Posttraumatic Cardiac Contrecoup
In Vivo Evidence by Cardiac Magnetic Resonance Imaging
A 33-year-old previously healthy man, victim of a motorcycle accident, had been violently ejected from the vehicle falling to the ground on his right-hand side. At admission he was conscious, hemodynamically stable, and without skin wounds. Chest x-ray examination performed immediately after the accident at a district hospital revealed a fracture of the sixth right rib; ECG showed repolarisation abnormalities with T-wave inversion in inferior and lateral leads (Figure 1). Cardiac enzymes were negative at admission, but an increase in Troponin I was noted in the following 4 hours (peak 3.19 ng/mL at 12 hours).
The patient was transferred to our institution where transthoracic echocardiography excluded pericardial effusion and demonstrated normal global and segmental left ventricular systolic and diastolic function (ejection fraction 65%). Aortic dissection was excluded by computed tomography of the chest, which confirmed the presence of the fracture of the sixth right rib (Figure 2). During the 36 hours of hemodynamic and ECG monitoring in the intensive care unit (ICU), no arrhythmias were observed. Cardiac magnetic resonance (CMR) showed normal global and segmental contractility of the left ventricle on cine (steady-state free-precession) images and the presence of a finding suggesting intramyocardial edema on T2-weighted black-blood images in the short-axis plane at basal and midventricular lateral level (Figure 3A). Late contrast enhancement at the level of the posterolateral myocardial segments, confined to the midventricular wall without involvement of the subendocardium was demonstrated on inversion recovery CMR images (Figure 4A and 4B). At follow-up 6 weeks after the trauma, complete resolution of myocardial edema was seen on the T2-weighted short-axis CMR images (Figure 3B). These findings are in favor of posttraumatic myocardial damage. Coronary angiography showed normal epicardial arteries without evidence of plaques, stenosis, or dissection of the coronary arteries. We postulate that the patient suffered a contrecoup cardiac contusion of the posterolateral left ventricular wall after a violent shock of the right chest wall.
This case highlights the potential role of cardiac magnetic resonance imaging for detecting, localizing, and showing the extent of myocardial damage in case of cardiac trauma and indicates how cardiac magnetic resonance imaging may add further relevant diagnostic information beyond the usual evaluation using ECG, cardiac enzymes, and echocardiography.
Sources of Funding
Drs Wyttenbach and Gallino are supported by a grant of the Swiss Heart Foundation. Dr Corti is supported by a grant of the Swiss National Science Foundation.