Electrocardiographic changes after injury in a rat model of combined crush injury

Crush injury from debris, combined with hypoxia and water and food deprivation (combined crush injury), is common in industrial accidents and events such as earthquakes and terrorist attacks. Whether electrocardiographic changes are associated with combined crush injury is unclear.

Thirty-six rats underwent electrocardiography at baseline then were randomly assigned to 6 groups of 6. Bilateral hind limbs of all rats were compressed with custom-made clips (pressure 4.5 ± 0.3 kg), and the rats were put into a hypoxic compartment (oxygen concentration 10% ± 0.1%) for 72 hours without food or water. After 72 hours, the rats were moved to a normoxic environment, where the clips were removed (decompression) and food and water were freely accessible. Electrocardiography was performed in a different group at each of days 0, 1, 3, 7, 14, and 28 after decompression.

One rat died at 0.6 days. Among the remaining 35 rats, 28 (80%) had abnormal electrocardiographic changes: ST-segment depression (n = 25), tall-peaked T waves (n = 16), arrhythmias (n = 4), abnormal Q waves (n = 2), wide QRS complexes (n = 2) and QT prolongation (n = 1). The abnormality rates among assessed rats were 100% on days 0, 1, and 3; 83% on day 7; and 50% on days 14 and 28.

The findings suggest that abnormal electrocardiographic changes were seen in rats after simulated combined crush injury and decompression and were slow to resolve.