EKGs in PE
                                ==========
þ Pulmonary Embolism Simulating Acute Coronary Syndrome 
 - Typical ECG findings 
  + S1Q3 or S1Q3T4 
  + RBBB or incomplete RBBB (often transient) 
  + Rightward axis 
  + T-wave inversions, especially in right precordial leads (V1-V3) +/- 
    inferior leads 
 - Marriott and others: 
  + combination of T-wave inversions in right precordial and inferior leads 
    is highly specific for acute pulmonary hyptertension, pulmonary 
    embolism 
 - May also (less commonly) cause 
  + ST-segment depression or elevation in right precordial leads 
  + ST-segment depression in leads I or II 
  + ST-segment elevation in lead III 
 - Important point: PE often causes ECG changes that resemble cardiac ischemia 
 - Don't just "rule out MI" when the EKG seems to show cardiac iscnemia
 - Recent study shows inferior + anterior T inversions 99% specific for PE