Effect of smoking on QT interval, QT dispersion and rate pressure product.
BACKGROUND
Smoking may predispose to ventricular fibrillation and sudden cardiac death by altering ventricular recovery time dispersion indices. However, effect of acute smoking on QT interval and QT dispersion in chronic smokers has not been studied so far.


RESULTS
Effect of cigarette smoking on ventricular recovery time dispersion indices and rate pressure product (product of heart rate and systolic blood pressure) was investigated in 25 chronic smokers and compared with 25 age- and sex-matched non-smoker controls. There was increase in R-R interval (p<0.05). corrected QT interval, QT dispersion (p<0.001) and rate pressure product (p<0.05) in chronic smokers at baseline (before smoking) compared to non-smoker controls. On cigarette smoking, there was further increase in heart rate, blood pressure, QT dispersion and rate pressure product (p<0.001) with reduction in R-R interval (p<0.05) in chronic smokers compared to non-smoker controls.


CONCLUSIONS
Our observations indicate that there may be some relationship between prolonged ventricular recovery time dispersion indices and ventricular fibrillation and sudden cardiac death associated with smoking.
Singh
K
K
Department of Physiology, Post Graduate Institute of Medical Sciences, Rohtak.
D000328:Adult; D000367:Age Factors; D016022:Case-Control Studies; D016757:Death, Sudden, Cardiac / Q000453:epidemiology*; D004562:Electrocardiography; D005500:Follow-Up Studies; D006801:Humans; D008133:Long QT Syndrome / Q000175:diagnosis / Q000209:etiology / Q000401:mortality*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011336:Probability; D012016:Reference Values; D018570:Risk Assessment; D012907:Smoking / Q000009:adverse effects*; D014693:Ventricular Fibrillation / Q000175:diagnosis* / Q000209:etiology / Q000401:mortality*; D020257:Ventricular Remodeling / Q000502:physiology