Effects Of Different Pacing Modes (DDD) On Cardiac Output

Objective: The aim of our study was to compare cardiac output (CO) during short-term atrioventricular sequential pacing from the right ventricular apex and from the outflow tract of the right ventricle, to assess if short-term right ventricular outflow tract pacing were much better than right ventricular apical pacing. Three pacing modes including right atrium pacing , right ventricular septal pacing and right ventricular apex pacing were performed on 18 patients with sick sinus syndrone. The haemodynamics parameters including pulmonary capillary wedge pressure(pcwp), cardiac output(CO), cardiac index(CI) and QRS duration were measured after each pacing mode was achieved stablely for five minutes. Results: Compared with right atrium pacing, CO decreased 19%(P<0.01)in right ventricular septal pacing, However, CO increased 12%(P<0.05)in right ventricular septal pacing compared with right ventricular apex pacing. The QRS duration of right ventricular apex pacing and septal pacing was longer than right atrium pacing, but the QRS duration in surface ECG of right ventricular septal pacing was shorten averagely about 18 ms(P<0.001). Conclusion: Short-term right ventricular outflow tract pacing is associated with more favorable CO, compared with right ventricular apical pacing.