Characteristics and outcomes of patients who achieve high workload (≥10 metabolic equivalents) during treadmill exercise echocardiography.
OBJECTIVE
To determine the frequency and prognostic significance of abnormal exercise echocardiographic results for patients achieving a workload of 10 or more metabolic equivalents during treadmill exercise echocardiography.


PATIENTS AND METHODS
Patients who underwent treadmill exercise echocardiography from November 1, 2003, through December 31, 2008, and exercised for 9 or more minutes using the Bruce protocol (N=7236) were included. Clinical and exercise echocardiographic characteristics and outcomes were evaluated. Variables associated with abnormal exercise echocardiographic results and mortality were identified.


RESULTS
Exercise echocardiographic results were positive for ischemia in 862 patients (12%). Extensive ischemia developed in 265 patients (4%). For patients with normal exercise echocardiographic results, all-cause and cardiovascular mortality rates were 0.30% and 0.05% per person-year of follow-up, respectively. For patients who had extensive ischemia, all-cause and cardiovascular mortality rates were 0.84% and 0.25% per person-year of follow-up, respectively. Patients at highest risk were those who had extensive and severe regional wall motion abnormalities at rest (n=58), and their all-cause and cardiovascular mortality rates were 2.65% and 0.76% per person-year of follow-up. Exercise echocardiographic variables did not identify sizable patient subgroups at risk for death and did not provide incremental prognostic information (C statistic was 0.74 compared with 0.73 for the clinical plus exercise electrocardiography model).


CONCLUSION
Patients achieving a workload of 10 or more metabolic equivalents during treadmill exercise testing do not often have extensive ischemic abnormalities on exercise echocardiography. Although exercise echocardiographic results provide some prognostic information, it is not of incremental value for these patients, whose short-term and medium-term prognosis is excellent.
['Fine|Nowell M|NM|', 'Pellikka|Patricia A|PA|', 'Scott|Christopher G|CG|', 'Gharacholou|S Michael|SM|', 'McCully|Robert B|RB|']
D000328:Adult D000368:Aged D015897:Comorbidity D003324:Coronary Artery Disease D025401:Echocardiography, Stress D004562:Electrocardiography D005080:Exercise Test D005260:Female D006339:Heart Rate D006801:Humans D053208:Kaplan-Meier Estimate D008297:Male D055686:Metabolic Equivalent D008875:Middle Aged D011237:Predictive Value of Tests D011379:Prognosis D016896:Treatment Outcome D014481:United States
metabolic equivalent OR regional wall motion abnormalities CAD ECG HR IDI LV LVEF LVESV MAPHR MET MI MPI RWMAs coronary artery disease electrocardiographic hazard ratio integrated discrimination improvement left ventricular left ventricular ejection fraction left ventricular end-systolic volume maximal age-predicted heart rate myocardial infarction myocardial perfusion imaging odds ratio