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Left ventricular muscle mass and diastolic function in patients with essential hypertension under long-term clonidine
J Hüting1, V Mitrovic, J Thormann
1Kerckhoff-Klinik, Max-Planck-Society, Bad Nauheim, Germany.
Insights
Clonidine therapy for hypertension reduced left ventricular hypertrophy but did not improve overall cardiac function. Echocardiography showed structural changes without significant functional enhancement in patients with essential hypertension.
Area of Science:
- Cardiology
- Pharmacology
- Hypertension Research
Background:
- Essential hypertension often leads to left ventricular (LV) hypertrophy.
- Clonidine is used for hypertension management, but its effects on LV structure and function require detailed investigation.
Purpose of the Study:
- To assess if structural changes in the left ventricle (LV) correlate with improved LV function during chronic clonidine monotherapy for essential hypertension.
- To evaluate the impact of clonidine on blood pressure, heart rate, and cardiac hemodynamics.
Main Methods:
- Prospective study involving 11 male patients with essential hypertension treated with clonidine (300-450 g/day).
- Utilized echocardiography and Doppler echocardiography to assess LV structure, mass, volume, and various functional parameters over 5.4 months.
- Monitored blood pressure and heart rate throughout the study period.
Main Results:
- Blood pressure significantly decreased (168/105 to 150/96 mmHg), while heart rate remained unchanged.
- LV muscle mass regressed (350 +/- 73g to 297 +/- 56g), and LV volume/muscle mass ratio increased (0.58 +/- 0.13 to 0.69 +/- 0.12 ml/g).
- Ejection time increased, and isovolumic relaxation time improved, but no significant changes were observed in ejection fraction, cardiac index, or other diastolic/systolic function parameters.
Conclusions:
- Chronic clonidine monotherapy in essential hypertension leads to regression of left ventricular hypertrophy and normalization of blood pressure.
- Despite structural improvements, clonidine does not reliably enhance overall diastolic or systolic left ventricular function in these patients.
Abstract:
To determine whether alterations of left ventricular (LV) structure are associated with improved LV function under chronic clonidine monotherapy (300-450 g/day) of essential hypertension, 11 male patients (age range 47-61 years) were followed for 5.4 +/- 0.9 months using echocardiography and Doppler echocardiography. Blood pressure decreased from a mean of 168/105 to 150/96 mmHg (p less than 0.01), heart rate remained unchanged (73 +/- 10 vs. 71 +/- 10 beats/min). LV muscle mass decreased from 350 +/- 73 to 297 +/- 56 g (p less than 0.02), LV volume/muscle mass ratio increased from 0.58 +/- 0.13 to 0.69 +/- 0.12 ml/g (p less than 0.005). Ejection time increased from 276 +/- 17 to 296 +/- 17 ms (p less than 0.01), whereas no significant change was found for pre-ejection period, ejection fraction, cardiac index and LV dimensions. Doppler analysis revealed improved isovolumic relaxation time (116 +/- 17 vs. 84 +/- 28 ms; p less than 0.05), but no change in isovolumic contraction duration, maximal inflow velocities, time-velocity integrals and their duration, rate of acceleration and deceleration of early and atrial filling, and of their ratios. It is concluded that no reliable improvement in diastolic or systolic LV function is observed in chronic clonidine monotherapy of essential hypertension despite a normalization of blood pressure and a regression of LV hypertrophy.