RESUMO
Post operative Atrial Fibrillation [AF]. Occurs up to 50% in cardiac surgery patients and represent the most common post operative complication. Although malignant ventricular tachycardia [V.T.] is uncommon arrhythmic complication early after cardiac surgery - it has a negative impact on mortality. The etiology of these arrhythmias [AF, V.T] after open heart surgery is incompletely understood and their prevention remains suboptimal. Identification of patients vulnerable for post operative [AF, V.T.] would allow targeting of these patients to benefit from aggressive prophylactic intervention. The aim of this work is to evaluate the incidence and identify risk factors of [AF, sustained V.T.] early postoperatively after cardiac surgery. 40 patients with a mean of age [55 +/- 10] years old [20 male, 20 female] under went isolated elective cardiac surgery [20 patients for valve replacement and 20 patients for CAPG]. Demographic and clinical data preoperative, operative and postoperative were collected. Patients continuously monitored and hemodynamically significant [AF, VT] were recorded. Detailed analysis was performed to define the risk factors. Post operatively AF occurred in [17/40] 42.5%. The mean age for patients with postoperative AF was 55 +/- 7.3 years old compared with 47.7 +/- 9.3 years old for patients without AF P<0.05. The mean heart rate variability [RMSSD] significantly differed between patients with post operative AF and patients without [15 +/- 2.1 msec VS 25 +/- 3 msec P<0.05]. The mean of P wave dispersion for patients with po AF was significantly prolonged compared to patients without AF [80 + 11 msec VS 42 +/- 12 msec, P<0.05]. Multivariate logesitic analysis [odds ratio +/- 95% CI, P value] was used to identify the following independent predictors of post operative AF: increasing age above VS below the mean age [OR = 2.8 CI [1.2-3.5] P<0.0] valve surgery VS CAPG [OR= 2.75 CI [1.2- 3.2] P<0.05], preoperative non use of beta blockers [OR= 1.5 CI [1.1-4.2] P<0.05] Considering several operative variables, use of internal mammary artery, pulmonary venting, cardiopulmonary bypass time, and aortic cross clamping time were significantly differed between the group with AF. And the group without AF. [26.6% VS 73.4% P=0.001] [71.4% versus 28.6% P=0.001], [113.8 +/- 33.5 m versus 92.4 +/- 36.3 m, P=0.002]. [97.8 +/- 21.5, versus 71.3 +/- 9.3, P = 0.001] respectively. Only one patient developed sustained VT post operatively [2.5%] of total study population, she was female had longer pump time than patient without sustained VT [120 min VS 80 +/- 9.5 min P<0.05]; longer Aortic cross clamping time [103 min VS 60 +/- 20 min P<0.05]; had increased QT[c]D than patient without sustained VT [120 msec VS 80 +/- 5 msec, P<0.05]. Patients with and without hemodynamically significant AF and sustained VT had similar body mass index preoperative heart rate and preoperative blood pressure. AF remains the most common complication after cardiac surgery. Increasing age and type of surgery identifies patients at risk for development of AF after cardiac surgery. Female sex, longer pump time, aortic cross clamping time, are independent predictors of developing sustanined VT post operatively. Increased QT[c] dispersion, decreased HRV, Root square of the mean of the sum of the Square of differences between adjacent R-R intervals [RMSSD] and increased PWD after cordic surgery may reflect disrupted electrophysiological stability of the myocardium and thus electrophysiological substrate for triggering malignant arrhythmias