A medical device system for determining capture during delivery of a ventricular pacing therapy, comprising: a subcutaneous sensing device comprising a subcutaneous electrode configured to sense a subcutaneous cardiac signal and an emitting device configured to emit a trigger signal in response to the sensed cardiac signal; an intracardiac therapy delivery device configured to be implantable within a left ventricle of a heart and configured to receive the trigger signal and deliver the ventricular pacing therapy to the left ventricle in response to the emitted trigger signal; and a processor positioned within the subcutaneous sensing device, the processor configured to compare a beat of the subcutaneous cardiac signal sensed by the sensing device subsequent to the ventricular pacing therapy being delivered to a baseline template associated with a non-paced beat, and determine whether the delivered ventricular pacing therapy captures the left ventricle in response to the comparing, wherein the processor is configured to determine whether the sensing device is in one of a VDD pacing mode and a VVI pacing mode, determine a timing window including the sensed beat in response to determining whether the device is in one of a VDD pacing mode and a VVI pacing mode, compare the sensed beat within the timing window to the baseline intrinsic template and determine a correlation between the sensed beat within the timing window and the baseline intrinsic template, and determine whether the delivered ventricular pacing therapy captures the left ventricle in response to the correlation; and wherein the processor is configured to determine the delivered ventricular pacing therapy does not capture the left ventricle in response to the correlation being greater than a correlation threshold, and adjust a pacing output of the delivered ventricular pacing therapy in response to the delivered ventricular pacing therapy not capturing the left ventricle. a subcutaneous sensing device comprising a subcutaneous electrode configured to sense a subcutaneous cardiac signal and an emitting device configured to emit a trigger signal in response to the sensed cardiac signal; an intracardiac therapy delivery device configured to be implantable within a left ventricle of a heart and configured to receive the trigger signal and deliver the ventricular pacing therapy to the left ventricle in response to the emitted trigger signal; and a processor positioned within the subcutaneous sensing device, the processor configured to compare a beat of the subcutaneous cardiac signal sensed by the sensing device subsequent to the ventricular pacing therapy being delivered to a baseline template associated with a non-paced beat, and determine whether the delivered ventricular pacing therapy captures the left ventricle in response to the comparing, wherein the processor is configured to determine whether the sensing device is in one of a VDD pacing mode and a VVI pacing mode, determine a timing window including the sensed beat in response to determining whether the device is in one of a VDD pacing mode and a VVI pacing mode, compare the sensed beat within the timing window to the baseline intrinsic template and determine a correlation between the sensed beat within the timing window and the baseline intrinsic template, and determine whether the delivered ventricular pacing therapy captures the left ventricle in response to the correlation; and wherein the processor is configured to determine the delivered ventricular pacing therapy does not capture the left ventricle in response to the correlation being greater than a correlation threshold, and adjust a pacing output of the delivered ventricular pacing therapy in response to the delivered ventricular pacing therapy not capturing the left ventricle.