All ATTRwt patients on tafamidis 61 mg treatment will be clinically evaluated before treatment initiation and subsequently every six months for the eligibility to continue tafamidis treatment, according to Italian Medicines Agency regulations. C onsidering the significant risk of developing heart rhythm disturbances due to cardiac amyloidosis, especially in transthyretin form (ATTRwt), in routine clinical practice a stricter heart rhythm monitoring is recommended in ATTRwt patients. Moreover, particular attention is usually paid for those who present atrio-ventricular and/or intraventricular block at the baseline electrocardiogram. Data about rhythm disturbances and diuretic dose need will be collected during the planned physical examination every six months and the Holter ECG monitoring requested by the physician at the end of every planned clinical evaluation.

Inclusion Criteria:

• Diagnosis of ATTRwt amyloidosis.
• 18 years or older;
• evidence of cardiac involvement at echocardiography or cardiac MRI.
• No known prior history of atrial fibrillation or major bradyarrhythmia (second degree atrioventricular block, third-degree atrioventricular block, high-grade atrioventricular block or alternating right and left branch block)
• female patients who are postmenopausal for at least 1 year before the screening visit
• patients on therapy or candidates for therapy with tafamidis 61 mg
• voluntary written consent must be given before performance of any study-related procedure not part of standard medical care with the understanding that consent may be withdrawn by the patient at any time without prejudice to future medical care.

Exclusion Criteria:

• Non-ATTR amyloidosis;
• NYHA class III and IV;
• Pregnant or nursing women;
• Previous pacemaker implantation;
• any serious medical or psychiatric illness that could, in the investigator's opinion, potentially interfere with a fully comprehension of the written consent form

All patients with a diagnosis of ATTRwt disease and eligible for tafamidis treatment according to the national drug regulatory agency criteria and no prior history of atrial trachy-arrhythmia and/or bradyarrhythmias in their past medical history will undergo screening procedure to be enrolled in the present study.