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Circadian variation of cardiac performance in coronary heart disease
1Medical Clinic II, University Erlangen-Nuernberg, F.R.G.
Insights
Cardiac performance decreases throughout the day in coronary heart disease patients, even with nitrate therapy. Cardiovascular effects of nitrates show a significant circadian-phase dependency.
Area of Science:
- Cardiology
- Circadian Biology
- Pharmacology
Background:
- Coronary heart disease (CHD) affects cardiac performance.
- Circadian variations may influence cardiovascular health.
- Nitrate therapy is common for CHD management.
Purpose of the Study:
- To investigate the circadian variation of cardiac performance in patients with CHD.
- To assess the impact of nitrate therapy on these circadian variations.
- To determine the circadian-phase dependency of cardiovascular effects of nitrates.
Main Methods:
- Ten male patients with angiographically documented CHD underwent bicycle ergometry.
- Exercise tests were performed at 10 a.m., 2 p.m., and 6 p.m. under placebo and nitrate therapy conditions.
- Measurements included ST-segment depression and pulmonary capillary wedge pressure.
Main Results:
- Cardiac performance gradually decreased throughout the day, indicated by increased ST-depression and pulmonary capillary wedge pressure at equal workloads, during both placebo and nitrate therapy.
- High nitrate concentrations significantly reduced ST-depression and preload.
- Cardiovascular effects of nitrates exhibited a marked circadian-phase dependency.
Conclusions:
- A daily decline in cardiac performance occurs in CHD patients.
- Nitrate therapy can mitigate some of these effects but is subject to circadian variations.
- Understanding these circadian rhythms is crucial for optimizing cardiovascular treatment in CHD.
Abstract:
To study the circadian variation of cardiac performance in patients with coronary heart disease, three exercise tests on a bicycle ergometer were performed during the active part of the day (10 a.m., 2 p.m. and 6 p.m.), recording ST-segment depression and pulmonary capillary wedge pressure. Ten male patients with angiographically documented coronary heart disease underwent bicycle ergometry during placebo and during nitrate therapy (placebo controlled, double-blind crossover 2 x 20 mg IS-5-MN and 1 x 120 mg ISDN sustained release). During placebo as well as during nitrate therapy there was a gradual decrease of cardiac performance during the day, documented by the increase in ST-depression and pulmonary capillary wedge pressure at equal work loads. High nitrate concns led to a significant reduction of both ST-depression and preload with a marked circadian-phase dependency of cardiovascular effects.