Criteria for monitoring intrathoracic impedance

• US 7,574,255 B1
• Filed: 11/07/2005
• Issued: 08/11/2009
• Est. Priority Date: 11/07/2005
• Status: Active Grant

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Inventors: Min, Xiaoyi
• Primary Examiner(s): Mallari; Patricia C
• Application Number:
  US11/269,234
• Time in Patent Office: 1,373 Days
• Field of Search: 600/300, 600/481, 600/484, 600/529, 600/547
• US Class Current: 600/547
• CPC Class Codes: A61B 5/02028 Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/053 Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/0538 invasively, e.g. using a catheter
• CPC Class Codes: A61B 5/4878 Evaluating oedema
• CPC Class Codes: A61N 1/36521 the parameter being derived from measurement of an electrical impedance
• CPC Class Codes: A61N 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371
• CPC Class Codes: A61N 1/3943 for threshold determination
• CPC Class Codes: A61N 1/39622 Pacing therapy

Abstract

An exemplary method includes providing information (e.g., a left atrial pressure, a NYHA class, echocardiographic information, etc.), based at least in part on the information, determining a weight and, based at least in part on the weight, determining a threshold for use in intrathoracic impedance monitoring. Such an exemplary method may include comparing an intrathoracic impedance to the threshold, comparing an intrathoracic impedance change to the threshold, or comparing a product of intrathoracic impedance and time to the threshold. Various exemplary methods, devices, systems, etc., are disclosed.

Claims

1. A method comprising:

providing a New York Heart Association (NYHA) class of a patient;

based on the NYHA class, determining a weight;

based at least in part on the weight, determining a threshold for use in intrathoracic impedance monitoring of the patient;

comparing an intrathoracic impedance of the patient to the threshold; and

implementing control logic of a module, operable in conjunction with a processor, to decide, based on the comparing, whether to trigger a pulmonary edema alarm for the patient.

2. The method of claim 1 wherein the intrathoracic impedance comprises an intracardiac impedance.

3. The method of claim 1 wherein the threshold pertains to pulmonary edema occurring in a period of less than one day.

4. The method of claim 1 wherein the threshold comprises a percentage decrease in intrathoracic impedance from a base value or baseline.