1. Injury may be divided in to penetrating and non-penetrating.
2. Presentation depends upon the location of the injury and the cardiac structures involved.
3. EKG is usually not as helpful as the physical exam and the CXR in the evaluation of penetrating injuries.
4. In the evaluation of non-penetrating injuries, the EKG is helpful.

Causes

1. MVA. Most common cause. Heart can be compressed between the sternum and the spine.
2. Sudden acceleration and deceleration.
3. Fist, a kick, a blunt object or an animal.
4. Cardiopulmonary Resuscitation (CPR).
5. Serious damage may be present in the absence of fractures.

1. Pericardium
   • disruption
   • hemopericardium and tamponade
   • pericarditis
2. Myocardium
   • contusion
   • rupture
   • septal perforation
   • late aneurysm
3. Valves
   • chordae tendineae
   • papillary muscle rupture
4. Coronary arteries
   • contusion
   • thrombosis

1. 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.
2. Reduction of QRS voltage
   • suggests effusion, possible tamponade
3. Pseudoinfarction pattern
   • rare
4. IVCD
   • reported to be as high as 23% in one series, “Chou feels this is an overestimate”
   • RBBB is the most common abnormality
5. SVTs and VT
   • VF may be responsible for sudden death

1. Sudden death due to electrocution is usually secondary to VF or cardiac standstill.
2. The heart s most sensitive to a low frequency current of 40 to 60 cycles/second
3. Current flow causes tissue coagulation by heat damage.
4. Damage is proportional to voltage, resistance of the tissue, and the duration of the flow.
5. EKG abnormalities are present in 10 to 46% of patients with electrical injury.
6. Arrhythmias (a. fib, VT, VF) may appear hours after the injury and may be recurrent for several months.
7. ST segment changes and T wave changes some of which resemble those of myocardial ischemia or injury may occur.
8. The QT interval may prolong.
9. Pseudoinfarct patterns have been observed.

Adapted from Chou’s Electrocardiography in Clinical Practice Third Edition. pp. 525-540.

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