Impact of optimal medical therapy on left ventricular ejection fraction recovery and the occurrence of arrhythmia in patients with HFrEF fitted with the wearable cardioverter defibrillator

Patients with heart failure (HF) and severely reduced left ventricular ejection fraction (LVEF) ≤ 35% (HFrEF) are at elevated risk for arrhythmias and sudden cardiac death. To evaluate potential recovery in LVEF under optimal guideline-directed medical therapy (GMDT) after initial diagnosis, patients can be provided with a wearable cardioverter-defibrillator (WCD) within the first 3 months to bridge this time. According to the ESC-HF guideline (HF-GL) introduced in 2021 GMDT consists of the "fantastic four" including Sodium-Glucose-linked-transporter-2 inhibitors (SGLT-2i).

The objective of this analysis was to evaluate the change/adherence in GMDT therapy before/after HF-GL, rate of LVEF recovery to > 35% and the occurrence of ventricular arrhythmia in a well-defined WCD patient cohort.

We retrospectively analyzed all patients in our tertiary care center fitted with a WCD from 03/2018 until 03/2024. 104 patients were included before and 63 patients after implementation of the HF-GL in 09/2021. Baseline (BL) characteristics are listed in figure 1. For every patient we calculated Quad Medical Score (QMS) as surrogate of guideline adherence in HF therapy, which is calculated on the presence of all four substance classes and their dosages. LVEF was assessed at baseline and 3 months (FU) after the initiation of GDMT.

A total of 167 patients were analyzed: Men 80% (n= 134), women 20% (n=33); ischemic heart disease (ICM) in 56% of included patients (n=94). Median LVEF overall at baseline was 24% and after a median of 84 days of follow up (FU) mean LVEF improved to 34% with ΔLVEF of +9%.

Patients treated with WCD before HF-GL implantation LVEF was 24.0% at baseline and 32% with ΔLVEF of +8% at FU, while patients treated after HF-GL implementation had a recovery to mean LVEF 36% resulting in a ΔLVEF of 11% at FU (p<0.05) BL vs. FU; figure 1). Analysis of ΔLVEF revealed a significant difference between the groups only for the ICM cohort (p<0.05 before vs. after HF-GL).

The rate of ICD indication was significantly reduced in patients treated after HF-GL update (55 vs. 21 patients; (p<0.05). In total, 5 (3.4%) ventricular tachycardia occurred during WCD prescription.

Mean QMS in all patients before and after guideline initiation was 9 vs. 21 respectively (p<0.001). Higher QMS resulted in significant LVEF improvement (p<0.05).

In patients with HFrEF equipped with a WCD significantly more patients were prescribed with a SGLT-2 inhibitor after HF-GL update 2021, these patients showed a significantly higher rate of LVEF recovery resulting in fewer ICD indications after 3 months. During the period of risk, the WCD is an important opportunity to protect patients against SCD in this cohort.Figure 1:

Baseline characteristics