Creatine kinase MB and M-mode echocardiographic changes in cardiac contusion

Cardiac contusion was suspected in 95 patients with severe blunt chest trauma of whom 93 did not require hospitalization. Creatine kinase (CK) MB isoenzyme activity was elevated over 4.0 U/l in 10 (10.5%) patients (CK MB positive) by between 2% and 8% (mean +/- SE 4.1 +/- 0.6%), when the total CK was 296 +/- 74 (mean +/- SE). Two patients had a pericardial rub. M-mode echocardiography was performed on 16 patients: 7 CK MB positive (CK MB+) and 9 CK MB negative (CK MB-) without the physician's knowledge of the CK MB status of the patients. The left ventricular end-diastolic diameter, in healthy subjects 48.3 +/- 4.9 mm, was increased to 55.4 +/- 1.8 mm (p less than 0.01) in CK MB+ patients and to 56.3 +/- 6.0 mm (p less than 0.01) in CK MB- patients. The end-systolic left ventricular diameter, in healthy subjects 36.7 +/- 5.2 mm, was increased to 42.4 +/- 6.7 mm (p less than 0.01) in CK MB+ patients and to 41.3 +/- 6.5 mm (p less than 0.01) in CK MB- patients. The mean ejection fraction was 48.6 +/- 11.0 in CK MB+ and 53.6 +/- 11.8 in CK MB- group. Minor contractile abnormalities occurred in all CK MB+ patients in 2 or more left ventricular regions and in 7 out of 9 CK MB- patients in 1 or 2 regions. The regional motion pattern was hypokinesia with sharp systolic deflections at abnormal areas and hyperkinesia on normal segments. Aortic root was enlarged in all patients with contusion and CK MB+. There was no apparent increase in left atrial size. "Flattened" ST-segment and T-waves were seen in 5 CK MB+ patients but not in the CK MB- patients.(ABSTRACT TRUNCATED AT 250 WORDS)