The Contribution of Tool Testing to the Challenge of Responding to an IT Adversary (Keynote).

An artificial heart pacemaker and control circuit having an atrial synchronous pacing mode includes an output pulse generator for delivering stimulating pulses to the ventricle of the heart, and atrial and ventricular sensing amplifiers for detecting, respectively, atrial and ventricular contractions. The atrial sense amplifier starts an A-V delay timer which provides a delayed triggering pulse to the pulse generator to maintain A-V synchrony. Circuitry is provided for blanking or turning off the atrial sensing amplifier during the time that the ventricular sensing amplifier is refractory, and preferably for a short time interval thereafter, to prevent delivery of an output pulse in response to a premature ventricular contraction erroneously sensed as an atrial contraction.