Myocardial contusion: emergency investigation and diagnosis

Cardiac contusions in the acute care setting: Historical background, evaluation and management

INTRODUCTION

Albeit described since 1763, cardiac contusions is still an under-recognised clinical condition in the acute care setting. This evidence-based review aims to provide an overview of the topic by focusing on etiopathogenesis, classification and clinical presentation of patients with cardiac contusions, as well as on the diagnostic work-up and therapy options available for this subset population in the acute care setting.

METHODS

A targeted research strategy was performed using PubMed, MEDLINE, Embase and Cochrane Central databases up to June 2022. The literature search was conducted using the following keywords (in Title and/or Abstract): ("cardiac" OR "heart" OR "myocardial") AND ("contusion"). All available high-quality resources written in English and containing information on epidemiology, etiopathogenesis, clinical findings, diagnosis and management of cardiac contusions were included in our research.

RESULTS

Biochemical samples of cardiac troponins together with a 12‑lead ECG appear to be sufficient screening tools in hemodynamically stable subjects, while cardiac ultrasound provides a further diagnostic clue for patients with hemodynamic instability or those more likely to have a significant cardiac contusion.

CONCLUSIONS

The management of patients with suspected cardiac contusion remains a challenge in clinical practice. For this kind of patients a comprehensive diagnostic approach and a prompt emergency response are required, taking into consideration the degree of severity and clinical impairment of associated traumatic injuries.

Development and Validation of Indicators for Population Injury Surveillance in Hong Kong: Development and Usability Study

BACKGROUND

Injury is an increasingly pressing global health issue. An effective surveillance system is required to monitor the trends and burden of injuries.

OBJECTIVE

This study aimed to identify a set of valid and context-specific injury indicators to facilitate the establishment of an injury surveillance program in Hong Kong.

METHODS

This development of indicators adopted a multiphased modified Delphi research design. A literature search was conducted on academic databases using injury-related search terms in various combinations. A list of potential indicators was sent to a panel of experts from various backgrounds to rate the validity and context-specificity of these indicators. Local hospital data on the selected core indicators were used to examine their applicability in the context of Hong Kong.

RESULTS

We reviewed 142 articles and identified 55 indicators, which were classified into 4 domains. On the basis of the ratings by the expert panel, 13 indicators were selected as core indicators because of their good validity and high relevance to the local context. Among these indicators, 10 were from the construct of health care service use, and 3 were from the construct of postdischarge outcomes. Regression analyses of local hospitalization data showed that the Hong Kong Safe Community certification status had no association with 5 core indicators (admission to intensive care unit, mortality rate, length of intensive care unit stay, need for a rehabilitation facility, and long-term behavioral and emotional outcomes), negative associations with 4 core indicators (operative intervention, infection rate, length of hospitalization, and disability-adjusted life years), and positive associations with the remaining 4 core indicators (attendance to accident and emergency department, discharge rate, suicide rate, and hospitalization rate after attending the accident and emergency department). These results confirmed the validity of the selected core indicators for the quantification of injury burden and evaluation of injury-related services, although some indicators may better measure the consequences of severe injuries.

CONCLUSIONS

This study developed a set of injury outcome indicators that would be useful for monitoring injury trends and burdens in Hong Kong.

A deep learning-based system capable of detecting pneumothorax via electrocardiogram

PURPOSE

To determine if an electrocardiogram-based artificial intelligence system can identify pneumothorax prior to radiological examination.

METHODS

This is a single-center, retrospective, electrocardiogram-based artificial intelligence (AI) system study that included 107 ECGs from 98 pneumothorax patients. Seven patients received needle decompression due to tension pneumothorax, and the others received thoracostomy due to instability (respiratory rate ≥ 24 breaths/min; heart rate, < 60 beats/min or > 120 beats/min; hypotension; room air O₂ saturation, < 90%; and patient could not speak in whole sentences between breaths). Traumatic pneumothorax and bilateral pneumothorax were excluded. The ECGs of 132,127 patients presenting to the emergency department without pneumothorax were used as the control group. The development cohort included approximately 80% of the ECGs for training the deep learning model (DLM), and the other 20% of ECGs were used to validate the performance. A human-machine competition involving three physicians was conducted to assess the model performance.

