EPICARDIAL PACING

TIME RELATED EFFICACY OF ELECTRODES FOLLOWING CARDIAC SURGERY

Abstract

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. Objectives: To determine the
time related efficacy of these pacing electrodes after cardiac surgery, to find out the optimum time of their removal. Period: July 2008 to
October 2008. Patients & Methods: 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 5t h postoperative day. The patients were divided
into two subgroups according to their left ventricle ejection fraction ( > 40% verses < 40%). Results: There was significant difference in the
effective pacing threshold in groupl 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 5t h 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 5t h 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. Conclusions: 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.