TECHNICAL FIELD

The disclosure generally relates to cardiac device systems, such as an implantable cardiac device system configured to deliver anti-tachyarrhythmia therapy.

BACKGROUND

For patients at risk of tachyarrhythmias, such as ventricular fibrillation (VF) and/or non-perfusing ventricular tachycardia (VT), an implantable cardiac device system, such as an implantable cardioverter defibrillator (ICD) system, may be used to delivery anti-tachyarrhythmia therapy to a heart of the patient. An ICD system may include an electrical housing electrode (sometimes referred to as a can electrode) that is coupled to one or more electrical lead wires placed within the heart. If an arrhythmia is sensed, the ICD may send a pulse via the electrical lead wires to shock the heart and restore its normal rhythm. In some examples, rather than placing and attaching electrical leads directly within the heart of a patient, extravascular ICD systems have been devised to provide shocks to the heart without placing electrical lead wires within the heart.

SUMMARY

Aspects of the disclosure are directed to medical device systems, such as ICD systems, configured to coordinate delivery of anti-tachyarrhythmia therapy (e.g., in the form of defibrillation shock(s) or cardioversion shock(s)) to a patient with respiration of the lungs of a patient. For example, the ICD system may be in the form of an extravascular implantable cardiac device configured to determine a time when one or both lungs of a patient are at approximately end tidal volume or less, and then deliver anti-tachyarrhythmia shocks (e.g., one or more defibrillation shocks) to the heart of a patient when the respiratory volume of the one or both lungs is at approximately tidal volume or less to treat, e.g., VF or VT of the heart. For example, an ICD system may coordinate the delivery of one or more defibrillation shocks such that the shocks are delivered substantially coincidentally with approximately an end of exhalation by a patient, as determined by the ICD system.

In some instances, timing the delivery of anti-tachyarrhythmia shock(s) in coordination with the respiration and respiratory volume of the lung(s) of the patient in such a manner may allow for defibrillation of the heart of a patient at a lower threshold (e.g., as compared to anti-tachyarrhythmia shock(s) delivered when the lung(s) respiratory capacity is at or near maximum tidal volume), resulting in less electroporation and/or troponin release. Additionally or alternatively, timing the delivery of defibrillation shock(s) in coordination with the respiration and respiratory volume of the lung(s) of the patient in such a manner may allow for a relatively higher defibrillation efficacy rate for a shock having an energy amount, e.g., as compared to the efficacy of a defibrillation shock having the same amount of energy but delivered when the lung(s) respiratory capacity is at or near maximum tidal volume.

In examples, the disclosure is directed to a method comprising identifying a time at which a respiratory volume of a lung of a patient is at approximately end tidal volume or less; and delivering, via a medical device system, an anti-tachyarrhythmia shock to a heart of the patient at the time that the respiratory volume of the lung of a patient is at the approximately end tidal volume or less.

In another example, the disclosure is directed to a medical device system comprising therapy generation circuitry configured to generate an anti-tachyarrhythmia shock; and processing circuitry configured to identify a time at which a respiratory volume of a lung of a patient is at approximately end tidal volume or less; and control the therapy generation circuitry to deliver the anti-tachyarrhythmia shock to a heart of the patient at the time that the respiratory volume of the lung of a patient is at the approximately end tidal volume or less.

This summary is intended to provide an overview of the subject matter described in this disclosure. It is not intended to provide an exclusive or exhaustive explanation of the systems, devices, and methods described in detail within the accompanying drawings and description below. Further details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the statements provided below.

