Approaches to rank potential left ventricular (LV) pacing vectors are described. Early elimination tests are performed to determine the viability of LV cathode electrodes. Some LV cathodes are eliminated from further testing based on the early elimination tests. LV cathodes identified as viable cathodes are tested further. Viable LV cathode electrodes are tested for hemodynamic efficacy. Cardiac capture and phrenic nerve activation thresholds are then measured for potential LV pacing vectors comprising a viable LV cathode electrode and an anode electrode. The potential LV pacing vectors are ranked based on one or more of the hemodynamic efficacy of the LV cathodes, the cardiac capture thresholds, and the phrenic nerve activation thresholds.

A cardiac medical system, such as an implantable cardioverter defibrillator (ICD) system, receives a cardiac electrical signal by and senses cardiac events when the signal crosses an R-wave sensing threshold. The system determines at least one sensed event parameter from the cardiac electrical signal for consecutive cardiac events sensed by the sensing circuit and compares the sensed event parameters to P-wave oversensing criteria. The system detects P-wave oversensing in response to the sensed event parameters meeting the P-wave oversensing criteria; and adjusts at least one of an R-wave sensing control parameter or a therapy delivery control parameter in response to detecting the P-wave oversensing.

A pacemaker system includes a drive-sense circuit (DSC) operably coupled to a pacemaker lead. The DSC generates a pace signal including electrical impulses based on a reference signal. The DSC provides the pace signal via the pacemaker lead to an electrically responsive portion of a cardiac conductive system of a subject to facilitate cardiac operation of a cardiovascular system of the subject. The DSC senses, via the pacemaker lead, cardiac electrical activity of the cardiovascular system of the subject that is generated in response to the pace signal and electrically coupled into the pacemaker lead and generates a digital signal that is representative of the cardiac electrical activity of the cardiovascular system of the subject that is sensed via the pacemaker lead. The DSC provides digital information to one or more processing modules that includes and/or is coupled to memory and that provide the reference signal to the DSC.

The present invention relates to the field of medical devices and discloses an implantable medical device for treating arrhythmia. The implantable medical device includes a control unit and, each coupled to the control unit, a sense amplifier, a first switch and a second switch. The sense amplifier includes a polarity selection module, an amplification unit and a filtering unit, which are sequentially connected. The first switch is disposed within the polarity selection module, and the second switch within the filtering unit. The control unit is configured to shield the sense amplifier from interference from a pacing pulse signal by providing multi-stage on/off control over the first and second switches according to a pacing period and a discharging period in a pacing interval. According to embodiments of the invention, the shielding switches in the sense amplifier are switched on/off in multiple stages according to pacing and discharging periods of a pacing pulse signal so as to shield the sense amplifier from interference from the pacing pulse signal and enhance its pacing pulse signal suppression performance.

A pericardial implantable cardioverter defibrillator (ICD) may be delivered to the heart through the chest wall using an ultrasound image guided catheter. The ICD may comprise a patch and wire leads which may be secured by a clam shell-like pad at a distal end and comprise a pig-tail shaped securing tail at the other end so that the ICD is firmly attached to the pericardium of a human heart. The ICD may be attached where most needed and serve as either a pacemaker or a defibrillator. In one embodiment, the ICD may emit radio frequency warning signals of heart failure sensed when pacemaker or defibrillator usage is rendered necessary.

Computer implemented methods and systems for detecting arrhythmias in cardiac activity are provided. The method is under control of one or more processors configured with specific executable instructions. The method obtains a far field cardiac activity (CA) data set that includes far field CA signals for beats. The method applies a feature enhancement function to the CA signals to form an enhanced feature in the CA data set. The method calculates an adaptive sensitivity level and sensitivity limit based on the enhanced feature from one or more beats within the CA data set and automatically iteratively analyzes a beat segment of interest by comparing the beat segment of interest to the current sensitivity level to determine whether one or more R-waves are present within the beat segment of interest. The method repeats the iterative analyzing operation while progressively adjusting the current sensitivity level until i) the one or more R-waves are detected in the beat segment of interest and/or ii) the current sensitivity level reaches the sensitivity limit. The method detects an arrhythmia within the beat segment of interest based on a presence or absence of the one or more R-waves and records results of the detecting of the arrhythmia.

A method and device for detecting phrenic nerve stimulation (PNS) in, or using, a cardiac medical device. A test signal sensitive to contraction of a diaphragm of a patient may be sensed and signal artifacts of the test signal within each of a first window of the test signal prior to a predetermined cardiac signal and a second window of the test signal subsequent to the predetermined cardiac signal may be determined. The PNS beat criteria may be evaluated, for example, using the test signal, which may be a heart sounds signal.

Techniques are described for discriminating SVT and, in particular, rapidly conducting AF. The techniques include detecting an onset of a fast rate of ventricular events sensed from a cardiac electrical signal and detecting a pause in the fast rate of ventricular sensed events. A threshold number of ventricular event intervals required to detect a ventricular tachyarrhythmia is detected with each of the threshold number of ventricular event intervals being less than a tachyarrhythmia detection interval. Detection of the ventricular tachyarrhythmia and an electrical stimulation therapy for treating the ventricular tachyarrhythmia are withheld in response to at least the pause being detected.

Medical device systems include processing circuitry configured to acquire sensed cardiac signals associated with cardiac activity of a heart of a patient, and to analyze the sensed cardiac signals to determine if a noise signal is present within the cardiac signals.

An intracardiac pacemaker system is configured to produce physiological atrial event signals by a sensing circuit of a ventricular intracardiac pacemaker and select a first atrial event input as the physiological atrial event signals. The ventricular intracardiac pacemaker detects atrial events from the selected first atrial event input, determines if input switching criteria are met, and switches from the first atrial event input to a second atrial event input in response to the input switching criteria being met. The second atrial event input includes broadcast atrial event signals produced by a second implantable medical device and received by the ventricular intracardiac pacemaker.