RESULTS

The areas under the receiver operating characteristic (ROC) curves (AUCs) of the DLM in the validation cohort and competition set were 0.947 and 0.957, respectively. The sensitivity and specificity of our DLM were 94.7% and 88.1% in the validation cohort, respectively, which were significantly higher than those of all physicians. Our DLM could also recognize the location of pneumothorax with 100% accuracy. Lead-specific analysis showed that lead I ECG made a major contribution, achieving an AUC of 0.930 (94.7% sensitivity, 86.0% specificity). The inclusion of the patient characteristics allowed our AI system to achieve an AUC of 0.994.

CONCLUSION

The present AI system may assist the medical system in the early identification of pneumothorax through 12-lead ECG, and it performs as well with lead I ECG alone as with 12-lead ECG.

Traumatic tricuspid regurgitation following equine related blunt chest trauma and review of the literature

Myocardial injury following blunt chest trauma may be difficult to detect. We advocate for cardiac screening in such scenarios. Observation versus intervention should be based on symptoms and the degree of intracardiac disease.

A Fatal Case of Cardiac Contusion After Blunt Chest Injury

ABSTRACT

In this article, we report the autopsy findings of a 48-year-old man who sustained blunt trauma to the thorax. A medical record review revealed no history of cardiac disease. He presented to the hospital with a computed tomography-verified fracture of the left fourth and fifth ribs, and pulmonary and cardiac contusion. He was released from the hospital in stable condition at his own request 7 days later. Because of sudden deterioration, he was readmitted to the hospital the next day. Electrocardiogram detected cardiac arrhythmia on the 15th day after chest trauma. Electrocardiography detected pericardial effusion and severe mitral insufficiency resulting in left ventricular failure. Death was attributed to diffuse alveolar damage-complicating pneumonia due to cardiac contusion with mitral insufficiency occurring 25 days after hospital admission. Internal examination revealed diffuse fibrinous pericarditis, left atrial tear right above the anterior mitral valve leaflet with intrapericardial granulation tissue, and no sign of myocardial damage. Immunohistochemistry showed significantly more CD68-positive macrophages within tissue taken from the heart, a finding indicative of previous atrial and ventricular myocardial contusion. This case report demonstrates that routine hematoxylin and eosin staining may not always reveal significant myocardial damage.

The Association of Early Electrocardiographic Abnormalities With Brain Injury Severity and Outcome in Severe Traumatic Brain Injury

The aim of this study was to evaluate the frequency of electrocardiographic (ECG) abnormalities in the acute phase of severe traumatic brain injury (TBI) and the association with brain injury severity and outcome. In contrast to neurovascular diseases, sparse information is available on this issue. Data of adult patients with severe TBI admitted to the Intensive Care Unit (ICU) for intracranial pressure monitoring of a level-1 trauma center from 2002 till 2018 were analyzed. Patients with a cardiac history were excluded. An ECG recording was obtained within 24 h after ICU admission. Admission brain computerized tomography (CT)-scans were categorized by Marshall-criteria (diffuse vs. mass lesions) and for location of traumatic lesions. CT-characteristics and maximum Therapy Intensity Level (TILmax) were used as indicators for brain injury severity. We analyzed data of 198 patients, mean (SD) age of 40 ± 19 years, median GCS score 3 [interquartile range (IQR) 3–6], and 105 patients (53%) had thoracic injury. In-hospital mortality was 30%, with sudden death by cardiac arrest in four patients. The incidence of ECG abnormalities was 88% comprising ventricular repolarization disorders (57%) mostly with ST-segment abnormalities, conduction disorders (45%) mostly with QTc-prolongation, and arrhythmias (38%) mostly of supraventricular origin. More cardiac arrhythmias were observed with increased grading of diffuse brain injury (p = 0.042) or in patients treated with hyperosmolar therapy (TILmax) (65%, p = 0.022). No association was found between ECG abnormalities and location of brain lesions nor with thoracic injury. Multivariate analysis with baseline outcome predictors showed that cardiac arrhythmias were not independently associated with in-hospital mortality (p = 0.097). Only hypotension (p = 0.029) and diffuse brain injury (p = 0.017) were associated with in-hospital mortality. In conclusion, a high incidence of ECG abnormalities was observed in patients with severe TBI in the acute phase after injury. No association between ECG abnormalities and location of brain lesions or presence of thoracic injury was present. Cardiac arrhythmias were indicative for brain injury severity but not independently associated with in-hospital mortality. Therefore, our findings likely suggest that ECG abnormalities should be considered as cardiac mimicry representing the secondary effect of traumatic brain injury allowing for a more rationale use of neuroprotective measures.

