Effekt der biventrikulären und rechtsventrikulären Stimulation bei Patienten mit Left Ventricular Assist Device

Heart transplantation remains the gold standard in the treatment of terminal heart failure. But there is still a shortage of available donor organs wherefore mechanical cardiovascular assist devices became more important in recent years. Left Ventricular Assist Devices (LVADs) have been chosen more frequently for patients with end staged heart failure, who may live with the device for over years (destination therapy). As part of heart failure therapy, some patients may be candidate for Cardiac Resynchronisation Therapy (CRT) prior to LVAD implantation. However, LVAD implantation dramatically alters the anatomy and physiology of the heart. Regarding this situation, there is no consensus on the use of pacing systems and the optimal mode of cardiac pacing. Thus, this controlled, prospective, and randomized study was designed to evaluate biventricular versus right ventricular pacing for every suitable patient receiving an LVAD in the department of cardiac surgery at the Campus Bad Neustadt a.d. Saale from September 7, 2018, until July 15, 2020. Additionally, in patients with sinus rhythm, right ventricular pacing alone was to be compared with intrinsic rhythm. In the sense of a pilot study, close attention should be paid to descriptive statistics in order to able to follow up on possible trends. For this purpose, data was collected intraoperatively, six and 24 hours postoperatively. This data was analyzed in all patients (n =37) and in groups divided by QRS complex width (< 130 ms, n = 18, vs ≥ 130 ms, n = 16) and by the presence of sinus rhythm (yes, n = 22, vs. no, n = 16). In addition, data collection was performed in patients with sinus rhythm during intrinsic rhythm and during right ventricular pacing alone (n = 15). The parameters evaluated before and after every pacing course were cardiac output (CO in L/min), mean peripheral blood pressure (RR in mmHg), central venous oxygen saturation (SVO2 in %), and echocardiographically determined right ventricular function (RV function). Comparison between sinus rhythm during intrinsic rhythm with right ventricular pacing alone showed that all hemodynamic parameters worsened during intraoperative right ventricular pacing alone, CO even decreased significantly (p = 0,041), and there were also cardio-vascular related terminations of the pacing course. The examination of biventricular versus right ventricular pacing in the overall collective revealed neither any trends nor significant differences intraoperatively and early postoperatively. However, 24 hours postoperatively, the group analysis showed a significant decrease in SVO2 under biventricular pacing. This significant deterioration of SVO2 occurred in patients with a QRS complex width ≥ 130 ms (p = 0,019) and in patients without sinus rhythm (p = 0,029). Furthermore, we were able to demonstrate that cardiac pacing induces arrythmias, with biventricular pacing leading to more ventricular arrhythmias than right ventricular pacing (62,5 % vs. 37,5 %). In the overall collective of LVAD patients investigated in this study, neither biventricular nor right ventricular pacing is clearly superior. But the group examination in the late postoperative course showed a trend which leads towards the conclusion that right ventricular pacing would be more beneficial to LVAD patients than biventricular pacing under certain conditions. According to that, the decrease of SVO2, as possibly the most sensitive parameter during late postoperative course, may indicate that active CRT pacing in LVAD patients with wide QRS complexes or LVAD patients without sinus rhythm may be harmful. Our results suggest reevaluating the indication of CRT systems for LVAD patients and preserving sinus rhythm if present. Also, in the use of pacing systems for LVAD patients, attention should be paid to patient-specific cardiac characteristics, such as the width of the QRS complex, the presence of sinus rhythm, and the occurrence of arrhythmias.