Management of cardiac injury in severely injured patients

INTRODUCTION — While life-threatening cardiac injury is rare, it is important for clinicians to maintain a high index of suspicion for injury. Traumatic cardiac injury can occur with blunt or penetrating trauma. Among those presenting with penetrating thoracic injury, cardiac injury occurs in about 6 percent [1,2]. The wide range in the reported incidence of blunt cardiac injury (7 to 76 percent) reflects both the lack of a common definition for blunt cardiac injury as well as the challenge in diagnosing it [1,3,4].

The management of cardiac injury in severely injured patients, including the approach to treatment, damage control surgery, and repair of cardiac injuries, is reviewed. The initial approach to penetrating and blunt chest trauma and the management of isolated blunt cardiac injury are discussed separately. (See "Initial evaluation and management of penetrating thoracic trauma in adults" and "Initial evaluation and management of blunt thoracic trauma in adults" and "Initial evaluation and management of chest wall trauma in adults" and "Initial evaluation and management of blunt cardiac injury".)

ANATOMY AND MECHANISM OF INJURY — The heart occupies the majority of the middle mediastinum (figure 1) and is normally situated left of center in the thorax. The middle mediastinum also contains the superior vena cava, ascending aorta, tracheal bifurcation, as well as the pulmonary arteries and veins.

The heart has four chambers, the right and left atria and right and left ventricles (figure 2). Externally, these are marked by several grooves: the atrioventricular groove containing the coronary sinus, the interatrial groove containing the ascending aorta and pulmonary artery, and the interventricular grooves (anterior, posterior) (figure 3). The entire heart is surrounded by the dense, fibrous, parietal pericardium.

The blood supply to the heart arises from the ascending aorta at the right and left main coronary os and then divides into the right and left coronary arteries. The left coronary artery divides into the left anterior descending artery and the left circumflex artery. The right coronary artery gives off acute marginal branches and then terminates as the posterior descending artery. Typically, the left system supplies the left atrium, ventricle, and anterior two thirds of the interventricular septum. The right system supplies the right atrium, ventricle, and posterior one third of the interventricular septum. There is little collateral circulation.

The heart also has significant internal anatomy (figure 2). The anterior right atrium is trabeculated and then gives way to a smooth posterior wall where the coronary sinus enters. The interatrial septum is marked by the fossa ovalis. Antero-infero-medially, the tricuspid valve leads into the right ventricle. The tricuspid valve has three papillary muscle projections to its leaflets, anterior, posterior, and septal. The triangular right ventricle has an inflow area that then leads to the smooth outflow area of the pulmonary artery through the three-cusped pulmonic valves. The left atrium is squarer in shape with smooth walls. The origins of the pulmonary veins are posterior. The mitral valve sits anterior and inferior, and its two leaflets lead to the left ventricle. The left ventricle is muscular with anterior and posterior papillary muscles. The aortic outflow is anterior to the mitral orifice and separated from it by the anterior leaflet of the mitral valve. The aortic valve is three cusped and positioned to the left and just posterior to the interventricular septum.

Knowledge of the relationship of the heart relative to other structures is important for assessing the patient with blunt or penetrating cardiac injury (figure 4). Other structures in the mediastinum that may be injured in conjunction with injuries to the heart include the aortic arch, brachiocephalic veins, the superior vena cava, the left common carotid, subclavian artery, brachiocephalic trunk, descending aorta, azygous vein, esophagus, and thoracic duct.

The borders of the heart are as follows:

●The superior border of the heart is located behind the sternum in the second intercostal space. The pulmonary arteries lie along a line at this level extending from just right of the sternum to 2 cm left of the sternum.

●The right border of the heart is comprised of the right atrium and extends to the sixth costal cartilage.

●The left border of the heart is formed by the left ventricle and extends from the point of maximum impulse (often the fifth interspace) to 2 cm to the left of the sternum in the second interspace.

●The inferior border of the heart is comprised of the right ventricle and runs from the sixth costal cartilage to the point of maximum impulse.

