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[Smoking habit and cardiovascular diseases]
S Handa1, H Yamazaki, S Ohonishi
1Department of Medicine, School of Medicine, Keio University, Tokyo.
Insights
Smoking significantly reduces exercise capacity and coronary flow reserve in patients with ischemic heart disease. Quitting smoking for over two days can restore coronary flow reserve, highlighting the benefits of smoking cessation.
Area of Science:
- Cardiology
- Cardiovascular Physiology
- Public Health
Context:
- Smoking is a major modifiable risk factor for ischemic heart disease (IHD).
- Understanding the acute and chronic effects of smoking on the cardiovascular system is crucial for IHD management.
- Prevalence of smoking is notably higher in younger IHD patients.
Purpose:
- To analyze smoking habits in IHD patients.
- To evaluate the impact of smoking on exercise capacity and coronary flow reserve.
- To investigate the physiological mechanisms underlying smoking's effects on the cardiovascular system.
Summary:
- Analysis of 1000 IHD patients revealed high smoking rates, particularly in younger age groups (up to 86% in the 4th decade).
- In healthy volunteers, smoking decreased exercise time, elevated blood carbon monoxide and lactic acid, increased myocardial oxygen consumption, and reduced coronary flow reserve.
- Smoking lowers the threshold for myocardial ischemia, but coronary flow reserve improves after smoking cessation exceeding two days.
Impact:
- Demonstrates smoking's detrimental effects on cardiovascular function and exercise tolerance in IHD.
- Provides evidence for the reversibility of smoking-induced coronary flow reduction upon cessation.
- Reinforces the critical importance of smoking cessation as an intervention for patients with ischemic heart disease.
Abstract:
The relationship between smoking and ischemic heart disease was discussed, in terms of the smoking habit and the mechanisms of acute and chronic effects of smoking on the cardiovascular system as one of the coronary risk factors, with reference to exercise capacity and coronary flow reserve. The smoking habits of 1000 consecutive patients with ischemic heart disease, who were evaluated with coronary angiography, were analyzed. High percentages of smokers were observed in the younger generation. It was up to 86% in the 4th decade, though it was only 48% in the 8th decade. There was no large difference in other risk factors between smokers and non-smokers. The exercise capacity with and without smoking was evaluated with treadmill exercise test in 6 healthy volunteers. The exercise time was decreased with smoking, compared to without smoking, indicating a decrease in exercise capacity due to smoking. The elevated concentration of carbon monoxide in blood decreased the ability of oxygen transport. The increased lactic acid level in blood with smoking suggested anaerobic energy production acting as a part of the energy source. The smoking increased the myocardial oxygen consumption in relation to increase in heart rate and blood pressure. It decreased coronary flow reserve, shown by a peak to resting flow velocity ratio measured with the Doppler flow velocimeter. In coronary heart disease, therefore, the threshold of myocardial ischemia was decreased by smoking. The decrease in coronary flow reserve recovered with cessation of smoking for more than 2 days.