Pacemaker upgrade to CRT-D or CRT-P without prior ventricular arrhythmias: a long-term single-centre retrospective analysis

Abstract

Abstract Background Cardiac Resynchronization Therapy (CRT) can reverse the harmful effects of right ventricular pacing (RVP). Data are sparse on comparing all-cause mortality among patients undergone CRT-defibrillator (CRT-D) or CRT-pacemaker (CRT-P) upgrade from pacemakers without prior ventricular arrhythmias (VAs). Purpose We compared the differences in long-term all-cause mortality, postprocedural complications and the occurrence of VAs among patients receiving CRT-D or CRT-P upgrade. Methods Patients with a previously implanted conventional pacemaker (PM) developing heart failure (HF) despite optimal medical treatment and high rates of RVP, were included. Altogether 270 patients were investigated, 83 (30.7%) upgraded to CRT-D, 187 (69.3%) to CRT-P in our retrospective registry. The primary endpoint was all-cause mortality, secondary endpoints were malignant VAs and implantation-related complications. Results CRT-D upgrade patients were more likely to be males, have a favourable renal function and lower left ventricular ejection fraction (LVEF). During the median follow-up time of 3.7 years, 25 (30.1%) of CRT-D and 131 (70.1%) of CRT-P upgrade patients reached the primary endpoint. The CRT-D upgrade group showed a lower risk of all-cause mortality in the total cohort (HR: 0.55; 95% CI: 0.38–0.78; p=0.004) and in the ischaemic subgroups compared to CRT-P. After adjustment, CRT-D, ischaemic HF aetiology and LVEF have been confirmed as independent predictors of all-cause mortality. Malignant VA occurrence was higher among CRT-D patients (10.8% vs 1.1%; p=0.001), while no difference was observed in the rate of complications between the two patient groups. However, lead removal was performed more frequently (13.3% vs 1.1%; p<0.001) during CRT-D upgrade procedures compared to CRT-P. Conclusions Patients among the total and ischaemic HF aetiology subgroup benefited more from the CRT-D upgrade, although VAs and lead removal were more common than in the CRT-P group. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This work was supported by the ÚNKP-20-3-I-SE-43 New National Excellence Program if the Ministry for Innovation and Technology in Hungary. Project no. NVKP_16-1–2016-0017 (“National Heart Program”) has been implemented with the support provided by the National Research, Development and Innovation Fund of Hungary, financed under the NVKP_16 funding scheme. The research was financed by the Thematic Excellence Programme (2020-4.1.1.-TKP2020) of the Ministry for Innovation and Technology in Hungary, within the framework of the Therapeutic Development and Bioimaging thematic programmes of the Semmelweis University. All-cause mort of pts after UPG