Abstract Case report: a 81 years old man with systemic hypertension, dyslipidemia, past smoking habit, was admitted to the ER of our hospital with acute decompensated heart failure. Since July he complained of worsening of dyspnea and paroxysmal nocturnal dyspnea. His blood pressure was of 155/80 mmHg, the HR was of 78 bpm in atrial fibrillation. He reported past myocardial infarction at the age of 32, thenceforth he underwent periodic cardiac check–up. From 2013 he had developed atrial fibrillation. He had suspended Amiodarone because of dysthyroidism, rate control was obtained with Bisoprolol. In 2015, he underwent coronary angiography for a positive scintigraphy showed absence of lesions. During the same hospitalization there was evidence of nocturnal bradycardia (35 bpm). In 2016, a cardiac MR showed subendocardial and intramyocardial fibrosis at mid–basal wall resembling post ischemic events. He underwent past carpal tunnel syndrome surgery. During the actual hospitalization, the EKG showed atrial fibrillation (78 bpm), complete left bundle branch block (both already known). Serum and urinary light–chain assessment and determination of immunoglobulin light chains levels were negative for AL amyloidosis. The echocardiogram documented: hypertrophy of the interventricular septum, mildly reduced LV systolic function (EF=43%). Invasive coronary angiography showed absence of lesions. CMR showed: left ventricular size at the upper limit of normal with hypertrophy of the interventricular septum and the anterior wall, diffused left transmural LGE, focal fibroadipose infiltration of lower basal SIV. During the hospitalization multiple episodes of non sustained ventricular tachycardia occurred, so that a CRT–D device was implanted in secondary prevention. There was a strong suspicion of cardiac amyloidosis so that definitive diagnosis was obtained by the use of 99m Tc scintigraphy coupled with haematologic tests (already done, resulted negative). Scintigraphy showed myocardial uptake of the radiotracer greater than the bone (Grade 3 Perugini score). Conclusion cardiac amyloidosis is a restrictive cardiomyopathy. Early diagnosis is really important, firstly, because new treatments, such as a TTR stabilizer, have transformed this once incurable disease to a treatable condition. Secondly, diagnostic tools now allow earlier and more accurate non–invasive diagnosis. It is crucial to put the attention on red flags which have to be found to rise the clinical suspicion.