Review Article Understanding traumatic blunt cardiac injury Ayman El-Menyar1,2, Hassan Al Thani1, Ahmad Zarour1, Rifat Latifi1,2 1Department of Surgery, Section of Trauma Surgery, Hamad Medical Corporation, 2Clinical Medicine, Weill Cornell Medical School, Qatar ABSTRACT Cardiac injuries are classified as blunt and penetrating injuries. In both the injuries, the major issue is missing the diagnosis and high mortality. Blunt cardiac injuries (BCI) are much more common than penetrating injuries. Aiming at a better understanding of BCI, we searched the literature from January 1847 to January 2012 by using MEDLINE and EMBASE search engines. Using the key word “Blunt Cardiac Injury,” we found 1814 articles; out of which 716 articles were relevant. Herein, we review the causes, diagnosis, and management of BCI. In conclusion, traumatic cardiac injury is a major challenge in critical trauma care, but the guidelines are lacking. A high index of suspicion, application of current diagnostic protocols, and prompt and appropriate management is mandatory. Received: 17-3-2012 Accepted: 29-6-2012 Key words: Blunt trauma, Blunt cardiac injury, Aortic injury INTRODUCTION echocardiographic analysis, 24 prospective studies, 20 retrospective studies, and 1 Cardiac injuries are classified as blunt meta-analysis. Herein, we review the causes, and penetrating injuries. In both the type diagnosis, and management of BCI. of injuries, the major issue is missing the diagnosis and high mortality. Blunt cardiac BLUNT CARDIAC INJURY injuries (BCIs) are much more common than penetrating injuries. Penetrating trauma is seen BCI ranges from asymptomatic myocardial in urban trauma centers and predominantly bruise to cardiac rupture and death.[2-4] BCIs due to stab wounds, gunshot wounds, or less most often occur during motor vehicle crashes commonly other iatrogenic instrumentation. (MVC). Based on the associated injuries, In penetrating injuries, up to 90% of victims intensity of chest injury, and complexity of die before reaching hospital and resuscitation injuries the incidence of BCI varies from is of limited benefit; therefore, survival 20 to 76%. Falls and crush injuries are less depends on rapid pre-hospital transport.[1] frequently associated with BCI. BCIs are characterized by patchy areas of muscle Access this article online Aiming at better understanding of BCI, we necrosis and hemorrhagic infiltrate(s), rupture Website: www.annals.in reviewed the literature from January 1847 of small vessels, and hemorrhage into the PMID: to January 2012 by utilizing MEDLINE interstitium and around the muscle fibers.[4] *** and EMBASE search engines. Using the Myocardial contusion has been reported in DOI: 10.4103/0971-9784.101875 key word “Blunt Cardiac Injury,” we found 60–100% autopsy series of patients with BCI.[3] Quick Response Code: 1814 articles; out of which 716 articles were relevant. Of the relevant articles, 559 were Commotio Cordis published in English language; there were 100 Commotio Cordis is a rare type of BCI in reviews, 135 case reports (some case reports which low-impact chest trauma causes sudden were followed by review of the literature), 22 cardiac arrest, usually occurs from being struck pediatric-related articles, 35 articles based on by a projectile during sports. Cardiac arrest Address for correspondence: Dr. Ayman El-Menyar, Weill Cornell Medical School, Clinical Medicine, Cardiologist and Clinical Research, Trauma Surgery, Hamad General Hospital, PO Box 3050, Doha, Qatar. E-mail: [email protected] Annals of Cardiac Anaesthesia Vol. 15:4 Oct-Dec-2012 287 El-Menyar, et al.: Traumatic blunt cardiac injury appears to stem from blow during a period of electrical Table 1: Summary of the mechanism of BCI vulnerability (10 to 30 ms before the peak of the T Direct impact Commtio cordis wave). A direct blow to the precordium accounts for a Myocardial contusion sizable number of cases. Patients involved in a MVC Rapid deceleration Aortic tear, Cardiac rupture with sudden deceleration, or who sustains significant Rapid deceleration or Compression Ruptured myocardium chest trauma or severe multiple trauma are at risk of Commotio Cordis.[5] and aortic valve insufficiency, respectively. [4] Other less common pathological findings in patients with Cardiac Rupture BCI include septal tears (Atrial septal defect: 7% Between 1847 and 1952, 13 cases of rupture of Ventricular septal defect : 4%) Coronary artery injury interventricular septum due to BCI were described. [6] and thrombosis (3%).[3] The mechanism of injury and factors necessary to produce rupture of the heart after blunt injury were Indirect cardiac injury reported between 1935 and 1938. A full chamber in early Even if the heart is not directly involved in the trauma, systole is more vulnerable if compressed over its outflow cardiac injury remains a possible concern. The stressful tract; the myocardial fibers may rupture at a point away impact of trauma may result in myocardial infarction from the area of direct contusion.