Amyloid : the international journal of experimental and clinical investigation : the official journal of the International Society of Amyloidosis
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Background: Impaired aerobic capacity in cardiac amyloidosis patients may be related to limited inotropic myocardial reserve and heart rate (HR) response limiting cardiac output rise. This study sought to investigate whether chronotropic incompetence (CI) and blunted HR recovery would be prevalent in patients with mutant transthyretin (ATTRv) cardiomyopathy. Methods and results: Eighteen ATTRv (Val122Ile) patients (72 ± 8-year) and 15 age-matched controls (73 ± 3-year) were prospectively enrolled. ⋯ HR recovery, as percent decrease in peak HR at 1 and 3-min, was blunded ATTv patients. Conclusions: In Val122Ile ATTRv patients, chronotropic response was appropriate relative to exercise intensity with only few patients displaying CI. HR response to exercise was further characterised by blunted HR recovery in ATTRv patients suggesting lower parasympathetic activity and greater sympathetic stimulation compared with controls.
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Background: There is a growing need for a non-invasive test to detect cardiac involvement in patients with transthyretin-related hereditary amyloidosis (ATTR) caused by V30M mutation. 99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid (DPD) scintigraphy is a promising method, but its accuracy in this particular mutation remains unknown. Methods: A cohort of 179 patients: 92 with early-onset disease (EoD, symptoms <50-years-old), 33 with late-onset disease (LoD) and 54 asymptomatic carriers were prospectively evaluated and underwent DPD scintigraphy, which was compared with the results of echocardiogram, ambulatory blood pressure monitoring, 24 h-Holter, myocardial 123I-metaiodobenzylguanidine imaging and NT-proBNP. Results: Amyloid cardiomyopathy, defined as septal thickness ≥13 mm, was present in 32 patients (17.9%) and was more frequent in those with LoD (OR: 3.68, p = .003). ⋯ DPD imaging was strongly influenced by the age of disease onset: among patients with myocardial thickening, cardiac DPD retention was present in 11/15 (73.3%) with LoD, in contrast to only 4/17 (26.7%) with EoD (p = .005). Two patients with myocardial thickening and normal DPD scintigraphy underwent endomyocardial biopsy that confirmed ATTR amyloidosis. Conclusion: DPD scintigraphy presents suboptimal sensitivity to detect cardiac involvement in ATTRV30M, particularly in symptomatic patients with EoD.