Objectives: To determine the suitability of serologic biochemical tests to diagnose myocardial cell injury in dogs with suspected cardiac contusion.
Background: Myocardial contusion after blunt thoracic trauma will frequently be overlooked or missed unless hemo-dynamic instability or dramatic electrocardiographic findings are observed. There are no available non-invasive tests to definitely detect blunt myocardial lesions in dogs.
Methods: Circulating biochemical markers of skeletal muscle and myocardial cell integrity (aspartate aminotransferase, lactate dehydrogenase, a-hydroxybutyrate dehydrogenase, creatine kinase [CK], CK isoenzyme MB, and cardiac troponins I [cTnT] and T [cTnT]) were analyzed in 33 dogs with blunt chest injury and in 40 control dogs. Results were compared with ECG abnormalities diagnosed from serial short-time surface ECGs.
Results: Cardiac TnI and CK-MB in serum were not detectable in 36 and 26 healthy dogs (median and range were 0 and 0 to 1.37 ng/ml and 0 and 0 to 3.17 ng/ml, respectively). Serum cTnT was not found in normal dogs. In dogs with thoracic trauma, circulating cTnI was elevated in 18 dogs (range 0 to 160.1 ng/ml), CK-MB in 14 dogs (range 0 to 24.9 ng/ml) and cTnT in 9 dogs (range 0 to 2.35 ng/ml), suggesting myocardial cell injury in 58% of dogs. Relevant electrocardiographic abnormalities were observed in 10/33 (30%) dogs. No differences in serum concentrations of markers of myocardial injury were found between dogs with or without relevant ECG abnormalities.
Conclusion: Myocardial cell injury is a frequent event in dogs with blunt thoracic trauma. Analysis of serum cTnI is more sensitive in detecting myocardial abnormalities than determination of circulating cTnT and CK-MB or electrocardiography.