RESUMO
Placement of epicardial wires on the right atrial and right ventricle surfaces is a routine practice in cardiac surgery. These pacing electrodes are used for invasive pacing of the myocardium for a variety of emergent and elective conditions postoperatively. There is uncertainty in actual practice about the optimum time for their removal, and practice varies widely between different institutions. To determine the time related efficacy of these pacing electrodes after cardiac surgery, to find out the optimum time of their removal. July 2008 to October 2008. 47 patients those underwent coronary artery bypass surgery were prospectively enrolled and evaluated with standard 12 lead ECG and ventricle pacing threshold immediately after surgery and on the 5[th] postoperative day. The patients were divided into two subgroups according to their left ventricle ejection fraction [> 40% verses < 40%]. There was significant difference in the effective pacing threshold in group 1 and 2 on immediate post operative period and on day 5. [P = 0.002 and P = 0.02 respectively] The sensing threshold immediately after operation and on 5[th] post operative day also differed significantly [P = 0.009 in group 1 and 0.02 in group 2] The effective VVI pacing was lost in 17 patients [40.5%] on the 5[th] post operative day and comparison of effective pacing threshold in the two groups showed no significant difference during the same period of time [P = NS]. Ventrculo-ventrical inhibition. The epicardial pacing wires have little usefulness after the fifth postoperative day and should be removed by this time. In addition postoperative pacing threshold was not affected by the decreased left ventricular function