Electrocardiography of traumatic heart disease: Difference between revisions
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Latest revision as of 17:04, 4 September 2012
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
General Principles
- Injury may be divided in to penetrating and non-penetrating.
- Presentation depends upon the location of the injury and the cardiac structures involved.
- EKG is usually not as helpful as the physical exam and the CXR in the evaluation of penetrating injuries.
- In the evaluation of non-penetrating injuries, the EKG is helpful.
Non-Penetrating Injuries
Causes
- MVA. Most common cause. Heart can be compressed between the sternum and the spine.
- Sudden acceleration and deceleration.
- Fist, a kick, a blunt object or an animal.
- Cardiopulmonary Resuscitation (CPR).
- Serious damage may be present in the absence of fractures.
Potential Damage
- Pericardium
- disruption
- hemopericardium and tamponade
- pericarditis
- Myocardium
- contusion
- rupture
- septal perforation
- late aneurysm
- Valves
- chordae tendineae
- papillary muscle rupture
- Coronary arteries
- contusion
- thrombosis
Potential EKG Changes
- ST and T wave changes
- the most common change (17 to 58%)
- develop within 24 to 48 hours of the injury and mimic the changes due to myocardial ischemia.
- in most, the changes are transient, but they may persist.
- myocardial contusion or traumatic pericarditis is the usual underlying abnormality.
- if the abnormality persists, then extensive myocardial scarring may be present.
- CK MB and technetium-99 pyrophosphate scintigraphy have been found to be even less sensitive than the EKG in the diagnosis of myocardial contusion.
- Reduction of QRS voltage
- suggests effusion, possible tamponade
- Pseudoinfarction pattern
- rare
- IVCD
- reported to be as high as 23% in one series, "Chou feels this is an overestimate"
- RBBB is the most common abnormality
- SVTs and VT
- VF may be responsible for sudden death
Electrical Injury
- Sudden death due to electrocution is usually secondary to VF or cardiac standstill.
- The heart s most sensitive to a low frequency current of 40 to 60 cycles/second
- Current flow causes tissue coagulation by heat damage.
- Damage is proportional to voltage, resistance of the tissue, and the duration of the flow.
- EKG abnormalities are present in 10 to 46% of patients with electrical injury.
- Arrhythmias (a. fib, VT, VF) may appear hours after the injury and may be recurrent for several months.
- ST segment changes and T wave changes some of which resemble those of myocardial ischemia or injury may occur.
- The QT interval may prolong.
- Pseudoinfarct patterns have been observed.
References
Adapted from Chou's Electrocardiography in Clinical Practice Third Edition. pp. 525-540.