Traumatic myocardial dysfunction

Traumatic myocardial dysfunction is a frequently unsuspected, undiagnosed contributor to deaths from trauma. Electrocardiography, serum enzymes, and radionuclide myocardial scans are insensitive indicators of cardiac injury following blunt chest trauma. First-pass biventricular radionuclide angiography can accurately determine right and left ventricular ejection fractions and assess left ventricular segmental wall motion. Since August, 1980, we have evaluated 74 consecutive patients with blunt chest and multisystem trauma. Electrocardiograms and measurements of the myocardial band isoenzyme of creatine kinase were obtained at admission and repeated at 24 hour intervals for 3 days. Radionuclide angiography was performed 24 to 48 hours after admission. The electrocardiogram was abnormal in 21 patients (28%), levels of creatine kinase isoenzyme were elevated in six, and radionuclide angiographic abnormalities were present in 55 patients (74%). Electrocardiographic abnormalities correlated anatomically with angiographic abnormalities in 16 patients (76%). On follow-up radionuclide angiography, abnormalities had disappeared in nine of 12 patients restudied at 3 weeks. This study documents that the electrocardiogram and creatine kinase isoenzyme elevations are static, insensitive indicators of traumatic myocardial dysfunction. Radionuclide angiography with studies of left ventricular segmental wall motion demonstrate that traumatic myocardial dysfunction, although sometimes transitory, is a dynamic phenomenon that is more common than previously suspected. First-pass radionuclide angiography and wall motion studies are practical and valuable adjuncts to the management of the injured patient.     

Blunt chest trauma with severe pulmonary contusion and traumatic myocardial infarction

In the literature the incidence of cardiac involvement in blunt chest trauma varies considerably. This reflects the diagnostic problems encountered in polytraumatised patients. We report the case of an 18 year old man who suffered bilateral pulmonary contusion and traumatic myocardial infarction following a motorbike accident. The myocardial infarct was diagnosed by means of ECG, cardiac enzymes and echocardiography. When the diagnosis was made the time for successful interventional treatment had lapsed. A coronary angiography was performed after stabilisation which revealed a proximal dilatation of the left anterior descending artery. Left ventricular function was severely impaired (ejection fraction 26%). Due to the pulmonary contusion respiratory support was required for 14 days. The course was further complicated by left ventricular failure with low output.     

Myocardial dysfunction following blunt chest trauma

We prospectively studied 35 patients with blunt chest trauma using ECG multi-gated and first-pass nuclear angiography. Radionuclide angiography (RNA) is a sensitive test of myocardial function demonstrating right and left ventricular ejection fractions. First-pass angiography, in addition, shows left ventricular segmental wall motion, a qualitative as well as anatomic indicator of left ventricular function. We saw RNA abnormalities in 26 patients (74.2%). Eight patients (22.8%) had ECG abnormalities, and these findings correlated with RNA, suggesting that this technique is a very sensitive indicator of myocardial dysfunction following trauma. These studies warrant further experimental and clinical evaluations to determine the cause, significance, and long-term prognosis of posttraumatic myocardial dysfunction.     

