Review of eligibility for cardiac resynchronization therapy

Future research prioritization in cardiac resynchronization therapy

BACKGROUND

Although cardiac resynchronization therapy (CRT) is effective for some patients with heart failure and a reduced left ventricular ejection fraction (HFrEF), evidence gaps remain for key clinical and policy areas. The objective of the study was to review the data on the effects of CRT for patients with HFrEF receiving pharmacological therapy alone or pharmacological therapy and an implantable cardioverter-defibrillator (ICD) and then, informed by a diverse group of stakeholders, to identify evidence gaps, prioritize them, and develop a research plan.

METHODS

Relevant studies were identified using PubMed and EMBASE and ongoing trials using clinicaltrials.gov. Forced-ranking prioritization method was applied by stakeholders to reach a consensus on the most important questions. Twenty-six stakeholders contributed to the expanded list of evidence gaps, including key investigators from existing randomized controlled trials and others representing different perspectives, including patients, the public, device manufacturers, and policymakers.

RESULTS

Of the 18 top-tier evidence gaps, 8 were related to specific populations or subgroups of interest. Seven were related to the comparative effectiveness and safety of CRT interventions or comparators, and 3 were related to the association of CRT treatment with specific outcomes. The association of comorbidities with CRT effectiveness ranked highest, followed by questions about the effectiveness of CRT among patients with atrial fibrillation and the relationship between gender, QRS morphology and duration, and outcomes for patients either with CRT plus ICD or with ICD.

CONCLUSIONS

Evidence gaps presented in this article highlight numerous, important clinical and policy questions for which there is inconclusive evidence on the role of CRT and provide a framework for future collaborative research.

Eligibility for cardiac resynchronization therapy in patients hospitalized with heart failure

Aims

Recent guidelines recommend cardiac resynchronization therapy (CRT) in mildly symptomatic heart failure (HF) but favour left bundle branch block (LBBB) morphology in patients with moderate QRS prolongation (120–150 ms). We defined how many patients hospitalized with HF fulfil these criteria.

Methods and results

A single‐centre retrospective cohort study of 363 consecutive patients hospitalized with HF (438 admissions) was performed. Electronic imaging, electrocardiograms, and records were reviewed. Overall, 153 patients (42%) had left ventricular ejection fraction (LVEF) ≤ 35%, and 34% of patients had QRS prolongation. Eighty patients (22%) were potentially eligible with LVEF ≤ 35% and QRS ≥ 120 ms or existing CRT. The majority (68 of 80) had a Class I or IIa recommendation according to international guidelines (LBBB or non‐LBBB QRS ≥ 150 ms or right ventricular pacing). Only a minority (12 of 80) had moderate QRS prolongation of non‐LBBB morphology. One‐quarter (n = 22) of patients fulfilling criteria were ineligible for reasons including dementia, co‐morbidities, or palliative care. A further eight patients required optimization of medical therapy. CRT was therefore immediately indicated in 50 patients. Of these, 29 were implanted or had existing CRT systems. Twenty‐one of the 80 patients eligible for CRT were not identified or treated (6% of the total hospitalized cohort).

Conclusions

Twenty‐two per cent of elderly real‐life patients hospitalized with HF fulfil LVEF and QRS criteria for CRT, most having a Class I or IIa indication. However, a large proportion is ineligible owing to co‐morbidities or requires medical optimization. Although uptake of CRT was reasonable, there remain opportunities for improvement.