[6] Between 1994 and secondary to acute thrombosis or severe coronary 2009, several other mechanisms of blunt traumatic spasm (with patent coronary arteries). Also, significant cardiac rupture have been reported, and include arrhythmia and stress-induced cardiomyopathy precordial impaction with cardiac squeeze between the (Takotsubo cardiomyopathy) have been reported in many sternum and spine and rapid deceleration resulting in cases secondary to the fear and stress of trauma. [13,14] disruption of the atria from their connections to the vena cava and pulmonary veins.[7,8] Minimal force is required Blunt aortic injury for a deceleration type contusion injury that may occur Blunt aortic injury (BAI) is a common cause of traumatic at a relatively low velocity of 20 miles/h.[9,10] pericardial tamponade. It should be considered in patients with a deceleration or acceleration injury with Cardiac rupture is the most devastating BCI and the signs suggestive of mediastinal injury. [15] BAI is the incidence of the site of injury varies in various autopsy second most common cause of death in blunt trauma series (Cardiac wall: 0.16–2%, Right ventricle: 19–32%, patients.[16] Most patients with BAI die at the place of Right atrium: 10–15%, Left ventricle: 5–44%, and Left injury, and only 13–15% reach alive to hospitals.[16,17] atrium: 1–7%).[3,11] The most common mechanism of BAI is motor vehicle crash, pedestrian injury, and falls.[15,18] Forces involved in BCI Include compression of the heart between the spine and Cardiac herniation sternum, abrupt pressure fluctuations in the chest and It is a potentially fatal complication of BCI and abdomen, shearing from rapid deceleration and blast reported in 0.4% of severe blunt trauma. [19,20] Cardiac injury, and fragments from rib fractures causing injury herniation frequently results in early death, and thus to the heart. Table 1 summarizes the mechanism of BCI. the diagnosis is mainly based on autopsy findings.[20] In a series of BCI, patients who survived to hospital The right heart is most commonly injured.[12] This is probably due to its position closest to the anterior chest admission had favorable outcome with survival rate of [21] wall. High-pressure ventricular injuries appear to be as 36.4-42.9%. The high in-hospital mortality rate (up common as low-pressure atrial injuries, but findings to 64%) is probably a reflection of not only pericardial may vary based on the type of study (i.e. clinical or rupture and cardiac herniation but also of the associated autopsy). In autopsy series, ventricular injuries are the injuries.[19,22] dominant findings. Aortic and mitral valve damage has been reported as a complication of blunt chest injury. [4] Pericardial effusion The incidence of tricuspid or mitral valvular injury is Definite diagnosis of traumatic pericardial effusions is around 5% which include chordal rupture, anterior not easy even with Focused Assessment with Sonography papillary muscle and/ or leaflet tear.[3,4] Ismailov et al. for Trauma (FAST), repeat cardiac echocardiography, reported that BCI is independently associated with and computed tomography (CT). [23] Patients who survive 11 and 3 times increase in the incidences of tricuspid to the hospital usually have minor tears in the low- 288 Annals of Cardiac Anaesthesia Vol. 15:4 Oct-Dec-2012 El-Menyar, et al.: Traumatic blunt cardiac injury pressure chamber with a blood clot that temporarily significant BCI are usually present at the time of stops the bleeding or have decompression of blood admission or occasionally within 24 h. [3,34] However, into the pleural cavity because of a pleuropericardial it can be difficult to determine whether the ECG defect.[23] Compared with penetrating chest injuries, abnormality is a primary event (e.g. an acute coronary cardiac injury is more easily neglected in blunt trauma, syndrome (ACS) that preceded trauma), a direct especially when associated with head or abdominal result of cardiac injury, or a problem brought on by injury.[23,24] Huang et al. reported that 87.1% of traumatic the physiologic stress of severe trauma.[2,34] Several pericardial effusions were due to blunt trauma and studies concluded that in hemodynamically stable 51.7% were associated with cardiac injury or rupture.[23] young patients, normal ECG rules out the need for further evaluation to detect BCI. [3,35] Patients with Associated injuries unexplained tachycardia that persists over several In BCI, the most common associated injuries are: hours despite adequate fluid resuscitation and pain rib fractures (18–69%), lung contusion (6–58%), flail control, or with a new bundle branch block, or with chest (3–38%), sternal fracture (0–60%), head injury significant arrhythmia, should be admitted for rhythm (20–73%), and abdominal solid organ injury (5–43%).[3] monitoring and possible echocardiographic study. Life- threatening ventricular arrhythmias were reported in Delayed complications up to 16% of patients with BCI.[4] A 24 h monitoring Pericardial, myocardial or valvular injuries may present with ECG telemetry is required if a patient suspected of late after trauma.