# Compliance with Guideline-Directed Medical Therapy and Early Implantable Cardioverter-Defibrillator Activation in Heart Failure: A Retrospective Study

## TL;DR

This study found that most heart failure patients did not receive optimal medical therapy before getting an ICD, and early ICD activation was rare.

## Contribution

The study provides new insights into OMT compliance and ICD activation patterns in heart failure patients.

## Key findings

- Only 23.8% of patients received the maximum tolerated dose of OMT before ICD implantation.
- Early ICD activation occurred in less than 3% of patients, regardless of OMT compliance.
- About 20-30% of patients without OMT showed improved ejection fraction after ICD implantation.

## Abstract

This study was conducted to evaluate compliance with
guideline-directed optimal medical therapy (OMT) and its association with early
implantable cardioverter-defibrillator (ICD) activation in patients with heart
failure and reduced ejection fraction (HFrEF).

Retrospective
data from 307 patients who underwent ICD implantation for primary prevention from
2011 to 2017 were collected and analyzed.

Among the study
participants, only 23.8% received the maximum tolerated dose of OMT prior to ICD
implantation, with 59.0% receiving all three OMT medication groups. No
significant difference in OMT compliance was found between patients with ischemic
cardiomyopathy (ICM) and those with non-ischemic dilated cardiomyopathy (DCM).
However, DCM patients received ICDs more frequently at the time of diagnosis than
ICM patients (13.8% vs. 0.7%). Early ICD activation (within 3 months) occurred
in only one patient who had not received appropriate OMT, representing 0.7% of
all ICM patients. Furthermore, early activation was also infrequent in patients
who received OMT (2.9% of ICM patients and 2.6% of DCM patients).
Echocardiography follow-up data revealed that 20.4% of ICM patients and 29.8%
of DCM patients who did not receive OMT before ICD implantation showed
improvement in the left ventricular ejection fraction (EF) to 35% or more.

This study found suboptimal compliance with OMT prior to
ICD implantation in HFrEF patients. The results showed that early ICD activation
was rare in all patient groups, especially those who did not receive the
prescribed 3 months of OMT. More research is needed to investigate longer waiting
periods for the evaluation of potential EF improvement, and to better evaluate
the eligibility of HFrEF patients for ICD. The current findings have potential
implications for clinical practice and patient outcomes.