Abstract 3583: Increase of Lower Pacing Rate Reduces Cardiac Congestion in Patients with Heart Failure and CRT
Objective:CRT improves central hemodynamics in pts with HF and ventricular asynchrony. It is generally accepted that programming of CRT devices should be adjusted to achieve optimal hemodynamic outcome. However, the hemodynamic impact of programming different heart rates has not been evaluated. Methods:Ten HF pts were implanted with both a CRT device and an implantable hemodynamic monitor (IHM, Chronicle®, Medtronic), consisting of a memory device and a right ventricular (RV) pressure lead. The IHM continuously recorded RV pressure parameters including the estimated pulmonary artery diastolic pressure (ePAD). The lower pacing rate was randomly programmed to 50–120 bpm for 1 min each, followed by 1 min at nominal (60/70 bpm based on clinical judgement). We hypothesized, that low ePAD values reflect favorable hemodynmamics. Thus, optimal heart rate was defined as the HR at minimum ePAD.
Results:In all pts, the lowest ePAD value was observed at HR higher than 70 bpm. At optimal HR, ePAD was significantly lower compared with nominal settings of 60/70 bpm (opt. 16.6±7.2 vs. 18.3±7.1 mmHg, p=0.013, paired Wilcoxon test). However, at HR above “optimal” the ePAD significantly increased again in 8/10 pts (120 bpm: 18.5±6.8 mmHg, p=0.012), resulting in a U-shaped ePAD response.
Conclusions:In HF pts with CRT, increased lower pacing rates acutely improve cardiac filling characteristics. This finding supports the use of higher pacing rates in the context of severe congestion to reduce the cardiac preload. An implanted hemodynamic monitor may be helpful to adjust the lower pacing rate to an individual optimum. The chronic hemodynamic impact of different heart rates remains to be established.