Short-term effect of cigarette smoking on homogeneity of ventricular repolarization in patients with congestive heart failure

Opinions differ about the role of smoking cigarettes on homogeneity of ventricular repolarization. The aim of this study was to investigate the short term effect of cigarette smoking on QT dispersion (QTD) as a measure to evaluate the ventricular repolarization homogeneity in patients with Congestive Heart Failure (CHF) and healthy smokers. In this experimental study، 40 patients with CHF and 40 healthy individuals، (all smokers)، matched for gender and age، were enrolled. The magnitude of QTD before and immediately after smoking a cigarette with 1. 7 mg nicotine was measured and compared between them. QTD in patient with CHF was 55. 1±13. 7 msec before and 64. 2±13. 7 msec after smoking a cigarette; in the control group، the figures were 42. 16 ±14. 2 and 47. 3±17. 1 respectively. Difference between two groups was statistically significant (p=0. 001). Also، the scale of QTD was significantly higher in patients with CHF before and after smoking compared to control group (p=0. 032 and 0. 001 respectively). Finally we observed that increase in QTD in patients with CHF (9. 4±4 msec) was significantly greater than that of healthy group (4. 7±2. 5). (p=0. 001). Cigarette smoking، even for a short period، can increases QTD and may lead to ventricular arrhythmia and sudden cardiac death both in healthy smokers and in patients with CHF; magnitude of this effect is much higher in the latter group. It is crucial that patients with CHF stop smoking and avoid places polluted with cigarette smoke.