Acute Hemodynamic Effects of Different Pacing Strategies in LVAD Recipients

Abstract

Purpose Cardiac resynchronization therapy (CRT) improves quality of life and survival in patients with heart failure, but it has not been rigorously investigated in LVAD patients. Furthermore, the effects of different pacing strategies on hemodynamics in LVAD recipients is unknown. Methods Hospitalized adult LVAD patients with a CRT device and a pulmonary artery catheter (PAC) in place were eligible to be enrolled. Patients who required vasopressor or high-dose inotropic support, or who had been shocked from their defibrillator in the prior 24 hours were excluded. The following pacing strategies were tested for each patient: right ventricular pacing (RVP), left ventricular pacing (LVP), biventricular pacing (BiVP), and no pacing. Right atrial pressure (RAP), pulmonary artery systolic (PASP) and mean (mPAP) pressures, pulmonary capillary wedge pressure (PCWP), and cardiac index (CI) were measured after 5 minutes at each pacing setting. Mean values of each hemodynamic parameter were compared between the different settings. Results Between 9/1/2017 and 8/31/2018, 5 patients were enrolled. Mean age was 66.7 years and mean frequency of biventricular pacing at baseline was 71.8%. Two patients had HeartWare and 3 patients had HeartMate III LVADs. RAP appeared similar across all settings. PASP, mPAP, and PCWP were each slightly lower at the “no pacing” setting compared to RVP, LVP, or BiVP. CI was highest at the “no pacing” setting (Table). Statistical testing was not performed due to the small number of patients enrolled. No adverse events were observed. One patient developed atrial fibrillation during the study period that resolved spontaneously within 24 hours. Conclusion While all pacing strategies were safe and well tolerated acutely, the “no pacing” strategy was associated with a possible signal towards the most favorable hemodynamic profile. Whether these differences will persist upon further enrollment and meaningfully impact quality of life, exercise tolerance, or survival in LVAD recipients requires further study.