Cardiac magnetic resonance T1 mapping for amyloid cardiomyopathy in patients with heart failure.

AIMS: This study investigates the diagnostic accuracy of cardiac magnetic resonance (CMR) T1 mapping for the evaluation of cardiac amyloidosis (CA) in elderly patients with heart failure (HF). METHODS AND RESULTS: We prospectively enrolled consecutive patients aged ≥60 years with symptomatic HF, left ventricular ejection fraction (LVEF) ≥ 40%, increased left ventricular (LV) wall thickness (≥12 mm), and elevated cardiac biomarkers. All patients underwent standardized CMR, bone scintigraphy, and screening for monoclonal proteins. Primary endpoint was the diagnosis of CA with T1 mapping. The reference standard was a confirmed CA diagnosis by bone scintigraphy. One hundred and twelve patients (median age 81 years, 45% female) were included. CA was diagnosed in 38 patients (34%). Patients with CA showed advanced LV remodelling, indicated by higher LV mass index, lower LVEF, higher native T1 values, and higher extracellular volume fraction (ECV). Diagnostic accuracy on ROC curve analysis was 0.836 for native T1 and 0.904 for ECV. Native T1 < 1303 ms excluded CA. In patients with native T1 ≥ 1303 ms, there was no CA as cause of HF observed if ECV < 30%, while 85% of patients with an ECV 40-49% and 100% with ECV ≥ 50% had CA (P < 0.0001). By this approach, contrast application could have been avoided in 33%. A definite confirmation or exclusion of CA by CMR was established in 50%. CONCLUSION: In elderly patients with symptomatic HF, LVEF ≥ 40%, LV hypertrophy, and elevated cardiac biomarkers, a CMR approach with native T1 and ECV measurements is useful to identify underlying CA. TRIAL REGISTRATION: NCT04862273 at clinicaltrials.gov.