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Left ventricular filling in hypertensive blacks and whites following adrenergic blockade

S B Dianzumba1, D DiPette, C R Joyner

  • 1Department of Medicine, Allegheny General Hospital, Pittsburgh, PA 15212.

American Journal of Hypertension
|January 1, 1990
PubMed

Insights

Combined alpha- and beta-blockade improved left ventricular diastolic filling more than beta-blockade alone in hypertensive patients. This study compared labetalol and atenolol effects on cardiac function in diverse groups.

Area of Science:

  • Cardiology
  • Pharmacology
  • Hypertension Research

Background:

  • Left ventricular diastolic dysfunction is a hallmark of hypertension.
  • Understanding racial differences in antihypertensive treatment response is crucial.
  • Adrenergic receptor blockade impacts cardiac function and hemodynamics.

Purpose of the Study:

  • To investigate the effects of combined alpha- and beta-adrenergic blockade (labetalol) versus beta-blockade alone (atenolol) on left ventricular diastolic filling in hypertensive patients.
  • To compare treatment efficacy between black and white subjects.
  • To assess changes in transmitral flow velocity ratios (A/E) as a measure of diastolic function.

Main Methods:

  • Double-blinded, randomized trial comparing labetalol and atenolol in mild to moderate hypertension.
  • Echocardiographic assessment of left ventricular dimensions and transmitral flow velocities (A/E ratio) before and after six weeks of treatment.
  • Analysis of treatment effects stratified by race (black and white subjects).

Main Results:

  • Labetalol treatment led to a significant reduction in blood pressure and improvement in the A/E ratio in white subjects, which was more pronounced than in black subjects.
  • Atenolol treatment showed a significant increase in early filling velocity (E) in whites, while late filling velocity (A) decreased significantly only in blacks, with no significant improvement in the A/E ratio.
  • While initial analysis suggested greater improvement with labetalol in whites, this difference diminished when controlling for age and blood pressure.

Conclusions:

  • Combined alpha- and beta-blockade (labetalol) demonstrated a trend towards greater improvement in left ventricular diastolic filling compared to beta-blockade alone (atenolol).
  • Differences in diastolic filling response to antihypertensive medications may exist between racial groups.
  • Further research is needed to elucidate the mechanisms behind these observed differences and optimize treatment strategies.

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