AVR ST Elevation: A Guide for Junior DoctorsIntroduction

ST elevation in lead aVR on an ECG can be a subtle but critical finding in emergency medicine. It often signifies severe underlying pathology, such as left main coronary artery (LMCA) stenosis, proximal left anterior descending (LAD) artery occlusion, or global subendocardial ischemia. This blog aims to help junior doctors approach a patient with this ECG finding, focusing on history-taking, examination, investigations, and management.

History-Taking

When faced with a patient showing ST elevation in aVR, your history-taking should aim to uncover signs of ischemia, shock, or other life-threatening conditions.

Key Questions:

·     Chest Pain:

o  Ask about the onset, duration, character, and radiation of chest pain.

o  "When did the pain start? Is it crushing or pressure-like? Does it radiate to the jaw, neck, or left arm?"

·     Associated Symptoms:

o  "Have you experienced shortness of breath, diaphoresis, nausea, or vomiting?"

o  "Do you feel dizzy or lightheaded?"

·     Risk Factors for Coronary Artery Disease (CAD):

o  "Do you have a history of hypertension, diabetes, dyslipidemia, or smoking?"

o  "Is there a family history of premature CAD?"

·     Previous Cardiac History:

o  "Have you had a heart attack, angioplasty, or bypass surgery before?"

·     Medication History:

o  "Are you on any antiplatelet agents or anticoagulants?"

·     Red Flags for Shock:

o  "Have you noticed any severe fatigue, confusion, or a sense of impending doom?"

Examination

A focused physical examination can help identify signs of hemodynamic instability or complications of ischemia.

Key Findings to Look For:

·     Vital Signs:

o  Check for hypotension, tachycardia, or bradycardia.

o  Look for evidence of shock (e.g., cold, clammy skin).

·     Cardiac Examination:

o  Auscultate for murmurs (e.g., new mitral regurgitation).

o  Check for an elevated jugular venous pressure (JVP) or peripheral edema.

·     Respiratory Examination:

o  Look for signs of pulmonary edema (e.g., crackles on auscultation).

·     Peripheral Signs:

o  Assess for delayed capillary refill or cyanosis.

o  Look for signs of poor perfusion (e.g., mottled skin).

Investigations

Prompt and accurate investigations are critical for diagnosing the underlying cause of ST elevation in aVR.

First-Line Investigations:

·     Electrocardiogram (ECG):

o  Confirm ST elevation in aVR (>1 mm).

o  Look for reciprocal changes in other leads, particularly widespread ST depression.

o  Consider patterns suggestive of LMCA or severe proximal LAD disease.

·     Blood Tests:

o  Troponin levels: Assess for myocardial injury.

o  Arterial blood gas (ABG): Look for metabolic acidosis or hypoxia.

o  Full blood count (FBC) and renal function: Rule out anemia or electrolyte disturbances.

·     Chest X-Ray:

o  Identify pulmonary edema or other cardiac complications.

·     Point-of-Care Ultrasound (POCUS):

o  Assess for left ventricular function and evidence of tamponade or aortic dissection.

·     Coronary Angiography:

o  This is the gold standard for diagnosing LMCA or proximal LAD occlusion.

Management Plan

Management should focus on stabilizing the patient and addressing the underlying cause.

Initial Stabilization:

·     ABC Approach:

o  Ensure airway patency, adequate oxygenation, and stable circulation.

·     Oxygen Therapy:

o  Provide supplemental oxygen if SpO2 is <94%.

·     Analgesia:

o  Administer nitrates cautiously if no hypotension exists.

o  Consider morphine for severe pain.

Pharmacological Management:

·     Antiplatelet Therapy:

o  Administer aspirin (300 mg) and consider a second antiplatelet agent (e.g., clopidogrel or ticagrelor).

·     Anticoagulation:

o  Start low-molecular-weight heparin or unfractionated heparin.

·     Other Medications:

o  Administer beta-blockers if no contraindications exist (e.g., hypotension or bradycardia).

o  Consider glycoprotein IIb/IIIa inhibitors in high-risk cases.

Definitive Management:

·     Emergency Revascularization:

o  Refer urgently for percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG).

·     Treat Shock:

o  Consider inotropes or vasopressors (e.g., noradrenaline) for hemodynamic support.

·     Manage Complications:

o  Treat pulmonary edema with diuretics.

o  Address arrhythmias promptly.

Key Takeaways

·     ST elevation in aVR is often a marker of severe cardiac ischemia and warrants immediate attention.

·     A structured approach—covering history, examination, investigations, and management—is essential.

·     Early recognition and urgent referral for definitive treatment can save lives.

By mastering these steps, junior doctors can confidently manage this critical ECG finding and ensure timely, life-saving interventions.