WORSENING LEFT-VENTRICULAR PERFORMANCE ON SERIAL EXERCISE RADIONUCLIDE ANGIOGRAPHY DOES NOT IDENTIFY HIGH-RISK PATIENTS

Objective: To determine whether worsening exercise performance on seri al exercise radionuclide angiography identifies patients at increased risk of future cardiac events. Material and Methods: One hundred nine medically treated patients with previous Q-wave myocardial infarction underwent two exercise radionuclide angiographic studies at least 6 mo nths apart (median, 16 months) without an intervening clinical event. Worsening exercise performance between the two studies was defined by five criteria: (1) lower (5% or more) peak exercise ejection fraction; (2) worsening peak exercise wall motion score; (3) combination of cri teria 1 and 2; (4) worsening serial delta (exercise rest) ejection fra ction; or (5) increasing exercise ST-segment depression of 1 mm or mor e. Patients were followed up for a median duration of 3.9 years after the second exercise study. Results: Five cardiac deaths and 10 nonfata l myocardial infarctions occurred during follow-up. A Cox proportional hazards analysis failed to show an association between any of the afo rementioned variables and cardiac events. Of the 15 patients with card iac events, 4 (27%) had a lower (5% or more) exercise ejection fractio n and 2 (13%) had a worsening exercise wall motion score. Of the 94 pa tients without cardiac events, 37 (39%) had a lower (5% or more) exerc ise ejection fraction and 28 (30%) had a worsening serial exercise wal l motion score (not a statistically significant difference). Conclusio n: Worsening exercise performance on serial exercise radionuclide angi ography does not identify patients at increased risk of future cardiac events.