II. Epidemiology
- Limited diagnostic value in Pulmonary Embolism
- EKG Changes have low sensitivity and low Specificity for Pulmonary Embolism
- However, in combination, may add to likelihood of Pulmonary Embolism
- Normal EKG does not exclude Pulmonary Embolism
III. Findings: General
- See Right Ventricular Strain EKG Pattern
- Electrocardiogram shows nonspecific changes in 80% of cases
- Classic Findings (Right heart strain): S1 Q3 T3 (seen in under 20% of cases)
- S Wave in Lead I
- Q Wave in Lead III
- T Wave Inversion in Lead III
- Findings with increased probablity of Pulmonary Embolism (especially moderate to severe PE)
- T Wave Inversion especially in anteroseptal (v1-v4) and possibly inferior (II, III, aVF) leads
- Common Findings
- Sinus Tachycardia
- Dysrhythmias
- Right sided strain pattern
- Findings that mimic Myocardial Infarction
- ST Segment changes
- T Wave changes
- Atrial Fibrillation (new onset)
- ST Segment Elevation in aVR
- Also seen in Proximal LAD Occlusion
- P Pulmonale
- Suggests right atrial enlargement
- Peaked P Waves in the inferior leads >2.5 mm and taller in I than III
IV. Findings: Daniel EKG Criteria for Massive PE
- Criteria (21 points possible)
- Score 2: Sinus Tachycardia
- Score 2: Incomplete Right Bundle Branch Block
- Socre 3: Complete Right Bundle Branch Block
- Score 3-12: T-wave inversion in leads V1 through V4 (score 3 points for each lead with T inversion)
- Score 1: Q Wave in lead III
- Score 1: Inverted T Wave in lead III
- Score 2: Right heart strain pattern of S1 Q3 T3 (as described above)
- Interpretation
- Score >5 is consistent with Pulmonary Embolism
- Score >10 is consistent with severe or massive Pulmonary Embolism
- References
- Daniel (2001) Chest 120(2):474-81 +PMID:11502646