Means and method for the detection of cardiac events

• US 20070293778A1
• Filed: 06/22/2007
• Published: 12/20/2007
• Est. Priority Date: 05/26/2004
• Status: Active Grant

• Current Assignee: Angel Medical Systems, Inc.
• Original Assignee: Angel Medical Systems, Inc.
• Inventors: Harwood, Jonathan, Fischell, Tim, Fischell, David, Johnson, Steven, Fischell, Robert
• Granted Patent: US 7,860,559 B2
• Time in Patent Office: Days
• US Class Current: 600/515
• 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 electrogram, the method including the steps:

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

(b) causing the patient'"'"'s heart to have at least two different heart rates where a first heart rate is a lower rate compared to a second heart rate which is a higher heart rate;

(c) measuring the patient'"'"'s ST segment voltage at each of the at least two different heart rates;

(d) programming the detection thresholds for excessive shift in the voltage of the ST segment of the patient'"'"'s electrogram based on the electrogram data processed for the at least two different heart rate ranges.

2. The method of claim 1 where the means for causing the patient'"'"'s heart rate to increase to the second, higher heart rate is a stress test.

3. The method of claim 2 where the stress test is an exercise stress test.

4. The method of claim 2 where the stress test is a drug induced stress test where medications are used to increase the patient'"'"'s heart rate.

5. The method of claim 1 where the means for causing the patient'"'"'s heart rate to increase to the second, higher heart rate is to have the patient go about his normal daily activities and to record electrogram data during a period of increased physical activity which results in the second, higher heart rate.