Reverse Left Ventricular Remodeling in a Patient With Concurrent Wild-Type Transthyretin Cardiac Amyloidosis and Heart Failure With Reduced Ejection Fraction: The Role of Conventional Heart Failure Therapy

Wild-type transthyretin amyloid (ATTRwt) amyloidosis is a systemic, progressive disease that often affects older adults and is characterized by ATTRwt deposition in multiple organs and tissues. When the heart is involved, this deposition leads to cardiac amyloidosis (CA), which can result in life-threatening heart failure (HF) and arrhythmias. In general, as left ventricular (LV) wall thickening increases because of ATTRwt deposition, the LV cavity decreases in size. Additionally, as the disease progresses, the myocardial ATTR burden increases, and the LV ejection fraction (LVEF) decreases. Thus, at ATTRwt-CA diagnosis, the most common LV characteristics are a slightly reduced LV cavity and preserved or mildly reduced LVEF. We report the case of an 83-year-old man with HF with reduced EF (HFrEF) and ATTRwt-CA who had an LVEF of 22% and a dilated LV cavity with an end-diastolic diameter (EDD) of 58.0 mm and end-diastolic volume index (EDVI) of 86 mL/m2. Additionally, the LV wall thickness was 11.3 mm, and his National Amyloidosis Centre Stage, determined using N-terminal pro-B-type natriuretic peptide and estimated glomerular filtration rate, was 1, suggesting early-stage ATTRwt-CA despite reduced LVEF and a dilated LV cavity. Conventional medications for HFrEF, including loop diuretics and neurohumoral blockers, beta-blockers, angiotensin-converting enzyme inhibitors, and mineralocorticoid receptor antagonists, were administered. Nonetheless, disease-modifying drugs for ATTRwt-CA were not administered because of dementia and frailty. Three years later, "discordant" LV remodeling was observed, with improvement in LVEF and LV dilatation, alongside inappropriate progression of LV wall thickening: LVEF increased to 36%, LVEDD decreased to 51.5 mm, and LVEDVI decreased to 66 mL/m2, whereas LV wall thickness increased to 13.2 mm. Subsequently, tachycardiac atrial fibrillation and new decompensated HF developed. Early initiation of combination therapy with disease-modifying agents for ATTRwt-CA, currently the only standard therapies proven to modify disease progression, together with guideline-directed HF therapy, may be the optimal approach.