An implantable medical device for stimulating a heart, comprising a control unit, a memory unit, a stimulation unit for stimulating a cardiac region of a heart, and a detection unit for detecting an electrical signal of the heart. The memory unit comprises a computer-readable program that causes the control unit to perform the following steps: a) detecting capture thresholds during an observation period, each capture threshold detected in response to a sequence of pacing pulses delivered by the stimulation unit; b) storing the detected capture thresholds in the memory unit; c) determining threshold-to-threshold differences between two consecutive capture thresholds; and d) if a maximum determined threshold-to-threshold difference within the observation period is equal to or greater than a predetermined limit, adjusting a pacing output of the stimulation unit based on the maximum capture threshold determined within a first time period which is equal to or shorter than the observation period.

An implantable medical device for stimulating a heart, comprising a control unit, a memory unit, a stimulation unit for stimulating a cardiac region of a heart, and a detection unit for detecting an electrical signal of the heart. The memory unit comprises a computer-readable program that causes the control unit to perform the following steps: a) detecting capture thresholds during an observation period, each capture threshold detected in response to a sequence of pacing pulses delivered by the stimulation unit; b) storing the detected capture thresholds in the memory unit; c) determining threshold-to-threshold differences between two consecutive capture thresholds; and d) if a maximum determined threshold-to-threshold difference within the observation period is equal to or greater than a predetermined limit, adjusting a pacing output of the stimulation unit based on the maximum capture threshold determined within a first time period which is equal to or shorter than the observation period.

A cardiac pacing threshold acquisition method, a pacing control method and apparatus, and a medical device. The acquisition method comprises: in a pacing test phase, using an initial pacing frequency and an initial pacing output to perform pacing on a patient; under the pacing operation, measuring first response information of the ventricle of a patient to the initial pacing frequency; according to whether an R wave is present in the first response information, adjusting pulse voltage amplitude or pulse width of the initial pacing frequency so as to obtain a cardiac pacing threshold corresponding to the patient.

A medical device system and method estimate a time from a first voltage of a power source of a medical device to a second voltage of the power source. The medical device includes a sensor coupled to the power source for generating a physiological signal. The medical device system determines a current drain from the power source required for generating the physiological signal and/or processing the physiological signal for detecting events from the physiological signal. A processor of the medical device system is configured to estimate the time from the first voltage of the power source until the second voltage based on at least the determined current drain.

An implantable medical device system and method for delivering cardiac resynchronization therapy (CRT) pacing that includes determining capture associated with the delivered CRT pacing is ineffective in response to the delivered CRT pacing. A reason for capture being ineffective is determined and a safety margin is adjusted if the determined reason for capture being ineffective is loss of capture and a left ventricle (LV) pre-excitation is adjusted if the determined reason for capture being ineffective is delayed LV depolarization. Monitoring for a change in effective cardiac resynchronization therapy is used to confirm that the adjustment of the CRT pacing was effective in resolving the ineffective capture.

A cardiac stimulation system and associated capture management method are provided in which capture and device longevity are improved. The device determines a series of capture thresholds. Capture threshold is the minimum pulse level (pulse energy or pulse amplitude or pulse width) that captures the heart. Each determination requires delivery of pacing pulses at several (at least two) known levels (pulse energy, pulse amplitude and/or pulse width) over time. The individual determined capture thresholds are combined into a set and the variability of the set is used to set the safety margin. The greater the variability in the capture thresholds, the bigger the safety margin.

A method and implantable medical device system for delivering a left ventricular (LV) cardiac pacing therapy via a single-pass coronary sinus lead and sensing far-field cardiac signals via one or more far-field sensing vectors formed between the plurality of electrodes. Beat morphologies corresponding to the far-field cardiac signals are determined, and a beat morphology match between each of the far-field beat morphologies and an intrinsic beat morphology template is determined so that one of loss of LV capture, pseudo fusion and loss of synchrony is determined in response to the determined beat morphology match. One of a loss of capture adjustment, a pseudo fusion adjustment, and a resynchronization adjustment is performed in response to the determined one of loss of LV capture, pseudo fusion and loss of synchrony in response to the determined beat morphology match to generate an adjusted LV cardiac pacing therapy.

Cardiac anodal electrostimulation detection systems and methods are described, such as for distinguishing between cathodal-only capture and at least partially anodal capture (e.g., combined anodal and cathodal capture, or between two anodes of which only one captures nearby cardiac tissue, etc.).

A medical device for stimulating the heart using biventricular stimulation. The device includes a sensor for detecting an endocardial acceleration parameter and a processing circuit configured to receive the endocardial acceleration parameter. The device further includes stimulation electronics coupled to the processing circuit. The processing circuit is configured to use the EA parameter to evaluate the biventricular stimulation. The evaluation includes comparing the value of the EA parameter in biventricular mode to the value of the EA parameter in left only mode or right only mode, and using the comparison and an assessment of the variability of the EA parameter as a function of the AVD in the left or right mode to distinguish between cases comprising: (a) normal operation, (b) a loss of RV or LV capture, (c) possible anodal stimulation. The processing circuit is further configured to conduct at least one update to operational parameters of the device based on the determined case.

An example system and method associated with identifying and treating a source of a heart rhythm disorder are disclosed. In accordance therewith, a spatial element associated with a region of the heart is selected. Progressive rotational activations or progressive focal activations are determined in relation to the selected spatial element over a period of time. The selecting and determining are repeated over multiple periods of time. A source parameter of rotation activations or focal activations is determined, wherein the source parameter indicates consistency of successive rotational activations or focal activations in relation to a portion of the region of the heart. The determining of a source parameter is repeated for multiple regions of the heart. Thereafter, representation of the source parameter is displayed for each of the multiple regions of the heart to identify a shape representing the source of the heart rhythm disorder.