Beyond Agreement: a real-world study of the workflow gap between echocardiography and timely structural cardiac assessmentHow a Validation Study Exposed a Hidden Gap in Cardiac Care

Objectives To assess agreement between Cardio-HART (CHART) and echocardiography for left ventricular ejection fraction (LVEF) estimation and heart failure (HF) classification in a real-world predominantly ischaemic cohort, while examining whether a point-of-care structural and functional assessment tool could reveal a broader workflow gap between the nominal availability of echocardiography and timely cardiac assessment in routine care. Design Prospective single-centre cohort study. Setting Secondary-care cardiology service at Cascais Hospital, Lisbon, Portugal. Participants Forty-seven adults referred for cardiology evaluation with suspected HF or followed in a hospital HF clinic. Primary and secondary outcome measures Agreement between CHART-derived and echocardiographic LVEF by Bland-Altman analysis; diagnostic performance for HF phenotypes; comparison with the Teichholz method. Results Mean age was 65.6+-15.9 years; 78.7% of participants had HF and 43.2% of HF cases were ischaemic. CHART showed a mean LVEF bias of +1.92% versus echocardiography, with 95% limits of agreement from -14.6% to +18.4% and a mean absolute error of 6.09%. Agreement was strongest in HF with reduced ejection fraction (HFrEF) and HF with mildly reduced ejection fraction (HFmrEF), and lower in HF with preserved ejection fraction (HFpEF). Diagnostic area under the curve for HFrEF classification was 0.89. Compared with the Teichholz method, CHART showed a lower root mean square error relative to Simpson's biplane LVEF. Conclusions CHART showed clinically credible performance for LVEF estimation and HF stratification, particularly in reduced-EF phenotypes. However, the most important finding of this study was not agreement alone. By performing credibly in a cardiology-based real-world setting, CHART exposed a previously under-recognised workflow gap between the nominal availability of echocardiography and timely access to structural cardiac assessment in routine care. The study therefore suggests that the value of CHART lies not only in diagnostic performance, but in making visible, and potentially narrowing, a hidden but consequential gap in cardiac assessment pathways. Larger studies are warranted, particularly for HFpEF and across broader clinical workflows.