Background Early diagnosis of cardiac amyloidosis (CA) is necessary to initiate specific treatment and improve outcomes. Conventional echocardiography is unable to reliably differentiate CA from other causes of increased left ventricular (LV) wall thickness while global longitudinal strain (GLS) of the left ventricle has shown to be useful.

Aim To demonstrate that left atrial (LA) strain is more sensitive and specific than LV GLS in discriminating CA from other pathological causes of increased LV wall thickness.

Methods 32 patients with CA, 190 patients with hypertrophic cardiomyopathy (HCM), 23 patients with Fabry disease and 20 patients with hypertensive heart disease (HTN) were studied. Speckle tracking echocardiography was used to analyse LA strain and GLS of left ventricle, and these measurements were compared between CA and non-CA group.

Results Patients with CA had the highest LV posterior wall (PW) thickness and lowest LV GLS, myocardial E’ velocity, LA reservoir and conduit strain (p<0.00001) among all groups. LA reservoir strain is more sensitive and specific than LV GLS in differentiating CA from non-CA (HCM+Fabry+HTN) group (LA strain 14.0±9.0 vs 33.4±10.8, sensitivity 90.3%, specificity 76.7%, AUC 0.906; LV GLS 10.6±3.3 vs 15.1±4.1, sensitivity 84.4%, specificity 68.2%, AUC 0.822).

Conclusion LA strain is more sensitive and specific than LV strain in discriminating CA from other pathological causes of increased LV wall thickness. Future studies involving larger cohorts are required to validate these findings.