Acute MI in Emergency Department

Each year five million patients present to emergency rooms with acute chest pain, a common complaint that frequently causes a diagnostic dilemma. Triage and therapy decisions are made based on patient history, physical exam, laboratory, and ECG findings. Because of diagnostic uncertainty, many patients are admitted unnecessarily and many are discharged inappropriately.

Several studies have been published that address the issue of misdiagnosis of acute Cardiac ischemia in the emergency department:

In a multi-center study on misdiagnosis of acute cardiac ischemia, 2.1% of patients with acute myocardial infarction were mistakenly discharged and 2.3% of patients with unstable angina were mistakenly discharged. These patients had risk adjusted mortality of 1.9x and 1.7x, respectively. (Pope, et al., NEJM 2000; 342:1163)

In a prospective, multi-center trial 3,077 patients presenting to the emergency department with acute chest pain were analyzed. 4% of patients with acute myocardial infarction were inappropriately discharged. The most common reasons for misdiagnosis were younger age, atypical symptoms and normal ECG. The authors found that the misdiagnosed patients had a higher mortality than those admitted (26% mortality vs. 12% at 72 hours). (Lee, TH, et al., Am J. Cardiol: 1987; 60:219)

In another study focusing on the prevalence, clinical characteristics and mortality among patients with MI, of the 434,877 patients with confirmed myocardial infarction, 33% did not have chest pain. Chest pain was defined as any symptom of chest discomfort, sensation or pressure, or arm, neck or jaw pain, occurring at a period of time before hospital arrival or preceding a diagnosis of acute myocardial infarction. (Canto, et al., JAMA 2000; 283:3223-3229)

In another study focusing on chest pain evaluation in the emergency room, sixty-nine patients underwent 16-slice MDCT. The authors were attempting to differentiate between cardiac and non-cardiac (pulmonary embolism and aortic dissection) causes of chest pain. The sensitivity and specificity for the establishment of a cardiac cause of chest pain was 83% and 96%, respectively. The sensitivity and specificity for all causes of chest pain was 87% and 96%, respectively. (White, CS, et al., AJR 2005; 185:533-540)

Case Presentation

48 year old male admitted to Emergency Department with;

• Chest & Left Arm Pain
• Shortness of Breath
• Smoker 1PPD x 20 Years, Recently quit
• Negative Cardiac Enzymes & EKG
• History of Hypertension
• Positive family history
  

Upon examination, 4 differential diagnoses:

• ACS
• PE
• Chest wall pain
• Cervical radiculopathy

Decision Process for Coronary CTA

• Chest Pain
• Negative enzymes and EKG
• Hypertension, smoker,
• Family History of heart disease
• CT Triple-rule-out was performed

CT Results:

Severe 3 vessel CAD, occlusion distal RCA,
Negative PE, Negative Dissection.

Cath Results:

Severe 3 Vessel disease LAD 75 stenosis,
LMB 90% stenosis, RCA 100% stenosis.
RCA was ballooned and underwent
aspiration thrombectomy, stent implanted.

Patient Follow up:

5 months post exam, the patient remains symptom free
and has resumed an active life style.