Cardiac Symptoms After Recent Orthopedic Surgery

Scenario: A 78-year-old woman arrived at the emergency department (ED) with arm numbness, chest heaviness, and diaphoresis. She had undergone total knee replacement 2 weeks prior, complicated by hematoma and fever, but had no cardiac symptoms after surgery or at discharge. At home, she began feeling chest discomfort 2 days before her ED arrival. Her medical history included hypertension, hyperlipidemia, thrombocytopenia, and asthma. In the ED, her vital signs were heart rate 82/min, respiratory rate 22/min, oxygen saturation 99% on 2 L (nasal cannula), body temperature 101 °F (38 °C), and blood pressure 90/52 mm Hg. Below is the first 12-lead electrocardiogram (ECG) recorded in the ED.Sinus rhythm at 83/min with inferior wall ST-segment elevation myocardial infarction (STEMI), suspected right ventricular wall involvement; 2 multifocal PVCs.Myocardial infarction after noncardiac surgery is not uncommon. In patients undergoing total knee or hip replacement, acute MI is a recognized complication that may occur shortly after surgery, often within the first 30 days. Risk factors include advanced age, female sex, and a cardiovascular risk profile, all present in this scenario.Acute inferior wall MI is identified by ST-segment elevation in the 3 contiguous leads (II, III, and aVF) seen on this ECG. The presence of developing Q waves in leads II and aVF suggests that infarction has occurred, most likely owing to the patient’s delayed ED presentation. Of note is that the ST-segment elevation is taller in lead III than in lead II, accompanied by marked ST-segment depression in leads I and aVL. These features suggest a coronary occlusion in the proximal or mid portion of the right coronary artery, associated with right ventricular (RV) MI. Occlusion of the right coronary artery is associated with a reduction in oxygenated blood flow to the sinoatrial node, often leading to beat-to-beat variability and premature beats, as observed here. An isoelectric ST segment in lead V1 with significant ST-segment depression in lead V2 also suggests RVMI. Because leads V1 and V2 provide only a partial view of the right ventricle, further evaluation by recording right-sided ECG leads (V3R to V6R) would be useful for RVMI diagnosis.Approximately 15% of patients with inferior wall MI may also have posterior wall involvement. Although the criteria for posterior MI are challenging to detect on a standard 12-lead ECG, it may be suspected based on leads V1 through V3: (1) horizontal ST-segment depression (see leads V2 and V3); (2) tall, broad R waves >30 ms (see leads V2 and V3); and (3) dominant R waves (R/S ratio >1), as seen in V2 and V3 in the ECG strip shown. Confirmation can be determined by obtaining posterior leads V7 to V9.If time allows, right-sided ECG leads should be obtained in patients with inferior MI because an RVMI is sensitive to fluid management and vasodilators. This is particularly important in this patient, given the cardiac dysfunction that can occur with sepsis (fever on admission, quick SOFA score of 2). Nurses play a critical role in obtaining these additional ECG views, ensuring accurate lead placement, and labeling the leads on the standard 12-lead ECG. Inferior wall STEMI with RV and posterior involvement indicates a much larger area of myocardial damage, putting this patient at a very high risk for adverse outcomes due to reduced cardiac output; thus, continuous ECG and symptom monitoring are important.Given this patient’s history, postsurgical complications, and delayed arrival at the hospital after the onset of chest pain, the medical team determined that invasive revascularization would most likely entail more risk than benefit. The patient was instead managed conservatively in the cardiac intensive care unit. This patient was in the hospital for 9 days and was subsequently discharged to a skilled nursing facility.