Cardiac contusion in pediatric patients with blunt thoracic trauma

To investigate the prevalence of myocardial contusion associated with blunt chest trauma in the pediatric age group, all patients admitted to our institution during a 6-month period with blunt thoracic trauma severe enough to produce a pulmonary contusion or rib fracture were prospectively evaluated. Cardiac evaluation was undertaken, including a multiple-gated acquisition (MUGA) cardiac scan, serial electrocardiograms (ECG), and serum creatine phosphokinase (CPK) and CPK isoenzymes. Seven patients, ranging in age from 2 1/2 to 18 years, with rib fractures or pulmonary contusion by chest roentgenograph were identified. One patient was injured as a passenger in a motor vehicle accident, five were struck by automobiles as pedestrians, and one sustained traumatic asphyxia when a car, supported by a jack, fell on his chest. All had at least one other major organ system injured. All patients had pulmonary contusions as determined by chest radiograph, and two had associated rib fractures. In 43% (three of seven) of patients, a significant cardiac contusion was identified, defined by abnormal right or left ventricular wall motion and a decreased ejection fraction on MUGA scan, and confirmed by an increase in cardiac enzymes and isoenzymes. However, in contrast with adults, no patients had ECG abnormalities. This limited series suggests that cardiac contusion may occur frequently in pediatric patients who have suffered from blunt thoracic trauma significant enough to result in pulmonary contusion. An MUGA scan provides a rapid, noninvasive assessment of cardiac damage in this setting. Further studies will be required to determine the clinical significance and long-term consequences of traumatic myocardial damage in the pediatric population.     

Blunt cardiac injury and intraoperative hypoxaemia

A 28-yr-old man sustained blunt chest trauma in a motor vehicle accident. Severe intraoperative hypoxaemia occurred, unresponsive to oxygen and positive expiratory pressure therapy. Transoesophageal echocardiography revealed myocardial contusion and tricuspid valve rupture. Dobutamine improved left ventricular function and ejection fraction resulting in an immediate improvement in arterial oxygenation and saturation. Tricuspid injury and the diagnosis of myocardial contusion are discussed. The case highlights the importance of a non-pulmonary mechanism of hypoxaemia.     

Imaging in blunt cardiac injury: Computed tomographic findings in cardiac contusion and associated injuries

BackgroundBlunt cardiac injury (BCI) may manifest as cardiac contusion or, more rarely, as pericardial or myocardial rupture. Computed tomography (CT) is performed in the vast majority of blunt trauma patients, but the imaging features of cardiac contusion are not well described.PurposeTo evaluate CT findings and associated injuries in patients with clinically diagnosed BCI.Materials and methodsWe identified 42 patients with blunt cardiac injury from our institution's electronic medical record. Clinical parameters, echocardiography results, and laboratory tests were recorded. Two blinded reviewers analyzed chest CTs performed in these patients for myocardial hypoenhancement and associated injuries.ResultsCT findings of severe thoracic trauma are commonly present in patients with severe BCI; 82% of patients with ECG, cardiac enzyme, and echocardiographic evidence of BCI had abnormalities of the heart or pericardium on CT; 73% had anterior rib fractures, and 64% had pulmonary contusions. Sternal fractures were only seen in 36% of such patients. However, myocardial hypoenhancement on CT is poorly sensitive for those patients with cardiac contusion: 0% of right ventricular contusions and 22% of left ventricular contusions seen on echocardiography were identified on CT.ConclusionCT signs of severe thoracic trauma are frequently present in patients with severe BCI and should be regarded as indirect evidence of potential BCI. Direct CT findings of myocardial contusion, i.e. myocardial hypoenhancement, are poorly sensitive and should not be used as a screening tool. However, some left ventricular contusions can be seen on CT, and these patients could undergo echocardiography or cardiac MRI to evaluate for wall motion abnormalities.     

Myocardial contusion in the stable patient: what level of care is appropriate?

To evaluate the significance of myocardial contusion, we evaluated 243 stable patients hospitalized for blunt chest trauma between 1982 and 1986. The groups were identified according to results of radionuclide angiography, mean injury severity score (ISS), and outcome. Group I (n = 71; mean ISS = 12.7) patients were those without myocardial contusion by radionuclide angiography. Two patients with cardiac complications were in this group. The patients with myocardial contusion were divided into two groups. Group II (n = 69; ISS = 19.5) patients had myocardial contusion as an isolated injury, and group III (n = 103; ISS = 30.9) patients had myocardial contusion and injury to at least one other organ system. Three patients from group II had cardiac complications. Eleven patients from group III had cardiac complications. There were no significant differences between the cardiac complication rate in the three groups, and each complication was present when the patient arrived in the emergency department. The predicted mortality rate based on ISS was 10% to 20% for patients with myocardial contusion, whereas the observed mortality rate for the groups (II and III) overall was 0.58%. We conclude that in the stable trauma patient myocardial contusion (1) does not by itself increase the risk of complication, (2) does not necessitate intensive care unit monitoring, (3) should be devalued when computing ISS scores, (4) may account for lengthy and often unnecessary hospitalization, and (5) in patients at risk for complications may be identified by ECG abnormalities on arrival to the emergency department.     

