Sports Medicine: Just the Facts

CHAPTER 20 • EXERCISE TESTING 123

SIGNS AND SYMPTOMS

• The presence or absence of symptoms such as chest
  pain, claudication, or exercise-induced wheezing
  needs to be mentioned in the report. Patients with
  exercise-induced angina have been shown to have a
  worse prognosis than patients with only ST depres-
  sion (Ellestad, 1996c). Therefore, these patients, even
  in the absence of EKG ischemic changes, should be
  regarded as having a test “suggestive of myocardial
  ischemia.” Another parameter worth mentioning is the
  rate of perceived exertion(RPE). It is valuable to
  measure during exercise testing as it correlates well
  with HR and VO 2. The Borg scale assigns a number
  0–10 to the RPE with a higher number indicative of
  more difficult exertion (Borg, Holmgren, and
  Lindblad, 1981).

DYSRHYTHMIAS/CONDUCTION
DISTURBANCES

• Ectopy or dysrhythmias that occur during the exercise
  test should be mentioned on the report. Unifocal pre-
  mature ventricular contractions(PVCs) are seen fre-
  quently during testing and are not specific for
  myocardial ischemia, although if frequent may
  increase the long-term risk of cardiovascular death in
  asymptomatic patients (Evans and Froelicher, 2001;
  Jouven et al, 2000). High-grade ectopy (couplets,
  mutiforme/ multifocal PVCs, ventricular tachycardia)
  is more suggestive of severe ischemic heart disease
  and higher mortality than those without ectopy (Califf
  et al, 1983). Supraventricular dysrhythmias (atrial-fib-
  rillation/flutter) require termination of the test and
  further intervention. Intracardiac blocks can occur
  before, during, or after testing and advanced forms of
  AV block (Mobitz II and higher) are abnormal.
  Bundle branch blocks occur very infrequently with
  exercise and require further evaluation, especially
  LBBB which may portend an increased mortality if
  there is structural heart disease (Evans and Froelicher,
  2001).

AEROBIC CAPACITY

• The EST can either measure the maximal functional
  aerobic capacity (VO2max) by direct gas analysis or
  estimate from workload performed in a maximal test.
  A nomogram is used to convert minutes (or METs)
  into VO2max. The results can then be compared with
  standard tables of fitness levels for age and sex
  (American College of Sports Medicine, 2000b).

ELECTROCARDIOGRAPHIC RESPONSES

TO EXERCISE TESTING

• ST segment changes are the most common signs of
  ischemia. ST segment depression is subendocardial,
  and one cannot localize ischemia based on EKG
  location of the ST depression. ST segment elevation
  is transmural, and the location of the anatomic
  obstruction correlates with the associated EKG
  changes.

NORMALRESPONSES WITHEXERCISE

• The PR segment shortens and slopes downward in the
  inferior leads. The QRS complex may show
  increased Q wave negativity and a decrease in R wave
  amplitude with an increased S wave depth. The J
  point becomes depressed with exercise. If already
  elevated at rest, it will commonly normalize. The T
  wave decreases in amplitude and the ST segment
  develops a positive upslope that returns to baseline
  within 60–80 m.

ABNORMALRESPONSES WITHEXERCISE(FARDY,

YANOWITZ, ANDWILSON, 1988)

• ST segment depression: This is the hallmark of
  ischemia and a positive treadmill (see next section).


• ST segment normalization: ST segments that are
  depressed and return to normal (pseudonormalization)
  are suggestive of ischemia.


• ST segment elevation: In patients without a prior his-
  tory of MI, consider acute MI (if accompanied by
  chest pain), or serious transmural ischemia. ST eleva-
  tion over Q waves in patients with a previous history
  of an MI suggests areas of dyskinesis or ventricular
  aneurysm (Evans and Karunarante, 1992b).
  •U wave inversion: U wave inversion during exercise is
  suggestive of ischemia.

FINAL DETERMINATION FOR

MYOCARDIAL ISCHEMIA

• One of four descriptions should appear in the patient’s
  written report to represent the final determination for
  myocardial ischemia (American Heart Association
  Scientific Statement, 2001; Ellestad, 1996b; Evans
  and Karunarante, 1992b; Lachterman et al, 1990):
  a. Positive
  
  
  1. Horizontal or downsloping ST segment depres-
     sion that is ≥1mm at 60 ms past the J point
  
  
  2. Horizontal or upsloping ST segment elevation
     that is ≥1mm at 60 ms past the J point
     3.Upsloping ST depression that is ≥1.5 mm
     depressed at 80 ms past the J point