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Influence of left ventricular hypertrophy on heart period variability in patients with essential hypertension
M Petretta1, V Bianchi, F Marciano
1Institute of Internal Medicine, University of Naples Federico II, Italy.
Insights
Hypertension impairs sympathovagal balance, indicated by reduced heart rate variability. This imbalance is more pronounced in hypertensive patients with left ventricular hypertrophy, correlating with increased cardiac mass.
Area of Science:
- Cardiology
- Autonomic Nervous System Research
- Hypertension Studies
Background:
- Hypertension is a major cardiovascular risk factor.
- Left ventricular hypertrophy (LVH) is a common complication of hypertension.
- Sympathovagal balance, assessed via heart period variability, reflects autonomic nervous system function.
Purpose of the Study:
- To investigate the association between left ventricular hypertrophy in hypertensive patients and impaired sympathovagal balance.
- To quantify the impact of LVH on heart rate variability in hypertension.
Main Methods:
- Study included 40 hypertensive patients (20 with LVH, 20 without) and 20 controls.
- 24-hour ambulatory blood pressure monitoring and Holter recordings were performed.
- Power spectrum analysis of heart period variability was conducted using fast Fourier transform.
Main Results:
- Hypertensive patients showed reduced low- and high-frequency power compared to controls.
- Low-frequency power progressively decreased from controls to hypertensives without LVH, and then to hypertensives with LVH.
- Left ventricular mass index negatively correlated with both low- and high-frequency power.
Conclusions:
- Hypertension is associated with parasympathetic withdrawal, indicating sympathovagal imbalance.
- This imbalance is exacerbated in hypertensive patients with cardiac hypertrophy.
- The degree of sympathovagal imbalance is related to the extent of left ventricular mass increase.
Objective:
To evaluate whether left ventricular hypertrophy in hypertensive patients is associated with a greater impairment of sympathovagal balance assessed by means of heart period variability.
Design And Methods:
Forty hypertensive patients, 20 with echocardiographic evidence of left ventricular hypertrophy and 20 without, and 20 control subjects, were subjected to 24 h blood pressure monitoring and Holter recording on 2 consecutive days. Power spectrum analyses of heart period variability were performed utilizing the fast Fourier transform algorithm.
Results:
No difference was detectable in 24 h, daytime and night-time blood pressure values between hypertensive patients with and without left ventricular hypertrophy. Low- and high-frequency powers were higher in controls than in hypertensives; in particular, low-frequency power showed a progressive decrease through control subjects and hypertensives without and with left ventricular hypertrophy. Furthermore, significant negative correlations were found between left ventricular mass index and low- and high-frequency power. No difference was detectable in ultra-low- and very low-frequency power. During daytime low- and high-frequency power were higher in controls than in hypertensives; during night-time, low- and high-frequency power increased significantly in all groups and low-frequency power was still higher in control subjects.
Conclusions:
Considering that, when analysed over 24 h Holter recording, low- and high-frequency power both reflected the parasympathetic modulation of heart rate, the present results demonstrate a parasympathetic withdrawal in hypertension; this sympathovagal imbalance is greater in patients with cardiac hypertrophy and is related to the increase in left ventricular mass.