Anterior to the majority of the heart is the sternum, and posteriorly the spine, esophagus, and descending thoracic aorta are in close association. The anterior surface of the heart is formed by the right atrium and ventricle. The posterior surface is the left atrium and ventricle. The diaphragmatic surface of the heart is occupied by one third of the right ventricle and two thirds of the left ventricle. The phrenic nerve runs on the surface of the pericardium just anterior to the pulmonary hilum on the right (figure 5), and across the middle of the pericardial surface on the left (figure 6).

Mechanism of injury

●Blunt cardiac injury – Blunt cardiac injury often occurs in the context of multisystem trauma. The mechanisms of injury are similar to the blunt trauma population, in general [5]. In one autopsy study of blunt trauma deaths, 56 percent of cardiac injuries were due to motor vehicle accidents, 38 percent from falls, 4 percent from crush injury, and 1 percent from explosions [6]. The mechanism of blunt injury can also be related to deceleration injury, or compression of the heart between the sternum and spine, among other potential mechanisms. Blast injury from a penetrating missile that passes adjacent to but not into the heart can also lead to blunt cardiac injury. Blunt cardiac injury can lead to myocardial contusion, valvular or septal abnormalities, acute coronary syndrome, rhythm disturbances, or, less commonly, cardiac rupture. (See "Initial evaluation and management of blunt cardiac injury".)

●Penetrating cardiac injury – Penetrating cardiac injuries are primarily the result of stab or firearm injuries (ie, gunshot, shotgun). The frequency of these injuries varies greatly depending on geographic characteristics. In a review from a level I trauma center in Atlanta, Georgia, gunshot wounds accounted for 57 percent of penetrating cardiac injuries [7]. Compared with stab wounds, gunshot wounds resulted in more multi-chamber injuries and higher mortality.

The extent of penetrating cardiac injury is directly related to the size, speed, and trajectory of the missile or implement. Less commonly, cardiac injury can be due to penetration into the heart from a fractured rib. The left ventricle is involved in 25 percent, and more than one chamber of the heart is involved in 30 percent [8]. Among patients with stab wounds who reach the hospital, approximately 35 percent have an isolated right ventricular injury [9]. Other cardiac injuries include coronary artery lacerations (most often the left anterior descending and diagonal branches), valve injury, and ventricular septal defects. Missile injuries may produce through-and-through injuries resulting in hemorrhage, tamponade, and shock.

Cardiac injury scale — The American Association for the Surgery of Trauma (AAST) cardiac injury scale is based upon the severity of penetrating or blunt cardiac injury and provides a standard scheme primarily for the purposes of research and documentation (table 1) [10,11]. (See "Initial evaluation and management of blunt cardiac injury".)

TRAUMA EVALUATION — The initial resuscitation, diagnostic evaluation, and management of the patient with blunt or penetrating thoracic injury, including suspected cardiac injury, are based upon protocols from the Advanced Trauma Life Support (ATLS) program, established by the American College of Surgeons Committee on Trauma. Complete details and steps involved in this evaluation are reviewed separately. The aspects relevant to diagnosis of cardiac injury in the context of multisystem trauma are reviewed below. (See "Initial evaluation and management of blunt thoracic trauma in adults" and "Initial evaluation and management of penetrating thoracic trauma in adults" and "Initial evaluation and management of chest wall trauma in adults".)

Clinical features — The history should include the details of the mechanism of injury, particularly high-energy blunt force such as a motor vehicle accident, or specific penetrating missile or implement. Bruising, such as from a seatbelt, tenderness, or crepitus across the chest, should raise the possibility of significant thoracic trauma. However, for hemodynamically stable patients with blunt trauma, the appearance of the chest may be entirely normal.

For penetrating injuries, any entry into the torso (chest or abdomen) has the potential to cause a cardiac injury. An increased risk to the heart has been ascribed to penetrating injuries that occur within the "cardiac box," which is the area bounded superiorly by the clavicles, laterally by the midclavicular lines, and inferiorly by the costal margins (figure 7). While wounds within the cardiac box should increase the suspicion of cardiac injury, their absence does not exclude injury, particularly for gunshot wounds. For stab wounds, and low-velocity injuries, the cardiac box is more reliable for estimating the risk for cardiac injury [12]. Stab injuries to the heart are through this area 80 percent of the time, whereas gunshot injuries to the heart occur through this area in fewer than half of patients. In a study that included 263 patients, gunshot wounds to "the box" caused cardiac injury in 31 percent of cases, and gunshot wounds outside "the box" resulted in cardiac injury 21 percent of the time [13].

