ABSTRACT
Background: Cardiomyopathy caused by aggregation and deposition of transthyretin amyloid fibrils in the heart (ATTR-CM) is divided into a hereditary (ATTRv) and a wild-type (ATTRwt) forms. While ATTR-CM has been considered a rare disease, recent studies suggest that it is severely underdiagnosed and an important cause of heart failure in elderly patients. Familial occurrence is implicit in ATTRv, but it is not expected in ATTRwt. Case summary: We report a case series of two unrelated families each with two brothers diagnosed with ATTRwt. Genetic testing did not reveal mutations in the transthyretin gene. Family screening with electrocardiogram, echocardiography, and genetic testing did not raise any suspicion of ATTR in first-line family members. Discussion: Familial occurrence of a rare, non-hereditary disease is statistically unlikely. Two siblings in two different families diagnosed with ATTRwt highlight that the aetiology of ATTRwt is poorly understood, and that genetic factors distinct from mutations in the transthyretin gene, as well as environmental factors, might contribute to the pathogenesis. Identifying such factors might reveal new therapeutic targets. To investigate this further, clinicians need to be aware of the possibility of familial occurrence of ATTRwt.
ABSTRACT
Advances in treatment warrant earlier diagnosis of cardiac amyloidosis (CA). Common cardiac and extracardiac manifestations of CA, such as pacemaker implantation and carpal tunnel syndrome (CTS), might provide screening opportunities for CA. However the association between CTS and CA in patients undergoing pacemaker implantation has not been well studied. This study examined the association between previous CTS surgery and adverse cardiovascular outcomes in patients who underwent pacemaker implantation. Using Danish nationwide registries, we identified all patients ≥50 years who underwent first-time pacemaker implantation during 2000 to 2018, examining the association between previous CTS surgery and adverse cardiovascular outcomes 5 years after pacemaker implantation. Cumulative incidence functions and Cox proportional hazard models were used to assess the differences. Among 57,315 patients who underwent pacemaker implantation, 2.2% (n = 1,266) had previous CTS surgery. Patients in the CTS cohort were older, more often female, and had more co-morbidities than patients without CTS. The cumulative 5-year mortality was higher among patients with CTS (44.6% [41.1% to 47.9%] versus 40.2% [39.7% to 40.6%], p = 0.04). In the adjusted models, previous CTS surgery was not associated with increased 5-year mortality, but it was associated with an increased rate of hospitalization for new-onset heart failure, (hazard ratio 1.32 [1.11 to 1.57], p = 0.002) and a higher risk of amyloidosis diagnosis after pacemaker implantation (hazard ratio 7.72 [2.96 to 20.10], p <0.0001), compared with no previous CTS surgery. In patients who underwent pacemaker implantation, adjusted models showed that previous CTS surgery was associated with a higher incidence of hospitalization for new-onset heart failure and amyloidosis diagnosis after pacemaker implantation. Screening for CA may be considered in patients undergoing pacemaker implantation.