Other

Medtronic, Inc.

Raul Chirife

William J Combs

Russell R Lundstrom

Russell L Lundstrom

Graciela Aurora Ruiz

Eliana Aversa

Jose Maria Piccinini

An electronic device and method for continuous noninvasive blood pressure monitoring in a subject having an electronic device capable of receiving, storing and processing data from an arterial pulse waveform sensor. The electronic device detects key landmarks on the arterial pulse waveform allowing the calculation of pulse rate and left ventricular ejection time (LVET). Based on experimentally determined regression equations between rate-corrected LVET and systolic diastolic and pulse blood pressures, prevailing beat-to-beat blood pressure values are calculated. The only input required for continuous blood pressure monitoring is an arterial pulse waveform, detected in the present invention by a single sensor device, for example a photoplethysmography pulse detector. An electronic device suitable for performing this noninvasive method is further provided.

Electronic device and method for noninvasive, continuous blood pressure monitoring

The invention consists of a device and method for the prediction of left ventricular ejection fraction (EF) and other cardiac hemodynamic parameters using systolic time intervals in patients with narrow QRS, right bundle branch block, left bundle branch block, right ventricular and/or left ventricular cardiac pacing and in the presence of arrhythmia, such as atrial fibrillation. The device has three inputs: the ECG, a peripheral pulse and a phonocardiogram. Timing parameters are obtained from these signals to calculate a systolic function index, used for the prediction of ejection fraction. Given the invention's features it would be now possible to assess cardiac performance and specifically left ventricular ejection fraction in ambulatory patients as well as during invasive procedures such as the implant of cardiac rhythm management devices. Also, an implantable embodiment of the invention would allow constant monitoring of cardiac performance, parameter adjustment of cardiac devices and automatic drug infusion.

Device and method for assessment of left ventricular ejection fraction and other parameters of cardiac performance

An implantable medical device provides ventricular pacing capabilities and optimizes AV intervals for multiple purposes. In general, intrinsic conduction is promoted by determining when electromechanical systole (EMS) ends and setting an AV interval accordingly. EMS is determined utilizing various data including QT interval, sensor input, and algorithmic calculations.

System and method of AV interval selection in an implantable medical device

Method and apparatus for automatically setting a variable upper rate limit for the pacing pulse signal provided by a rate adaptive implantable pacemaker which relies on a non-physiological sensor to determine the pacing needs of the patient. A physiological parameter of the patient's condition is sensed and used to determine an upper limit for the pacing rate otherwise called for based on the reading of the non-physiological sensor. In a disclosed embodiment, the ventricular preejection period is monitored as the physiological parameter, and the rate of change of this parameter is utilized to set the upper limit of the pacing pulse rate.

Cardiac pacemaker upper rate limit control

A dual-chamber AV sequential pacemaker with the capability of automatically adjusting right heart AV interval to optimize left heart AV interval by compensating for pacing-induced inter-atrial and inter-ventricular conduction delays. Depending on the pacing and sensing action, as determined by the patient's native rate, the predetermined threshold rate and intrinsic AV interval, the pacemaker selects the AV interval. Right heart AV interval is adjusted to compensate for the heart's inter-atrial and inter-ventricular delays. Threshold values are previously estimated, using mean values measured using non-invasive techniques. The pacemaker has a dual phase operating mechanism consisting of an analysis phase followed by a pacing phase. The P wave rate is sensed and compared to a predetermined base rate. If the sensed P wave rate is above the baseline, atrial depolarizations will be sensed by the pacemaker and small number (default=4) of consecutive native AV intervals will be averaged. If this average is less than a predetermined threshold value, the system will continue in the demand mode, sensing P and R waves. If the average is greater than said value, then the ventricle is paced for n number of times the analysis phase (default=100 cycles), each followed by a short AV delay (Default=50 ms) that is intended to compensate for the delay introduced in the onset of left ventricular depolarization after pacing the right ventricular apex. When P wave rate is below the predetermined rate, atrial pacing will occur.

Cardiac pacemaker with automatic A-V programming for optimization of

A sensor for developing a control signal to be injected into the mechanism of a cardiac diagnosis and therapy device is disclosed. An external or internal pulse generator associated with the sensor includes a pulse width timer and an oscillator circuit to deliver constant voltage pulses through a capacitor to a lead for delivery of therapy or diagnosis. Means for detecting the peak trailing edge voltage or the current are included as an indicator of the volume of blood present in the heart or the thoracic volume at the time of stimulation. The volume signal is then directed to implantable or external devices by a control signal output to be used in the circuit of the other device.

Sensor for right ventricular and thoracic volumes using the trailing

A rate responsive pacemaker uses isovolumic contraction time (IVCT) as a control signal responsive to metabolic demands. This control signal is injected into the timing circuit of a standard rate adaptive pacemaker to enhance the pacer's ability to respond in direct relation to the patient's changing metabolic needs as he performs his daily activities. A typical configuration, uses the duration of either right or left heart IVCT for rate control. The device has two inputs to measure IVCT: one, signaling the onset of mechanical activation of the ventricle, and another, signaling the onset of ejection. The time interval between these two signals is the duration of IVCT, which is processed by the pacemaker to determine the escape interval.

Rate responsive pacemaker controlled by isovolumic contraction time

A rate adaptive pacer designed to accommodate changes in a patient's metabolic demand utilizes ventricular ejection fraction (EF) as the rate controlling parameter. Ejection fraction is measured by sensing intracardiac impedance at end-diastole and end-systole and then using these measurements to compute stroke volume (SV). Ejection fraction is the stroke volume divided by the end-diastolic volume. This calculated value of EF is processed by the pacemaker to determine the escape interval (pacing rate) through a simple conversion algorithm.

Rate adaptive pacemaker controlled by ejection fraction

A cardiac stimulator apparatus for effecting cardioversion or defibrillation in the event of pathologic tachycardia or ventricular fibrillation in which the rate of heart depolarization signals is compared to a predetermined heart rate value indicative of the onset of tachycardia while, simultaneously, the heart's pre-ejection period is monitored to sense whether an increase in heart rate above the predetermined value is accompanied by a decrease in the pre-ejection period. If not, a pathologic rather than a physiologic episode is diagnosed and a cardioversion pulse protocol is initiated. By also monitoring the mechanical pulse of the heart, if an inordinately high heart rate is accompanied by a low or non-existing mechanical pulse, ventricular fibrillation is diagnosed and the cardioverter is triggered to shock the heart back into sinus rhythm. If the mechanical pulse rate tracks the electrical rate of depolarization, tachyarrythmia is confirmed. The diagnosis may be further confirmed by taking into account the rate at which the heart rate increases.

Antitachyarrythmia pacemaker using pre-ejection period to distinguish

A cardiac pacemaker has a pacing pulse generator whose rate is adjusted as a function of the cardiac output requirements of the body that are commensurate with the activity of the individual. The length of the ventricular preejection period (PEP) is governed by body hormones as well as direct nerve action upon the heart in relation to stress. The PEP is determined by marking occurrence of the onset of a natural ECG signal or artificial pacing pulse, whichever is first to occur in a heart cycle, and detecting left or right ventricular ejection by a pressure or flow pulse in the arterial system or a volume change in the right ventricle. The length of time between the onset of a natural or artificial stimulus and onset of ventricular ejection is the PEP. An electric signal that depends on the PEP is used to regulate the pulse generator rate and escape mechanisms in any of the conventional pacing modes including the AAI, VVI, DVI, VDD and DDD modes.

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Acassuso, Argentina

Raul Chirife