Cardiac tamponade is most often the result of penetrating injury but can also be seen with blunt trauma. The normal pericardial sac is tough and fibrous, and, when fluid builds quickly, only 75 to 100 cubic centimeters (cc) are needed to cause tamponade physiology. The classic Beck's triad (jugular venous distention [JVD], hypotension, and muffled heart sounds) is only present in one third of patients. While Kussmaul's sign (rise in central venous pressure with inspiration) is reliable, it is not practical in the trauma setting, since few patients have a central line in place before the diagnosis must be made. A systolic to diastolic gradient of less than 30 mmHg may also suggest tamponade.

Injury to the pericardium with or without underlying myocardial injury can present with acute tamponade, delayed tamponade, or with later signs of constrictive pericarditis related to the earlier injury. (See "Post-cardiac injury syndromes".)

An electrocardiogram (ECG) should be obtained in all patients suspected of blunt cardiac injury. Arrhythmia may suggest blunt cardiac injury; however, sinus tachycardia should be assumed to be from hemorrhage until the patient has been resuscitated and it has been ruled out [14]. A normal ECG has a negative predictive value of 98 percent and a sensitivity of 89 percent, making it a useful tool for ruling out blunt cardiac injury. However, ECG alone is not sufficient; some patients observed for 24 hours following an initially normal ECG have been diagnosed with a significant blunt cardiac injury. ECG is, therefore, combined with laboratory testing such as troponin I [14]. (See "Initial evaluation and management of blunt cardiac injury", section on 'Electrocardiogram'.)

In addition to standard trauma laboratory studies, a cardiac-specific serum troponin I should be measured [14]. This should be obtained in all patients with suspected blunt cardiac injury. Normal cardiac-specific troponin levels, when combined with a normal ECG, rule out blunt cardiac injury with a negative predictive value of 100 percent. Troponin may also be useful for prognosis, with retrospective studies showing an association between higher troponin levels and mortality [3,14,15]. (See "Initial evaluation and management of blunt cardiac injury", section on 'Cardiac biomarkers'.)

Chest radiographs may be useful in gunshot and shotgun injuries to determine the path of the projectile. Bullet fragments seen traversing the mediastinum should raise concern for cardiac injury. Injuries associated with blunt cardiac injury seen on plain radiography include sternal fracture, first or second rib fracture, and widened mediastinum. First or second rib fracture indicates a high-force injury to the chest and may also be associated with vascular injury. Although widened mediastinum can be seen associated with cardiac injury, this finding is nonspecific and is more commonly associated with injury to the aorta.

Associated injuries — Associated injuries are common. In a retrospective review of thoracoabdominal gunshot wounds at a level 1 trauma center, 42 percent of patients with cardiac injury also had an additional thoracic vascular injury, and 85 percent had major abdominal injury [16]. In a review of patients with thoracoabdominal stab wounds who underwent thoracotomy, 14.5 percent of patients with cardiac injury had an associated thoracic vascular injury at operation [16]. For blunt cardiac injury, autopsy studies have been revealing regarding injury patterns. In a review of 881 blunt traumatic deaths, 77 percent of patients with cardiac injury had an associated abdominal injury [5]. The most common injuries associated with blunt cardiac injury were liver (60 percent), spleen (40 percent), and kidney (18 percent). Although this was an autopsy study, 22 percent of the patients arrived to the hospital alive, indicating an opportunity for intervention.

APPROACH TO DIAGNOSIS AND TREATMENT — Following initial assessment, patients are approached based upon their hemodynamic status and the mechanism of injury (blunt, penetrating), and taking into consideration other injuries. A diagnosis of cardiac injury may be suggested by ongoing hypotension without an obvious source of blood loss.

Hemodynamically unstable — Management of hemorrhage from the hemodynamically unstable patient with penetrating cardiac trauma begins with fluid resuscitation and immediate transfer to the operating room. While resuscitative thoracotomy can occasionally salvage patients with penetrating cardiac injury who are in extremis, this technique has significant limitations with respect to ability to adequately expose the injury and clinician experience. (See 'Damage control surgery' below and 'Chest exploration' below and "Resuscitative thoracotomy: Technique".)

