Ambulatory ECG (Holter) monitoring in management of acute myocardial ischemia.
Ambulatory ECG monitoring for detection of transient myocardial ischemia is useful because most ischemic episodes that occur outside the exercise laboratory are not accompanied by symptoms. Special considerations, not required for AEM when used for arrhythmia analysis, must be employed. Although many commercially available recorders provide excellent ST-segment reproduction, some playback systems may have a nonlinear phase response resulting in signal distortion, making ST-segment analysis difficult. Conventional Holter-type AEM devices do not allow for patient or physician intervention during acute myocardial ischemia. Considerable cost and time are required to analyze ST-segment data of prolonged monitoring periods from these tape-recorded signals, and human error and fatigue play an important role in diminishing accuracy of ST-segment interpretation. Automated analysis is done with computer and technician interaction but the accuracy and validation of the various systems for ST-segment analysis from tape recordings requires further detailed study. Newer, real-time ambulatory ECG analyzers are designed for prolonged monitoring periods and directed toward ST-segment analysis. Some devices also alert the patient to an acute ischemic or arrhythmic event allowing for intervention immediately. Some real-time systems have undergone some very encouraging validation studies. These recent studies suggest excellent sensitivity and specificity for detection of ischemic-type ST-segment depression. However, more work is needed before the accuracy of other such devices is known with certainty. As the central goal of therapy for patients with coronary artery disease evolves from simply controlling angina to reduction or elimination of ischemic episodes and their consequences, use of AEM devices will play an increasingly important role in management of these patients.
Imperi
G A
GA
Lambert
C R
CR
Hill
J A
JA
Pepine
C J
CJ
D000553:Ambulatory Care; D003327:Coronary Disease / Q000175:diagnosis*; D004562:Electrocardiography / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes / Q000592:standards; D006801:Humans; D005082:Physical Exertion