Latent myocardial ischemia in healthy middle age chronic smokers: exercise stress test study

ABSTRACT

60 apparently healthy males participated in this study, group 1 comprised 20 non smoker individuals, group IIA comprised 22 males with < 20 years of cigarette smoking and group IIB comprised 18 males with > 20 years of cigarette smoking. Smokers were selected to fulfill criterion of smoking at least 20 cigarettes per day for at least 10 years. Treadmill exercise ECG was conducted according to Bruce protocol to predict latent myocardial ischemia. Some blood chemistry [F.B.S., uric acid, lipoprotein profile] was also done. Subjects with coronary artery disease risk factors were excluded. Basal as well as maximal heart rates in smokers nearly similar to non smokers. Maximal systolic and diastolic B.P. were higher in group IIB than other groups, also shorter duration of exercise in smoker groups was noted. Three subjects [7.5%] of smokers developed VPBs, one of them in group IIB who developed ventricular bigeminy associated with typical chest pain and positive ECG for ischemia. Among smokers latent myocardial ischemia was diagnosed in two cases [5%] and according to duration of smoking the incidence was 11% versus 0% in group IIB and group IIA respectively. Neither latent myocardial ischemia nor arrhythmias was reported among non smokers. Total cholesterol / HDL and LDL/HDL ratios were higher in smokers than non smokers but did not correlate with duration of smoking. In conclusion: [1] chronic cigarette smoking is a risk not only for acute myocardial infarction as previously reported but also for latent myocardial ischemia even in absence of other risk factors. This risk is related to duration of smoking and increases with increasing age, LDL/HDL and total cholesterol/HDL ratio's. [2] lipoprotein derangement in smokers is not related to duration of smoking. [3] serial treadmill ECG rather single entrance test and a large sample of population would likely have improved the sensitivity for prediction of latent myocardial ischemia in young and middle age smokers