CURRENT Essentials of Critical Care.pdf

Chapter 9 Cardiology 129Unstable Angina (USA) & Non–ST–SegmentElevation Myocardial Infarction (NSTEMI)■ Essentials of Diagnosis• Heavy, pressure-like substernal chest discomfort with radiationto neck, jaw, left arm; nausea, diaphoresis, dyspnea• Complications: arrhythmia, hypotension, pulmonary edema• ECG may reveal 1 mm ST segment depression or T wave inversion• Elevated cardiac enzymes (troponin, CK-MB) indicate myocardialnecrosis■ Differential Diagnosis• Angina pectoris, Prinzmetal angina, pericarditis, myocarditis,aortic dissection• Pneumothorax, pulmonary embolism, pneumonia• Reflux esophagitis, esophageal spasm, gastritis, pancreatitis• Musculoskeletal pain and costochondritis■ Treatment• Bed rest, oxygen, monitoring, serial cardiac enzymes• Initiate aspirin and continue indefinitely• Beta-blockers for heart rate and blood pressure control; nondihydropyridinecalcium antagonists if beta-blockers contraindicated• Nitrates for relief of symptoms• Morphine for persistent pain or pulmonary edema• ACE inhibitors when hypertension persists: especially if EF 40% or if diabetic• HMG-CoA reductase inhibitors with goal LDL 100• Clopidogrel for those intolerable of aspirin or as adjunct for percutaneouscoronary intervention (PCI)• Unfractionated or low-molecular-weight heparin with benefits• Platelet glycoprotein IIb/IIIa antagonists if PCI planned• Early PCI for high-risk patients: recurrent symptoms on medications,congestive heart failure, ventricular arrhythmia, unstablehemodynamics, elevated troponin■ PearlA minority of patients with normal coronary arteries may present withUSA due to increased workload on the heart: anemia, thyrotoxicosis,hypoxemia, hypotension.ReferenceBraunwald E et al: ACC/AHA 2002 guideline update for the management ofpatients with unstable angina and non-ST-segment elevation myocardial infarction.J Am Coll Cardiol 2002;40:1366. [PMID: 12383588]