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Hot Line: The role of CRT upgrade in patients with symptomatic HFrEF, wide-paced QRS and with intermittent or permanent RV pacing

27 Aug 2023

Until yesterday’s Hot Line session, there was a lack of conclusive evidence on the efficacy and safety of upgrading to cardiac resynchronisation therapy (CRT) in patients with heart failure with reduced ejection fraction (HFrEF) who have implanted pacemakers or defibrillators (ICD). 

Professor Béla Merkely (Semmelweis University Heart and Vascular Center - Budapest, Hungary) presented results from the BUDAPEST CRT Upgrade investigator-initiated international trial, the first to compare the efficacy and safety of a CRT upgrade compared with an ICD alone.

A total of 360 patients were enrolled if they had HF and LVEF 35%, a pacemaker or ICD implanted at least 6 months previously, NYHA functional class II–IVa, paced QRS 150 ms and intermittent or permanent RV pacing 20%. The mean age was 72.8 years and 11% were women. Participants were randomised to receive CRT with a defibrillator (CRT-D) or an ICD in a 3:2 ratio. For patients with an ICD at baseline who were assigned to the ICD arm, the physician could choose either no procedure or a CRT-D upgrade with the CRT function turned off.

CRT-D upgrade was associated with a significantly lower occurrence of the primary outcome, a composite of HF hospitalisation, all-cause mortality or <15% reduction of LV end-systolic volume.

During a median of 12.4 months, the primary outcome occurred in 32.4% of patients in the CRT-D arm and 78.9% in the ICD arm (adjusted odds ratio 0.11; 95% CI 0.06 to 0.19; p<0.001). The beneficial effect of a CRT-D upgrade was consistent across all prespecified subgroups.

Regarding secondary endpoints, the composite of HF hospitalisation and all-cause mortality was significantly reduced with CRT-D compared with ICD (adjusted hazard ratio 0.28; 95% CI 0.17 to 0.46; p<0.001). LV morphological and functional response according to echocardiography also favoured CRT-D, with a difference at 12 months in LV end-diastolic volume of -39.00 mL compared with ICD (95% CI -51.73 to -26.27; p<0.001) and a difference at 12 months in LVEF of 9.76% (95% CI 7.55 to 11.98; p<0.001).

The rate of serious adverse events was 30.2% in the CRT-D arm and 60.0% in the ICD arm. The incidence of procedure- or device-related complications was 12.3% in the CRT-D arm and 7.8% in the ICD arm, but major ventricular arrhythmias were substantially lower with CRT-D (0.5%) than ICD (14.5%).

According to Prof. Merkely, these findings support performing a CRT upgrade in this vulnerable patient population. He comments, “HFrEF patients with a pacemaker or ICD should be strictly followed in clinical practice and, in those with intermittent or permanent RV pacing, a CRT upgrade should be performed immediately without deferring the procedure to a later date (e.g. battery replacement) to avoid or reduce the risk of further adverse events such as mortality, HF hospitalisation or LV remodelling.”