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[Effects of antihypertensive therapy with selective and non-selective beta blocking agents on dimensions and function
Insights
Beta-blockers effectively lower blood pressure in hypertensive patients. Cardioselective beta-blockers impact left ventricular dimensions, while those with intrinsic sympathomimetic activity affect peripheral resistance.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Hypertension management often involves beta-blockers.
- Understanding the influence of beta-blocker properties like cardioselectivity and intrinsic sympathomimetic activity (ISA) is crucial for optimizing treatment.
- Echocardiography provides valuable insights into cardiac dimensions and function.
Purpose of the Study:
- To investigate the effects of different beta-blockers, varying in cardioselectivity and ISA, on hemodynamic parameters and left ventricular (LV) characteristics in hypertensive patients.
- To compare the antihypertensive efficacy and impact on LV structure and function among various beta-blockers.
Main Methods:
- A randomized study involving 72 hypertensive patients (mean age 43).
- Patients received placebo for 15 days, followed by 1 month of active therapy with acebutolol (ACEB), atenolol (ATEN), pindolol (PIND), timolol (TIMO), or nadolol (NADO).
- Echocardiography was used to assess hemodynamic effects, LV dimensions, and function.
Main Results:
- All studied beta-blockers demonstrated effective antihypertensive activity.
- Beta-blockers without ISA (atenolol, timolol, nadolol) reduced cardiac output, while those with ISA (acebutolol, pindolol) decreased total peripheral resistance.
- Cardioselective beta-blockers (atenolol, acebutolol) increased LV end-diastolic dimension and stroke volume.
- Interventricular septum thickness decreased with timolol and nadolol, but LV mass remained unchanged.
- No beta-blocker impaired LV function as assessed by fractional shortening.
Conclusions:
- Beta-blockers exhibit distinct hemodynamic profiles based on their cardioselectivity and ISA.
- Cardioselective agents influence LV dimensions and stroke volume, while ISA-possessing agents modulate peripheral resistance.
- These findings highlight the importance of beta-blocker subclass selection for tailored antihypertensive therapy without compromising LV function.
Abstract:
The influence of cardioselectivity and/or intrinsic sympathomimetic activity (ISA) of betablockers on hemodynamic antihypertensive effect and on left ventricular (LV) dimensions and function was studied by echocardiography in 72 hypertensive patients, mean age 43 years. After 15 days of placebo, active therapy was given for 1 month: acebutolol (ACEB, n: 16, 400-800 mg/day), atenolol (ATEN, n: 16, 50-100 mg/day), pindolol (PIND, n: 13, 15-30 mg/day), timolol (TIMO, n: 15, 10-20 mg/day) and nadolol (NADO, n: 12, 80-160 mg/day). All betablockers showed effective antihypertensive activity. Betablockers without ISA (ATEN, TIMO, NADO) reduced cardiac output (p less than 0.05), those with ISA (ACEB, PIND) decreased total peripheral resistance (p less than 0.01 and p less than 0.05 respectively). Independently from ISA, cardioselective betablockers (ATEN, ACEB) increased LV end diastolic dimension and stroke volume (p less than 0.05). LV mass was not changed, although interventricular septum thickness decreased after TIMO and NADO (p less than 0.05). LV function, as assessed by fractional shortening, was not impaired by any betablocker.