Otherwise, hemodynamically unstable patients are evaluated with focused assessment with sonography for trauma (FAST) to identify a source of bleeding either in the emergency department or in the operating room. Cardiac views should be performed during FAST examination, if possible, to identify the presence of fluid in the pericardial sac, which may reflect hemopericardium [17]. In addition to the subcostal view, a parasternal view may be helpful. FAST examination is highly accurate for identifying pericardial effusion [18]. However, at least one study showed a significant rate of incidental pericardial effusion with FAST [19]. FAST cannot exclude blunt cardiac injury. Penetrating injuries can result in a negative FAST examination, such as when blood is leaking directly into the chest cavity through a pericardial defect [20].

A subxiphoid pericardial window, which is more typically performed in the operating room, is another option to evaluate for pericardial effusion depending on local experience, resources, and clinical scenario [21]. (See 'Pericardial window' below.)

Hemodynamically stable — Hemodynamically stable patients with traumatic injuries typically undergo computed tomography (CT) of the chest and/or abdomen [22]. CT angiography is routinely performed to evaluate the thoracic aorta. (See "Initial evaluation and management of penetrating thoracic trauma in adults" and "Initial evaluation and management of blunt thoracic trauma in adults".)

CT of the chest may identify effusion, which should prompt exploration of the pericardium [1,23]. Subxiphoid pericardial window demonstrating blood or clot confirms the diagnosis and mandates further chest exploration. (See 'Pericardial window' below and 'Chest exploration' below.)

Sternal fracture identified on CT does not require further workup beyond electrocardiogram (ECG) and troponin screening for blunt cardiac injury [24].

For patients with multiple injuries, a diagnosis of blunt cardiac injury can be challenging, particularly in patients without symptoms [25]. Unfortunately, there are no definitive diagnostic tests for blunt cardiac injury. Guidelines published by the Eastern Association for the Surgery of Trauma (EAST) include screening with ECG and serial troponin levels when blunt cardiac injury is suspected [26]. ECG-gated scans do not have a routine role in the workup of blunt cardiac injury; however, these may be helpful in cases where a diagnosis of acute myocardial infarction is also being considered. Patients with a new ECG abnormality or elevated troponin level are closely monitored (continuous ECG). If there is concern for hemodynamically significant blunt cardiac injury, a transthoracic echocardiography should be performed. (See 'Observation of blunt injury' below.)

SURGICAL MANAGEMENT

Damage control surgery — The goals of damage control surgery are to stop bleeding and then to limit contamination, such as from gastrointestinal tract injury. For patients with penetrating injuries to multiple body cavities, the surgeon is faced with the choice of where to begin. In the case of known pericardial tamponade on focused assessment with sonography for trauma (FAST) or imaging, decompression of the pericardium should take priority. By contrast, in patients with penetrating thoracoabdominal trauma, no demonstrated tamponade, and free intra-abdominal fluid, the surgeon should prioritize controlling abdominal hemorrhage. (See "Overview of damage control surgery and resuscitation in patients sustaining severe injury".)

Pericardial window — Pericardial fluid mandates exploration with a subxiphoid pericardial window [27]. Blood within the pericardial window generally mandates sternotomy and open exploration, particularly in the setting of hemodynamic instability. (See 'Chest exploration' below.)

However, if an effusion is present in a hemodynamically stable patient, practice is varied [28]. Some authors have advocated that if the pericardium clears and there is no active bleeding, and the patient is hemodynamically stable, a drain can be placed and the patient observed. A randomized trial from South Africa demonstrated that hemodynamically stable patients with hemopericardium, who are not bleeding, can safely be managed with pericardial drainage alone [29].

To perform subxiphoid pericardial window, an upper midline abdominal incision is made in the skin over the xiphoid process and extending at least 6 cm caudad (picture 1). Dissection is carried through the midline fascia but external to the peritoneum. The retrosternal space is then bluntly developed up to the diaphragm. The membranous portion of the diaphragm with the pericardium and heart behind it should be palpable. This is then grasped with long Allis clamps and elevated. The elevated diaphragm is opened using scissors or a #15 blade. The pericardium should be opened 2 cm to allow for inspection and any fluid or blood should be evacuated and the pericardium irrigated. A transdiaphragmatic approach may also be used at the time of an exploratory laparotomy.

