Study of ECG changes and left ventricular diastolic dysfunction as hemodynamic markers of myocardial stress in chronic smokers

Background: Nicotine being the chief component of cigarette smoke, is a potent inhibitor of the cardiac A type potassium channels, which contributes to the changes in the electrophysiol­ogy of heart and affects the cardiac diastolic functions. The present study was undertaken to evaluate the ECG changes, left ventricular diastolic functions and dyslipidemia in chronic smokers.Methods: 127 healthy male volunteers without any systemic illnesses, drug or alcohol intake, in the age group of 20-60 years, who attended the outpatients department of a tertiary care government hospital were recruited for the study. They were subsequently divided into smoker group consisting of 64 subjects with ≥20 pack years of smoking duration and the non-smoker group consisting of 63 subjects, who were never smokers. All the subjects were evaluated for lipid profile and 2D echocardiography was done to assess the Left Ventricular Ejection Fraction (LVEF). The ECG was recorded for all the subjects and parameters such as the heart rate, the PR interval and the QRS complex and ST interval were assessed in seconds. The QTc (cor­rected QT interval) was calculated by using Bazet’s formula.Results: The lipid profile of smokers indicated significantly high Total Cholesterol, LDL, VLDL, TG and significantly low levels of HDL in comparison to non-smokers. (p<0.001) The ECG and echocardiography analysis showed significant increase in the heart rate and shortening of QRS complex and ST interval along with significant reduction in LVEF (P <0.001) in the smokers.  Conclusion: Along with conventional markers of dyslipidemia, shortening of QRS complex, ST segment and reduced LVEF should be considered as markers of myocardial stress in chronic smokers while screening them for risk of coronary artery disease.

Association between Maternal FUT2 204A>G (rs492602) Genetic Polymorphism and Congenital Heart Disease in the Indian Population: A Study in Maternal-fetal Dyads

Background: FUT2 secretor genetic variants are strongly associated with absorption and circulatory levels of vitamin B12, thereby affecting folate metabolism pathway. The aim of this study was to evaluate the association between maternal FUT2 204A>G (rs492602) genetic polymorphism and CHD in the Indian population. Materials and method: One hundred and ten pregnant women who were vitamin B12 deficient with fetuses diagnosed with CHD were included in the case group and an equal number of healthy pregnant women with normal fetuses were selected as the control group. DNA was extracted from blood and umbilical cord tissue samples, and genotyped for FUT2 rs492602 polymorphism using allele-specific polymerase chain reaction. Hardy–Weinberg equilibrium test was used to calculate allele and genotype frequencies. Results: Significant increase in the frequency of AG (odds ratio=2.25; 95% CI: 1.25–4.05; p=0.009) and GG (odds ratio=3.51; 95% CI: 1.47-8.43; p=0.006) genotypes as well as G allele of FUT2 rs492602 were observed in the maternal case group. Furthermore, in the fetus case group, there was a significantly higher incidence of GG genotype (odds ratio=2.87; 95% CI: 1.26–6.57; p=0.018) and G allele (odds ratio=1.70; 95% CI: 1.15–2.53; p=0.009). Conclusion: FUT2 rs492602 are associated with CHD in the Indian population. Maternal genetic polymorphism that regulates vitamin B12 metabolic pathway might influence fetal cardiac development, thus serving as a predictor for CHD. Keywords: congenital heart disease, FUT2, single nucleotide polymorphism (SNP), vitamin B1

Impact of smoking on erythrocyte indices and oxidative stress in acute myocardial infarction

Context: The free radicals generated by cigarette smoke are responsible for the production of excessive oxidative stress, causing damage to the cellular and subcellular components in acute myocardial infarction (AMI). Aims: The present study is aimed to evaluate the impact of smoking on erythrocytic oxidative stress and erythrocyte indices in patients with AMI. Materials and Methods: Two hundred consecutively admitted male patients with AMI were enrolled in our study and were subsequently divided into two groups, smokers and nonsmokers. All the subjects were evaluated for lipid profile, red blood cell (RBC) indices and the antioxidant enzyme activities-catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPX) were studied. Statistical Analysis Used: The independent sample t-test was used, and P values were calculated. Results: We found significantly high (P < 0.001) hematocrit, hemoglobin (Hb) concentration, mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) in smokers. While evaluating the antioxidant enzymes, we observed a reduction in GPX activity in the erythrocytes of smokers in comparison to nonsmokers and this was found to be highly significant (P < 0.001) whereas, CAT and SOD activities even though were reduced, they were not as highly significant (P = 0.023, P = 0.006 respectively) as GPX activity. Conclusions: Along with altered RBC indices, the erythrocyte GPX activity is more reliable and sensitive indicator of oxidative stress than CAT and SOD activities for the assessment of oxidative stress in AMI patients who are smokers