Table 5

Prognostic Gradient of Ischemic Responses During an ECG-Monitored Exercise Test in Patients With Suspected or Proven CAD

Risk LevelIschemic Response Gradient
High
  • Ischemia induced by low-level exercise(less than 4 METs or heart rate less than 100 bpm or less than 70% of age-predicted heart rate) manifested by 1 or more of the following:

  • • Horizontal or downsloping ST depression greater than 0.1 mV

  • • ST-segment elevation greater than 0.1 mV in noninfarct lead

  • • Five or more abnormal leads

  • • Persistent ischemic response greater than 3 min after exertion

  • • Typical angina

  • • Exercise-induced decrease in systolic blood pressure by 10 mm Hg

Intermediate
  • Ischemia induced by moderate-level exercise(4 to 6 METs or heart rate 100 to 130 bpm [70% to 85% of age-predicted heart rate]) manifested by 1 or more of the following:

  • • Horizontal or downsloping ST depression greater than 0.1 mV

  • • Persistent ischemic response greater than 1 to 3 min after exertion

  • • Three to 4 abnormal leads

Low
  • No ischemia or ischemia induced at high-level exercise(greater than 7 METs or heart rate greater than 130 bpm [greater than 85% of age-predicted heart rate]) manifested by:

  • • Horizontal or downsloping ST depression greater than 0.1 mV

  • • One or 2 abnormal leads

Inadequate testInability to reach adequate target workload or heart rate response for age without an ischemic response. For patients undergoing noncardiac surgery, the inability to exercise to at least the intermediate-risk level without ischemia should be considered an inadequate test.

bpm indicates beats per min; CAD, coronary artery disease; ECG, electrocardiogram; and MET, metabolic equivalent.

  • Based on Weiner et al., 1984 (60); Morris et al., 1991 (61); Chaitman, 1986 (62); Gianrossi et al., 1989 (63); Detrano et al., 1989 (64); Mark et al., 1987 (65); Mark et al., 1991 (66); and Gibbons et al. (67).

  • Workload and heart rate estimates for risk severity require adjustment for patient age. Maximum target heart rates for 40- and 80-year-old subjects taking no cardioactive medication are 180 and 140 bpm, respectively (63–70).