Two cases of hemodynamic improvement by modulation of atrioventricular delay in cardiac operations

Background Symptomatic sick sinus syndrome is one of the indications for pacemaker implantation, and we have to consider to program the pacemaker to an asynchronous pacing mode during an operation. Case presentation We reported two cases with a pacemaker implanted for sick sinus syndrome undergoing cardiac operation. We changed programming of the pacemaker to an asynchronous pacing mode (DOO) and modulated the programmed atrioventricular delay to avoid ventricular pacing, resulting in better hemodynamic condition. Although we observed premature ventricular contraction, no lethal arrhythmias induced by the R-on-T phenomenon were noted. Conclusion Programming of the pacemaker to an asynchronous pacing mode and modulation of the programmed atrioventricular delay to avoid ventricular pacing may be an option for pacemaker management during an operation.