Chest exploration — The urgency, approach, and technique for chest exploration depends on the hemodynamic status of the patient and mechanism of injury. The temporizing management of hemorrhage for patients in extremis, and initial measures for controlling cardiac injury, are reviewed separately. (See 'Approach to diagnosis and treatment' above and "Resuscitative thoracotomy: Technique".)

Once the need for surgical exploration has been determined (hemorrhage, fluid in the pericardial sac, tamponade), it is important to communicate the approach with the operating room to ensure that a sternal saw, bone wax, and appropriate sternal retractors are available. For hemodynamically unstable patients, preparation should also be made to perform concomitant exploratory laparotomy. The role of cardiopulmonary bypass is discussed below. (See 'Cardiopulmonary bypass' below.)

In the emergency setting, patients are positioned supine. The arms can be tucked at the sides if pericardial window and possible sternotomy will be the approach; however, this will limit performing a trap door and the patient will need to be repositioned if a thoracotomy incision is needed. Standard preoperative antibiotics should be administered.

Once the heart has been exposed, all surfaces should be examined. To view the posterior surface of the heart, it can be gently lifted from the pericardium and inspected. Elevation of the heart can result in inferior vena cava (IVC) kinking and reduced preload and can result in cardiac arrest. Clear communication with the anesthesiologist during cardiac manipulation is important. (See "Anesthesia for thoracic trauma in adults".)

There may not be any significant bleeding in the hypotensive or pulseless patient, but once the heart is repaired, the patient is resuscitated, and the circulation is restored, the divided tissues will bleed.

Left anterolateral thoracotomy — For patients in extremis (or pulseless), left anterolateral thoracotomy is the incision of choice for a cardiac injury. (See "Resuscitative thoracotomy: Technique".)

The incision is made in the fourth or fifth intercostal space (figure 8). After accessing the chest, the inferior pulmonary ligament is sharply incised and the lung retracted cephalad. This provides access to the mediastinum, and the pericardium will be visible with the phrenic nerve running over it. The pericardium is incised (figure 9 and picture 2) and opened anterior and parallel to the phrenic nerve (figure 6). This allows for the release of any tamponade and delivers the heart into the field. This provides access to the apex of the heart and anterior right and left ventricles. However, it is not possible to access the superior right ventricle or right atrium through this incision, and a clamshell extension may be necessary.

Clamshell thoracotomy — For patients in extremis with suspected injury to the upper right ventricle or atria, extension of a left anterolateral thoracotomy to a clamshell thoracotomy should be performed (figure 10). In more stable patients where there is time, a median sternotomy can be considered. (See 'Median sternotomy' below.)

The incision is extended over the sternum and into the contralateral intercostal space. The sternum is divided horizontally using a Lebsche knife or sternal saw, if available. The internal thoracic (internal mammary) arteries will need to be divided and ligated. Once the incision is completed, the rib cage can be retracted cephalad to expose the mediastinum. The pericardial incision can be extended to expose the entire anterior surface of the heart.

Median sternotomy — Median sternotomy is the incision of choice for anterior (precordial) injuries (figure 11). A median sternotomy provides excellent access to the anterior mediastinum. It also has the advantage, in the trauma setting, that it can be extended to a midline laparotomy or into the neck if the patient's injuries require it.

The skin incision is made in the midline chest from the sternal notch to the xiphoid process right down to the bone of the anterior table of the sternum. In the suprasternal notch, electrocautery can be used to divide the ligament over the strap muscles and allow access to the mediastinum. Using blunt dissection, the retrosternal plane is developed from both the xiphoid and the sternal notch. The sternum is divided from the sternal notch to the xiphoid, taking care to stay in the midline and avoiding excessively pulling upward on the sternal saw as this may cause it to bind, preventing a smooth cut. When ready to divide the sternum, the anesthesiologist should hold respirations and resume respirations once the sternum is divided.

A retractor is placed to spread the ribs, and the pleura are dissected off the chest wall (picture 3). If time allows, hemostasis from the bone edges can be obtained at this time. The anterior pericardium should be visible. The pericardium can then be opened with scissors from the diaphragm to the aortic root. Near the apex of the heart along the diaphragm, the pericardium can be "T'd" off to open it more widely [30]. Stay sutures can then be placed within the pericardium to hold this open and expose the anterior surface. Following cardiac repair, the pericardium should be closed using absorbable sutures and leaving a small area inferiorly to allow drainage.