Diagnostic approach for myocardial contusion: a retrospective evaluation of patient data and review of the literature

Purpose

Myocardial contusion can be a life-threatening condition in patients who sustained blunt thoracic trauma. The diagnostic approach remains a subject of debate. The aim of this study was to determine the sensitivity and specificity of echocardiography, electrocardiography, troponins T and I (TnT and TnI), and creatine kinase muscle/brain (CK-MB) for identifying patients with a myocardial contusion following blunt thoracic trauma.

Methods

Sensitivity and specificity were first determined in a 10-year retrospective cohort study and second by a systematic literature review with meta-analysis.

Results

Of the 117 patients in the retrospective study, 44 (38%) were considered positive for myocardial contusion. Chest X-ray, chest CT scan, electrocardiograph, and echocardiography had poor sensitivity (< 15%) but good specificity (≥ 90%). Sensitivity to cardiac biomarkers measured at presentation ranged from 59% for TnT to 77% for hs-TnT, specificity ranged from 63% for CK-MB to 100% for TnT. The systematic literature review yielded 28 studies, with 14.5% out of 7242 patients reported as positive for myocardial contusion. The pooled sensitivity of electrocardiography, troponin I, and CK-MB was between 62 and 71%, versus only 45% for echocardiography and 38% for troponin T. The pooled specificity ranged from 63% for CK-MB to 85% for troponin T and 88% for echocardiography.

Conclusion

The best diagnostic approach for myocardial contusion is a combination of electrocardiography and measurement of cardiac biomarkers. If abnormalities are found, telemonitoring is necessary for the early detection of life-threatening arrhythmias. Chest X-ray and CT scan may show other thoracic injuries but provide no information on myocardial contusion.

Electronic supplementary material

The online version of this article (10.1007/s00068-020-01305-4) contains supplementary material, which is available to authorized users.

Traumatic blunt cardiac injuries: An updated narrative review

Blunt cardiac injury (BCI) is defined as injuries sustained due to blunt trauma to the heart, and it remains unchanged for long time. The spectrum of BCI ranges from a minor "bruise" to specific postcontusion cardiac conditions such as free-wall rupture. This is a narrative review provides a continued and updates details regarding BCIs from 2008 to 2017. For this purpose, a narrative review of literature was conducted using appropriate database for retrieval of articles through systematic search methodology. Autopsy-based studies are very limited. It can be concluded that regardless of the variability in the spectrum of modalities and medical/surgical resources, BCIs diagnosis and management remain a puzzle and needs further prospective studies.

Interaction of the hydrogen sulfide system with the oxytocin system in the injured mouse heart

Background

Both the hydrogen sulfide/cystathionine-γ-lyase (H₂S/CSE) and oxytocin/oxytocin receptor (OT/OTR) systems have been reported to be cardioprotective. H₂S can stimulate OT release, thereby affecting blood volume and pressure regulation. Systemic hyper-inflammation after blunt chest trauma is enhanced in cigarette smoke (CS)-exposed CSE^−/− mice compared to wildtype (WT). CS increases myometrial OTR expression, but to this point, no data are available on the effects CS exposure on the cardiac OT/OTR system. Since a contusion of the thorax (Txt) can cause myocardial injury, the aim of this post hoc study was to investigate the effects of CSE^−/− and exogenous administration of GYY4137 (a slow release H₂S releasing compound) on OTR expression in the heart, after acute on chronic disease, of CS exposed mice undergoing Txt.

Methods

This study is a post hoc analysis of material obtained in wild type (WT) homozygous CSE^−/− mice after 2-3 weeks of CS exposure and subsequent anesthesia, blast wave-induced TxT, and surgical instrumentation for mechanical ventilation (MV) and hemodynamic monitoring. CSE^−/− animals received a 50 μg/g GYY4137-bolus after TxT. After 4h of MV, animals were exsanguinated and organs were harvested. The heart was cut transversally, formalin-fixed, and paraffin-embedded. Immunohistochemistry for OTR, arginine-vasopressin-receptor (AVPR), and vascular endothelial growth factor (VEGF) was performed with naïve animals as native controls.

Results

CSE^−/− was associated with hypertension and lower blood glucose levels, partially and significantly restored by GYY4137 treatment, respectively. Myocardial OTR expression was reduced upon injury, and this was aggravated in CSE^−/−. Exogenous H₂S administration restored myocardial protein expression to WT levels.

