| CPC A61B 5/305 (2021.01) [A61N 1/3625 (2013.01); A61N 1/365 (2013.01)] | 20 Claims | 

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               1. An ambulatory cardiac device for improving a signal to noise profile of an ECG signal of a patient, the ambulatory cardiac device comprising: 
              a garment configured to be worn about a torso of the patient; and 
                a plurality of active electrocardiogram (ECG) electrodes configured to be disposed in a plurality of locations about the patient, each active ECG electrode comprising 
                an ECG electrode substrate configured to be in physical contact with skin of the patient, 
                a local biasing substrate proximate to the ECG electrode substrate and configured to be in physical contact with the skin of the patient, 
                local biasing circuitry that is electrically connected to the local biasing substrate, wherein the local biasing circuitry is configured to provide a local biasing signal into a body of the patient via the local biasing substrate, and 
                a housing that is removably attached to the garment, encloses the local biasing circuitry, and holds the local biasing substrate, 
              wherein the garment is configured to hold the plurality of active ECG electrodes in contact with the skin of the patient when the patient wears the garment. 
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