已知吸纸烟对心血管系有许多有害的效应。患冠状动脉疾病的吸烟者死亡率增高,心肌梗塞或猝死的发生率较高。吸烟后运动诱发的心绞痛与心肌缺血在较低的运动量即发生。一致认为尼古丁及一氧化碳是烟草中主要引起心血管系及代谢改变(如收缩及舒张压升高、心率加快、心肌氧耗增多、循环中的儿茶酚胺量及碳氧血红蛋白增加)的成分。吸大量尼古丁含量高的纸烟引起的改变较吸中等量尼古丁含量低的纸烟严重。因为关于纸烟或雪茄烟对心肌收缩力的效应所知极少,我们打算确定在增加心肌氧耗的因素中,收缩力的改变是否起着主要作用。特别是尼古丁及一氧化碳对左室功能的急性影响 Smoking cigarettes are known to have many detrimental effects on the cardiovascular system. Smokers with coronary artery disease have a higher mortality rate and a higher incidence of myocardial infarction or sudden death. Post-smoking exercise-induced angina and myocardial ischemia at a lower amount of exercise that occurs. It is agreed that nicotine and carbon monoxide are components of tobacco that cause mainly changes in cardiovascular system and metabolism such as increased systolic and diastolic blood pressure, increased heart rate, increased myocardial oxygen consumption, circulating catecholamines and carboxyhemoglobin. Absorption of a large amount of nicotine increased cigarette smoke caused more changes than the same amount of nicotine in cigarettes with low cigarette smoke. Because little is known about the effect of cigarettes or cigars on myocardial contractility, we intend to determine whether a change in contractility plays a major role in factors that increase myocardial oxygen consumption. In particular, the acute effects of nicotine and carbon monoxide on left ventricular function