A 72-year-old woman comes to the emergency department due to intermittent chest pain for the last 2 days. She describes the pain as chest pressure associated with shortness of breath. She has never had similar symptoms. Her past medical history is significant for hypertension and hyperlipidemia. Physical examination reveals no heart murmurs. ECG shows normal sinus rhythm with T wave inversion in leads V4-V6. Initial troponin I level is undetectable. Two hours after the initial evaluation, she becomes unresponsive. Bilateral arm twitching is noted by the nurse. Her telemetry strip is shown on the image below. Which of the following is the best next step in managing this patient?

Question

A 72-year-old woman comes to the emergency department due to intermittent chest pain for the last 2 days.  She describes the pain as chest pressure associated with shortness of breath.  She has never had similar symptoms.  Her past medical history is significant for hypertension and hyperlipidemia.  Physical examination reveals no heart murmurs.  ECG shows normal sinus rhythm with T wave inversion in leads V4-V6.  Initial troponin I level is undetectable.  Two hours after the initial evaluation, she becomes unresponsive.  Bilateral arm twitching is noted by the nurse.  Her telemetry strip is shown on the image below.  Which of the following is the best next step in managing this patient?

Quizplus · Accepted Answer

11ec25c8_d194_80e4_bc81_1709e20dc0d5_MD0003_00 This patient, presenting with pressure-like chest pain, associated dyspnea, and T wave inversions in the lateral ECG leads, likely has myocardial ischemia or a non-ST elevation myocardial infarction. Serum troponin I levels may not be detectable for 6-12 hours from initial presentation. At the time the patient becomes unresponsive, the telemetry strip demonstrates poorly formed, irregular waves consistent with ventricular fibrillation (VF). Ventricular arrhythmias (eg, ventricular tachycardia [VT], VF) are common in patients with myocardial ischemia, and VF is the most common cause of sudden cardiac death during acute myocardial infarction. In patients with sudden cardiac arrest due to VF, survival depends on early identification, effective cardiopulmonary resuscitation (CPR), and successful defibrillation with return of spontaneous circulation. According to the advanced cardiac life support (ACLS) protocol, all patients with VF or pulseless VT detected on ECG should be managed with immediate defibrillation in an effort to restore a perfusing heart rhythm. protocol (Choices A and E) Amiodarone is indicated in patients with cardiac arrest due to VF or pulseless VT, but not until several attempts at defibrillation have been made. Lidocaine can be used as an alternate agent if amiodarone is not immediately available. (Choice C) Epinephrine should be administered every 3-5 minutes in patients who have persistent VF or pulseless VT following initial defibrillation and CPR. (Choice D) Fosphenytoin is an antiseizure drug used in the management of patients with status epilepticus. This patient's chest pain and VF on ECG are consistent with cardiac arrest rather than seizure. Patients with cardiac arrest can occasionally have arm twitching or seizure-like activity due to cerebral hypoperfusion. (Choice F) Intravenous magnesium sulfate is useful for the treatment of polymorphic VT associated with acquired QT prolongation (torsades de pointes) (eg, due to medication side effect) but is not used in VF due to myocardial ischemia. (Choice G) Patients with a persistent, narrow or wide QRS complex tachyarrhythmia (eg, atrial fibrillation, atrial flutter, VT with a pulse) causing hemodynamic instability should be managed with synchronized cardioversion. This patient with VF detected on ECG requires immediate defibrillation. Educational objective: Patients with ventricular fibrillation or pulseless ventricular tachycardia (VT) should be managed with immediate defibrillation. In contrast, patients with hemodynamic instability due to a narrow or wide QRS complex tachyarrhythmia (eg, atrial fibrillation, atrial flutter, VT with a pulse) should be managed with synchronized cardioversion. References: Part 1: Executive Summary: 2015 American Heart Association Guidelines Update for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. (http://www.ncbi.nlm.nih.gov/pubmed/26472989)

A 72-Year-Old Woman Comes to the Emergency Department Due to Intermittent