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Automobile airbags have been universally installed to save lives in motor vehicle accidents, but have also been linked with facial and thoracic burns and chest trauma during rapid deployment. Blunt trauma to the chest may result in electrical and mechanical injuries to the heart and great vessels. We report a case of a 19-year-old man who presented with acute myocardial infarction following a blunt chest trauma from an automobile airbag deployment. Although mechanical complications resulting from airbag injury have been reported in the past, this is the first report of an acute thrombotic coronary occlusion triggered by the rapid airbag deployment. The case underscores the importance of systematic clinical evaluation to guide management in patients with confounding clinical presentation.

Background: We observed marked myocardial bridging of the left anterior descending coronary artery (LAD) in the acute stages of inferior wall myocardial infarction (MI) in a group of patients who developed shock despite successful reperfusion of the infarct-related lesion (IRL)., Hypothesis: The purpose of this study was to elucidate the clinical significance of myocardial bridging in patients with inferior wall MI and shock., Methods: The study group consisted of 53 patients with single-vessel disease of the right coronary artery, who underwent coronary angiography for acute inferior wall MI. Clinical characteristics, coronary angiographic findings, and left ventricular function during the chronic phase were compared between the patients who developed shock (the shock group) and those who did not (the non-shock group). In addition, a multiple logistic analysis was performed to identify independent predictors of shock in patients with acute inferior wall MI., Results: Reperfusion of the IRL was obtained in all 53 patients. The incidence of myocardial bridging of the LAD, the incidence of right ventricular MI, the peak creatine phosphokinase (CPK-MB). the pulmonary capillary wedge pressure, and the prevalence of pulmonary congestion seen on chest roentgenogram were significantly higher in the shock group than in the non-shock group. Myocardial bridging (p = 0.0018), right ventricular MI (p = 0.0374), and peak CPK-MB (p = 0.0189) were identified as independent predictors of shock in acute inferior wall MI., Conclusion: This study suggests that myocardial bridging plays a role in left ventricular function in the acute stage of inferior wall MI.

Background: The relationship between the severity of chronic-phase stenosis of infarct-related lesions (IRLs) and chronic left ventricular function in anterior acute myocardial infarctions (AMI) has not been adequately investigated., Hypothesis: This study investigated whether ST elevation in lead aVL of admission electrocardiogram (ECG) would be a determinant factor of the relationship between the severity of stenosis of the IRL and chronic left ventricular function after anterior wall AMI., Methods: One month after AMI, the IRL was evaluated by coronary angiography in 98 patients with anterior AMI, and left ventricular ejection fraction (LVEF) was determined using multigated radionuclide angiocardiography. Patients were classified according to the severity of the IRL: patients with 100% occlusion (Group O), patients with 90 to 99% stenosis (Group H), and patients with < or =75% stenosis (Group L). Patients with ST elevation > or =0.1 mV in the aVL lead on their admission ECG were included in the ST-elevation group, and those with ST elevation <0.1 mV were included in the non-ST-elevation group., Results: The LVEF was greater in the non-ST-elevation group than in the ST-elevation group (p<0.0001), and the LVEF in a whole group as follows: Group L LVEF>Group H LVEF>Group O LVEF (p = 0.0160). In the ST-elevation group, LVEF was higher in Group L than in the other groups (p = 0.0251). There were three independent predictors of a reduced LVEF: ST-elevation in aVL [odds ratio (OR): 3.38, p = 0.0044], IRL stenosis > or =90% (OR: 2.90, p = 0.0044), and the IRL occurring in the left anterior descending artery proximal to the first diagonal branch (OR: 6.31, p = 0.0024)., Conclusion: Left ventricular function was preserved, regardless of the severity of residual stenosis, in patients without ST elevation in aVL if the IRL was not totally occluded. In patients with ST elevation in aVL, LVEF was lower in patients with more severe stenosis, even if the IRL was patent.

