Clinical significance of silent ischemia in unstable angina pectoris.
In a prospective study the significance of silent ischemia was evaluated in 66 patients with a clinical diagnosis of unstable angina (no requirement for reversible ST-T changes during pain on 12-lead electrocardiograms before entry), and the results of continuous 2-channel electrocardiographic (ECG) recordings, begun within 24 hours of admission, were compared with other clinical and ECG predictors of adverse outcome. Ischemic changes were detected in 7 patients (11%) during a mean of 41 hours of recording. There were 37 episodes of transient ST-segment change (16 ST elevation, 21 ST depression) of which 11 (30%) were symptomatic and 26 (70%) were silent. All 7 patients had at least 1 silent episode and 5 also had symptomatic episodes during the recording but only 2 patients had exclusively silent episodes. During a mean follow-up of 13.3 months, 3 patients died, 5 had a nonfatal myocardial infarction and 32 required revascularization. Although transient myocardial ischemia during the continuous ECG recording, whether silent or symptomatic, was a specific predictor of subsequent nonfatal myocardial infarction or death (specificity 92%), its sensitivity for these events was low (25%). In contrast, recurrent rest pain (greater than or equal to 1 episode) occurred in all patients with these serious adverse events (sensitivity 100%, specificity 49%). Transient ischemia occurs infrequently during continuous ECG recordings in patients with unstable angina not selected by reversible ST-T changes on a 12-lead electrocardiogram at entry. Recurrent rest pain after hospital admission is a more sensitive predictor of serious events in this group.
Hallstrom Institute of Cardiology, Royal Prince Alfred Hospital, Camperdown, Australia.
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I
Wilcox
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Ben Freedman
D T
DT
Kelly
P J
PJ
Harris
D000787:Angina Pectoris / Q000175:diagnosis*; D000789:Angina, Unstable / Q000175:diagnosis*; D003327:Coronary Disease / Q000175:diagnosis* / Q000453:epidemiology; D015716:Electrocardiography, Ambulatory; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011379:Prognosis; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013997:Time Factors