Ambulatory monitoring of the digitized electrocardiogram for detection and early warning of transient myocardial ischemia in angina pectoris.
Patients with coronary artery disease have frequent asymptomatic episodes of ischemic ST-segment depression. A new solid-state recorder that analyzes the digitized electrocardiogram (ECG) in real time has been tested for accuracy in detection and quantitation of these events by comparison with a direct ECG during exercise testing and a frequency-modulated recorder during ambulatory monitoring. The device can also be programmed to produce a tone at the onset of ischemic ST-segment depression, and this tone is used to initiate self-administration of nitroglycerin in an attempt to control myocardial ischemic events. The solid-state recorder demonstrated adequate sensitivity and specificity during exercise (100% and 92%, respectively) for detection and quantitation of episodes of ischemic ST-segment depression. In addition, Monitor One accurately measured the duration of ischemic events during exercise testing (r = 0.95, p = 0.001) and the number (r = 0.92, p = 0.001) and duration (r = 0.97, p = 0.001) of ischemic events during ambulatory monitoring. When the audible tone was used to initiate use of nitroglycerin, the duration of episodes of ischemic ST-segment depression was reduced from 105 +/- 74 min/24 hours to 58 +/- 49 min/24 hours (p = 0.02). Thus, a solid-state ECG recorder capable of long-term monitoring appears to accurately detect and quantify episodes of ischemic ST-segment depression in patients with coronary artery disease. Also, patients can interact with an audible tone to key self-administration of therapy in an attempt to control asymptomatic episodes of transient myocardial ischemia.
D000328:Adult; D000368:Aged; D000787:Angina Pectoris / Q000175:diagnosis* / Q000188:drug therapy; D003327:Coronary Disease / Q000175:diagnosis; D004562:Electrocardiography / Q000295:instrumentation*; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods*; D005996:Nitroglycerin / Q000627:therapeutic use; D005082:Physical Exertion; D012646:Self Administration; D013997:Time Factors
D005996:Nitroglycerin