A system is provided for controlling a left univentricular (LUV) pacing therapy using an implantable medical device (IMD). The system also includes one or more processors configured to determine an atrial-ventricular (AV) conduction interval (AR.sub.RV) between the A site and a first RV sensed event at the RV site, determine an inter-ventricular (VV) conduction interval (R.sub.LV-R.sub.RV) between a paced event at the LV site and a second RV sensed event at the RV site, and set a ventricular refractory period (VRP) based on at least one of the AV conduction interval or the VV conduction interval and a predetermined offset. The one or more processors are also configured to blank signals over the RV sensing channel during the VRP.

Techniques are described for pacing assistance and automation. For example, a pacing device, such as an external defibrillator, provides electrical stimulations to an external surface of a patient based on a determination as to whether capture has been achieved. The pacing device determines whether capture has been achieved using multiple types of sensor data and/or historical sensor data. These techniques effect a particular treatment (e.g., pacing using an external pacing system) for a medical condition (e.g., bradycardia). In some examples, the pacing device provides notifications to assist with pacing to a healthcare provider that is administering pacing to a patient. Notifications may include an indication that multiple representations corresponding to different biological parameters of a patient may assist with pacing, that the patient has an internal pacemaker, and so forth.

Described herein are external devices, and methods for use therewith, that are configured to communicate with one or more implantable medical devices (IMDs) implanted within a patient using conductive communication, wherein the external device includes or is communicatively coupled to at least three external electrodes that are in contact with the patient. Certain such methods involve the external device identifying, for each IMD, of the plurality of IMDs, which one of the plurality of communication vectors is a preferred communication vector for communicating with the IMD, based on respective indicators of conductive communication quality that are determined for the plurality of communication vectors. Certain embodiments involve determining when there should be a reassessment of which one of the plurality of communication vectors is the preferred communication vector for communicating with an IMD, and in response thereto, identifying an updated preferred communication vector for communicating with the IMD.

Techniques are disclosed for treating arrhythmias using an implantable medical device. An implantable medical device that is adapted for implantation wholly within a heart chamber of the heart of a patient may include a reservoir containing one or more therapeutically useful doses of a drug for treating an arrhythmia. The implantable medical device may include processing circuitry configured to detect an occurrence of the arrhythmia in the heart of the patient. The implantable medical device may include a valve operable to be opened in response to detecting the occurrence of the arrhythmia in the heart of the patient to release a therapeutically useful dose of the drug into the heart of the patient to treat arrhythmia of the heart.

Described herein are methods, devices, and systems that enable a remote non-implantable device (RNID) to send commands to a leadless pacemaker (LP) implanted within a patient. The RNID provide commands to a local non-implantable device (LNID) over one or more communication networks, and the LNID sends the commands to a second implantable device (SID) by transmitting radio frequency (RF) communication signals, which include the commands, using an antenna of the LNID. After receiving the commands from the LNID, by receiving RF communication signals that include the commands using an antenna of the SID, the SID transmits conductive communication signals, which include the commands, using electrodes of the SID. The LP receives the commands from the SID by receiving the conductive communication signals, which include the commands, using electrodes of the LP, and the LP performs command responses based on the commands that originated from the RNID.

An implantable system for stimulating a human/animal heart, comprising a processor, a memory unit, a stimulation unit for stimulating a His bundle of a human/animal heart, and a detection unit for detecting an electrical signal of the heart. The memory unit includes a computer-readable program that prompts the processor to perform the following steps when the program is executed on the processor: a) detecting by way of the detection unit whether a tachycardia is present in a human/animal heart; and b) when a tachycardia is present, carrying out a His bundle stimulation by way of the stimulation unit using at least one stimulation pulse having an amplitude in a range of 7.5 V to 30 V, and having a pulse width in a range of 1 ms to 15 ms. The program prompts the processor to classify a detected tachycardia into one of at least two classes.

Systems, interfaces, and methods are described herein for evaluation and adjustment cardiac therapy. The systems, interfaces, and methods may utilize, or include, a graphical user interface to display various information with respect to a plurality of external electrodes and electrical activity monitored using such external electrodes and to allow a user to adjust what information to display.

A medical device is configured to generate fluid status signal data of a patient by determining impedance metrics from an impedance signal, determining cardiac electrical signal amplitudes from a cardiac electrical signal and determining a calibration relationship between the impedance metrics and cardiac electrical signal amplitudes. The medical device generates a fluid status signal data by adjusting cardiac electrical signal amplitudes according to the determined calibration relationship. The fluid status signal data may be displayed or monitored for detecting a change in the patient's fluid status.

In some examples, controlling delivery of CRT includes controlling an implantable medical device to deliver ventricular pacing according to a sequence of different values of a CRT parameter, and acquiring first and second electrograms from respective first and second electrode vectors. For each value of the CRT parameter, a value of a metric of comparison of a first activation interval between occurrences of a first fiducial of a cardiac cycle and a second fiducial of the cardiac cycle detected in the first electrogram to a second activation interval between occurrences of the first fiducial and the second fiducial detected in the second electrogram may be determined. A target value of the metric of comparison may be identified and an updated value of the CRT parameter determined based on the target value. The system then may control the IMD to deliver ventricular pacing at the updated value of the CRT parameter.

An implantable system for stimulating a human/animal heart, comprising a processor, a memory unit, a stimulation unit for stimulating a His bundle of a heart, and a detection unit for detecting an electrical signal of the heart. The memory unit includes a computer-readable program prompting the processor to perform the following steps when the program is executed on the processor: a) carrying out a cardiac stimulation via the stimulation unit; b) detecting a cardiac electrical signal, which was generated by a cardiac excitation as a result of the cardiac stimulation carried out beforehand, via the detection unit; c) ascertaining an excitation state of a heart stimulated by the cardiac stimulation based on the electrical signal; d) classifying the excitation state into one of at least three classes; and e) automatically adapting at least one control parameter of the system as a function of the classification that was carried out.