Worsening left ventricular performance on serial exercise radionuclide angiography does not identify high-risk patients.
OBJECTIVE
To determine whether worsening exercise performance on serial exercise radionuclide angiography identifies patients at increased risk of future cardiac events.


METHODS
One hundred nine medically treated patients with previous Q-wave myocardial infarction underwent two exercise radionuclide angiographic studies at least 6 months 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 criteria 1 and 2; (4) worsening serial delta (exercise - rest) ejection fraction; or (5) increasing exercise ST-segment depression of 1 mm or more. Patients were followed up for a median duration of 3.9 years after the second exercise study.


RESULTS
Five cardiac deaths and 10 nonfatal myocardial infarctions occurred during follow-up. A Cox proportional hazards analysis failed to show an association between any of the aforementioned variables and cardiac events. Of the 15 patients with cardiac events, 4 (27%) had a lower (5% or more) exercise ejection fraction and 2 (13%) had a worsening exercise wall motion score. Of the 94 patients without cardiac events, 37 (39%) had a lower (5% or more) exercise ejection fraction and 28 (30%) had a worsening serial exercise wall motion score (not a statistically significant difference).


CONCLUSIONS
Worsening exercise performance on serial exercise radionuclide angiography does not identify patients at increased risk of future cardiac events.
Chaliki
H P
HP
Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic Rochester, Minnesota 55905, USA.
Miller
T D
TD
Christian
T F
TF
Bailey
K R
KR
Gibbons
R J
RJ
D000368:Aged; D016757:Death, Sudden, Cardiac; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction; D016016:Proportional Hazards Models; D015635:Radionuclide Ventriculography; D012008:Recurrence; D012189:Retrospective Studies; D012306:Risk; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016277:Ventricular Function, Left