Assessment of cardiac function in patients who were morbidly obese

Cardiac function of 30 patients who were morbidly obese was studied before bariatric surgery. Twelve patients were studied 13 +/- 4 months after surgery. These patients had a mean age of 37.1 +/- 2.9 years and a body mass index of 50.0 +/- 1.4 kg/m2. Cardiac function was measured by echocardiography, radionuclide angiography scanning, and right heart catheterization. To determine the degree of cardiac dysfunction, the patients were studied with exercise and intravenous fluid challenges. Ultrasonography produced evidence of myocardial thickening with an increased interventricular septum in eight patients (32%) and increased left ventricular mass in 17 patients (53%). The radionuclide scan suggested that morbid obesity was associated with a significantly (p less than 0.05) increased end-diastolic volume and decreased left ventricular ejection fraction as compared with patients who were of normal weight. With exercise the patient who was of normal weight had an increase in the end-diastolic volume, stroke volume, and heart rate, but the patient who was morbidly obese only increased heart rate to produce the necessary increase in cardiac output. Right heart catheterization indicated that the relationship of the pulmonary wedge pressure and the left ventricular stroke work index was abnormal in 14 of 29 patients (48.3%) and depressed in six of 29 patients (20.7%) with exercise. One liter of fluid caused an abnormal relationship of the pulmonary wedge pressure and the left ventricular stroke work index in 12 of 30 patients (40%) and a depressed response in 10 of 30 patients (33.3%). Cardiac studies were repeated in 12 patients after a 54.8 +/- 1.9 kg weight loss. Echocardiography indicated a decrease in dilatation (27.3% to 9.1%) and a significant (p less than 0.05) decrease in hypertrophy (45.5% to 0%). After the weight loss, radionuclide and right heart catheterization studies indicated improved cardiac function with reduced filling pressures and increased left ventricular work during fluid and exercise challenges. These results support the presence of obesity-related cardiomyopathy with ventricular dysfunction, which appears to be caused by a noncompliant ventricle. Significant weight loss achieved with gastroplasty results in increased ventricular compliance and improved cardiac function.     

Clinical and pathophysiological study of myocardial contusion

Myocardial contusion was observed in 25 patients (7.5%) out of 333 blunt chest trauma victims. As the cause of injury, 19 patients (76%) were due to traffic accident and 12 out of 19 patients had steering wheel injuries. There were a total of 72 associated thoracic injuries, and this means 2.9 injuries for each patient. As ECG abnormalities, sinus tachycardia on admission and ST, T change in time course were mostly found in this series. Chest X-ray findings revealed the maximum value (55.2 +/- 1.3%) of CTR (cardio-thoracic ratio) on the 2nd-4th hospital days, followed the decreasing tendency. CPK-MB showed its peak on the 1st-3rd hospital days, and was nearly normalized on the 5th hospital day. There were 10 expired cases, and the mortality was 40%. Cardiac death due to cardiac tamponade or cardiogenic shock was observed in 4 cases. Ventricular function study showed 2 right ventricular dysfunction. 1 left ventricular dysfunction, and 4 biventricular dysfunction, and showed extremely poor prognosis in the biventricular dysfunction group. The cases of myocardial contusion were classified into the following 3 types by the clinical findings. Type I: ECG abnormality type 13 cases; Type II: Cardiac tamponade type 7 cases; Type III: Cardiogenic shock type 6 cases. I conclude that measuring the ventricular function is useful for the evaluation of the severity and prognosis of myocardial contusion if the blunt chest trauma victim is in shock state.     

