Noninvasive assessment of myocardial cell injury in dogs with suspected cardiac contusion

To determine the suitability of serologic biochemical tests to diagnose myocardial cell injury in dogs with suspected cardiac contusion. 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. 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. 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. 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.