2.1. Study Population

We enrolled consecutive adult patients between August 2010 and August 2018 who underwent a complete CMR study at our tertiary care center at the Vienna General Hospital. Our center is located at the Medical University of Vienna and has a high-volume cardiac catheterization unit and a high-volume cardiac transplantation program. Moreover, we are part of the European Reference Network for Amyloidosis and a national referral center for patients with heart failure and preserved ejection fraction (HFpEF). Patients underwent clinical and laboratory assessment, electrocardiogram (ECG), transthoracic echocardiography, CMR, and, if any suspicion of CA was present, 99 mTc-DPD bone scintigraphy, as well as blood and urine tests for the detection of pathological light chains. The pre-CMR suspicion of CA was raised when patients presented with LV-hypertrophy, in particular those with interventricular septum thickness ≥15 mm and shortness of breath. In case of suspicion of AL-CA, myocardial biopsy was performed. In case of suspicion of TTR-CA, endomyocardial biopsy (EMB) was performed until 2016, when the paper by Gillmore et al. [8] on the diagnostic algorithm of CA was published. Thereafter, only AL-CA cases and TTR-CA with presence of monoclonal protein underwent myocardial biopsy. All patients provided written informed consent. The study was approved by the Ethics Committee of the Medical University of Vienna (EK no. 796/2010).