A STUDY OF CARDIOVASCULAR AUTONOMIC FUNCTIONS IN SMOKERS

BACKGROUND AND AIM - Cigarette smoking is a prime risk factor for cardiovascular morbidity and mortality. Chronic smoking results in autonomic dysfunction leading to increased cardiovascular risk in smokers. The current study was aimed to evaluate the cardiovascular autonomic function in smokers. MATERIALS METHODS - 60 male subjects in the age group of 25 to 40 years were included in this study out of which 30 were smokers and 30 were non smokers. All the study and control subjects were informed about the study. Written and informed consents were obtained from them. The sixty study and control subjects were subjected to a battery of autonomic function tests along with resting heart rate variability which is measured using Niviqure ambulatory digital ECG recorder. The results were analysed with SPSS version 17. RESULTS - Smokers group showed a significant (P0.05) increase in mean heart rate and LF nu, LFHF ratio as compared to age matched controls. There was a statistically significant (P 0.001) reduced RR interval and HF nu (P 0.05) found among smokers. Also there was significant difference (P 0.05) observed between the mean values of autonomic function test for parasympathetic system EI ratio, Valsalva ratio, 3015 ratio among the smokers and the controls. Highly significant difference (P 0.001) was observed between the mean values of autonomic functions test for sympathetic system orthostatic standing test and isometric hand grip test among the smokers and the controls. CONCLUSION - Abnormalities of autonomic function were found in smokers which manifested as sympathetic over activity and parasympathetic withdrawal. Chronic sympathetic over activity may be associated with the adverse cardiac events in smokers. Early recognition and treatment of these may improve quality of life of smokers. The battery of autonomic function tests and resting heart rate variability identify the autonomic dysfunction at the earliest stage.