Electrocardiographic Changes in Young Healthy Male Smokers

Background: Smoking increases the risk of CVD, however, the magnitude of this increase in risk varies substantively according to a range of factors. Smoking-related CVD risks are highest in current and recent smokers, compared to never smokers and those who have quit in the more distant past. Risk also increases with increasing duration of use and with greater intensity of smoking, as measured by the number of cigarettes smoked per day. Methods: In the present study, a total of 60 male smokers having a history of smoking of more than 2 years and smoking at least 3 cigarettes per day were included in the study, provided they met the inclusion and exclusion criteria. 60 healthy male patients were included as controls/non-smokers. Demographic details were noted. Past, present and other relevant histories were recorded. Physical examination was done. Standard 12 lead ECG was done in the resting state after 2 hours of abstinence from strenuous physical activity, smoking and/or any caffeinated beverages. Results: In the present study, it was observed that the mean age of the non-smokers was lower (27.85 ± 5.11 years) than that of smokers (30.22 ± 5.26 years); P value: 0.014. Only males were included in the present study. The BMI and heart rate were similar in the smokers and non-smokers; P value: more than 0.05. The majority of the cases had normal axis on ECG in both the groups (86.66% in non-smokers and 70% in smokers). Left axis deviation was more common than the right axis deviation in both the groups. The difference between the two groups was statistically insignificant; P value: 0.063. The width and height of the P wave were similar in both the groups; P value: more than 0.05. The R wave was significantly bigger in the smokers (12.53 ± 4.63 mm) than in the non- smokers (10.05 ± 2.93 mm); P value: 0.001. The duration of PR interval was significantly more in the smokers (140.10 ± 18.37 ms) as compared to non-smokers (129.45 ± 19.90 ms); P value: 0.003. T wave inversion was present in 10% cases of smokers while no case in the non-smoker group had T wave inversion; P value: 0.027. The ST segment was normal in most of the cases (98.33% in the non-smokers and 96.66% in the smokers’ groups); P value: more than 0.05. All the cases in both the groups had normal sinus rhythm with normal PR interval, no tall T wave, no wide QRS interval or shortened QT interval. Conclusion: The study concluded that the smokers have a mean age of 30.22 ± 5.26 years. The heart rate is similar to non-smokers. In general, normal axis on ECG is more common. Left axis deviation is more prevalent than right axis deviation. Smokers have bigger R waves, increased PR duration and inverted T waves. This may be because smoking generally causes a transient increase in heart rate and ECG changes, especially those pertaining to ST-T segment.