Prognostic significance of silent myocardial ischemia in patients with unstable angina

• Published in: Journal of the American College of Cardiology 1987-07, Vol.10 (1), p.1-9
• Main Authors: Nademanee, Koonlawee, Intarachot, Vanida, Josephson, Martin A., Rieders, Daniel, Mody, Freny Vaghaiwalla, Singh, Bramah N.
• Format: Article
• Language: English
• Subjects: Angina Pectoris - complications; Angina, Unstable - complications; Angiography; Biological and medical sciences; Cardiology. Vascular system; Coronary Angiography; Coronary Disease - complications; Coronary Disease - diagnostic imaging; Coronary Disease - drug therapy; Coronary Disease - physiopathology; Coronary heart disease; Electrocardiography; Heart; Humans; Medical sciences; Monitoring, Physiologic; Prognosis; Prospective Studies; Time Factors
• ISSN: 0735-1097; 1558-3597
• DOI: 10.1016/S0735-1097(87)80152-3

Silent myocardial ischemia is common in unstable angina, but its prognostic significance is unknown. Fifty-two (42 with subsequent angiography) of 81 patients prospectively evaluated for unstable angina had ambulatory electrocardiographic (Holter) recordings analyzed by compact analog technique after they had received medical treatment (3 of the 52 had unanalyzable recordings and were excluded). From 1,103 hours of recordings, 298 ischemic episodes were identified, only 9% associated with angina. By Ridit analysis a significant correlation was found between the cumulative duration of transient myocardial ischemia and the number of diseased coronary vessels and indexes of proximal stenosis. During a 3 to 6 month follow-up period, there was one death and one patient was lost to follow-up among 20 patients without transient ischemia; in the group of 11 patients with a cumulative duration of transient ischemia 60 minutes/24 h, only 1 developed a stable angina pattern; 12 required coronary surgery (n = 11) or angioplasty (n = 1) and 5 developed myocardial infarction (2 died, 2 needed surgery for postinfarction angina and 1 recovered). A favorable clinical outcome occurred in only 6% of patients in the group with ischemia duration >60 minutes/24 h; this rate was significantly lower (p < 0.001) than that (70%) for the group with ischemia duration 60 minutes/24 h or that (95%) for the group without ischemia. In patients who underwent coronary surgery or angioplasty, ischemia was abolished. Thus, silent ischemia persisting after medical therapy of unstable angina is associated with an adverse short-term prognosis.