Method and apparatus for predicting arrhythmias using diurnal heart rate

• US 7,313,439 B2
• Filed: 12/03/2004
• Issued: 12/25/2007
• Est. Priority Date: 12/03/2003
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Jackson, Troy E, Belk, Paul A
• Primary Examiner(s): Schaetzie, Kennedy J.
• Assistant Examiner(s): Reidel, Jessica L.
• Application Number:
  US11/004,176
• Publication Number:
  US 20050137489A1
• Time in Patent Office: 1,117 Days
• Field of Search: 600/515, 600518-520, 600/509, 600/513, 607/14, 607 17- 19, 607/9, 607/25
• US Class Current: 607/19
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/02405 Determining heart rate variability
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/02455 provided with high/low alarm devices
• CPC Class Codes: A61B 5/363 Detecting tachycardia or bradycardia
• CPC Class Codes: A61B 5/7275 Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions
• CPC Class Codes: A61N 1/365 controlled by a physiological parameter, e.g. heart potential evoked response A61N1/371
• CPC Class Codes: G16H 20/30 relating to physical therapies or activities, e.g. physiotherapy, acupressure or exercising
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems
• CPC Class Codes: G16H 50/30 for calculating health indices; for individual health risk assessment

Abstract

A method of predicting an arrhythmia, such as ventricular tachycardia, for example, in a medical device using a quantitative measure in order to allow assessment of patient risk and to enable preventative interventions by the device and clinicians. The trending of day and night average heart rates, along with patient physical activity can be analyzed to provide prediction of impending arrhythmia within weeks. By examining day and night average heart rate for crossover points, where the night heart rate equals or exceeds the day rate, and monitoring for a concomitant elevation in the night heart rate from a reference value, specific days heralding an increased risk of arrhythmia can be determined and therapy can be updated accordingly.

Claims

1. A method of automatically predicting the occurrence of arrhythmias in a patient for use in a medical device, comprising:

monitoring a heart rate;

determining the heart rate corresponding to a plurality of predetermined time periods, wherein the plurality of predetermined time periods include a first time period corresponding to the patient being asleep and a second time period corresponding to physical activity of the patient;

predicting an arrhythmia event in response to the determined heart rates;

delivering a preventative therapy in response to the predicted arrhythmia event;

monitoring physical activity of the patient;

comparing the determined heart rate corresponding to the first time period and the determined heart rate according to the second time period; and

determining whether the determined heart rate corresponding to the first time period is greater than a first threshold and whether the determined heart rate according to the second time period is greater than a second threshold, wherein predicting an arrhythmia event includes predicting an arrhythmia event in response to the determined heart rate corresponding to the first time period being greater than the determined heart rate according to the second time period, and the determined heart rate corresponding to the first time period being greater than the first threshold and the determined heart rate according to the second time period being greater than the second threshold.

2. The method of claim 1, wherein the first threshold and the second threshold correspond to the monitored physical activity of the patient.

3. The method of claim 1, wherein the preventative therapy includes generating a notification of the predicted arrhythmia.

4. A method of automatically predicting the occurrence of arrhythmias in a patient for use in a medical device, comprising:

determining a first average rate corresponding to a first portion of a day and a second average rate corresponding to a second portion of the day;

determining an average activity level over a predetermined period of time;

calculating a first reference value associated with the first average rate and a second reference value associated with the second average rate;

determining whether the difference between the first average rate and the second average rate is less than a diurnal threshold;

determining whether the difference between the second average rate and the second reference value is greater than a second average rate threshold; and

determining whether the difference between the first average rate and the first reference value is greater than a first average rate threshold;

predicting an arrhythmia event in response to one of the difference between the first average rate and the second average rate being less than the diurnal threshold, the difference between the second average rate and the second reference value being greater than the second average rate threshold, and the difference between the first average rate and the first reference value being greater than the first average rate threshold; and

delivering a preventative therapy in response to the predicted arrhythmia event.