Pulmonary contusion causes long-term respiratory dysfunction with decreased functional residual capacity

To elucidate the mechanism of persistent dyspnea after blunt chest trauma, we prospectively studied the pulmonary function of 18 patients with blunt chest trauma for 6 months. Nine of the patients had flail chest and 12 had pulmonary contusion (PC). Pulmonary function was evaluated using spirometry, arterial blood gas analysis, chest x-ray studies and CT scans. Functional residual capacity (FRC) remained significantly reduced throughout the 6 months in patients with PC. Such patients experienced a fall in Pao2 when changed from a sitting position to a supine position and they had fibrous changes in the contused lung as demonstrated by CT scans at 6 months after injury. These findings were supported in an additional study of another 20 patients who had suffered PC 1 to 4 years previously. This study demonstrated that pulmonary function recovered within 6 months in patients without PC even with a residual deformity of the thoracic wall caused by flail chest, while patients with PC had decreased FRC and a fall in Pao2 when moved to the supine position even several years after injury. This might be related to the persistent dyspnea seen after blunt chest trauma.     

Longitudinal evaluation of left ventricular performance in dogs following nonpenetrating cardiac trauma

To investigate the temporal changes of global left ventricular function following nonpenetrating cardiac impact, studies were performed in ten purpose-bred dogs. Under full anesthesia and after hemodynamic and angiographic measurement, a midline thoracotomy was performed and a 12 m/sec blunt impact was delivered to the anterior surface of the heart in eight dogs with an air-pressurized impactor. Two dogs were sham operated and did not undergo trauma. After closing the chest, the hemodynamic measurements were repeated at 3 hours, 3 days, 2 weeks, and 5 weeks after impact. Hemodynamic measurements included left ventricular end-diastolic pressure and peak left ventricular positive and negative rates of change of pressure. Left ventricular ejection fraction was calculated from ventriculograms obtained with the dog positioned on its right side. All indices of left ventricular performance in dogs that underwent trauma were depressed at 3 hours after impact and recovered gradually to near normal levels at 2 to 5 weeks after trauma. Recovery of left ventricular function occurred in spite of residual patchy scarring of the left ventricular myocardium in the region of impact. No variability of left ventricular function indices was observed over the course of the study in the two sham-operated dogs. The results indicate that blunt cardiac impact can cause depression of left ventricular performance in the immediate post-impact period, but near complete recovery of function occurs within 2 to 5 weeks after the injury, in spite of residual scarring.     

The Incidence of Myocardial Contusion in 160 Patients with Blunt Chest Trauma Diagnostic Criteria and Outcome

The incidence of myocardial contusion after blunt chest trauma has been reported in 8.2 to 75% of trauma patients. We performed this study to report on the incidence of myocardial contusion in order to determine the frequency and to describe the type of complications in these patients. We conducted a retrospective analysis over a period of 4 years. There were 160 patients with a blunt chest trauma which were admitted to our hospital. Myocardial contusion occurred in 27 of our patients with blunt chest trauma (16.9%). In all these patients typical ECG-changes could be found during hospitalization (100%). The incidence of further pathological findings in the 27 patients was 30% for the auscultation, 37% for cardiac enzymes (MB-fraction), and 41% for the echocardiography. Cardiac complications like arrhythmias, cardiac failure and tamponade occurred in 20 patients (74%). Early diagnosis of myocardial contusion in patients with blunt chest trauma is important to prevent and to treat possible complications. ECG-controls have the highest sensitivity to detect a myocardial contusion, whereas cardiac enzymes and echocardiograms seem to be poor markers of blunt myocardial injury.     

