A 56-year-old man comes to the emergency department due to sudden-onset epigastric pain and dizziness that began 2 hours ago. The patient also has nausea but no shortness of breath. He has a history of hypertension, hyperlipidemia, and gastroesophageal reflux disease. The patient drinks 3 or 4 beers per week and smoked a pack of cigarettes daily for 15 years until quitting 2 years ago. Blood pressure is 85/52 mm Hg, pulse is 55/min, and respirations are 16/min. On physical examination, the patient is diaphoretic and appears uncomfortable. Cardiac auscultation reveals normal heart sounds with no murmurs. The abdomen is nontender to palpation. Chest x-ray reveals no cardiac enlargement or pulmonary edema. ECG reveals sinus bradycardia with symmetric T-wave inversion in leads II, III, and aVF. Which of the following is the most appropriate next step in the management of this patient?
Comparison of left ventricular & right ventricular myocardial infarction | ||
Left ventricular MI | Right ventricular MI | |
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Hemodynamic findings |
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Management |
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JVD = jugular venous distension; LV = left ventricular; MI = myocardial infarction; RV = right ventricular; SVR = systemic vascular resistance. | ||
This patient's presentation is concerning for right ventricular myocardial infarction (RVMI). The right ventricle is involved in up to half of inferior wall MIs, which are recognized by ischemic changes in ECG leads II, III, and aVF and commonly present with atypical epigastric pain rather than classic substernal chest pain. Nausea is also common, but when MI primarily affects the right ventricle, shortness of breath is rarely present (due to absence of pulmonary edema). Because inferior wall MI usually results from obstruction of the right coronary artery, which usually supplies blood to the sinoatrial and atrioventricular nodes, bradyarrhythmias (eg, sinus bradycardia, atrioventricular block) are frequently present.
Marked hypotension is a characteristic feature of RVMI. The infarcted right ventricle experiences acute contractile dysfunction and is often unable to pump adequate blood through the pulmonary circulation, resulting in decreased left ventricular preload, reduced cardiac output, and hypotension. Management of RVMI differs from left ventricular MI in that the failing right ventricle is highly sensitive to inadequate preload. Nitrates (eg, sublingual nitroglycerin) should be avoided because they reduce RV preload and can profoundly worsen hypotension (Choice D). Intravenous normal saline is often needed to further increase RV preload and assist blood flow through the pulmonary circulation to improve hypotension.
Whenever inferior wall MI is suspected based on ischemic changes in the inferior ECG leads, RV involvement should be evaluated using a right-sided precordial ECG, which is obtained via precordial lead placement in a mirror image on the right side of the chest. ST-segment elevation in lead V4R is highly accurate in confirming RVMI.
(Choice A) CT pulmonary angiography is indicated to evaluate for acute pulmonary embolism (PE), which can present with hypotension and ischemic changes in the inferior ECG leads. However, epigastric pain location is not typical for PE, and this patient's absence of shortness of breath and tachycardia make PE less likely.
(Choice B) Diuretics (eg, furosemide) reduce RV preload and should be avoided with suspected RVMI.
(Choice E) Upright abdominal x-ray can recognize air under the diaphragm and is indicated to evaluate for a ruptured peptic ulcer. Although epigastric pain is common, abdominal tenderness and tachycardia are also expected.
Educational objective:
Right ventricular myocardial infarction commonly presents with epigastric pain and nausea and is commonly associated with hypotension and bradycardia. A right-sided precordial ECG should be obtained to confirm the diagnosis.