Earlier recognition of transthyretin amyloid cardiomyopathy (ATTR-CM) remains challenging when left ventricular (LV) wall thickness is absent or only mildly increased. A single-center retrospective observational study published in the European Heart Journal - Imaging Methods and Practice found that combining electrocardiographic S-wave amplitude in lead aVR (SaVR) with echocardiographic relative apical sparing (RELAPS) improved the detection of ATTR-CM in this lower-wall-thickness population.

The analysis included 39 patients with confirmed ATTR-CM, median age 72 years, of whom 45% were women. Diagnosis was established by technetium-99m–DPD scintigraphy and/or biopsy. Comparator groups included patients with mild LV hypertrophy without evidence of amyloidosis and age-matched healthy controls.

Peripheral neuropathy was the most common presentation (66%), while overt cardiomyopathy was present in 28%, consistent with early-stage disease. Left ventricular ejection fraction was preserved in 92%, and restrictive filling was absent. RELAPS ≥1 was present in 87%, and SaVR <7 mm in 85%.

Individually, RELAPS and SaVR showed good discrimination for ATTR-CM versus LV hypertrophy, with area under the curve (AUC) values of 0.83 and 0.85, respectively. The combined RELAPS-SaVR model improved discrimination to AUC 0.90, with sensitivity 86%, specificity 94%, positive predictive value 76%, negative predictive value 97%, and overall accuracy 89%.

Likelihood ratio testing confirmed incremental value over RELAPS alone (LR 19.54; P<0.001). The findings support a simple noninvasive strategy for earlier ATTR-CM detection that warrants prospective validation.