Special article

Ventricular arrhythmias in ischemic heart disease: Mechanism, prevalence, significance, and management☆

Coronary artery disease is thought to be responsible for up to 60%-80% of out-of-hospital cardiac arrests. The utility of Computed Tomography (CT) chest when it comes to identifying acute coronary occlusion in patients following an arrest has not been studied. We evaluated whether myocardial perfusion on a contrast-enhanced chest CT performed for a non-cardiac cause can predict culprit coronary occlusion as the cause of cardiac arrest and if the absence of a perfusion defect can exclude an ischemic etiology. A retrospective cohort of 53 consecutive patients presenting with VT or VF arrest and successful resuscitation who had contrast chest CT before angiography were identified. CT scans were reviewed for myocardial perfusion defects by a cardiologist and radiologist blinded to angiogram findings. CT results were then compared with angiograms. On coronary angiography, 22 (42%) of the patients presenting with out-of-hospital arrest had critical stenosis. Sensitivity and specificity of perfusion defect on CT in identifying critical stenosis on catheterization was 0.45, 95% CI [0.24, 0.68] and 0.77, 95% CI [59%, 90%], respectively. The positive likelihood ratio was 2.01 (0.91, 4.46) and the negative likelihood ratio was 0.70 (0.46, 1.08). The diagnostic accuracy was 64.2%. Our study did not show much utility for the use of myocardial perfusion defect on an incidental pre-angiography contrast chest CT to predict acute thrombotic occlusion in out-of-hospital cardiac arrest patients. However, this shouldn't discourage further studies evaluating the utility of contrast-enhanced CT images in predicting acute coronary occlusion.

A clinical or pathologic event caused by myocardial ischemia when there is evidence of myocardial injury or necrosis is named as myocardial infarction. Acute ST elevation myocardial infarction (STEMI) is a medical emergency that requires application of multiple therapies at the same time. The first step in the management of the patient with an acute STEMI is early diagnosis, because reperfusion therapy can result in great benefit when performed early. In the emergency department, STEMI can be diagnosed in patients with chest pain suspicious for an acute coronary syndrome, by the electrocardiogram. Biomarkers may be normal in the first examination. The reperfusion approach of infarct-related artery by either percutaneous coronary intervention or fibrinolytic therapy can improve survival in comparison with no reperfusion approach. STEMI complications include arrhythmia (especially ventricular tachyarrhythmia) and conduction abnormalities, mechanical complications (left ventricular free wall rupture, mitral regurgitation, and perforation of the interventricular septum), and pericardial complications of myocardial infarction.

A clinical or pathologic event caused by myocardial ischemia when there is evidence of myocardial injury or necrosis is named myocardial infarction. Acute ST elevation myocardial infarction (STEMI) is a medical emergency that requires application of multiple therapies at the same time. The first step in the management of the patient with an acute STEMI is early diagnosis, because reperfusion therapy can result in great benefit when performed early. In the emergency department, STEMI can be diagnosed in patients with chest pain suspicious for an acute coronary syndrome, by the electrocardiogram. Biomarkers may be normal in the first exam. The reperfusion approach of infarct-related artery either by percutaneous coronary intervention or fibrinolytic therapy can improve survival in comparison with no reperfusion approach. STEMI complications include arrhythmia (especially ventricular tachyarrhythmia) and conduction abnormalities, mechanical complications (left ventricular free wall rupture, mitral regurgitation, and perforation of the interventricular septum), and pericardial complications of myocardial infarction.