Measuring cardiac hemodynamics subcutaneously offers a novel and minimally-invasive means of monitoring mechanical heart performance. Four accelerometer-based hemodynamic sensors were implanted at various subcutaneous sites of the thorax in one dog. Three of the sensors were on the tips of cardiac pacing leads, one was embedded inside an inactive pacemaker device can. The first heart sound could be well identified and its amplitude quantified in all subcutaneous sensors on a beat-to-beat basis. Its magnitude was comparable to that of the external signal, and about half that of the intracardiac signal. It also correlated well to cardiac contractility during transient pharmacologically induced hemodynamic challenges. This is the first evidence that heart sounds can be measured in the subcutaneous space to monitor heart function.