Cardiac contusion. The effect on operative management of the patient with trauma injuries

Sixty-four patients with cardiac contusion documented by electrocardiographic changes and creatine kinase MB fraction assay following blunt chest injury were reviewed to assess the impact of cardiac contusion on subsequent management. Fifty-eight patients had elevated creatine kinase MB levels; 35 patients had electrocardiographic abnormalities, including ST-segment and T-wave changes (25), premature ventricular contraction (ten), right bundle-branch block (nine), atrioventricular block (three), atrial fibrillation (three), and premature atrial contraction (two). Thirty patients underwent general anesthesia. There were only four perioperative complications: ventricular ectopy, ventricular fibrillation, nodal rhythm, and pulmonary edema. There were no deaths attributable to cardiac contusion. In summary, patients with blunt trauma who have sustained a cardiac contusion can undergo elective operation with a low incidence of complication. In the emergency setting, however, hemodynamic monitoring for early detection of arrhythmias is indicated.     

Seat belt-related chondrosternal disruption with lung herniation

A case of blunt chest trauma resulting in anterior chondrosternal separation with right lung herniation and hemothorax is presented. The injury is related to the use of a seat belt restraint. The patient underwent surgical repair with polytetrafluoroethylene chest wall reconstruction. Postoperative recovery was complicated by respiratory insufficiency due to underlying pulmonary contusion and multiple rib fractures.     

Cardiovascular evaluation in blunt thoracic trauma using transesophageal echocardiography (TEE)

Blunt chest trauma can result in significant cardiothoracic injury, which can include cardiac contusion, aortic injury, and myocardial valvular injury. Nineteen patients with no prior history of cardiac abnormalities who sustained severe blunt chest trauma and had widening of the mediastinum on chest radiographs were prospectively evaluated using transesophageal echocardiography (TEE). In each instance TEE was performed without difficulty, excellent images were obtained of the aorta and heart, and no complications were noted. Abnormalities were seen in 12 (63%) patients, with hypokinetic regional wall motion consistent with cardiac contusion demonstrated in five (26%) patients. Tricuspid regurgitation was found in three (16%) patients, and aortic and mitral regurgitation in one (5%) patient each. Aortic wall hematomas were seen in two patients, one of whom had an intimal tear on aortography, and a pericardial effusion was seen in one patient with an aortic intimal tear confirmed angiographically. Thus TEE can be performed safely in the acute setting of patients sustaining severe blunt chest trauma and yield useful information with respect to cardiovascular function and the aorta.     

The Incidence of Myocardial Contusion in 160 Patients with Blunt Chest Trauma

The incidence of myocardial contusion after blunt chest trauma has been reported in 8.2 to 75% of trauma patients. We performed this study to report on the incidence of myocardial contusion in order to determine the frequency and to describe the type of complications in these patients. We conducted a retrospective analysis over a period of 4 years. There were 160 patients with a blunt chest trauma which were admitted to our hospital. Myocardial contusion occurred in 27 of our patients with blunt chest trauma (16.9%). In all these patients typical ECG-changes could be found during hospitalization (100%). The incidence of further pathological findings in the 27 patients was 30% for the auscultation, 37% for cardiac enzymes (MB-fraction), and 41% for the echocardiography. Cardiac complications like arrhythmias, cardiac failure and tamponade occurred in 20 patients (74%). Early diagnosis of myocardial contusion in patients with blunt chest trauma is important to prevent and to treat possible complications. ECG-controls have the highest sensitivity to detect a myocardial contusion, whereas cardiac enzymes and echocardiograms seem to be poor markers of blunt myocardial injury.     

Methylprednisolone in the Treatment of Lung Contusion Following Blunt Chest Trauma

The effects of large doses of methylprednisolone (MP) (30 mg per kg. b.w.) in patients with lung contusion following blunt chest trauma were studied in 10 patients selected at random and compared with 10 chest trauma patients receiving no steroids, but otherwise treated in the same way. All patients survived. Serious post-traumatic complications were reduced in the steroid group. All patients were followed with haemodynamic and metabolic observations for 6 weeks using Swan-Ganz flow directed therrmodilution catheters. The most pronounced effect of MP was a significant reduction of pulmonary vascular resistance which may prevent right heart failure. The study demonstrates that MP should be given in sufficient doses in patients with respiratory insufficiency following blunt chest trauma.     

