post-MI exercise testing; rehabilitation treadmill testing; predischarge exercise testing

Introduction

Post-MI exercise testing limited exercise testing on selected patients with myocardial infarction may be done 8-10 days post-MI, &/or pre-hospital discharge.

Indications

• prognosis/mortality risk assessment
• to select patients for earlier discharge & more rapid rehabilitation
• to detect patients with conduction instability
• to determine adequacy of medical management
• to facilitate planning a safe home activity program
• to achieve a favorable psychologic impact

Selection of patients:

• patient physically able to walk on treadmill
• electrically stable - controlled ventricular ectopy
• hemodynamically stable
  • no symptoms congestive heart failure
    • no pulmonary edema
    • no persistent venous stasis
  • no persistent hypotension as a complication of myocardial infarction
  • special consideration given to patients with
    • resting pulse > 95/min
    • diastolic BP > 95
    • systolic BP < 95
    • > 10 mm Hg postural drop in BP
    • 2nd or 3rd degree heart block
    • active myocarditis
    • recently implanted pacemaker

Procedure

Naughton protocol is generally used.

Termination of test

• 70% of maximum predicted heart rate (MPHR)
• heart rate of 130/min
• 4 mets of activity
• ischemia
• excessive fatigue, dyspnea or dizziness
• progressive decrease in heart rate of systolic BP
• increased AV block
• significant new or increasing ventricular ectopy
• excessive vasoconstriction (cool & clammy)
• musculoskeletal symptoms or difficulty with balance
• supervening atrial fibrillation or flutter

Interpretation

• indications for cardiac catherization
  • unable to exercise
  • exercise-induced ST-segment depression
  • failure to acheive 5 METS
  • failure to increase systolic blood pressure by 10-30 mm Hg

More general terms

• exercise stress testing

Additional terms

• maximum predicted heart rate MPHR
• Naughton protocol