Advanced Echocardiography and Myocardial Work in Idiopathic Carpal Tunnel Syndrome with Presumptive Concurrent Cardiac Amyloidosis: An Exploratory Cross-Sectional Study.

Background/Objectives: Idiopathic carpal tunnel syndrome (CTS) can frequently precede the clinical diagnosis of transthyretin cardiac amyloidosis (ATTR-CA). This study aimed to comprehensively characterize the standard and advanced echocardiographic phenotype in a screening cohort of patients with CTS assessed for concurrent ATTR-CA. Methods: Thirty-three patients with idiopathic CTS underwent comprehensive standard and advanced echocardiography. The presence of concurrent ATTR-CA was assessed using 99mTc-DPD scintigraphy, allowing the stratification of the cohort into an amyloidosis group and a non-amyloidosis control group for comparative analysis. Results: Based on scintigraphy, 8 patients (24.2%) were diagnosed with presumptive ATTR-CA, acknowledging that AL amyloidosis was not systematically excluded, while 25 served as scintigraphy-negative controls. Standard echocardiography revealed greater wall thickness and worse diastolic function (p < 0.001) in the scintigraphy-positive group. Advanced imaging demonstrated profound left ventricular (LV) mechanical dysfunction, with severely reduced global longitudinal strain (p < 0.001) and a high prevalence of apical sparing (p < 0.001). Non-invasive myocardial work (MW) analysis showed a marked reduction in Global Constructive Work (p = 0.005) and Global Work Index (p = 0.017) in scintigraphy-positive patients, despite a relatively preserved LV ejection fraction. Multi-chamber strain analysis unmasked a pan-cardiac myopathy in the amyloid group, characterized by severe impairment of right ventricular (RV) global strain (p = 0.004) and profound depression of both left (p = 0.002) and right (p < 0.001) atrial reservoir strains. Conclusions: In patients with CTS, positive scintigraphy is characterized by severe, afterload-adjusted LV mechanical failure and profound biatrial and RV dysfunction. Advanced multi-chamber strain and MW indices show potential as non-invasive markers to help identify previously unrecognized pan-cardiac amyloid infiltration, guiding prompt diagnostic referral.