System for the detection of cardiac events

摘要

Heart disease is the leading cause of death in the United States. A heart attack (also known as an Acute Myocardial Infarction (AMI)) typically results from a thrombus that obstructs blood flow in one or more coronary arteries. The extent of damage to the myocardium from an AMI is strongly dependent upon the length of time prior to restoration of blood flow to the heart muscle. Acute myocardial infarction and ischemia may be detected from a patient's electrocardiogram (ECG) by noting an ST segment shift (i.e., voltage change) over a relatively short (less than 5 minutes) period of time. The present invention is a guardian system including electrodes, a cardiosaver device having AMI detection capability and an alarm means to warn the patient that they have had an AMI or other serious cardiac event and should immediately seek medical attention. Such a warning would facilitate getting medical treatment quickly to restore blood flow to the patient's heart muscle. The present invention provides accuracy of detection by comparing a recently collected electrogram data with baseline electrogram data collected at an earlier time when the heart signals were normal. False positives are reduced by requiring multiple detections separated by a predetermined time interval. The present invention can identify and differentiate between an acute myocardial infarction, exercise induced ischemia and other anomalous cardiac conditions. In the preferred embodiment of the present invention the electrodes and the cardiosaver are implanted and the guardian system includes an external alarm system that can produce an external alarm signal and also has means to turn off the alarm.