The effect of contrast dye injection and balloon inflation on QTC and QTC dispersion in 12 leads surface EKG during PTCA

BACKGROUND: Considering that determining the effect of both contrast dye injection and balloon inflation on electrophysiological parameters would help us to predict the ischemic event during PTCA, the aim of this study was to determine the effects of these factors on QTc and QTc dispersion during PTCA in Isfahan. METHODS: In this cross-sectional study, consecutive patients undergoing elective PTCA in Chamran hospital in Isfahan enrolled. All patients were in sinus rhythm. A 12-lead electrocardiogram was continuously recorded before (baseline) and during PTCA after dye injection and balloon inflation. QTc and QT dispersion was calculated in all 12 leads of electrocardiogram during the mentioned times and compared with each other. RESULTS: 33 patients with mean age of 49.1±16.2 years were studied. Anatomic distribution of the coronary artery stenosis was as follows: left anterior descending artery (LAD) in 76.7% patients, left circumflex (Cx) in 16.6% and right coronary (RCA) in 6.66%. Mean of QTc at baseline, after contrast dye injection and after balloon inflation was 423.9±28.5, 437±29 and 437±22 msec, respectively (P<0.05). Mean of QTc dispersion at baseline, after contrast dye injection and after balloon inflation was 92.3±7.2, 95.4±8.3 and 93.75±7.5, respectively (P>0.05). CONCLUSION: The findings of this research supports the fact that during PTCA a transient myocardial ischemia occurs but further studies is recommended to accurately determine the stages at which ischemia occurred and the extent of its effect of it on cardiac depolarization and repolarization periods.