In hemodynamically stable patients undergoing definitive cardiac repair, the sternum should be closed using wires or a cabling system. If the chest is closed, a mediastinal drain is placed. In the damage control setting, the sternotomy can be left open with temporary closure in the damage control setting.

Trap door extensions — A trap door extension (figure 12) (right or left) from a median sternotomy may be useful if there is suspected concomitant injury to the subclavian artery, or innominate artery. (See "Overview of blunt and penetrating thoracic vascular injury in adults" and "Surgical and endovascular techniques for aortic arch branch and upper extremity revascularization", section on 'Arterial exposure and control'.)

Cardiopulmonary bypass — Cardiopulmonary bypass (CPB) plays a limited role in hemodynamically unstable patients undergoing immediate surgery for cardiac injury or tamponade. For direct repair of most ventricular lacerations, bypass is not necessary. Unfortunately, most patients with injuries that would require CPB to repair do not survive [31]. However, in cases involving the coronary arteries, valve structures, or some posterior injuries, CPB may be necessary and requires a multidisciplinary approach. In the acute setting, if a controlled injury is discovered at sternotomy that cannot be accessed and CPB is available, cardiac surgery consultation is warranted. CPB may also be required for later repair in patients with valve injury or rupture, or injuries to the base of the heart identified on imaging.

Veno-arterial extracorporeal membrane oxygenation (ECMO) and extracorporeal cardiopulmonary resuscitation (E-CPR) have both been used in patients in arrest due to blunt or penetrating cardiac injury [32]. While some successes are reported, this is limited to small case series or reports [33].

It is important to remember that both CPB and ECMO require systemic anticoagulation and, therefore, should be undertaken only after considering the full scope of the traumatic injuries.

Definitive repair of cardiac injuries — Definitive cardiac repair is performed by suture repair of cardiac tissue using double-armed polypropylene suture on a cardiovascular (CV) needle.

For ventricular injuries, 3-0 interrupted horizontal mattress sutures are used (with or without pledgets, as needed). Finger occlusion can be used to control hemorrhage while sutures are placed and then tied down (figure 13). If the injury is too large for finger occlusion, a balloon catheter can be used to temporarily occlude the defect, but care must be taken not to further tear cardiac muscle tissue. Pledgets are commonly used for repair of ventricular injuries, but evidence supporting their use is indirect and extrapolated from elective repair [34,35]. Occasionally, larger cardiac injuries may require patch placement (eg, pericardium, Dacron) to decrease tension on repair.

Atrial injuries can be repaired with running 4-0 polypropylene suture or interrupted suture (with or without pledgets, as needed). If an atrial injury is too large for finger occlusion, a side biting vascular clamp may be used (figure 13).

Care must be taken not to ligate or damage cardiac vessels with sutures. For injuries near a coronary artery, a mattress suture can be placed deep to the artery to avoid its ligation. If such repair is completed, the patient should undergo immediate coronary angiography since the risk of angulation, restriction, and flow limitation is high.

Most coronary artery injuries warrant bypass grafting, excepting injury to the very distal coronary artery. Coronary bypass grafting for trauma can usually be accomplished without the use of cardiopulmonary bypass, unless ventricular function is markedly compromised [36]. (See 'Cardiopulmonary bypass' above.)

Following cardiac repair, a thorough exploration of the remainder of the mediastinum should be performed, including inspection of the pleural spaces, posterior pericardium, and the internal thoracic (internal mammary) arteries, which are often injured but may not be actively bleeding due to spasm.

Subsequent cardiac evaluation — Patients undergoing surgery for cardiac injury should undergo a postoperative echocardiography to look for complications such as wall motion abnormality, aortic hematoma, vascular dissection, pseudoaneurysm, arteriovenous fistula, chronic effusion, valve injury, or structural defect [37].

Cardiac evaluation may be undertaken in the operating room where resources are available to perform transesophageal echocardiogram, and there are no contraindications for its use. (See "Intraoperative rescue transesophageal echocardiography (TEE)" and "Intraoperative transesophageal echocardiography for noncardiac surgery".)

