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Hemodynamic long-term effects of timolol at rest and during exercise in essential hypertension
Insights
Timolol effectively treated essential hypertension in men, significantly reducing blood pressure, heart rate, and cardiac output. This beta-blocker therapy lowered resting and exercise hemodynamics with no severe side effects observed.
Area of Science:
- Cardiovascular Medicine
- Clinical Pharmacology
Background:
- Essential hypertension is a prevalent cardiovascular risk factor.
- Hemodynamic alterations characterize untreated hypertension.
Purpose of the Study:
- To evaluate the hemodynamic effects of timolol in patients with essential hypertension.
- To assess changes in blood pressure, heart rate, and cardiac output after one year of timolol treatment.
Main Methods:
- A prospective study involving sixteen out-patients with WHO stage I essential hypertension.
- Hemodynamic parameters including oxygen consumption, heart rate (HR), cardiac output (Q), and intraarterial brachial pressure were measured at rest and during exercise.
- Measurements were repeated after one year of treatment with timolol as the sole antihypertensive medication.
Main Results:
- Timolol treatment resulted in significant reductions in resting blood pressure (approx. 18%) and exercise blood pressure (approx. 14%).
- Heart rate (HR) decreased by approximately 26% at rest, and cardiac index (CI) reduced by 28% (supine) and 32% (sitting).
- Cardiac output (Q) decreased by 25-30% during exercise, while total peripheral resistance significantly increased. The product of mean arterial pressure and HR was reduced by about 40%.
Conclusions:
- Timolol effectively reduces blood pressure and cardiac output in patients with essential hypertension.
- The drug appears to increase total peripheral resistance, contributing to blood pressure reduction.
- Timolol demonstrates a favorable hemodynamic profile for managing essential hypertension without severe adverse events.
Abstract:
Sixteen men with previously untreated essential hypertension in WHO stage I have been studied as out-patients. Oxygen consumption, heart rate (HR), cardiac output (Q) (Cardiogreen) and intraarterial brachial pressure were recorded at rest in supine and sitting position and during steady state work at 300, 600 and 900 kpm/min. The subjects were treated with timolol as the sole drug for one year and the hemodynamic study was repeated. BP was reduced approximately 18% at rest and 14% during exercise, HR approximately 26% and the cardiac index 28% at rest supine and 32% at rest sitting. During exercise the reductions in Q were 25-30%. The calculated total peripheral resistance was significantly increased at rest as well as during exercise. The product of mean arterial pressure and HR was reduced about 40%. No severe side-effects were seen.