Background: Cardiac amyloidosis (CA) is a serious though increasingly treatable cause of heart failure. Diagnosis is challenging and frequently unclear at echocardiography, which remains the most often used imaging tool. Objectives:We aimed to study the accuracy of a broad range of echocardiographic variables to develop multiparametric scores to diagnose CA in patients with proven light chain (AL) amyloidosis or those with increased heart wall thickness (IWT) in whom amyloid was suspected. We also aimed to further characterise structural and functional changes associated with amyloid infiltration. Methods:We studied 1187 consecutive patients evaluated at 3 referral centres for CA and analysed morphological, functional and strain-derived echo parameters with the aim of developing a score-based diagnostic algorithm. Cardiac amyloid burden was quantified using extracellular volume measurements at cardiac magnetic resonance.Results: 332 patients were diagnosed with AL amyloidosis and 339 patients with transthyretin (ATTR) CA. Concentric remodelling and strain-derived parameters displayed the best diagnostic performance. A multivariable logistic regression model incorporating relative wall thickness, E/e'ratio, longitudinal strain and tricuspid annular plane systolic excursion had greatest diagnostic performance in AL amyloidosis (area under the curve -AUC-0.90[95% confidence interval 0.87-0.92]), whilst addition of septal apical-to -base ratio yielded the best diagnostic accuracy in the IWT group (AUC 0.87[0.85-0.9]).Conclusions: Specific functional and structural parameters characterize different burdens of CA deposition with different diagnostic performances, and enable to define two scores that are sensitive and specific tools to diagnose or exclude CA.

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Background: Truncating variants in the TTN gene (TTNtv) are the commonest cause of heritable dilated cardiomyopathy. This study aimed to study the phenotypes and outcomes of TTNtv carriers. Methods: Five hundred thirty-seven individuals (61% men; 317 probands) with TTNtv were recruited in 14 centers (372 [69%] with baseline left ventricular systolic dysfunction [LVSD]). Baseline and longitudinal clinical data were obtained. The primary end point was a composite of malignant ventricular arrhythmia and end-stage heart failure. The secondary end point was left ventricular reverse remodeling (left ventricular ejection fraction increase by ≥10% or normalization to ≥50%). Results: Median follow-up was 49 (18–105) months. Men developed LVSD more frequently and earlier than women (45±14 versus 49±16 years, respectively; P =0.04). By final evaluation, 31%, 45%, and 56% had atrial fibrillation, frequent ventricular ectopy, and nonsustained ventricular tachycardia, respectively. Seventy-six (14.2%) individuals reached the primary end point (52 [68%] end-stage heart failure events, 24 [32%] malignant ventricular arrhythmia events). Malignant ventricular arrhythmia end points most commonly occurred in patients with severe LVSD. Male sex (hazard ratio, 1.89 [95%CI, 1.04–3.44]; P =0.04) and left ventricular ejection fraction (per 10% decrement from left ventricular ejection fraction, 50%; hazard ratio, 1.63 [95%CI, 1.30–2.04]; P <0.001) were independent predictors of the primary end point. Two hundred seven of300 (69%) patients with LVSD had evidence of left ventricular reverse remodeling. In a subgroup of 29 of74 (39%) patients with initial left ventricular reverse remodeling, there was a subsequent left ventricular ejection fraction decrement. TTNtv location was not associated with statistically significant differences in baseline clinical characteristics, left ventricular reverse remodeling, or outcomes on multivariable analysis ( P =0.07). Conclusions: TTNtv is characterized by frequent arrhythmia, but malignant ventricular arrhythmias are most commonly associated with severe LVSD. Male sex and LVSD are independent predictors of outcomes. Mutation location does not impact clinical phenotype or outcomes.