OBSERVATION OF BLUNT INJURY — Blunt cardiac injury rarely requires surgical intervention. Manifestations of blunt cardiac injury range from mild changes on electrocardiogram (ECG) to cardiac rupture.

Among patients with minor or isolated blunt cardiac injury, determining which patients require monitoring or additional treatment and those who can be discharged is not straightforward. Robust data on the evaluation and treatment of these patients are lacking, and much of the existing data are based on case series and retrospective data from higher-volume trauma centers. Nevertheless, in general, patients with isolated blunt injuries to the chest who are hemodynamically stable and have a normal ECG and normal troponin I can be safely discharged. (See "Initial evaluation and management of blunt cardiac injury", section on 'Management'.)

However, patients with blunt cardiac injury are often multiply injured. Admission to the intensive care unit (ICU) should be based on the patient's other injuries and hemodynamic condition. Hemodynamically stable patients with a new arrhythmia and other injuries that do not require monitoring may be appropriately monitored with telemetry outside an intensive care setting. Patients with ongoing hemodynamic abnormalities and blunt cardiac injury should be admitted to the ICU. (See 'Associated injuries' above.)

Supportive care — The management of patients with blunt cardiac injury is supportive and should focus on resuscitation and correction of hemodynamics [3]. Patients who are hemodynamically stable may not require any specific treatment.

For patients with blunt cardiac injury and persistent hemodynamic instability or dysrhythmias, echocardiography can be useful for identifying structural abnormalities like valve rupture or wall motion abnormality [23,26]. For patients with evidence of heart failure, inotropic or vasopressor support may be needed. Transthoracic echocardiography may be challenging in the multiply injured patient with other chest trauma. In these cases, transesophageal echocardiography should be considered [38].

Cardiology consultation should be obtained in patients with new-onset arrhythmia or concern for myocardial ischemia. Trauma-induced ischemia has been reported [39]. Myocardial ischemia should be treated as it would in the nontrauma setting; however, the risk of antithrombotic therapy must be assessed in context of other injuries. Patients with sudden decompensation should undergo immediate echocardiography to evaluate for tamponade or new structural changes.

Duration of observation period — There is no evidence-based duration for monitoring after blunt cardiac injury. This makes caring for the multiply injured patient with blunt cardiac injury challenging. One retrospective study suggested that 24 hours was sufficient for hemodynamically stable patients without other injuries [40]. However, delayed rupture following blunt injury has been reported [41,42].

Need for noncardiac surgery — The decision to proceed with other surgical procedures, such as orthopedic repair, should be determined on a case-by-case basis depending on the severity of blunt cardiac injury. In general, for patients without hemodynamic compromise or abnormality on echocardiography, it is reasonable to proceed with repair of other injuries.

MORBIDITY AND MORTALITY — Morbidity and mortality for blunt and penetrating cardiac injury has only been evaluated in case series or retrospective reviews, and mortality for those requiring surgery is high. In a review of the National Trauma Data Bank for blunt cardiac injury with rupture, overall mortality was 89 percent [43]. For patients who survived to reach the operating room, only 42 percent were alive at 24 hours. For penetrating injury, overall mortality was approximately 33 percent. These data likely underestimate overall mortality since they do not include patients who die at the scene of injury or before hospital arrival.

Surgical complications — Data on surgical complications for cardiac trauma are limited. In the immediate postoperative period, patients should be monitored for bleeding, or reaccumulation of pericardial fluid resulting in tamponade. Patients are at risk for pericarditis and postcardiac injury syndromes. (See "Post-cardiac injury syndromes".)

Complications may also include those similar to what is seen after elective cardiac surgery, including atrial fibrillation, surgical site infection, sternal dehiscence, and mediastinitis. (See "Postoperative complications among patients undergoing cardiac surgery".)

Deep sternal wound infections occur in 1 to 4 percent of all cardiac procedures. Risk factors for infection have been described for elective and emergent cardiac surgery, but these studies have excluded trauma. (See "Postoperative mediastinitis after cardiac surgery" and "Surgical management of sternal wound complications".)

