Integrated Hemodynamic Sensing, Electrical Sensing, and Ventricular Pacing from a Novel Substernal Lead: An Acute Human Study.

BACKGROUND: Implantable cardioverter-defibrillators (ICDs) rely primarily on electrical signals to guide therapy. Hemodynamic sensing may provide complementary information about the immediate physiologic consequences of arrhythmias. OBJECTIVE: Evaluate the acute feasibility and performance of a 3-dimensional substernal shock lead integrating hemodynamic sensing, electrical sensing, and ventricular pacing. METHODS: This prospective first-in-human feasibility study enrolled 5 patients undergoing cardiac surgery or epicardial ventricular tachycardia (VT) ablation. A substernal shock lead was temporarily placed through a percutaneous subxiphoid approach using a dedicated delivery system. Lead placement and removal, adverse events, synchronized sensor signals, surface electrocardiograms, substernal electrograms, and pacing thresholds were assessed. RESULTS: Lead placement and removal were successful in all patients without device- or procedure-related acute adverse events. Interpretable hemodynamic signals were obtained in all 5 patients and showed stable beat-to-beat temporal correspondence with the electrocardiogram and distinct rhythm-associated patterns across sinus rhythm (SR), atrial fibrillation, VT, and ventricular fibrillation (VF). All 147 VT episodes had interpretable hemodynamic-index recordings. The hemodynamic index decreased abruptly during VT and recovered after arrhythmia termination. Corresponding changes in the hemodynamic index were observed during transitions among VT, VF, and SR. Ventricular capture was achieved in all 5 patients at 11-17 V (mean, 13.8 V) at 0.5 ms. CONCLUSION: Acute placement of this multifunctional substernal lead was feasible and enabled integrated hemodynamic and electrical sensing with acute ventricular capture. These findings provide preliminary human support for further development of physiology-guided extravascular ICD systems; chronic performance and clinical validation of the hemodynamic sensing algorithm require further study.