Evaluation of new vectorcardiography algorithms for identifying left ventricular hypertrophy and impaired systolic function.

BACKGROUND: Timely diagnosis of impaired systolic function and left ventricular hypertrophy (LVH) remains a clinical challenge. Routine electrocardiography provides limited diagnostic accuracy for detecting early or subtle structural abnormalities. Vectorcardiography (VCG), which captures the spatial and temporal characteristics of cardiac electrical activation and repolarization, may offer a rapid, scalable, and cost-effective alternative for screening structural heart disease. OBJECTIVE: To evaluate the diagnostic performance of VCG for identifying impaired systolic function and left ventricular hypertrophy compared with cardiac magnetic resonance imaging. METHODS: This prospective case-control study included 245 participants undergoing both CMR and VCG. Among 245 participants, 40 had reduced LVEF (<40%) and 208 met CMR criteria for LVH; 34 patients had both conditions. Patients were classified as having impaired systolic function (left ventricular ejection fraction [LVEF] <40%), LVH (indexed left ventricular mass ≥ 55 g/m2), or controls with structurally normal hearts. VCG was obtained using a five‑lead system (cardisiography), and signals were processed by an AI algorithm extracting 583 parameters. Diagnostic performance was evaluated using CMR as reference. RESULTS: The repolarization time-difference ratio (Rpeak-Tonset / QRSend-Tpeak) showed the best diagnostic performance for impaired systolic function, with an area under the curve (AUC) of 0.843, sensitivity of 80.0%, and specificity of 83.9%. In LVH patients, three parameters-T-wave azimuth, T-wave magnitude, and azimuth variability-showed AUCs ranging from 0.739 to 0.791. Overall diagnostic accuracy was 81.7% for impaired systolic function and 78.2% for LVH, and 83.1% for the combined phenotype of reduced LVEF and LVH. CONCLUSION: VCG reliably detects left ventricular systolic dysfunction and hypertrophy. This approach offers a scalable and interpretable screening tool, especially valuable in settings with limited access to advanced cardiac imaging. Future multicenter studies are needed to validate these findings and support clinical implementation.