Obesity, diabetes, chronic obstructive pulmonary disease (COPD), operative duration, reoperation, postoperative transfusion, and ligation of the internal mammary artery have all been shown to increase the risk of infection [44,45]. One single-center retrospective series demonstrated that an emergency sternotomy was an independent risk factor for infection [46]. Another large series demonstrated that the infection rate varied by type of operation [47]. A retrospective review of patients with postoperative computed tomography (CT) scan identified asymmetric sternal division as a risk factor for infection as well [48]. While none of these series address trauma directly, with the emergent nature of the procedure, presence of a foreign body, and the need for transfusion, it is reasonable to think that patients with penetrating trauma or emergency surgery for blunt cardiac injury would be at elevated risk for infection.

Functional outcomes — Overall, there are minimal data on long-term functional outcomes after cardiac injury. There are also insufficient data to know if there are any important differences between blunt and penetrating injury. While evidence is limited, survivors of cardiac injury can expect overall good cardiovascular outcomes and functional recovery [49,50]. (See "Initial evaluation and management of blunt cardiac injury", section on 'Outcomes'.)

In a retrospective study of 68 penetrating cardiac injuries with functional and echocardiographic follow-up on 21 survivors, 43 percent of patients had a pericardial effusion on echocardiography and 33 percent had a wall motion abnormality [50]. In every case, these resolved on follow-up echocardiography with only one patient having long-term echocardiographic changes due to a patch repair. All survivors also had improvement in their ejection fraction. Functionally, all patients were New York Heart Association class 1 except for one who had mild dyspnea on exertion.

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: General issues of trauma management in adults" and "Society guideline links: Thoracic trauma".)

SUMMARY AND RECOMMENDATIONS

●Traumatic cardiac injury – Traumatic cardiac injury can occur with blunt or penetrating trauma mechanisms. Prompt diagnosis and management is the key to good outcomes, and it is important for clinicians to maintain a high index of suspicion for cardiac injury. For penetrating injuries, any entry into the torso has the potential to cause a cardiac injury. Knowledge of the relationship of the heart relative to other structures is important for assessing the patient with possible cardiac injury. (See 'Clinical features' above and 'Anatomy and mechanism of injury' above.)

●Initial evaluation – The initial evaluation of the patient with suspected cardiac injury is based upon protocols from the Advanced Trauma Life Support (ATLS) program and includes trauma history and physical, initial imaging, and, possibly, electrocardiogram (ECG) and cardiac-specific serum troponin I. Depending on the clinical scenario, additional imaging (eg, focused assessment with sonography for trauma [FAST], computed tomography [CT] of the chest, echocardiography) may be warranted. (See 'Trauma evaluation' above.)

●Approach to the patient

•Hemodynamically unstable – For hemodynamically unstable patients with clinical features suspicious for cardiac injury (blunt or penetrating), the cardiac portion of the FAST exam should be obtained. Patients with positive cardiac findings on FAST should undergo pericardial window, typically in the operating room. It is important to note that patients with negative cardiac findings on FAST can still have significant cardiac injury, such as when blood is leaking directly into the chest cavity through a pericardial defect. (See 'Hemodynamically unstable' above and 'Pericardial window' above.)

•Hemodynamically stable – For hemodynamically stable patients, CT of the chest and/or abdomen is typically obtained. Pericardial effusion identified on CT should prompt pericardial window. (See 'Hemodynamically stable' above and 'Pericardial window' above.)

●Management

•Blood identified within the pericardial window generally mandates open chest exploration, but if there is no active bleeding following drainage and irrigation, placement of a drain and observation may be an option. The surgical approach to chest exploration depends on the hemodynamic status of the patient and mechanism of injury. (See 'Pericardial window' above and 'Chest exploration' above.)

•Most blunt cardiac injuries are mild, but mortality related to blunt cardiac rupture is high. Any abnormalities on electrocardiography or troponin I, which should be obtained in all patients suspected of having blunt cardiac injury, mandate a period of observation with cardiac monitoring. There is no evidence to guide the duration of observation. Among patients with blunt cardiac injury who are multiply injured, admission to an intensive care unit (ICU) setting should be based on hemodynamic condition and the severity of the other injuries. The decision to proceed with other surgical procedures should be determined on a case-by-case basis depending on the severity of blunt cardiac injury. (See 'Observation of blunt injury' above.)