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Left ventricular function in mild hypertension after adrenergic blockade
S B Dianzumba1, D DiPette, C R Joyner
1Department of Medicine, Allegheny General Hospital, Allegheny-Singer Research Institute, Pittsburgh, PA 15212.
Insights
Labetalol improved left ventricular filling in mild hypertension, unlike atenolol. This combined alpha- and beta-blocker enhanced early filling velocity (E), improving the A/E and A/E/Age ratios.
Area of Science:
- Cardiology
- Pharmacology
- Hypertension Research
Background:
- Left ventricular filling abnormalities are detectable in mild hypertension using Doppler transmitral flow velocity ratios.
- Previous studies utilized the A/E and age-adjusted A/E/Age ratios to identify these abnormalities in untreated patients.
Purpose of the Study:
- To assess the double-blind effects of labetalol (combined alpha- and beta-blockade) versus atenolol (beta-blockade alone) on left ventricular filling in mild hypertension.
Main Methods:
- Twenty-seven patients with mild hypertension were randomized to receive either labetalol or atenolol.
- Echocardiographic and Doppler studies were conducted at baseline and after 6 weeks of therapy.
- Key parameters analyzed included transmitral flow velocity ratios (E, A, A/E, A/E/Age), blood pressure, and left ventricular dimensions/mass.
Main Results:
- No significant differences were observed between the groups in age, blood pressure, left ventricular dimensions, wall thickness, systolic function, or late filling velocity (A).
- Labetalol treatment significantly improved mean early filling velocity (E), and the A/E and A/E/Age ratios (p < 0.05).
- Atenolol treatment did not result in significant changes in these Doppler-derived filling parameters.
Conclusions:
- Combined alpha- and beta-blockade with labetalol positively impacts left ventricular filling in patients with mild hypertension.
- The improvement is primarily attributed to an increase in early diastolic filling velocity (E).
- Beta-blockade alone with atenolol did not demonstrate similar benefits on left ventricular filling dynamics in this patient group.
Abstract:
We previously used the Doppler transmitral flow velocity ratio A/E (A = late ventricular filling peak velocity; E = early ventricular filling peak velocity) and the age-adjusted ratio A/E/Age to detect left ventricular filling abnormalities in untreated mild hypertension. This study is a double-blind assessment of the effect of combined alpha- and beta-blockade (labetalol) and beta-blockade alone (atenolol) on left ventricular filling in mild hypertension. Twenty-seven patients blindly randomized to labetalol (12 patients) and atenolol (15 patients) treatment completed the echocardiographic and Doppler studies. Clinical and echo-Doppler data obtained at baseline and 6 weeks after initiation of therapy showed no difference between the two groups for age (49 +/- 10 vs 46 +/- 10 years), mean blood pressure (before therapy, 118 +/- 9 vs 117 +/- 8 mm Hg; after therapy, 108 +/- 12 mm Hg), left ventricular dimensions, wall thickness, systolic function, and mean late filling velocity A. There was no significant change in left ventricular mass and mass index with labetalol (left ventricular mass, 211 +/- 36 vs 216 +/- 38; mass index, 110 +/- 17 vs 112 +/- 16) or atenolol (245 +/- 41 vs 271 +/- 65; 120 +/- 18 vs 130 +/- 35). The mean velocity E, A/E, and A/E/Age ratios significantly improved with labetalol (p less than 0.05) but did not change significantly with atenolol. The improvement in A/E and A/E/Age ratios was primarily due to an increase in early filling velocity E.(ABSTRACT TRUNCATED AT 250 WORDS)