Myocardial Ischemia / Acute M.I. (as cause of SOB)

For patients complaining of Dyspnea, consider Coronary Ischemia if intermittent symptoms, usually exertional, last 1-5 minutes.  Frank M.I. lasts longer.  Index of Suspicion based on the following 3 components of History:

1.  Presence of Associated Chest Symptoms
  • “Pain” (usually), but maybe “Pressure,” “Tightness,” “Discomfort”
  • If not in “Chest,” maybe left shoulder, jaw, upper arm, right chest or epigastrium.
2.  Associated Symptoms (“Angina Equivalents”):
  • Nausea or vomiting
  • Diaphoresis (“do cold, wet, drops of sweat break out on your forehead?”)
  • Lightheadedness or dizziness
3.  Risk Factors for Coronary Artery Disease:
  • Age: Men >40; Post-menopausal Women
  • Tobacco (any cigarettes in past month; regular smoking in past 1-2 years)
  • Hypertension
  • Diabetes
  • Hyperlipidemia
  • Strong Family History of CAD
  • Same-day cocaine or amphetamine use
  • History of typical anginal exertional chest pain, even if that’s not the pain your patient is seeking care for today.

Don’t worry about soft risks like obesity or sedentary life-style.

Stress-Testing for Suspected Angina
  • If the baseline EKG is normal, order a basic exercise treadmill test (ETT).
  • If there are baseline S-T segment or T-wave abnormalities, must order a stress echocardiogram or an ETT with radionuclide scan (e.g. thallium).
  • If the patient can’t exercise (e.g. bum knee, too frail, etc.), order a pharmacologic stress test using dobutamine, dipyridamole (Persantine), adenosine, etc.
  • Baseline left bundle branch block necessitates a pharmacologic stress radionuclide scan.

Abnormal stress-echo or radionuclide scan means treatable ischemia if the study reverses to normal at rest.  If equally abnormal at rest & during stress, it reveals an untreatable old M.I.

See posting Chest Pain – 1.