervous system (ANS) dysfunction is implicated in essential hypertension.
- Limited data exists on the impact of antihypertensive treatments, specifically ACE inhibitors (ACEI), on cardiac ANS activity.
Purpose of the Study:
- To evaluate changes in circadian heart rate variability (HRV) in primary hypertension patients treated with ACE inhibitors.
- To assess the effect of enalapril on cardiac autonomic function over one year.
Main Methods:
- Fourteen "dipper" hypertensive patients and 14 healthy controls underwent 24-hour ambulatory blood pressure and ECG monitoring.
- Hypertensive patients were assessed before and after one year of enalapril treatment.
- Circadian HRV analysis utilized Fast Fourier Transformation (FFT) for time and spectral domain parameters.
Main Results:
- Healthy controls exhibited significant circadian fluctuations in sympathetic and parasympathetic activity, with increased night-time HRV parameters and a decreased night/day LF/HF ratio.
- After one year of ACEI treatment, hypertensive patients showed significant increases in RMSSD, pNN50, TP, VLF, LF, and HF, with a non-significant increase in the night/day LF/HF ratio.
- Daily HRV parameters improved with ACEI treatment (increased pNN50 and RMSSD, decreased LF/HF ratio), but night-time HRV parameters showed no significant changes.
Conclusions:
- Reduced night-time vagal activity may contribute to essential hypertension pathogenesis.
- ACEI treatment did not restore circadian cardiac autonomic function in hypertensive "dippers", despite blood pressure normalization.
- Persistent circadian cardiac autonomic dysfunction is suggested in this patient subgroup even after long-term ACEI therapy.
Introduction:
Abnormalities of autonomic nervous system function (ANS) exist in patients with hypertension and have been considered as one of the important factors in developing of essential hypertension. However the information about the effect of antihypertensive treatment (angiotensin-converting enzyme inhibitors--ACEI) on cardiac ANS activity is scarce. The main aim of our study was to evaluate circadian heart rate variability changes in primary hypertension treated with ACE inhibitors.
Methods:
Fourteen patients with essential hypertension with night/day differences of mean blood pressure of more than 10% (dippers) aged 26 to 61 years (mean 52.9 +/- 9.2) and 14 healthy volunteers, 14 healthy volunteers were recruited and matched for age and gender. Ambulatory 24 hour arterial blood pressure measurement using HolCARD (Aspel, Poland) recorder with simultaneous ECG monitoring using the Mediarc-Premier IV Holter Monitoring System (DRG-International) undertaken in both groups of patients. The hypertensive patients were tested before and after one year of the enalapril treatment. The HRV analysis was performed according to a standard Fast Fourier Transformation (FFT). The time and spectral analysis parameters were compared within the examined groups of patients during day and night.
Results:
The results obtained in the control group showed the great circadian fluctuations in sympathetic and parasympathetic activity. A simultaneous circadian HRV evaluation showed also significant increases in night RMSSD, TP, VLF, LF and HF mean values (p < 0.05) with significantly decreased night LF/HF ratio (p < 0.05) in comparison to the day time recordings. After one year of ACE inhibitors treatment, we noted the following circadian changes: Significant increase of RMSSD, pNN50 (p < 0.05), TP, VLF, LF and HF (p < 0.05) parameters with non-significant increases in LF/HF ratio during night recording. A comparison between daily HRV parameters, before and after 1 year of ACEI treatment, presented significant increases in pNN50 and RMSSD mean values (p = 0.01) and decreases in LF/HF ratio, with simultaneous withdrawal of spectral parameters. However, no significant changes in comparison of night HRV parameters before and after ACEI intake were observed.
Conclusions:
Our observations support an attenuation of night vagal activity as an important factor in the pathogenesis of essential hypertension. The lack of effect of ACEI treatment on circadian heart rate variability parameters in patients with essential hypertension, despite long-term normalisation of blood pressure, suggests persistent circadian cardiac autonomic dysfunction in the "dippers" subgroup of patients.
Related Concept Videos
01:30Factors Influencing Heart Rate
Let us explore the significant factors affecting heart rate, including age, body temperature, posture, acute pain, chemical influences,...
01:28Special considerations while measuring blood pressure
Monitoring Both Arms:
Monitoring BP in both arms during the initial assessment is advisable, as the systolic value may differ by five to ten mm Hg between arms. For subsequent BP assessments, use the arm with the higher reading.
01:18Hypertension and Regulation of Blood Pressure
01:15Chronopharmacokinetics: Circadian Rhythms and Influence on Drug Response
The time of drug administration is an important factor to consider, as it can influence the toxic dose of a drug. For example, a study conducted by Prins et al. in 1997 examined the effects of the timing of...
01:29Hypertension II: Pathophysiology
01:30Hypertension III: Clinical Manifestations and Diagnostic Studies