Conclusions

This study suggests that cardiac CSE regulates cardiac OTR expression, and this effect might play a role in the regulation of cardiovascular function.

Role of speckle tracking imaging in the assessment of myocardial regional ventricular function in experimental blunt cardiac injury

PURPOSE

To evaluate the usefulness and information collecting ability of speckle tracking imaging techniques in the assessment of myocardial regional ventricular contractility in a rabbit model with blunt cardiac injury.

METHODS

Fifteen healthy New Zealand rabbits weighing (2.70 ±0.28) kg were anesthetized (3% pentobarbital sodium/i.v) and impacted using the BIM-II biological impact machine to induce myocardial contusion (MC). Hemodynamic parameters, such as heart rate, systolic pressure, mean arterial pressure, diastolic pressure and central venous pressure, were determined before and after MC. Further, parameters reflecting left ventricular functions, such as left ventricular end systolic pressure, left ventricular end diastolic pressure, isovolumic pressure (IP) and the maximal increasing/decreasing rate of left intraventricular pressure (±dp/dtmax), were also determined before and after MC. Left ventricular functions were determined either by two dimensional transthoracic echocardiography or by speckle tracking imaging for segmental abnormal ventricular wall motions.

RESULTS

Heart rate, systolic pressure, diastolic pressure and mean arterial pressure decreased significantly but transiently, while central venous pressure markedly increased after MC. In contrast to significant changes in diastolic functions, there was no significant change in cardiac systolic functions after MC. The speckle tracking imaging demonstrated that strain values of different myocardial segment significantly decreased post impact, and that of the ventricular segment decreased from segment to segment.

CONCLUSION

Speckle tracking imaging is useful and informative to assess myocardial regional dysfunctions post MC.

Simultaneous "traumatic Gerbode" and aortic rupture due to blunt chest trauma

The Gerbode defect is characterized by a perimembranous ventricular septal defect between the left ventricle and the right atrium. This intracardiac shunt is a congenital defect but may be iatrogenic after valve surgery or atrioventricular node ablation, may be the result of endocarditis or may be traumatic. It is really rarely encountered as sequelae of non-penetrating heart trauma, and their clinical manifestations may often be unrecognized in the multi-injured patient. However, they are serious complications, and their diagnostic approach is not always feasible. We hereby present a case of a young man with the left ventricle to the right atrium communication after blunt thoracic trauma due to a car accident and concomitant rupture of the thoracic aorta. We present also the case and the ways of treatment according to the international bibliography.

Treatment Goals during Care of Adult Donors That Can Influence Outcomes of Heart Transplantation

Myocardial dysfunction during care of adult donors can result from injury occurring before hospital admission or during the progression of brain death. Few evidence-based data correlate specific hemodynamic goals during donor care with outcomes of heart transplantation, although many recommendations exist. Spontaneous reversal of early heart damage or correction of poor cardiac performance can yield outcomes equivalent to outcomes in recipients who had ideal donors. Hemodynamic goals developed in the operating room can be applied in intensive care to improve outcomes of transplantation. These goals include maintenance of mean arterial pressure greater than 60 mm Hg, central venous pressure less than 12 mm Hg, cardiac output greater than 3.8 L/min, cardiac index greater than 2.1, and systemic vascular resistance between 800 and 1200 dyne · sec · cm−5. The ejection fraction and other echocardiographic data also provide helpful guidance when determining whether a heart is suitable for transplantation and during therapy. Titration of cardiovascular variables often requires invasive monitoring to ensure that cardiac preload, afterload, and contractility are optimal.

Blunt Cardiac Injury in the Severely Injured - A Retrospective Multicentre Study

Background

Blunt cardiac injury is a rare trauma entity. Here, we sought to evaluate the relevance and prognostic significance of blunt cardiac injury in severely injured patients.

Methods

In a retrospective multicentre study, using data collected from 47,580 patients enrolled to TraumaRegister DGU (1993-2009), characteristics of trauma, prehospital / hospital trauma management, and outcome analysis were correlated to the severity of blunt cardiac injury. The severity of cardiac injury was assessed according to the abbreviated injury score (AIS score 1-6), the revised injury severity score (RISC) allowed comparison of expected outcome with injury severity-dependent outcome. N = 1.090 had blunt cardiac trauma (AIS 1-6) (2.3% of patients).

