Medtronic, Inc.

Futurecare Systems, Inc.

Thomas L Jirak

Dennis G Hepp

Paul Citron

David K Peterson

Michael R Hill

Robert G Dutcher

Robert A Neumann

Ren Zhou

Ronald H Rockland

Paul J Beckmann

Pieter M Mulier

Frank C Beert

Maynard J Hoffman

Thomas C Evans

A pacemaker provided with a mode switching feature adapted to stabilize ventricular heart rate during atrial fibrillation. In a preferred embodiment of the invention, the device nominally operates in an atrial synchronized pacing mode such as DDD, DDDR, VDD or VDDR. In response to detection of atrial rhythm characteristics consistent with atrial fibrillation, the device switches into a non-atrial synchronized, ventricular rate stabilization pacing mode with the base ventricular pacing rate modulated on a beat by beat basis based upon preceding intrinsic or paced ventricular heartbeat intervals to adjust the pacing interval towards a desired preset rate stabilization target pacing interval which is typically less than the programmed base pacing interval of the device. While the ventricular rate stabilization mode is in effect, the current pacing interval is set equal to the preceding intrinsic or paced interval, with an increment if the preceding interval is less than the desired or target pacing interval, as typically will be the case, or with a decrement if the preceding interval is greater than the desired pacing interval. In a preferred embodiment of the invention, the device paces both the atria and ventricles in a DDI rate stabilization pacing mode with the ventricular pacing interval being modulated.

Method and apparatus for diagnosis and treatment of arrhythmias

A telemetry base station for use in a system also including a patient worn EKG monitor and transmitter, and a physician monitoring station. The base station is microprocessor controlled, and includes a receiver for receiving FM EKG transmissions from the patient transmitter, an A to D converter, a conventional telephone set, used as an intercom to communicate with the physician, and a data modem which is used for digitized transmissions of the EKG signals. Base station functions including selection of data or voice transmission are controlled by a physician monitoring station. The base station includes simulated telephone ringing functions which assist in its use by patients without specialized training.

EKG telemetry base station

Apparatus for monitoring and storing heart activity signals is disclosed as including a data processor illustratively in the form of a digital microprocessor. The monitoring and storing apparatus comprises a memory comprising first and second pluralities of storage locations, a circuit operating in a real time frame for sampling at a regular rate the patient's heart activity and for storing such sample signals in corresponding locations of said first plurality, an the data processor for processing the signals stored in the first plurality and for storing the processed signals in selected locations of said second plurality. The storage of the signals in the second plurality is performed in a second computer time frame and at a rate faster than the real time sampling rate. A sampling clock provides a sampling clock signal to the sampling circuit whereby the samples of the patient's heart activity are taken. A second computer clock provides computer clock signals to at least a portion of the data processor whereby the processing of the heart activity is effected in the relatively fast computer time frame. The data processor comprises a first portion or means that operates in response to the sample clock signal for evaluating the heart activity signals to determine the existence of a valid heartbeat and a second portion operating in the computer time frame for processing the detected heartbeat and in particular for determining the interval therebetween, which is evaluated to determine whether the heartbeat is occurring with a regular rhythm or not.

Apparatus for monitoring and storing utilizing a data processor

Apparatus for monitoring and storing electrical signals indicative of a patient's heart activity is disclosed as including a memory comprising a first plurality of storage locations for receiving a series of the patient's heart signal and a second plurality of storage locations. Further, there is included a circuit for accessing or examining the heart signals stored in the first plurality of locations to determine their duration and amplitude and a further circuit for comparing the determined amplitude and duration with given criteria and, if met, for storing the evaluated heart signals in locations of said second plurality in a compacted manner adapted to be read out. More specifically, the comparing circuit compares the amplitudes of signals in adjacent locations of said first plurality to determine their difference and, if greater than a given threshold value, to determine the existence of a valid peak of the patient's heart signals, i.e., his heartbeat.

Apparatus for monitoring and storing heartbeats of a patient

Apparatus is disclosed for monitoring and storing electrical signals in a manner to detect the intervals between heartbeats and to provide a manifestation of whether the corresponding heart signals have a regular heart rhythm or not. Such apparatus comprises a memory having at least first and second areas, a circuit for receiving and sampling the heart signals, and a circuit for temporarily storing the heart sample signals in the first area. Further, there is included a circuit for processing or evaluating the heart signals stored in the first area to determine the occurrences of the patient's heartbeat and for determining the intervals between adjacent heartbeats. The determined intervals are stored in the second area and are evaluated to determine whether the patient's heart activity occurs with a regular rhythm. The monitoring and storing apparatus is operative over a monitoring period comprised of a plurality of trend sample intervals. If the heart activity signals occur with a regular rhythm, various characteristics of the heart activity signals including the average rate, and the minimum and maximum rate of the heartbeat as occur within an interval may be stored within a corresponding location of said area of the memory.

