Increased Pacemaker Lower Rate in ATTR Cardiac Amyloidosis

Inclusion Criteria: * ATTR-CM defined as one of the following: * a.Positive cardiac biopsy for ATTR amyloidosis * b.Positive extra-cardiac biopsy for ATTR amyloidosis AND cardiac involvement demonstrated by CMR or echocardiography * c.Grade 2-3 uptake on DPD-scintigraphy AND negative serum free light chain and negative urine and serum immunofixation AND cardiac involvement demonstrated by CMR or echocardiography * Ongoing treatment with a transthyretin stabilizer or silencer OR considered not to be a candidate for these therapies with no planned initiation during the study period. * NYHA functional class II-III * Pre-existing pacemaker and either: * a.Atrial pacing with minimal RV pacing (\<2%), or * b.His bundle or left bundle branch area pacing, or * c.Biventricular pacing, or * d.Ongoing RV pacing with a high degree of RV pace (\>80%) * NT-proBNP \>600 ng/L * Age ≥18 years * Ability and willingness to provide written informed consent * Pacing \>80% with a programmed lower rate of 60 (AAI/CSP/CRT/RV-pace) Exclusion Criteria: * Inability to perform the 6-minute walk test. * Planned coronary revascularization, ablation of atrial flutter/fibrillation, or any severe (obstructive or regurgitant) valvular heart disease expected to require intervention during the trial in the investigator's opinion. * MI, unstable angina, coronary revascularization (percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG)), ablation of atrial flutter/fibrillation, card…