A 52-year-old construction worker is brought to the emergency department due to the sudden onset of severe substernal chest pain. His initial ECG in the emergency department shows sinus rhythm with left bundle branch block. There is no previous ECG available for comparison.
On physical examination, the patient appears to be in significant distress. Temperature is 37.2 C (99 F), blood pressure is 122/75 mm Hg, pulse is 102/min, and respirations are 22/min. Pulse oximetry is 86% on room air. Lung examination reveals minimal bibasilar rales. Cardiac examination reveals regular rhythm with no significant audible murmurs or pericardial rub.
An emergency cardiac catheterization shows an occluded proximal left anterior descending artery (LAD). The left circumflex and right coronary arteries have mild luminal irregularities. An intra-aortic balloon counterpulsation (IABP) device is inserted, and the patient undergoes successful primary angioplasty of the proximal LAD with drug-eluting stent placement.
Over the next 36 hours, the patient's hemodynamics improve, and IABP support is weaned and eventually removed. He experiences several episodes of asymptomatic monomorphic ventricular ectopy. He feels well and he is able to ambulate with no symptoms. Current medications include low-dose aspirin, clopidogrel, atorvastatin, and lisinopril. The patient is started on low-dose metoprolol succinate and does well over the next 2 days.
ECG shows sinus rhythm with a persistent left bundle branch block pattern. A transthoracic echocardiogram shows a large area of akinesis in the mid- to distal anterior, anterolateral, and anteroapical segments, with a left ventricular ejection fraction of 25%. There is trace mitral and tricuspid regurgitation.
Which of the following is the most appropriate next step in management of this patient?

Question

A 52-year-old construction worker is brought to the emergency department due to the sudden onset of severe substernal chest pain.  His initial ECG in the emergency department shows sinus rhythm with left bundle branch block.  There is no previous ECG available for comparison.
On physical examination, the patient appears to be in significant distress.  Temperature is 37.2 C (99 F), blood pressure is 122/75 mm Hg, pulse is 102/min, and respirations are 22/min.  Pulse oximetry is 86% on room air.  Lung examination reveals minimal bibasilar rales.  Cardiac examination reveals regular rhythm with no significant audible murmurs or pericardial rub.
An emergency cardiac catheterization shows an occluded proximal left anterior descending artery (LAD).  The left circumflex and right coronary arteries have mild luminal irregularities.  An intra-aortic balloon counterpulsation (IABP) device is inserted, and the patient undergoes successful primary angioplasty of the proximal LAD with drug-eluting stent placement.
Over the next 36 hours, the patient's hemodynamics improve, and IABP support is weaned and eventually removed.  He experiences several episodes of asymptomatic monomorphic ventricular ectopy.  He feels well and he is able to ambulate with no symptoms.  Current medications include low-dose aspirin, clopidogrel, atorvastatin, and lisinopril.  The patient is started on low-dose metoprolol succinate and does well over the next 2 days.
ECG shows sinus rhythm with a persistent left bundle branch block pattern.  A transthoracic echocardiogram shows a large area of akinesis in the mid- to distal anterior, anterolateral, and anteroapical segments, with a left ventricular ejection fraction of 25%.  There is trace mitral and tricuspid regurgitation.
Which of the following is the most appropriate next step in management of this patient?

Quizplus · Accepted Answer

11ec193a_95cb_c6e4_853d_8703b348fc05_MD0002_00 This patient has a large area of akinesis in the myocardial segments corresponding with the occluded left anterior descending coronary artery. This likely represents an area of stunned myocardium, which can potentially recover function following coronary revascularization and optimal medical therapy. This patient should be continued on optimal medical therapy with a beta blocker and ACE inhibitor (or angiotensin II receptor blocker), and his symptoms and left ventricular function should be reassessed 3 months after coronary revascularization to determine the need for implantable cardioverter-defibrillator (ICD) placement for primary prevention of sudden cardiac death (SCD). Patients who do not undergo coronary revascularization can be reassessed for ICD placement 40 days following myocardial infarction. (Choice A) Ventricular ectopy (eg, premature ventricular contractions, nonsustained ventricular tachycardia [VT]) is common and expected during the first 48 hours after myocardial infarction. Although amiodarone may be indicated for episodes of sustained VT (>30 seconds), it is rarely indicated for nonsustained VT. (Choice C) Cardiac resynchronization therapy with placement of a biventricular pacemaker is indicated for symptomatic patients with left ventricular ejection fraction (LVEF) <35% and left bundle branch block with QRS duration >150 msec. Such therapy may eventually be appropriate for this patient; however, he should first receive optimal medical therapy for at least 3 months to evaluate for recovery of left ventricular function. < (Choice D) This patient had restoration of blood flow in the occluded artery and had only minimal disease in the other arteries. There is no indication for performing a submaximal exercise stress test at this time. (Choice E) Placement of an ICD is indicated in patients with persistent LVEF <30% (or <35% with heart failure symptoms) on repeat evaluation 3 months following revascularization. Patients considered at high risk of SCD in the meantime may be given a temporary wearable cardiac defibrillator (LifeVest). < < Educational objective: Patients with left ventricular (LV) dysfunction due to myocardial infarction may experience recovery of LV function following coronary revascularization and treatment with optimal medical therapy. Therefore, implantable cardioverter-defibrillator placement should be reserved for patients with significant LV dysfunction that persists for 3 months following revascularization or 40 days following myocardial infarction without revascularization. __________ References: ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the ACC/AHA/NASPE 2002 Guideline Update for Implantation of Cardiac Pacemakers and Antiarrhythmia Devices): developed in collaboration with the American Association for Thoracic Surgery and Society of Thoracic Surgeons. (http://www.ncbi.nlm.nih.gov/pubmed/18483207) Indications for ICD and cardiac resynchronization therapy for prevention of sudden cardiac death. (http://www.ncbi.nlm.nih.gov/pubmed/19210214) Device therapies in the post-myocardial infarction patient with left ventricular dysfunction. (http://www.ncbi.nlm.nih.gov/pubmed/18722189)

A 52-Year-Old Construction Worker Is Brought to the Emergency Department