Results

Predictors of blunt cardiac injury could be identified. Sternal fractures indicate a high risk of the presence of blunt cardiac injury (AIS 0 [control]: 3.0%; AIS 1: 19.3%; AIS 2-6: 19.1%). The overall mortality rate was 13.9%, minor cardiac injury (AIS 1) and severe cardiac injury (AIS 2-6) are associated with higher rates. Severe blunt cardiac injury (AIS 4 and AIS 5-6) is associated with a higher mortality (OR 2.79 and 4.89, respectively) as compared to the predicted average mortality (OR 2.49) of the study collective.

Conclusion

Multiple injured patients with blunt cardiac trauma are at high risk to be underestimated. Careful evaluation of trauma patients is able to predict the presence of blunt cardiac injury. The severity of blunt cardiac injury needs to be stratified according to the AIS score, as the patients’ outcome is dependent on the severity of cardiac injury.

N-terminal pro-B-type natriuretic peptide as a marker of blunt cardiac contusion in trauma

Cardiac contusion is usually caused by blunt chest trauma and, although it is potentially a life-threatening condition, the diagnosis of a myocardial contusion is difficult because of non-specific symptoms and the lack of an ideal test to detect myocardial damage. Cardiac enzymes, such as creatine kinase (CK), creatine kinase MB fraction (CK-MB), cardiac troponin I (cTn-I), and cardiac troponin T (cTn-T) were used in previous studies to demonstrate the blunt cardiac contusion (BCC). Each of these diagnostic tests alone is not effective for diagnosis of BCC. The aim of this study was to investigate the serum heart-type fatty acid binding protein (h-FABP), N-terminal pro-B-type natriuretic peptide (NT-proBNP), CK, CK-MB, and cTn-I levels as a marker of BCC in blunt chest trauma in rats. The eighteen Wistar albino rats were randomly allocated to two groups; group I (control) (n=8) and group II (blunt chest trauma) (n=10). Isolated BCC was induced by the method described by Raghavendran et al. (2005). All rats were observed in their cages and blood samples were collected after five hours of trauma for the analysis of serum h-FABP, NT-pro BNP, CK, CK-MB, and cTn-I levels. The mean serum NT-pro BNP was significantly different between group I and II (10.3 ± 2.10 ng/L versus 15.4 ± 3.68 ng/L, respectively; P=0.0001). NT-pro BNP level >13 ng/ml had a sensitivity of 87.5%, a specificity of 70%, a positive predictive value of 70%, and a negative predictive value of 87.5% for predicting blunt chest trauma (area under curve was 0.794 and P=0.037). There was no significant difference between two groups in serum h-FABP, CK, CK-MB and c Tn-I levels. A relation between NT-Pro BNP and BCC was shown in this study. Serum NT-proBNP levels significantly increased with BCC after 5 hours of the blunt chest trauma. The use of NT-proBNP as an adjunct to other diagnostic tests, such as troponins, electrocardiography (ECG), chest x-ray and echocardiogram may be beneficial for diagnosis of BCC.

Dual-source computed tomography may define cardiac contusion in patients with blunt chest trauma in ED

We report a 20-year-old woman with blunt chest trauma because of a motor vehicle injury who has traumatic asphyxia and hypotension. The diagnosis of blunt cardiac injury was put by using dual-energy computed tomography in the emergency department because other laboratory and imaging modalities were useless. After hospitalization in intensive care unit, she was treated with supportive and antiedema therapy. The patient was extubated on the fifth day and discharged on the ninth day without any sequel. Coexistence of traumatic asphyxia with blunt cardiac injury is rare. Several imaging techniques such as transthoracic and transesophageal echocardiography, contrast-enhanced multislice thorax computed tomography or initial electrocardiogram, and troponin I levels are used to detect the myocardial damage, but diagnostic capability is low. Dual-energy computed tomography is a promising new technology with the ability of defining blunt cardiac injuries and may have an indication in the emergency setting in patients with hemodynamic instability to rule in traumatic cardiac complications especially when electrocardiogram and transthoracic echocardiography are useless in the emergency department.

A Late Presentation of Dynamic ECG Conduction Abnormalities following Blunt Chest Injury

Cardiac abnormalities following blunt chest trauma can range from minor ST changes to arrhythmias, cardiac rupture, cardiogenic shock and death. A normal electrocardiogram (ECG) on presentation does not guarantee the absence of myocardial injury, and with no gold standard test to detect the condition, myocardial contusion is often identified only at autopsy. We describe the late presentation of evolving and dynamic conduction abnormalities on the ECG, including a sinusoidal conduction pattern, in a young trauma patient. This sequence of conduction abnormalities has not previously been observed and we discuss the potential explanations.

