Means and method for the detection of cardiac events

• US 7,860,559 B2
• Filed: 06/22/2007
• Issued: 12/28/2010
• Est. Priority Date: 05/26/2004
• Status: Active Grant

• Current Assignee: Angel Medical Systems, Inc.
• Original Assignee: Angel Medical Systems, Inc.
• Inventors: Fischell, David R., Fischell, Robert E., Johnson, Steven R., Harwood, Jonathan, Fischell, Tim A.
• Primary Examiner(s): Getzow; Scott M
• Application Number:
  US11/812,826
• Publication Number:
  US 20070293778A1
• Time in Patent Office: 1,285 Days
• Field of Search: 600508-523, 607 4- 30
• US Class Current: 600/517
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/02455 provided with high/low alarm devices
• CPC Class Codes: A61B 5/283 Invasive
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/333 Recording apparatus specially adapted therefor
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/352 Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval
• CPC Class Codes: A61B 5/361 Detecting fibrillation
• CPC Class Codes: A61B 5/363 Detecting tachycardia or bradycardia
• CPC Class Codes: A61B 5/366 Detecting abnormal QRS complex, e.g. widening
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61B 5/746 Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms alarms per se G08B
• CPC Class Codes: A61B 5/7465 Arrangements for interactive communication between patient and care services, e.g. by using a telephone network telemetry of measured physiological signal A61B5/0002
• CPC Class Codes: A61N 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371
• CPC Class Codes: A61N 1/37258 Alerting the patient
• CPC Class Codes: A61N 1/3756 Casings with electrodes thereon, e.g. leadless stimulators
• CPC Class Codes: G16H 40/67 for remote operation

Abstract

Disclosed is a system for the detection of cardiac events that includes an implanted device called a cardiosaver, a physician'"'"'s programmer and an external alarm system. The system is designed to provide early detection of cardiac events such as acute myocardial infarction or exercise induced myocardial ischemia caused by an increased heart rate or exertion. The system can also alert the patient with a less urgent alarm if a heart arrhythmia is detected. Using different algorithms, the cardiosaver can detect a change in the patient'"'"'s electrogram that is indicative of a cardiac event within five minutes after it occurs and then automatically warn the patient that the event is occurring. To provide this warning, the system includes an internal alarm sub-system (internal alarm means) within the cardiosaver and/or an external alarm system (external alarm means) which are activated after the ST segment of the electrogram exceeds a preset threshold.

Claims

1. A method for setting the thresholds for detecting excessive shift in the voltage of the ST segment of a patient'"'"'s heart beats, the method including the steps:

(a) implanting a device having the capability to sense and store electrical signals from the patient'"'"'s heart;

(b) measuring the patient'"'"'s ST segment voltage at each of a plurality of heart rates to determine normal ST segment values for the patient associated with each of the plurality of heart rates;

(c) selecting a plurality of heart rate ranges for the patient based on the normal ST segment values;

(d) for each of the plurality of heart rate ranges, programming the detection thresholds for excessive shift in the voltage of the ST segment of the patient'"'"'s heart beats based on the normal ST levels,

wherein excessive shift is a measure of the difference between a current ST segment of the patient and at least one prior ST segment of the patient.

2. The method of claim 1 wherein the excessive shift is a difference between current and an average of a plurality of prior ST segments.