Abstract 9045: Electrocardiographic Changes Associated with Smoking and Smoking Cessation: Outcomes from a Randomized Controlled Trial

Abstract

Background Cardiovascular disease (CVD) prevalence and risk can be detected and quantified by analysis of the electrocardiogram (ECG), however the effects of smoking and smoking cessation on the ECG have not been characterized.

Methods ECGs were performed on subjects enrolled in a prospective, randomized, placebo-controlled clinical trial of the effects of 5 smoking cessation pharmacotherapies. 12-lead ECGs from the baseline and 3-year visits were read in duplicate. Smoking burden was described by pack-years. Current smoking was described by cigarettes/day. Abnormalities were classified using the Minnesota ECG Code Classification (major and minor criteria). The effects of (i) smoking burden on the prevalence of ECG findings, and (ii) smoking and smoking cessation on ECG changes after 3 years were investigated by multivariable linear and multinomial regression analyses.

Results At baseline, the 532 smokers were (mean [SD]) 43.3 (11.5) years old, smoked 20.6 (7.9) cigarettes/day, and had a smoking burden of 26.7 (18.6) pack-years. Major and minor ECG criteria were identified in 87 (16.4%) and 131 (24.6%) of subjects, respectively. After adjusting for age, sex, race, education, body-mass index, fasting glucose, and lipids, major ECG criteria were associated with greater pack-years (p=0.02), but not current cigarettes/day (p=0.23). After 3 years, 42.9% of subjects were abstinent from smoking. New major and minor ECG criteria were observed in 7.2% and 15.6% of subjects respectively, but in a similar number of abstinent subjects and continuing smokers (p>0.2 for both). Continuing smokers had a significant reduction in current smoking (-8.4 [8.8] cigarettes/day, p<0.001) compared to baseline.

Conclusions Even in relatively young adults, major ECG abnormalities are independently associated with smoking burden. After 3 years, continued smoking was not associated with an increase in ECG abnormalities, though cigarettes smoked per day decreased among continuing smokers.