Abstract: In a heart display system a computer is operable to simulate different selected hearts, each with a different pattern of electrophysiological pathways, which conduct waves of depolarization. The computer determines the conduction in the pattern of pathways of a selected heart in accordance with selected parameters and inputs provided by the operator. In simulating the heart, the computer determines whether a depolarization wave proceeds from one pathway segment to an adjacent segment by examining whether the adjacent segment is polarized or depolarized and determines that the depolarization wave proceeds only if the adjacent segment is polarized. The operation of the simulated heart is displayed by showing an animation of the conduction of the depolarization waves in the pattern of electrophysiological pathways of the selected heart, by an ECG, and by a ladder diagram.

Abstract: A dual chamber cardiac stimulator provides sequential escape stimuli to the heart for bradycardia by synchronous following of normal sinus rhythm with prosthetic redundant AV coupling pre-empting or substituting for long or blocked physiologic AV delays. The automatic provision for prosthetic conduction of cardiac action in both antero and retrograde directions with pre-emption of pathologic delays prevents the initiation of reentry supraventricular tachyarrhythmias as well as the traditional disrhythms of pacing. Access to both chambers permits automatic injection of simple stimulus programs in either chamber upon the detection of a disrhythm, with immediate interruption by the first normal cardiac event. The pacer responds to arrhythmia provoking events by controlling the conduction time from atrium to ventricle and from ventricle to atrium to maintain cardiac stability and prevent pathological pathways from contributing to satisfy the criteria of reentry tachycardia.

Abstract: A cardiac pacemaker constructed for terminating tachyarrhythmias and including: an atrial electrode implantable in a patient's heart for supplying atrial stimulation pulses thereto and at which a pulse appears in response to each atrial contraction; a ventricular electrode implantable in the patient's heart for supplying ventricular stimulation pulses thereto, and at which a pulse appears in response to each ventricular contraction; separately switchable control paths connected to each electrode for causing one electrode to produce a stimulation pulse at a given time after the occurrence of a pulse on the other electrode; a first time delay unit connected to be actuated by signals derived from the heart behavior for supplying a stimulating pulse to the ventricular electrode at a time after the occurrence of a pulse on the atrial electrode, which is shorter than the physiological atrial-ventricular transfer time; and a second time delay unit connected to be actuated by signals derived from the heart behavior f