Prognosis in medically stabilized unstable angina: early Holter ST-segment monitoring compared with predischarge exercise thallium tomography.
OBJECTIVE
To assess the relative value of invasive and noninvasive predictors of outcome in patients after unstable angina.


METHODS
Cohort of 54 patients with unstable angina who had 6-month follow-up after stabilization on medical therapy.


METHODS
University-based hospital, tertiary referral center.


METHODS
Consecutive patients with unstable angina whose symptoms resolved while receiving medical therapy.


RESULTS
We prospectively compared 24-hour Holter ST-segment monitoring at admission, quantitative exercise thallium tomography, and cardiac catheterization 5 +/- 2 days after admission and analyzed their value for predicting a cardiac event in patients with unstable angina within 6 months. When patients with a favorable outcome (n = 40) were compared with patients with an unfavorable outcome (n = 11) no statistical difference was found in duration of ST shift of 1 mm or more on Holter monitoring (51 +/- 119 min compared with 37 +/- 43 min), exercise duration by the standard Bruce protocol (8.0 +/- 3.6 min compared with 7.9 +/- 3.1 min), exercise-induced ST depression (0.6 +/- 0.9 mm compared with 1.0 +/- 1.0 mm), and contrast left ventricular ejection fraction (70% +/- 10% compared with 69% +/- 15%). Patients with a favorable outcome were distinguished from those with an unfavorable outcome by a higher maximum rate-pressure product (24 x 10(3) +/- 6 x 10(3) compared with 18 x 10(3) +/- 7 x 10(3), P = 0.0025), smaller size of the reversible scintigraphic perfusion defect expressed as a percentage of total myocardium imaged (6% +/- 11% compared with 17% +/- 18%, P = 0.05) and a smaller number of vessels with stenosis of 50% or more (1.1 +/- 1.2 compared with 2.1 +/- 1.0, P = 0.01). On multiple logistic regression analysis, a history of previous myocardial infarction was the most powerful predictor of outcome. In patients without myocardial infarction, reversible exercise thallium perfusion defect size was the only predictor.


CONCLUSIONS
After stabilization of an episode of unstable angina, quantitative tomographic exercise thallium scintigraphy has greater value for risk stratification than Holter ST-segment monitoring, particularly in patients who have not had a previous infarction.
St. Michael's Hospital, Toronto, Ontario.
J D
JD
Marmur
M R
MR
Freeman
A
A
Langer
P W
PW
Armstrong
D000328:Adult; D000368:Aged; D000787:Angina Pectoris / Q000175:diagnosis*; D000789:Angina, Unstable / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy; D006328:Cardiac Catheterization; D017023:Coronary Angiography; D003331:Coronary Vessels / Q000000981:diagnostic imaging; D015716:Electrocardiography, Ambulatory / Q000379:methods*; D005080:Exercise Test; D005500:Follow-Up Studies; D006439:Hemodynamics; D006801:Humans; D008875:Middle Aged; D010351:Patient Discharge; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012044:Regression Analysis; D012307:Risk Factors; D013794:Thallium Radioisotopes; D013997:Time Factors; D014055:Tomography, Emission-Computed / Q000379:methods*
D013794:Thallium Radioisotopes