A catheter adapted or high density mapping and/or ablation of tissue surface has a distal electrode matrix having a plurality of spines arranged in parallel configuration on which a multitude of electrodes are carried in a grid formation for providing uniformity and predictability in electrode placement on the tissue surface. The matrix can be dragged against the tissue surface upon deflection (and/or release of the deflection) of the catheter. The spines generally maintain their parallel configuration and the multitude of electrodes generally maintain their predetermined relative spacing in the grid formation as the matrix is dragged across the tissue surface in providing very high density mapping signals. The spines may have free distal ends, or distal ends that are joined to form loops for maintaining the spines in parallel configuration.

In an example, an apparatus is described that includes an implantable housing, a heart signal sensing circuit configured to sense intrinsic electrical heart signals, a ventricular tachyarrhythmia (VT) detector circuit, operatively coupled to the heart signal sensing circuit, the detector circuit operable to detect a VT based on the sensed heart signals, a processor configured to control delivery of an anti-tachyarrhythmia pacing (ATP) therapy based on the detected VT, and an energy delivery circuit configured to deliver the ATP therapy in response to the detected VT, wherein the apparatus does not include a shock circuit capable of delivering a therapeutically-effective cardioverting or defibrillating shock.

A catheter with basket-shaped electrode assembly with spines configured for hyper-flexing in a predetermined, predictable manner when a compressive force acts on the assembly from either its distal end or its proximal end. At least one spine has at least one region of greater (or hyper) flexibility that allows the electrode assembly to deform, for example, compress, for absorbing and dampening excessive force that may otherwise cause damage or injury to tissue wall in contact with the assembly, without compromising the structure and stiffness of the remaining regions of the spine, including its distal and proximal regions. The one or more regions of greater flexibility in the spine allow the spine to flex into a generally V-shape configuration or a generally U-shape configuration.

A medical device performs a method for detecting an atrial tachyarrhythmia by determining RR intervals between successive R-waves of a cardiac electrical signal and determining classification factors from the R-waves identified over a predetermined time period by determining at least a first classification factor correlated to variability of the RR intervals and a second classification factor indicating a presence of a ventricular tachyarrhythmia. The device classifies the cardiac electrical signal of the predetermined time period as unclassified, atrial tachyarrhythmia or non-atrial tachyarrhythmia by comparing the determined classification factors to classification criteria. The predetermined time period is classified as unclassified when the second classification factor indicates the presence of a ventricular tachyarrhythmia.

A medical device is configured to detect an atrial tachyarrhythmia episode. The device senses a cardiac signal, identifies R-waves in the cardiac signal attendant ventricular depolarizations and determines classification factors from the R-waves identified over a predetermined time period. The device classifies the predetermined time period as one of unclassified, atrial tachyarrhythmia and non-atrial tachyarrhythmia by comparing the determined classification factors to classification criteria. A classification criterion is adjusted from a first classification criterion to a second classification criterion after at least one time period being classified as atrial tachyarrhythmia. An atrial tachyarrhythmia episode is detected by the device in response to at least one subsequent time period being classified as atrial tachyarrhythmia based on the adjusted classification criterion.

Electroanatomic mapping is carried out by inserting a multi-electrode probe into a heart of a living subject, recording electrograms from the electrodes concurrently at respective locations in the heart, delimiting respective activation time intervals in the electrograms, generating a map of electrical propagation waves from the activation time intervals, maximizing coherence of the waves by adjusting local activation times within the activation time intervals of the electrograms, and reporting the adjusted local activation times.

This disclosure is directed to a catheter having a basket-shaped electrode assembly at the distal end of the catheter body formed from a plurality of spines with electrodes. The basket-shaped electrode assembly structural elements at the proximal and distal ends. The structural elements may maintain the spines in a desired spatial relationship with each other and/or may couple the distal ends of the spines to a pulling member. The basket-shaped electrode assembly has expanded arrangement in which the spines bow outwards and a collapsed arrangement in which the spines are arranged generally along a longitudinal axis of the catheter body

Systems, devices, and methods for managing alerts associated with a target physiological event such as a worsening heart failure event are described. A system may detect one or more alert onsets using an onset threshold, and one or more corresponding alert terminations using a reset threshold. Alerts may be issued corresponding to the detected alert onsets and alert terminations. The system may compare the alerts to a specified alert characteristic, and iteratively adjust the onset or reset threshold until the alerts corresponding to the adjusted onset or reset threshold satisfy the specified alert characteristic. The adjusted onset and reset thresholds may be presented to a user or a process for detecting the target physiological event.

Implantable medical devices such as leadless cardiac pacemakers may include a rechargeable power source. In some cases, a system may include an implanted device including a receiving antenna and an external transmitter that transmits radiofrequency energy that may be captured by the receiving antenna and then be converted into electrical energy that may be used to recharge a rechargeable power source. Accordingly, since the rechargeable power source does not have to maintain sufficient energy stores for the expected life of the implanted device, the power source itself and thus the implanted device, may be made smaller while still meeting device longevity expectations.

An electrode for use with an implantable medical device includes an alloy and a conductive oxide layer on a surface of the alloy. The alloy includes iridium and at least one of cobalt and iron. The conductive oxide layer includes iridium oxide. The conductive oxide layer has a thickness greater than about 5 nanometers.