Tobacco: A Precipitating Factor in Angina Pectoris

Ten patients with classical angina pectoris due to coronary artery disease were exercised in an upright position with a fixed exercise load on a bicycle ergometer until they developed the first manifestation of angina pectoris. They each performed this exercise four times in a nonsmoking state and four times after smoking a cigarette of high nicotine content for 5 min. All subjects developed angina sooner if they smoked before exercising. The average percent of shortening of the exercise period before angina developed in the smoking state as compared with the nonsmoking state was 24. All patients developed an increase in the modified tension-time index after smoking. This increase represents an increase in myocardial oxygen consumption. After exercise, patients with diseased coronary arteries who smoke may not meet the increased demand for myocardial oxygen and, therefore, may develop angina sooner.