Identify cause of heart failure of unknown aetiology using cardiac magnetic resonance - a 10-year observational study
Authors: Ojrzynska N , Marczak M , Mazurkiewicz Ł , Petryka-Mazurkiewicz J , Milosz-Wieczorek B , Grzybowski J , Spiewak M 
Published: February 2021

Abstract

Funding Acknowledgements
Type of funding sources: None.

Background
Heart failure (HF) is a clinical syndrome caused by structural or functional cardiac abnormality and is diagnosed on the basis of typical symptoms. It is associated with significant morbidity and mortality and affects more than 25 million people worldwide.
HF of unknown aetiology is managed with symptomatic treatment. Patients with reduced (HFrEF) or mid-reduced ejection fraction (HFmrEF) and no clear cause of systolic dysfunction are usually classified as having DCM. In HFpEF group ejection fraction is preserved but diastolic dysfunction is present leading to HF symptoms.

Purpose
The aim of this study was to investigate the clinical significance of cardiac magnetic resonance (CMR) imaging to identify heart failure (HF) aetiology.

Methods
We retrospectively reviewed all medical charts of patients referred for CMR due to heart failure of unknown aetiology admitted to our hospital between 2008 and 2017. Only patients with no specific pre-CMR initial diagnosis were included. Patients with suspicion of any specific disease leading to HF were excluded. If a referring physician suspected myocarditis, cardiomyopathy, previous myocardial infarction or advanced stable coronary disease (based on clinical signs and symptoms, the patient’s and family history or all pre-CMR studies), these patients were omitted from our analysis. Thus, we included only patients whose diagnostic work-up did not reveal suspicion of any specific cardiac disease leading to HF.

Results
The study sample consisted of 243 patients (173 (71.2%) male, mean age 44.0 ± 14.2%). All patients underwent contrast-enhanced CMR. Late gadolinium enhancement (LGE) was detected in 74.9% cases. Cardiomyopathies comprised the main aetiology (174 cases, 71.6%), in particular dilated cardiomyopathy (143 patients, 58.8%). 17 patients (7.0%) were diagnosed with myocarditis and in 24 patients (9.9%) CMR-based diagnosis was ambiguous – pointing out myocarditis or dilated cardiomyopathy. In 23 cases (9.5%) CMR indicated the presence of prior infarction undetected by pre-CMR testing. In five patients (2.1%) valvular disease was revealed as the sole cause of HF.
We analysed the change in patients’ management guided by the CMR results defined as change of treatment and/or necessity of further tests leading to therapeutic consequences. Change of pre-CMR diagnosis occurred in 94 patients (38.7%) and was judged crucial in 41 patients (16,9%).
As crucial we adjudicated the diagnosis associated with a need immediately further investigation and treatment changing, as follows: newly diagnosed amyloidosis, ischaemic heart disease or complex advanced valvular disease and cardiomyopathies other than dilated, hypertrophic and restrictive.

Conclusion
Our study strongly suggests that cardiac magnetic resonance imaging is a valuable tool for determining the aetiology of heart failure and impacts patients" management.
Abstract Figure.