A 52-year-old man comes to the emergency department an hour after the onset of severe substernal chest pressure that lasted 30 minutes. The symptoms started when he was helping his brother move into his new house and were associated with mild dizziness and shortness of breath. His brother has coronary artery disease with stable angina and the patient took 3 of his brother's nitroglycerin tablets sublingually before his pain eventually subsided. He is currently pain free. Medical history includes hypertension and hyperlipidemia. The patient's daily medications include losartan, atorvastatin, and low-dose aspirin. Blood pressure is 152/93 mm Hg and pulse is 105/min. BMI is 32 kg/m². The lungs are clear to auscultation bilaterally. Cardiac examination indicates a prominent point of maximal impulse that is displaced downward and to the left. Auscultation reveals regular, normal heart sounds with an audible S4. There are no murmurs. The rest of the physical examination is within normal limits. ECG shows sinus tachycardia and voltage criteria for left ventricular hypertrophy, similar to the patient's ECG 6 months ago. His troponin level is normal. He says, "I feel fine! I just want to go home and I will see my primary care doctor." Which of the following is the most appropriate next step in management of this patient?

Question

Quizplus · Accepted Answer

Explanation: This patient has several cardiovascular risk factors (eg, hypertension, hyperlipidemia, family history) and developed typical anginal pain during exertion. Stable anginal pain usually resolves within a few minutes of rest or sublingual nitroglycerin administration; anginal pain lasting longer than 20 minutes is suggestive of acute coronary syndrome (ACS). Initial ECG may be nondiagnostic or normal in more than half of patients presenting with myocardial infarction (MI), and serum troponin levels can remain undetectable for 6-12 hours following the onset of MI symptoms. For patients in whom the initial ECG and troponin findings are unremarkable but there is reasonable suspicion for acute coronary syndrome (ACS), the most appropriate approach is further observation with serial ECG and troponin levels (eg, 3 troponin levels 6 hours apart and several ECGs 30 minutes apart). Subsequent elevation in serum troponin levels with or without ECG findings of ischemia (eg, ST segment depression, T-wave inversions with prominent R waves) will confirm non-ST-elevation MI. Alternatively, reoccurrence of typical anginal pain in the absence of serum troponin elevation may confirm unstable angina. (Choices B and C) Pharmacologic stress echocardiogram and exercise radionuclide perfusion scan are stress tests that allow for identification of myocardial regions that have inducible ischemia. These tests are appropriate in patients with low-risk non-ST-elevation MI or unstable angina based on thrombolysis in MI (TIMI) risk score, but they should not be performed until the diagnosis of ACS is confirmed and early risk stratification is completed. risk score (Choice D) Emergency cardiac catheterization with revascularization is indicated in patients with evidence of ST-elevation MI on initial ECG or ACS with hemodynamic instability. Cardiac catheterization is also indicated within 24-48 hours in patients with non-ST-elevation MI, but it should not be performed in this patient until a diagnosis is established. (Choice E) Reassurance and discharge with close follow-up may eventually be appropriate in this patient, but it is not appropriate without further observation and serial ECG and troponin levels to rule out ACS. Educational objective: Patients with suspected acute coronary syndrome but unremarkable initial ECG and serum troponin levels should be observed with serial ECG and troponin levels to confirm or rule out the diagnosis. References: 2012 ACCF/AHA focused update of the guideline for the management of patients with unstable angina/non-ST-elevation myocardial infarction (updating the 2007 guideline and replacing the 2011 focused update): a report of the American College of Cardiology Foundation/American Heart Association Task Force on practice guidelines. (http://www.ncbi.nlm.nih.gov/pubmed/22800849)

A 52-Year-Old Man Comes to the Emergency Department an Hour