A 54-year-old man is brought by his wife to the emergency department of a rural hospital due to chest discomfort. The pain began approximately an hour ago while he was mowing the lawn. He describes the chest pain as feeling "like a pickup truck is right on top of me." The patient took an aspirin at home, but the pain has not improved. He has a history of hypertension, chronic constipation, and onychomycosis. He smokes a pack of cigarettes a day and consumes 1-3 alcoholic drinks a night; he does not use illicit drugs. Temperature is 37.7 C (99.9 F), blood pressure is 142/90 mm Hg, pulse is 106/min, and respirations are 21/min. Oxygen saturation is 96% on room air. Weight is 115 kg (253.5 lb) and height is 175 cm (5' 9"). BMI is 37.4 kg/m². The patient appears uncomfortable and is diaphoretic. There is diffuse mild chest tenderness to palpation. Cardiac auscultation reveals a low-pitched sound at the apex just before S1. No edema of the extremities is evident. The remainder of the examination is unremarkable. The patient is given nitroglycerin, which improves the pain but does not relieve it. Which of the following findings on ECG most strongly indicates the need for tenecteplase?

Question

Quizplus · Accepted Answer

Explanation: Urgent coronary revascularization is indicated for acute ST elevation myocardial infarction (STEMI). Optimal therapy is with percutaneous coronary intervention (PCI) within 90 minutes of first medical contact or within 120 minutes for patients who require rapid transfer to a PCI-capable facility. In some rural settings, PCI within 120 minutes is not possible, and fibrinolytic therapy (eg, tenecteplase, alteplase, reteplase) is indicated within 30 minutes of hospital arrival. The following ECG findings are diagnostic of STEMI: New ST elevation at the J point in >2 anatomically contiguous leads with the following threshold: >1 mm (0.1 mV) in all leads except V2 and V31.5 mm in women, >2 mm in men age >40, and >2.5 mm in men age <40 in leads V2 and V3 New left bundle branch block with clinical presentation consistent with acute coronary syndrome The ECG finding of 1.5-mm ST elevation in leads I and aVL with reciprocal ST depression in leads II, III, and aVF is diagnostic of STEMI and warrants the administration of fibrinolytic therapy at this rural facility. ECG finding (Choice A) Diffuse ST elevation with PR depression is seen in patients with acute pericarditis, for which fibrinolytic therapy is not indicated. acute pericarditis (Choice B) An R prime wave (second R wave) in V1 accompanied by a widened S wave in V6 describes a right bundle branch block. Right bundle branch block can be benign or may occur in the setting of pulmonary hypertension or acute pulmonary embolism (PE); it is nonspecific and is not an indication for fibrinolytic therapy. (Choice D) More prominent ST elevation is required in leads V2 and V3 to meet criteria for STEMI. ST elevation of 1.5 mm in both of these leads is diagnostic of STEMI in women, but not in men of any age. (Choice E) T wave inversion in leads II, III, and aVF is suggestive of the right heart strain that can occur with acute PE; however, ECG findings are nonspecific for acute PE and are not diagnostic. Fibrinolytic therapy for acute PE is indicated only in patients with persistent hypotension or shock. Educational objective: Reperfusion therapy with primary percutaneous intervention or fibrinolytic therapy is indicated in patients with acute ST elevation myocardial infarction (STEMI). ECG findings that are diagnostic of acute STEMI include >1-mm (0.1-mV) ST elevation at the J point in >2 anatomically contiguous leads (except V2 and V3) and new left bundle branch block. References: 2013 ACCF/AHA guideline for the management of ST-elevation myocardial infarction: executive summary: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. (http://www.ncbi.nlm.nih.gov/pubmed/23247303)

A 54-Year-Old Man Is Brought by His Wife to the Emergency