25 Cardiac Trauma
Blunt Cardiac Trauma
Pericardial Sequelae
Myocardial Sequelae
Myocardial damage is produced in the area underlying the impact, but also may occur elsewhere in the heart, often on the opposite wall.
Echocardiographic features of myocardial contusion include
There is a spectrum of severity of myocardial contusion. Echocardiography is most likely to be sensitive to severe degrees of contusion, but some authors have questioned its sensitivity to less severe degrees of contusion.1
Cardiac rupture may occur due to breakdown of myocardium post-contusion, due to violent compression of the heart, puncture by a rib, or coronary disruption or thrombosis from trauma. Ventricular septal defect,2 free wall rupture, tamponade, and pseudoaneurysms have all occurred.
Valvular Sequelae
The aortic valve is most commonly injured,3 although any valve may be involved. Insufficiency results from damage to leaflets, chordae, or papillary muscles, or semilunar leaflet avulsion or retroversion.
Penetrating Cardiac Trauma
In the urban milieu, the missiles that most commonly penetrate the heart are knives and bullets.
Most (60–80%), but not all, of these wounds are fatal, often immediately.
The clinical presentation is usually tamponade or bleeding into the chest.
Left anterior stab wounds most often involve the right ventricle. Right anterior stab wounds may involve the right ventricle or atrium, and left lateral and posteriors stab wounds may involve the left ventricle.
Bullet wounds commonly involve the left ventricle.
Puncture of a cardiac chamber may result in the following:
Penetrating cardiac wounds often are multiple.
Shunt flow within the heart may have unusual color flow characteristics if caused by a knife, as on one plane the defect is seen as thin, and on another it is seen as wide.
Coronary artery laceration may occur, resulting acutely in tamponade and later in myocardial infarction.
Missiles within the Heart
Echocardiography may help localize a missile within the heart by imaging the location and motion6:
Some missiles may be free within a cardiac chamber.
Bullets and shotgun pellets are conspicuous by their tail of reverberations.
Blunt Aortic Trauma
As many as one sixth of motor vehicle deaths are caused by aortic rupture.
Eighty percent of patients with aortic rupture die outright.
Twenty percent get to the hospital; of those who survive to the hospital, 70% may survive.
From 2% to 5% of patients with partial tears will develop pseudo-aneurysms (usually saccular), and half of those aneurysms will expand.
Any high-speed sudden deceleration may produce shearing at the junction of mobile and fixed portions of the aorta. Rarely, blast injury may cause aortic rupture.
Ninety percent of blunt injuries to the aorta involve either: