Introduction Cardiac resynchronisation therapy (CRT) has revolutionised treatment of patients with heart failure and reduced ejection fraction. Currently 15% of CRT implantation is upgrading from a single or dual chamber systems in patients who experience worsening heart failure symptoms.
The aim of this study was to identify factors that best predict improvement in left ventricular ejection fraction (LVEF) over one year following CRT upgrade.
Methods All patients who had a CRT upgrade from a single or dual chamber pacemaker between January 2012 and May 2018 at University Hospital Wales Cardiology Department were included. Aetiology of heart failure, baseline demographics and electrocardiographs (sinus rhythm vs. atrial fibrillation (AF)) were recorded pre-upgrade. Left ventricular ejection fraction (LVEF), measured by echocardiography, was recorded pre-upgrade and at 3, 6 and 12 months post-upgrade.
Results 146 patients (16% female, mean age 73 years ± 11, 58% dual chamber pacemaker, mean LVEF 26.5% ± 7.8, 67% NYHA class I&II) underwent CRT upgrade procedure (CRT-P: 60 (41%) or CRT-D: 86 (59%)).The average time from initial pacemaker implantation to CRT upgrade was 5.8 yrs ± 3.0. Overall LVEF improved in 71% of patients at 12 months (mean ΔLVEF 7.5% ± 10.1).
The greatest difference in improvement in LVEF post CRT upgrade were seen in groups with sinus rhythm (ΔLVEF at 3 months: sinus 8.0±8.9 vs AF 3.3±8.6, p<0.01; ΔLVEF at 6 months: sinus 8.4±10.3 vs. AF 4.2±8.0, p=0.02; ΔLVEF at 12 months: sinus 8.9±10.6 vs. AF 5.6±9.0, p=0.09) and non-ischaemic cardiomyopathy (NICM) at 6 months (ΔLVEF at 3 months: NICM 6.5 ± 9.3 vs ICM 5.4 ± 8.9, p=0.52; ΔLVEF at 6 months: NICM 8.4 ± 9.8 vs ICM 4.8 ± 9.2, p=0.05; ΔLVEF at 12 months: NICM 8.7 ± 10.4 vs. ICM 6.0 ± 9.5, p=0.16). There was no significant difference observed between genders, years between initial implant and upgrade, age at time of upgrade, dual vs. single previous device type or type of upgrade (CRT-P vs. CRT-D).
The baseline factors that best predicted improvement in LVEF post-upgrade were sinus rhythm (3 months: R2 =0.07, p<0.01 and 6 months: R2 =0.05, p=0.02), non-ischaemic aetiology (6 months: R2 = 0.04, p=0.05) and NYHA Class of I or II compared to NYHA Class III or IV (12 months: R2 = 0.06, p=0.012).
Conclusions Not all patients with RV induced heart failure have a similar improvement with CRT upgrade. Our results suggest that underlying non-ischaemic aetiology and sinus rhythm are the two main independent predictors of improved EF following CRT upgrade, whereas gender does not appear to influence outcome.
Conflict of Interest None
Statistics from Altmetric.com
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.