Our study demonstrates that ST-segment elevation in both leads I and aVL noted on admission for an anterior acute myocardial infarction does portend a worse short-term survival. Independent predictors of short-term prognosis in an anterior acute myocardial infarction include ST elevation in both leads I and aVL, advanced age, female gender, left ventricular failure, and malignant arrhythmias.

There are patients in whom left ventricular (LV) wall motion decreases in the noninfarcted region and LV systolic function declines globally despite the presence of a localized myocardial infarct attributable to narrowing or occlusion of a single coronary artery. This study examines angiographic characteristics of patients with chronic hypokinesia of noninfarcted myocardium after anterior wall acute myocardial infarction (AMI) due to narrowing of a single coronary artery, namely, the left anterior descending (LAD) artery. The LV ejection fraction, abnormalities in the motion of the noninfarcted LV inferior wall (SD/chord value by Sheehan's technique), the angiographic characteristics of the infarct-related coronary artery, the effect of acute reperfusion therapy, and presence of coronary risk factors were examined in 85 consecutive patients. The SD/chord value in the noninfarcted region showed a positive correlation with the LV ejection fraction (r = 0.505, p <0.0001). By multivariate analysis, hypertension (odds ratio = 0.53, 95% confidence interval [CI] 0.36 to 0.80), an infarct-related narrowing proximal to the origin of the first diagonal branch (odds ratio = 0.56, 95% CI 0.38 to 0.84), and patency of the infarct-related lesion during AMI (odds ratio = 1.56, 95% CI 1.03 to 2.30) were independent predictors of wall motion in the noninfarct region. In some patients with single-vessel anterior wall AMI, the motion of the noninfarcted inferior LV wall decreases during the chronic stage and cardiac function declines severely. In most of these patients, the infarct-related narrowing or occlusion is proximal to the origin of the first diagonal branch of the LAD artery.

Background: The prognosis of acute inferior myocardial infarction is worse when it is complicated by right ventricular infarction. ST elevation in the right precordial leads is one of the reliable methods for detecting acute right ventricular infarction. The purpose of the study was to examine the relation between ST elevation in the right precordial electrocardiographic leads during acute inferior infarction and the severity of right ventricular systolic dysfunction., Methods: This study analyzed the relation between ST elevation > or = 0.1 mV in V4R and the severity of right ventricular systolic dysfunction in 43 consecutive patients (men/women: 35/8; average age 62+/-9 years) with acute inferior myocardial infarction with a rapid-response Swan-Ganz catheter to measure the right ventricular ejection fraction (RVEF)., Results: RVEF was significantly lower in patients with ST elevation (n = 18) than in those without (n = 25) (33%+/-6% vs 40%+/-9%, p = 0.010). If the infarct-related lesion was located in the proximal right coronary artery, RVEF tended to be lower than if the lesion was located in the distal right coronary artery or the left circumflex coronary artery (33%+/-10% vs 37%+/-9% vs 42%+/-9%, p = 0.101). Logistic regression analysis demonstrated that ST elevation in V4R was the only independent predictor of depressed RVEF (odds ratio = 5.31, 95% confidence interval = 1.28 to 22.1, p = 0.022)., Conclusion: ST elevation in lead V4R during acute inferior myocardial infarction predicts right ventricular systolic dysfunction.

This study investigated the clinical significance of hypoxemia without apparent clinical congestive heart failure in patients with acute myocardial infarction (AMI). Sixty-two patients with AMI of the Killip group I and Forrester subset I state were stratified into a hypoxemia group and a normoxemia group. The increase in the neutrophil count and the severity of the coronary artery disease as graded by Gensini's score were significantly higher in the hypoxemic group. The cardiac index was lower in hypoxemic than normoxemic patients. Myocardial scintigraphy revealed no acute difference in defect scores (DS) or left ventricular ejection fraction (LVEF) between the two groups, but DS was significantly higher (p < 0.01) and LVEF was lower (p < 0.01) in the hypoxemic group 2 years after infarction. Patients with hypoxemia have a more severe angiographic coronary pathology than normoxemic patients, and latent cardiac hypofunction occurs.