Medtronic, Inc.

The Cleveland Clinic Foundation

Medtronics, Inc.

David A Igel

John E Burnes

Yong Kyun Cho

D Curtis Deno

Michael R S Hill

Luc Roland Mongeon

John C Rueter

Lawrence J Mulligan

Jodi Zilinski

Harry Stone

Karen J Kleckner

Tommy Dean Bennett

Teresa A Whitman

Tom Dean Bennett

David E Euler

Edwin G Duffin

Mark Choi

Jeffrey M Gillberg

H Toby Markowitz

Douglas A Hettrick

Vincent E Splett

Robert A Betzold

Kenneth M Anderson

Ruth N Klepfer

Glenn C Zillmer

Kathleen A Prieve

Ren Zhou

Harold E Stone

Richard J Shaw

Bruce L Wilkoff

Curtis D Deno

Jeremy A Schroetter

A method of stimulation therapy and an apparatus for providing the therapy which addresses cardiac dysfunction including heart failure. The therapy employs atrial pacing pulses delivered to a heart after the atrial refractory period and timed so that they will not cause a ventricular contraction. These atrial pacing are timed to achieve beneficial effects on myocardial mechanics (efficacy) while maintaining an extremely low level of risk of arrhythmia induction. These methods may be employed individually or in combinations in an external or implantable ESS therapy delivery device.

Secure and efficacious therapy delivery for a pacing engine

Methods and devices for determining optimal Atrial to Ventricular (AV) pacing intervals and Ventricular to Ventricular (VV) delay intervals in order to optimize cardiac output. Impedance, preferably sub-threshold impedance, is measured across the heart at selected cardiac cycle times as a measure of chamber expansion or contraction. One embodiment measures impedance over a long AV interval to obtain the minimum impedance, indicative of maximum ventricular expansion, in order to set the AV interval. Another embodiment measures impedance change over a cycle and varies the AV pace interval in a binary search to converge on the AV interval causing maximum impedance change indicative of maximum ventricular output. Another method varies the right ventricle to left ventricle (VV) interval to converge on an impedance maximum indicative of minimum cardiac volume at end systole. Another embodiment varies the VV interval to maximize impedance change.

Algorithm for the automatic determination of optimal AV and VV intervals

Impedance, e.g. sub-threshold impedance, is measured across the heart at selected cardiac cycle times as a measure of chamber expansion or contraction. One embodiment measures impedance over a long AV interval to obtain the minimum impedance, indicative of maximum ventricular expansion, in order to set the AV interval. Another embodiment measures impedance change over a cycle and varies the AV pace interval in a binary search to converge on the AV interval causing maximum impedance change indicative of maximum ventricular output. Another method varies the right ventricle to left ventricle (VV) interval to converge on an impedance maximum indicative of minimum cardiac volume at end systole. Another embodiment varies the VV interval to maximize impedance change. Other methods vary the AA interval to maximize impedance change over the entire cardiac cycle or during the atrial cycle.

Algorithm for the automatic determination of optimal pacing intervals

A system and method for cardiovascular analysis includes an implantable medical device capable of generating hemodynamic pressure waveform data based upon sensed pressure. Hemodynamic waveform data is analyzed to identify artifactual data represented in the hemodynamic waveform.

System and method for detecting artifactual hemodynamic waveform data

A cardiovascular analysis system and method includes an implantable medical device with a sensor positioned to sense a hemodynamic pressure over time. The implantable medical device generates hemodynamic pressure waveform data based upon the hemodynamic pressure sensed. A processor analyzes the hemodynamic waveform data to provide an indication of cardiovascular health based upon prominent peaks in the hemodynamic waveform data.

System and method for detecting cardiovascular health conditions using hemodynamic pressure waveforms

A medical device, e.g., an implantable medical device, delivers one or more neurally-excitable stimulation pulses to myocardial tissue during a period when the tissue is refractory. The width of the pulses is less than or equal to approximately one half millisecond. In some embodiments, the current amplitude of the pulses is less than or equal to approximately twenty milliamps. In exemplary embodiments, the medical device delivers a pulse train of six or fewer pulses separated from each other by an interval that is greater than or equal to approximately ten milliseconds. In some embodiments, the medical device delivers pulses according to a schedule stored in a memory, or as a function of a monitored physiological parameter of a patient, such as an intracardiac pressure. In some embodiments, the medical device suspends or withholds delivery of neurally-excitable based on detection of cardiac ischemia.

