Blunt Cardiac Injury
A Case Report
A 53-year-old woman was kicked by her horse, with the hoof striking her in the center of the chest. She developed severe chest pain and was transported to our institution for treatment. Initial physical examination revealed a horseshoe-shaped contusion in the central chest (Figure 1). Cardiac auscultation was normal. Rib radiographs did not reveal any fractures. A chest x-ray showed clear lung fields and a normal cardiac silhouette (Figure 2). A 12-lead ECG demonstrated sinus tachycardia with a minor right ventricular conduction delay and no ischemic changes (Figure 3). Serum troponin I was elevated (3.60 ng/mL, normal <0.08 ng/mL). Two-dimensional transthoracic echocardiography revealed a partially flail septal leaflet of the tricuspid valve (Figure 4, online-only Data Supplement Movie I). Color Doppler demonstrated an anteriorly-directed jet of tricuspid regurgitation of moderate severity (Figure 5, online-only Data Supplement Movie II). Cardiac magnetic resonance imaging confirmed these findings (Figure 6, online-only Data Supplement Movie III). The tricuspid regurgitant volume was calculated at 25 cm3, yielding a regurgitant fraction of 32% (Figure 7). The patient received narcotics for pain control and was discharged home after 48 hours of electrocardiographic monitoring. At 4 months, the patient remains free of symptoms and has resumed training horses.
Blunt cardiac injury (BCI) encompasses a spectrum of myocardial lesions resulting from nonpenetrating chest trauma. Due to a lack of standard diagnostic criteria, the incidence of BCI remains uncertain; the Centers for Disease Control and Prevention estimates 30 000 cases per year in the United States.1 Injuries related to BCI range from benign, such as myocardial contusion, to fatal, such as chamber rupture. With regard to valvular injury, autopsy studies indicate that the aortic valve is most commonly involved, followed by the mitral and then tricuspid.2 These findings likely reflect the high incidence of left-sided valvular injury in severe thoracic injury that results in death at the scene. Valvular disruption is reported to be uncommon in patients presenting alive to the hospital. However, tricuspid valve injury may be under-diagnosed because the clinical manifestations are likely to be subtle.2,3 Electrocardiography and serum troponin measurement should be performed when BCI is suspected.1 Echocardiography is the test of choice when the initial evaluation leads to a high clinical suspicion of BCI. Surgical repair of the tricuspid valve is generally reserved for severe tricuspid regurgitation resulting in right ventricular volume overload.3
The online-only Data Supplement, which contains movies, can be found with this article at http://circ.ahajournals.org/cgi/content/full/117/e333/DC1.