Abstract: Pacing systems are disclosed including detectors for detecting the presence of electromagnetic interference and setting an interference state pacing mode and pacing rate. The interference state pacing mode and pacing rate are altered as a function of patient pacemaker dependency and the prevailing mean heart rate. When pacemaker dependency exists, the pacing rate is maintained and even increased from the prevailing mean heart for the duration of the interference state. When the patient is determined to not be pacemaker dependent, pacing is inhibited or suspended for the duration of the interference state.

Abstract: An implantable medical device includes a detector for detecting the presence of a magnetic field, where the presence of the magnetic field is detected in response to the strength of the magnetic field exceeding a first preselected magnetic field threshold. The device further includes a processor for adjusting a stimulation rate provided by the implantable medical device in response to determining that the strength of the detected magnetic field exceeds a second preselected magnetic field threshold. The second preselected magnetic field threshold is greater than the first preselected magnetic field threshold. In another embodiment, the implantable device includes a detector for detecting the presence of a high frequency (HF) radiation interference signal and a processor for adjusting a stimulation rate provided by the implantable medical device in response to determining that the strength of the detected HF radiation interference signal exceeds a preselected HF radiation threshold.

Abstract: Pacing systems are disclosed including detectors for detecting the presence of electromagnetic interference and setting an interference state pacing mode and pacing rate. The interference state pacing mode and pacing rate are altered as a function of patient pacemaker dependency and the prevailing mean heart rate. When pacemaker dependency exists, the pacing rate is maintained and even increased from the prevailing mean heart for the duration of the interference state. When the patient is determined to not be pacemaker dependent, pacing is inhibited or suspended for the duration of the interference state.

Abstract: A system intended for being at least partly implanted into a living body and comprising at least two modules or devices which are interconnected by a communication transmission channel, at least one of said modules being provided with transmitting and receiving means for a bidirectional exchange of information with at least one further module and at least one other module of which being provided at least with receiving means or transmitting means for receiving information from at least one further module or for transmitting information to at least one further module, respectively. Within the intracorporeal region, said communication transmission channel by data modulated ultrasound. The body mass provides for an ultrasonic coupling between two or more implantable modules and/or between at least one implantable module and an external skin transducer intended for connection to an external module.

Abstract: A dual chamber pacemaker having an atrial escape interval which is varied on a beat-to-beat basis in response to the measured time from a ventricular event to the next atrial sensed event. Additionally, a portion of the atrial escape interval is bifurcated in to a first sensing portion T1 and a second sensing portion T2 wherein atrial sense events occurring during T1 may be ignored by the pacemaker, while atrial sense events falling within T2 are used to compute a new atrial escape interval and are used to resynchronize the pacemaker and are used to inhibit the otherwise scheduled atrial pace event.

Abstract: A system intended for being at least partly implanted into a living body and comprising at least two modules or devices which are interconnected by a communication transmission channel, at least one of said modules being provided with transmitting and receiving means for a bidirectional exchange of information with at least one further module and at least one other module of which being provided at least with receiving means or transmitting means for receiving information from at least one further module or for transmitting information to at least one further module, respectively. Within the intracorporal region, said communication transmission channel is wireless. It includes the ion medium of the intra and extracellular body liquids and provides for an electrolytic-galvanic coupling between two or more implantable modules and/or between at least one implantable module and external skin electrodes intended for connection to an external module.

Abstract: A dual chamber pacemaker having an atrial escape interval which is varied on a beat-to-beat basis in response to the measured time from a ventricular event to the next atrial sensed event. Additionally, a portion of the atrial escape interval is bifurcated into a first sensing portion T1 and a second sensing portion T2 wherein atrial sense events occurring during T1 may be ignored by the pacemaker, while atrial sense events falling within T2 are used to compute a new atrial escape interval and are used to resynchronize the pacemaker and are used to inhibit the otherwise scheduled atrial pace event.

Abstract: A dual pace--dual sense cardiac pacemaker pulse generator having ventricular and atrial sensing and pulse generating means interconnected by circuit means to cause the atrium to be stimulated in the event that a natural atrial contraction is not sensed within a certain time from the last ventricular stimulus or natural contraction and the ventricle to be stimulated in the event that a naturally ventricular contraction is not sensed within a further time from the last atrial contraction or stimulus.

Abstract: An atrial pacemaker having an atrial pacing rate adjusted to correspond to a detected ventricular heart rate to maintain A-V synchrony in a range between a minimum and maximum pacing rate. Sensed ventricular depolarizations not associated with a preceding atrial pacing stimulus cause the atrial pacing rate to be increased. When A-V synchrony is restored at a higher rate, the rate is decreased. Underdrive stimulation to treat pathologic tachycardia is achieved as the atrial pacing rate is increased in steps to the maximum pacing rate, normally lower than typical tachycardia rates.