Cardiac stimulation during a refractory period

Algorithm for the automatic determination of optimal AV an VV intervals

An implantable stimulator and monitor measures a group of heart failure parameters indicative of the state of heart failure employing EGM signals, measures of blood pressure including absolute pressure P, developed pressure (DP&equals;systolic P&minus;diastolic P), and/or dP/dt, and measures of heart chamber volume (V) over one or more cardiac cycles. These parameters include: (1) relaxation or contraction time constant tau (&tgr;); (2) mechanical restitution (MR), i.e., the mechanical response of a heart chamber to premature stimuli applied to the heart chamber; (3) recirculation fraction (RF), i.e., the rate of decay of PESP effects over a series of heart cycles; and (4) end systolic elastance (E ), i.e., the ratios of end systolic blood pressure P to volume V. These heart failure parameters are determined periodically regardless of patient posture and activity level. The physician can determine whether a particular therapy is appropriate, prescribe the therapy for a period of time while again accumulating the stored patient data for a later review and assessment to determine whether the applied therapy is beneficial or not, thereby enabling periodic changes in therapy, if appropriate. Drug therapies and electrical stimulation therapies, including PESP stimulation, and pacing therapies including single chamber, dual chamber and multi-chamber (bi-atrial and/or bi-ventricular) pacing can be delivered. In patient's prone to malignant tachyarrhythmias, the assessment of heart failure state can be taken into account in setting parameters of detection or classification of tachyarrhythmias and the therapies that are delivered.

Implantable medical device for treating cardiac mechanical dysfunction by electrical stimulation

An implantable stimulator and monitor measures a group of heart failure parameters indicative of the state of heart failure employing EGM signals, measures of blood pressure including absolute pressure P, developed pressure (DP&equals;systolic P&minus;diastolic P), and/or dP/dt, and measures of heart chamber volume (V) over one or more cardiac cycles. These parameters include: (1) relaxation or contraction time constant tau (&tgr;); (2) mechanical restitution (MR), i.e., the mechanical response of a heart chamber to premature stimuli applied to the heart chamber; (3) recirculation fraction (RF), i.e., the rate of decay of PESP effects over a series of heart cycles; and (4) end systolic elastance (E ), i.e., the ratios of end systolic blood pressure P to volume V. These heart failure parameters are determined periodically regardless of patient posture and activity level. However, certain of the parameters are only measured or certain of the data are only stored when the patient heart rate is regular and within a normal sinus range between programmed lower and upper heart rates. The parameter data is associated with a date and time stamp and with other patient data, e.g., patient activity level, and the associated parameter data is stored in IMD memory for retrieval at a later date employing conventional telemetry systems. Incremental changes in the parameter data over time, taking any associated time of day and patient data into account, provide a measure of the degree of change in the heart failure state of the heart.

Implantable medical device for monitoring congestive heart failure

A pacing system provided with a mode switching feature and ventricular rate regularization (VRR) function adapted to stabilize or regularize ventricular heart rate during chronic or paroxysmal atrial tachyarrhythmia. In a preferred embodiment, the pacing system nominally operates in an atrial synchronized pacing mode such as DDD or DDDR pacing mode. In response to detection of atrial rhythm characteristics consistent with an atrial tachyarrhythmia, e.g., atrial fibrillation, a mode switch into a non-atrial synchronized, ventricular rate regularization pacing mode, e.g. DDIR or VDIR pacing mode, is made. If the VRR function is programmed on, the ventricular pacing rate based upon a rate responsive sensor derived ventricular pacing rate modulated on a beat by beat basis by preceding intrinsic or paced ventricular events, the stability of the intrinsic ventricular heart rate, and any atrial pace events to regularize the ventricular pacing rate. The pacing system may also be permanently programmed to the DDIR pacing mode with the VRR feature functioning continuously. The pacing system may also be permanently programmed to the VVIR pacing mode with VRR function activated, but without consideration of atrial pace events.

Regularization of ventricular rate during atrial tachyarrhythmia

A nonprogrammable automated heart rhythm classifier that may be used alone or in conjunction with a therapy system for delivering shock treatment or therapeutic drugs to a patient, a monitoring or recording system, a paging or alarm system, or other rhythm classifying device. The nonprogrammable heart rhythm classifier is used to determine whether a patient's heart rhythm is normal, monomorphic tachycardia or polymorphic tachycardia from extracted features of the cardiac signal of a patent's heart. The extracted features are cycle length and regularity, and preferably with the addition of morphology. Prior to feature extraction, the cardiac electrical signal is conditioned with a signal conditioning system. The classifier may comprise a trained neural network or a trained discriminant function, which has been previously trained by a known set of classified heart rhythm data. Morphology can be estimated by kurtosis or from the probability density function. Regularity can be determined from approximate entropy, information dimension, correlation dimension or from Lyapunov's exponents of the patient's cardiac electrical signal. In yet another embodiment of the invention, adaptive sampling may be utilized to selectively digitize the cardiac electrical signal before classification occurs.

Non-programmable automated heart rhythm classifier

Growing community of inventors

Lino Lakes, MN, United States of America

David A Igel