Abstract: A cardiac analysis system is provided that includes an implantable medical device (IMD), at least one sensor, and an external device. The IMD has electrodes positioned proximate to a heart that sense first cardiac signals of the heart and associated with a clinical ventricular tachycardia (VT) event and second cardiac signals associated with an induced VT event. The sensor measures first and second cardiac parameters of the heart associated with the clinical and induced VT events, respectively. The external device is configured to receive the first and second cardiac signals associated with the clinical and the induced VT events and the first and second cardiac parameters associated with the clinical and the induced VT events. The external device compares the first and second cardiac signals and compares the first and second cardiac parameters to determine if the clinical and induced VT events are a common type of VT event.

Abstract: A cardiac analysis system is provided that includes an implantable medical device (IMD), at least one sensor, and an external device. The IMD has electrodes positioned proximate to a heart that sense first cardiac signals of the heart and associated with a clinical ventricular tachycardia (VT) event and second cardiac signals associated with an induced VT event. The sensor measures first and second cardiac parameters of the heart associated with the clinical and induced VT events, respectively. The external device is configured to receive the first and second cardiac signals associated with the clinical and the induced VT events and the first and second cardiac parameters associated with the clinical and the induced VT events. The external device compares the first and second cardiac signals and compares the first and second cardiac parameters to determine if the clinical and induced VT events are a common type of VT event.

Abstract: An antitachycardia device, either implanted or external, which delivers a fixed pulse width truncated exponential waveform defibrillation shock and automatically adjusts the pulse duration based upon the impedance measured or calculated following a delivered shock. The apparatus operates by measuring or calculating the high voltage system impedance, selecting a pulse width for that impedance value and using a pulse width derived from the selected pulse width for the next defibrillation shock.