Traumatic coronary artery dissection after blunt thoracic trauma--a case report

We present a case of cardiac infarction after blunt chest trauma. The 49-year-old patient suffered from severe angina and the ECG demonstrated a pattern of acute anterior wall myocardial infarction. Acute coronary angiography was performed showing complete occlusion of the left interventricular coronary artery due to dissection. An attempted revascularization by percutaneous transluminal coronary angioplasty failed and the patient was then submitted to bypass surgery. We conclude that possible heart injury should be considered in patients with blunt chest trauma to lead them to adequate therapy.     

Blunt cardiac injury in children

Thirty-nine children admitted to the pediatric intensive care unit with multiple injuries from blunt trauma underwent serial EKGs, determination of creatinine phosphokinase (CPK) isoenzymes, echocardiography, and radionuclide angiography studies. Motor vehicle injuries were responsible for 83% (32 of 39) of admissions, the remainder (7 of 39) caused by falls from heights. Thirteen children sustained serious (Modified Injury Severity Score [MISS] greater than 25) multiple system injury. Chest injuries were sustained by 12 children, nine being serious thoracic injuries (MISS chest score greater than 2). Three children (7.7%) showed elevations of MB fraction of CPK isoenzymes in addition to EKG abnormalities and/or ejection fraction depression on radionuclide angiography and were considered to have sustained cardiac contusion. Eight other children (20%) had normal or borderline elevation of CPK-MB fraction and EKG abnormalities combined with abnormal echocardiograms or radionuclide angiograms, and were considered to have sustained cardiac concussion. An additional 14 children (36%) had EKG or radionuclide angiography abnormalities alone. Two children required lidocaine therapy for cardiac irritability manifesting as multifocal PVCs and ventricular tachycardia. Based on this study, a comprehensive diagnostic evaluation of the heart in all children sustaining multiple injuries from blunt trauma cannot be justified. Continuous cardiac monitoring should be initiated in the emergency room and maintained throughout intensive care unit confinement to identify transient dysrhythmias. In patients with significant dysrhythmias and in those with obvious thoracic injuries serial EKG and cardiac isoenzyme assay should be obtained. Dysrhythmias should be man-aged with appropriate anti-arrhythmic therapy.(ABSTRACT TRUNCATED AT 250 WORDS)     

Protamine: does it alter right ventricular function?

Protamine administration has been associated with cardiac decompensation secondary to acute pulmonary vasoconstriction and subsequent right ventricular failure. To determine whether protamine infusion produced alterations in right ventricular performance, we evaluated both right and left ventricular function in patients receiving protamine infusion. The dose of protamine administered was calculated as adequate to reverse heparin as measured by the activated clotting time (ACT). Indices of right and left ventricular function obtained included right atrial pressure, right ventricular pressure, right ventricular ejection fraction, pulmonary artery pressure, pulmonary capillary wedge pressure, cardiac output, blood pressure, and heart rate. These measurements were obtained prior to protamine administration, at 1/2 total protamine dose, at completion of protamine infusion, and prior to sternal closure. No significant changes in right ventricular ejection fraction, right ventricular end-diastolic pressure, mean pulmonary artery pressure, or pulmonary vascular resistance were seen at any point during the study. Left ventricular function remained unchanged. Even in patients who are possibly at an increased risk (pulmonary artery hypertension, PAP greater than 25 mm Hg), no deterioration in right or left ventricular function could be demonstrated following protamine administration. These data suggest that protamine does not consistently exert a significant detrimental effect on right ventricular performance.