Ambulatory vasoactivity monitor

#This document relates generally to medical devices, and more particularly, to systems, devices and methods for ambulatory monitoring of vasoactivity in a patient.

#Vasoactivity, or vascular activity, refers to constriction (vasoconstriction) or dilation (vasodilation) of the blood vessels. A vasoactive agent (e.g., a pharmaceutical drug) may modulate vasoactivity by adjusting vascular compliance and/or vascular resistance, which helps the body's homeostatic mechanisms to keep hemodynamics under control. Vasoactive drug therapy is typically used during constant monitoring of patient blood pressure and heart rate.

#Vasodilators are vasoactive drugs that help widen blood vessels. They affect the muscles in the walls of arteries and veins, preventing the muscles from tightening and the walls from narrowing. Vasodilators can dilate various blood vessels. For example, dilation of coronary arteries can improve blood flow in myocardium, dilation of leg veins can lower venous return to the heart and thereby limiting the fluid buildup in the lungs, and dilation of the pulmonary arteries and systemic arteries can help relieve the workload of the heart while maintaining adequate systemic circulation. Vasodilators are often combined with other medicines to treat a variety of conditions, including high blood pressure and heart failure (HF). When the blood vessels are widened (or dilated), it is easier for the heart to pump blood, such that the heart burden can be relieved, and the symptoms associated with HF can be improved.

#Various embodiments are illustrated by way of example in the figures of the accompanying drawings. Such embodiments are demonstrative and not intended to be exhaustive or exclusive embodiments of the present subject matter.

#FIG. 1 illustrates generally an example of a patient monitor system and portions of an environment in which the system may operate. [0036]1 FIG. 2 illustrates generally an example of a vasoactivity monitor system configured to monitor vasoactivity in a patient.

#FIGS. 3A-3B are graphs illustrating examples of a change in HS metrics following vasodilator intake in a group of patients.

#Disclosed herein are systems, devices, and methods for monitoring patient vasoactivity. An exemplary patient monitor system can monitor vasoactivity, such as degree of vasoconstriction or vasodilation, using heart sounds (HS) metrics generated from patient HS signal. The system can provide the monitored vasoactivity to a user to alert patient hemodynamic responses to vasoactive drugs, generate or adjust a vasoactive therapy according to the monitored vasoactivity, or to detect a medical condition, such as worsening heart failure, pulmonary edema, or syncope.

#FIG. 1 illustrates generally an example of a patient monitor system 100 and portions of an environment in which the system 100 may operate. The patient monitor system 100 may chronically monitor a patient 102 to detect and evaluate a syncopal event. Portions of the system 100 may be ambulatory. Portions of the system 100 may be disposed in the patient's home or office, a hospital, clinic, or physician's office. The patient monitor system 100 may include an ambulatory system 105 associated with the patient 102, an external system 125, and a telemetry link 115 providing for communication between the ambulatory system 105 and the external system 125.

#The ambulatory system 105 may include an ambulatory medical device (AMD) 110. In an example, the AMD 110 may be an implantable device subcutaneously implanted in a chest, abdomen, or other parts of the patient 102. Examples of the implantable device may include, but are not limited to, pacemakers, pacemaker/defibrillators, cardiac resynchronization therapy (CRT) devices, cardiac remodeling control therapy (RCT) devices, neuromodulators, drug delivery devices, biological therapy devices, diagnostic devices such as cardiac monitors or loop recorders, or patient monitors, among others. The AMD 110 alternatively or additionally may include a subcutaneous medical device such as a subcutaneous monitor or diagnostic device, external monitoring or therapeutic medical devices such as automatic external defibrillators (AEDs) or Holter monitors, or wearable medical devices such as patch-based devices, smart wearables, or smart accessories.