Tricuspid valve chordal rupture due to airbag injury and review of pathophysiological mechanisms

Blunt trauma to the chest is associated with significant morbidity and mortality. The latter is usually due to an aortic transection, whereas the former is related to myocardial contusion, cardiac valve injury, coronary artery disruption and intracardiac shunts due to the formation of septal defects. The main mechanisms causing these injuries are due to the sudden deceleration force and compression within the chest cavity. Moreover, there is also the sudden increase in intravascular pressure due to a mechanical compression effect and a hormonal adrenergic surge during the event. We report a case of a tricuspid valve injury caused by the deployment of the airbag during a high-speed impact car accident and the subsequent damage to the tricuspid valve chordal mechanism. The patient's management and the pathophysiological mechanisms involved in the injury are reviewed.

Role of imaging in penetrating and blunt traumatic injury to the heart

Cardiac injury due to blunt or penetrating chest trauma is common and is associated with significant morbidity and mortality. Understanding the mechanisms, types, and complications of cardiac injuries and the roles of various imaging modalities in characterizing them is important for appropriate diagnosis and treatment. These injuries have not been well documented at imaging, but there are now fast and accurate methods for evaluating the heart and associated mediastinal structures. The authors review the broad spectrum of injuries that can result from blunt or penetrating trauma to the chest, as well as the imaging modalities commonly used in the acute trauma setting for evaluation of the heart and mediastinal structures. A pictorial review of both common and, to date, rarely documented cardiac injuries imaged with a variety of modalities is also presented. While many imaging modalities are available, the authors demonstrate the value of multidetector computed tomography (CT) for the initial evaluation of patients with blunt or penetrating chest trauma. With the advent of multidetector CT, imaging of cardiac injury has increased and accurate identification of these rare but potentially lethal injuries has become paramount for improving survival. Selection of the most appropriate modality for evaluation and recognition of the imaging findings in cardiac injuries in the acute trauma setting is important to expedite treatment and improve survival.

Battlefield applications for handheld ultrasound

Combat medical care provides unique challenges and opportunities for military medical teams. The austerity of the environment severely limits access to many diagnostic and therapeutic tools. Because of their compact size, handheld ultrasound (US) machines are increasingly being used in these constrained environments. A growing body of literature documents the diagnostic utility of handheld US for trauma encountered in the battlefield. Furthermore, US guidance may assist in the performance of some procedures performed in battlefield medical care. This review will provide an overview of the history, current status, limitations and potential future of US utility for the battlefield.

Cardiac changes after simulated behind armor blunt trauma or impact of nonlethal kinetic projectile ammunition

BACKGROUND

Cardiac-related injuries caused by blunt chest trauma remain a severe problem. The aim of this study was to investigate pathophysiological changes in the heart that might arise after behind armor blunt trauma or impacts of nonlethal projectiles.

METHODS

Sixteen pigs were shot directly at the sternum with "Sponge Round eXact I Mpact" (nonlethal ammunition; diameter 40 mm and weight 28 g) or hard-plastic ammunition (diameter 65 mm and weight 58 g) to simulate behind armor blunt trauma. To evaluate the influence of the shot location, seven additional pigs where exposed to an oblique heart shot. Physiologic parameters, electrocardiography, echocardiogram, the biochemical marker troponin I (TnI), and myocardial injuries were analyzed.

RESULTS

Nonlethal kinetic projectiles (101-108 m/s; 143-163 J) did not cause significant pathophysiological changes. Five of 18 pigs shot with 65-mm plastic projectiles (99-133 m/s; 284-513 J) to the front or side of the thorax died directly after the shot. No major physiologic changes could be observed in surviving animals. Animals shot with an oblique heart shot (99-106 m/s; 284-326 J) demonstrated a small, but significant decrease in saturation. Energy levels over 300 J caused increased TnI and myocardial damages in most of the pigs.

CONCLUSION

This study indicates that nonlethal kinetic projectiles "eXact iMpact" does not cause heart-related damage under the examined conditions. On impact, sudden heart arrest may occur independently from the cardiac's electrical cycle. The cardiac enzyme, TnI, can be used as a reliable diagnostic marker to detect heart tissue damages after blunt chest trauma.

