Abstract: Orthogonal sensors, which are comprised of two or more electrodes and generally disposed circumferentially on the catheter at given longitudinal point along the catheter, receive signals which are differenced within a differential amplifier to produce a signal indicative only of the localized biopotential heart activity at a predetermined point in the myocardium. The orthogonal sensors are disposed in an ablative tip of the catheter to allow sensing of the localized cardiac activity which is adjacent to or in contact with the ablative tip during extirpation procedure or during the delivery of radio frequency energy during ablation. Sensing of the localized cardiac activity occurs simultaneously either with the ablation so that detailed and accurate electrocardiograms of the very tissue being ablated can be recorded.

Abstract: Accurate mapping of electrophysiologic activation within the human heart is achieved for discrete areas within the myocardium by utilizing a catheter having at least one pair of orthogonal sensors disposed on the catheter. Orthogonal sensors, which are comprised of two or more electrodes generally disposed circumferentially on the catheter at given longitudinal point along the catheter, receive signals which are differenced within a differential amplifier to produce a signal indicative only of the localized biopotential heart activity at a predetermined point in the myocardium. The orthogonal sensors are disposed adjacent to the stimulating tip of the catheter to allow sensing of the localized cardiac activity which is adjacent to or in contact with the stimulating tip during pacing procedure or during the delivery of radio frequency energy during ablation.

Abstract: Reprogramming of implanted pacemakers is made more reliable and secure by utilizing a pad having an adhesive surface provided on its upper and lower contacting layers. In the illustrated embodiment, the pad is generally circular with a central circular hole. The pad is placed over the implanted pacemaker at a predetermined position utilizing the central aperture hole for alignment of the pad on the site of pacemaker implantation. An auxiliary cardiac device, such as a programming head, is then disposed on the upper adhesive of the circular pad. The shape of the pad inherently induces the medical technician to appropriately register the auxiliary device relative to the pacemaker. The double adhesive layers of the pad provide temporary affixation of the auxiliary device relative to the pacemaker during the reprogramming or other pacemaker manipulation so that inadvertent relative movement of the auxiliary device relative to the programmable pacemaker is avoided.

Abstract: Accurate mapping of electrophysiologic activation within the human heart is achieved for discrete areas within the heart by utilizing a catheter having at least one pair of orthogonal sensors disposed on the catheter. Orthogonal sensors, which are comprised of two or more electrodes generally disposed circumferentially on the catheter at given longitudinal position along the catheter, receive signals which are differenced within a differential amplifier to produce a signal indicative only of the localized or near field biopotential heart activity. The orthogonal sensors are disposed adjacent to the stimulating tip of the catheter to allow sensing of the localized cardiac activity which is adjacent to or in contact with the stimulating tip during pacing procedures or during the delivery of radio frequency energy during ablation.

Abstract: A cardiac pacemaker with a single catheter for insertion into a heart through the vascular system. An electrode system for the catheter including a stimulating electrode at the distal end of the catheter for positioning at the apex of the right ventricle, with the stimulating electrode connected to the pulse generating unit of the pacemaker, and sensing electrodes on the catheter spaced from the stimulating electrode for positioning adjacent to the wall of the right atrium for sensing signals generated by the atrial excitation or P-wave, with the P-wave signals connected as input to the pacemaker for determining the timing of the ventricular stimulating pulses.The sensing electrodes are circumferentially equidistant from the stimulating electrode and provide one or more bipolar signals for the pulse generating unit.In alternative configurations, the stimulating electrode and the sensing electrodes are positioned in various locations within the heart to provide other methods of cardiac control.