Influence of the time of myocardial ischemia on the electrocardiographic conduction intervals after surgical correction of aortic valvular stenosis

UNLABELLED: The development of conduction disturbances after aortic valve replacement is a well-known complication. Since during the surgical procedure it is necessary to use extracorporeal circulation, it is plausible that the degree of myocardial ischemia (secondary to clamping of the aorta) contributes to the increase of the electrocardiographic conduction intervals. AIM: To understand if the time of myocardial ischemia performed at the surgical correction of valvular aortic stenosis is associated with increased post-operatory electrocardiographic PR, QRS and QT intervals. MATERIAL AND METHODS: 120 individuals were consecutively and retrospectively studied who exclusively underwent aortic valve replacement for aortic valve stenosis, between 2008 and 2010, at Centro Hospitalar de Vila Nova de Gaia/Espinho. Of the various parameters collected, were analysed the time of myocardial ischemia and electrocardiographic PR, QRS and QT corrected for heart rate intervals, at the time of admission and before hospital discharge. Then the value of the difference (variation) between the intervals after and before surgery was calculated. RESULTS: In the sample studied (age 72 ± 10 years, TIM 58 ± 16 minutes), there is insufficient statistical evidence to state that the myocardial ischemia time and the variation of the PR (p=0,108), QRS (p=0,065) and QT corrected for heart rate (p=0,799) are related. CONCLUSIONS: The duration of myocardial ischemia does not influence the electrocardiographic intervals after surgical correction of aortic valve stenosis. However, after surgical intervention, there is an increase in PR and QRS intervals.