Dobutamine stress echocardiography assessment of myocardial contusion due to blunt impact in dogs

We sought to investigate the role of two-dimensional stress echocardiography in the early assessment of myocardial contusion. For this purpose, 12 dogs, weighing 11.36 ± 1.50 kg, were selected and the myocardial contusion was experimentally induced. Two-dimensional dobutamine stress echocardiography (DSE) was used to detect abnormal myocardial motions segments at time phases of baseline and 0.5, 2, 4, and 8 h post-wounding. Finally, the above results were compared with pathological findings. The data show that after the dogs were induced to have severe myocardial contusion, 122 segments were found with abnormal myocardial wall motions at 0.5 h post-wounding, 133 segments at 2 h post-wounding, and 142 segments, each, at 4 h and 8 h post-wounding. The wall motion score (WMS) and wall motion score index (WMSI) increased (P < 0.001) as compared with the pre-impaction values. Considering the left ventricular axis view as the standard section, in the 60 segments examined by echocardiography, 54 segments were found to have wall motion abnormalities. Comparing with the results of pathological TTC staining, the sensitivity and specificity were found to be 100 and 66.6%, respectively. It was, therefore, concluded that two-dimensional DSE was a valuable technique in the early diagnosis of myocardial contusion due to its better sensitivity and specificity.

Blunt cardiac injury in trauma patients with thoracic aortic injury

Trauma patients with thoracic aortic injury (TAI) suffer blunt cardiac injury (BCI) at variable frequencies. This investigation aimed to determine the frequency of BCI in trauma patients with TAI and compare with those without TAI. All trauma patients with TAI who had admission electrocardiography (ECG) and serum creatine kinase-MB (CK-MB) from January 1999 to May 2009 were included as a study group at a level I trauma center. BCI was diagnosed if there was a positive ECG with either an elevated CK-MB or abnormal echocardiography. There were 26 patients (19 men, mean age 45.1 years, mean ISS 34.4) in the study group; 20 had evidence of BCI. Of 52 patients in the control group (38 men, mean age 46.9 years, mean ISS 38.7), eighteen had evidence of BCI. There was a significantly higher rate of BCI in trauma patients with TAI versus those without TAI (77% versus 35%, P < 0.001).

Challenges in the diagnosis of blunt cardiac injuries

INTRODUCTION

Blunt thoracic injuries (BTIs) are directly responsible for 20-25% of all deaths, worldwide. Involvement of heart in BTIs is largely underestimated and ignored, but reasonable estimate would be around 15%. This study was planned to emphasize on clinical-presentation and diagnosis of blunt cardiac injuries (BCIs).

RESULTS

Clinical presentation of BCIs, varied from mild chest discomfort to haemodynamic shock secondary to rapid exsanguinations. Non-specific presentation with associated injuries diverts physician's attention and delayed appearance of clinical features makes diagnosis further difficult. Cardiac markers and ECG are not specific, but high sensitivity of 100% could be reached using combination of elevated cardiactroponin levels and alterations in ECG. Transoesophageal or transthoracic echocardiography, angiography, intravascular ultrasound and nuclear scan have proven to detect cardiac injuries in BTIs, but lack specificity.

CONCLUSION

Patients with suspicious-ECG finding need cardiac-monitoring for at least 24 hours. Haemodynamically stable young (<55 years) subjects, without underlying cardiac diseases and with normal-ECG and cardiac marker, could be discharged safely.

The complete array of electrocardiogram abnormalities secondary to myocardial contusion in a single case

Myocardial contusion is a complication of blunt thoracic injuries. Transthoracic echocardiography and electrocardiography (ECG) monitoring are important in suspected cases. We report a 54-year-old man, who sustained a number of injuries including blunt chest injury as a consequence of a road traffic accident. Electrocardiography monitoring over a 48 h period demonstrated sequential degrees of conduction system block coupled with a temporary cardio-version from persistent atrial fibrillation to sinus rhythm, suggesting coincident pulmonary vein contusion.

Cardiac contusion: Ending myocardial confusion in this capricious syndrome

Symptoms of cardiac contusion are very greatly and sometimes are non recognized or are masked by associated injury in severe chest trauma. Cardiac contusion clinically presents as a spectrum of signs and symptoms of varying severity, ranging from precordial pain, dyspnoea, and non specific ECG changes to increased serum activity of several enzymes, early severe rhythm abnormalities, severe conduction defects and death. We present a fatal case in which the definitive diagnosis of myocardial contusion has proved complex. All clinical data were suggestive of acute myocardial infarction, but the history of chest wall injury and gross and histological examination of the heart and coronary vessels led us to conclude for a cardiac contusion without myocardial infarction. In case of chest blunt trauma, the ECG should be interpreted within the context of the clinical situation, on history of chest wall injury, since a fatal myocardial contusion may occur after apparently mild injury.