Apparatus for monitoring the rhythm of a patient's heartbeat

Heart monitoring and storing apparatus is disclosed for evaluating heart activity signals to determine if valid, for identifying a characteristic of the valid heart activity signal, and for storing the signal into a corresponding location of a memory depending upon the characteristic of the heart activity signal. Such apparatus comprises the memory including a first area and a second area, and a circuit for sampling the heart activity signals and for storing the heart signal samples into corresponding locations of such first area. There is further included an evaluation circuit for determining whether the sampled heart activity signals as stored within the first area are valid and particularly if they indicate the occurrence of a heartbeat. An addressing circuit is provided for determining the various characteristics of a valid heart signal and for selectively addressing a location within said second area to store the valid heart signal of the corresponding characteristic.

Apparatus for monitoring and storing a variety of heart activity signals

An atrial-ventricular demand pacemaker having improved atrial pulse artifact rejection includes a blanking circuit (30, 100) connected in the signal path from the ventricular output terminal (17) to the sensing amplifier (21) to blank the signal during an atrial pulse. A holding circuit including a low-pass filter (46, 137) and a switching element (43, 112) stores a prior signal value at the sensing amplifier input during the blanking interval, and delays return to normal operation until after the blanking circuit has returned to normal. Artifact rejection is also improved by limiting atrial pulse output circuit recharge time and by limiting polarization current driven into the ventricular output circuitry by an atrial output pulse.

Output pulse artifact rejection in demand pacemakers

Apparatus for stimulating body tissue and in particular the heart, is disclosed as including a device or circuit responsive to the initiation of stimulation and/or to the failure or pending failure of a component of the stimulating apparatus to provide the patient with a perceivable stimulation to a second, different portion of body tissue. There is disclosed an impedance level detector for sensing the impedance presented between the outputs of the stimulation apparatus to provide a warning signal indicating that the output impedance falls outside a predetermined range. In particular, the impedance level detector output is sensed by a stimulation control logic to apply a first train of pulses at a first rate to an auxiliary electrode for stimulating the second portion of tissue. Further, there is included a voltage level detector for sensing when the power source voltage depletes below a predetermined level, to actuate the stimulation control logic to provide a second train of warning pulses to the auxiliary electrode, at a second, different rate than that of the first train. In this fashion, the patient not only is warned as to the pending failure or failure of a component of his pacemaker, but also is able to identify the failing component.

Body tissue stimulation apparatus with warning device

Apparatus for indicating end of battery life in a cardiac pacemaker. A battery voltage monitoring circuit provides an indication of battery voltage drop below a predetermined level. A counter circuit and decode logic respond to the voltage drop indication to block a portion of a predetermined number of the generated pacing pulses from the heart to induce a benign arrhythmia in the heart thereby indicating end of battery life. In another embodiment a plurality of voltage sensors indicate progressive decreases in battery voltage and are connected with decode logic to block an increasing number of pacing pulses to indicate worsening battery condition.

Cardiac pacemaker

A pulsed energy coupling system for transferring energy from a detachable power source to a pulse generator module of an electromedical device. Periodically energy is transferred through coupling members to an energy storage device in the pulse generator module. Leakage current losses between coupling members at different electrical potentials is minimized by maintaining coupling members at the same potential during the time intervals between energy transfers. Energy transfers are triggered and effected either at independent, fixed intervals or as energy necessary to power the pulse generator module is dissipated from the energy storage device.

Detachable power source with low current leakage

A demand anti-arrhythmia pacemaker having a plurality of electrodes adapted for connection to a heart for sensing depolarizations. A first responsive circuit provides stimulation signals to at least one area of the heart if a depolarization corresponding to a natural heartbeat fails to occur within a first predetermined time period. A second responsive circuit provides stimulation signals to the heart in a plurality of areas in response to sensed depolarizations which occur within a second predetermined time period.

Demand anti-arrhythmia pacemaker

In a cardiac pacer including a source of timed pulses and means responsive to the timed pulses for providing controlled energy cardiac stimulating pulses, the improved apparatus including means for successively decreasing the energy of the cardiac stimulating pulses after every n pulses from the timed pulse source, n being a number greater than 1. The apparatus may also include means for increasing the energy of the cardiac stimulating pulses in the absence of a driven heartbeat and, in a preferred embodiment, may include additional apparatus to prevent loss of a heartbeat on loss of capture.

Growing community of inventors

Plymouth, MN, United States of America

Thomas L Jirak