A 76-year-old man is admitted to the hospital with nausea, vomiting, and generalized abdominal distension. He has a long-standing history of type 2 diabetes mellitus. His medical follow-up has been poor. Physical examination and diagnostic workup are consistent with a complicated small-bowel obstruction. He undergoes exploratory laparotomy with no operative complications and is extubated postoperatively in the surgical intensive care unit. A few hours after extubation, the patient experiences sudden onset of chest discomfort, nausea, and marked diaphoresis. Temperature is 36.1 C (97 F), blood pressure is 84/50 mm Hg, pulse is 32/min, and respirations are 26/min. Examination shows minimal crackles at both bases. There are no murmurs on cardiac examination. Fingerstick glucose level is 150 mg/dL. ECG shows sinus bradycardia with 3-mm ST-segment elevations in leads II, III, and aVF. Immediate chest x-ray shows increased interstitial markings bilaterally. Intravenous normal saline infusion is started and intravenous atropine is administered without significant improvement. Which of the following is the most appropriate next step in management of this patient?

Question

A 76-year-old man is admitted to the hospital with nausea, vomiting, and generalized abdominal distension.  He has a long-standing history of type 2 diabetes mellitus.  His medical follow-up has been poor.  Physical examination and diagnostic workup are consistent with a complicated small-bowel obstruction.  He undergoes exploratory laparotomy with no operative complications and is extubated postoperatively in the surgical intensive care unit.  A few hours after extubation, the patient experiences sudden onset of chest discomfort, nausea, and marked diaphoresis.  Temperature is 36.1 C (97 F), blood pressure is 84/50 mm Hg, pulse is 32/min, and respirations are 26/min.  Examination shows minimal crackles at both bases.  There are no murmurs on cardiac examination.  Fingerstick glucose level is 150 mg/dL.  ECG shows sinus bradycardia with 3-mm ST-segment elevations in leads II, III, and aVF.  Immediate chest x-ray shows increased interstitial markings bilaterally.  Intravenous normal saline infusion is started and intravenous atropine is administered without significant improvement.  Which of the following is the most appropriate next step in management of this patient?

Quizplus · Accepted Answer

Explanation: This patient is in cardiogenic shock due to an acute inferolateral wall ST-elevation myocardial infarction (STEMI) complicated by sinus bradycardia. Sinus bradycardia and atrioventricular (AV) block are commonly seen with acute inferior wall myocardial infarction (MI) and are explained by an increase in vagal tone. In the setting of acute inferior MI, these bradyarrhythmias are typically transient and often, but not always, responsive to intravenous atropine. In contrast to patients with inferior wall MI, bradyarrhythmias associated with anterior wall MI are commonly due to damage to the conduction system below the AV node; AV block in this setting is unlikely to respond to atropine. Temporary transcutaneous, followed by transvenous, cardiac pacing is the treatment of choice in patients with persistent symptomatic bradyarrhythmias (eg, hypotension, dizziness, heart failure, syncope) that are not responsive to atropine. Once cardiac pacing is initiated, this patient with STEMI should be taken for urgent revascularization by percutaneous coronary intervention (PCI). (Choice A) Anticoagulation with heparin is relatively contraindicated in patients with recent (<2 weeks) intraabdominal surgery, but it likely needs to be administered during PCI to adequately intervene on this patient's MI. Temporary pacing to improve the patient's bradycardia and hemodynamic instability prior to PCI is a more important next step. (Choice B) Dobutamine is a beta-1 agonist that can be used as an inotropic agent in patients with cardiogenic shock; however, inadequate chronotropy is the major cause of this patient's hypotension and is best addressed with temporary pacing. (Choice C) Norepinephrine stimulates both alpha-adrenergic and beta-1 adrenergic receptors, causing vasoconstriction and increased heart rate and contractility. It leads to a marked increase in myocardial oxygen demand and is therefore typically avoided in patients with acute MI. (Choice E) Thrombolytic therapy (eg, alteplase) is indicated for revascularization in patients with acute STEMI; however, revascularization by PCI is preferred in all settings when it is available. In this patient with recent intraabdominal surgery and high risk for bleeding, temporary pacing followed by PCI is the far better option, even if transfer to another facility is required. Educational objective: Sinus bradycardia and atrioventricular block are common and typically transient complications of acute inferior wall myocardial infarction. Symptomatic patients should be treated initially with intravenous atropine. Temporary cardiac pacing is the treatment of choice in patients with persistent symptomatic bradyarrhythmias (eg, hypotension, dizziness, heart failure, syncope) that are not responsive to atropine. References: 2013 ACCF/AHA guideline for the management of ST-elevation myocardial infarction: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. (http://www.ncbi.nlm.nih.gov/pubmed/23247304) Patterns of coronary compromise leading to bradyarrhythmias and hypotension in inferior myocardial infarction (http://www.ncbi.nlm.nih.gov/pubmed/16000883)

A 76-Year-Old Man Is Admitted to the Hospital with Nausea