[Chest injury. Part II: Management of specific injuries]

Significant injuries to the thorax comprise pneumothorax, rib fractures, lung contusion, cardiac contusion, aortic laceration, ruptured diaphragm, and the very rare injuries to the tracheo-bronchial tree and the esophagus. A surgeon dealing with chest trauma patients needs to be familiar with the indications for and execution of chest tube insertion for thoracic drainage, pericardial puncture, and thoracoscopy and thoracotomy. Interventional techniques are gaining increasing acceptance in the management of major vascular injuries. The vast majority of patients with chest injury do not need an operative intervention, but it is necessary to place a thoracic drain in 10-15% of cases or to perform in a much lower proportion a pericardial puncture or a thoracotomy.

Effect of Obstruction on Longitudinal Left Ventricular Shortening in Hypertrophic Cardiomyopathy

OBJECTIVES

We investigated the cause of the midsystolic drop (MSD) in left ventricular (LV) ejection velocities that are observed with hypertrophic cardiomyopathy (HCM) and severe obstruction.

BACKGROUND

Dynamic obstruction is an important determinant of symptoms and adverse outcome. The MSD in velocity and flow occurs in patients with gradients >60 mm Hg. The nadir velocity in the LV occurs simultaneously with peak gradient.

METHODS

We studied 36 patients with obstructive HCM and an MSD and compared them with 15 patients with HCM and no obstruction and with 25 age-matched normal control subjects. We measured LV ejection velocity proximal and distal to LV obstruction as well as tissue Doppler velocities and time intervals.

RESULTS

The duration of contraction of both the septum and lateral wall is shorter in obstructed patients with the MSD than in nonobstructed HCM patients: septal contraction 203 +/- 68 ms vs. 271 +/- 41 ms (p < 0.001). Parallel reduction in the length of shortening was noted: 1.2 +/- 0.6 cm vs. 1.9 +/- 0.4 cm (p < 0.001). The ejection velocity nadir follows the septal and lateral peak velocities by 100 ms and 60 ms, respectively. The velocity nadir occurs as both walls rapidly decelerate to their premature termination: septal deceleration 79 +/- 35 cm/s2 vs. 48 +/- 21 cm/s2 (p < 0.001). With medical abolition of obstruction the MSD disappears and the duration and length of contraction normalizes.

CONCLUSIONS

These data indicate that the MSD is caused by premature termination of LV segmental shortening and is a manifestation of systolic dysfunction.

Cardiac Trauma

Fifty years ago, nearly all significant cardiac injuries were fatal, many were untreatable, and most undiagnosed until the autopsy suite. In the last 20 years, however, dramatic improvements in prehospital trauma management, new diagnostic modalities, and the availability of cardiac surgery in many hospitals have rendered treatable most cardiac injuries. Knowledge of various types of cardiac injuries, the methods available to facilitate rapid diagnosis, and familiarity with techniques for surgical repair are no longer an academic exercise but a life-saving necessity.

Myocardial contusion injury: redefining the diagnostic algorithm

Myocardial contusion injury (MCI) is a complication of blunt thoracic trauma, which may occur at relatively low velocities. MCI may also occur from chest compressions during cardiopulmonary resuscitation. We review the clinical pathology, diagnostic tools, and treatment for MCI.

Sudden death from contusion of the right atrium after blunt chest trauma: case report and review of the literature

Occult cardiac injury following blunt trauma is more common than generally suspected. Myocardial lesions range from myocardial contusion to cardiac rupture. Myocardial contusion is not uncommon, it is usually a benign disorder which often remains undiagnosed. We report the case of a previously healthy 29-year-old man who was involved in a fight and suffered from blunt heart injury leading to contusion of the right atrium. The patient died soon after the injury and before admission to the Hospital. The diagnosis was made at autopsy. The present case is of special interest because of the unusual eliciting event and the rarity of the contusion site (right atrium). It is reported in order to raise the index of suspicion in physicians treating patients involved in a fight and aid in prompt diagnosis of myocardial contusion.