What could be causing burning sensations in the left chest near the armpit and tingling in the left arm, considering potential cardiac issues like myocardial infarction, or other conditions such as costochondritis, thoracic outlet syndrome, or gastroesophageal reflux disease (GERD)?

Immediate Cardiac Evaluation is Mandatory

Call 9-1-1 immediately and obtain a 12-lead ECG within 10 minutes, as burning left chest pain with left arm tingling represents a classic presentation of acute coronary syndrome (ACS) until proven otherwise. 1, 2

Why This is a Medical Emergency

Your symptom pattern—burning left chest pain near the armpit with left arm tingling—has high specificity for myocardial infarction. The American Heart Association identifies chest pain radiating to the left arm as a classic ACS presentation, and when accompanied by diaphoresis (sweating), this has 95% specificity (likelihood ratio 5.18) for acute coronary syndrome. 1, 3 Do not attempt self-transport to a hospital; activate emergency medical services (EMS) to reach the closest emergency department. 4

Immediate Actions While Awaiting EMS

• Chew and swallow 325 mg aspirin (or 2-4 baby aspirins of 81 mg each) immediately if you have no aspirin allergy or recent bleeding, as aspirin significantly decreases mortality from myocardial infarction. 4
• Remain calm and sit or lie in a position of comfort. 4
• If you lose consciousness or stop breathing normally before EMS arrives, bystanders should initiate CPR. 4

What the Emergency Department Will Do

The diagnostic workup follows a strict time-sensitive protocol:

• ECG within 10 minutes to identify ST-elevation myocardial infarction (STEMI), ST depression, or other ischemic changes. 1, 2, 3
• Immediate cardiac troponin measurement with repeat testing according to protocol, as elevated troponin with typical chest pain indicates non-ST elevation myocardial infarction (NSTEMI). 1, 3
• Focused cardiovascular examination for murmurs, lung crackles, signs of heart failure, and pulse differentials. 4, 1
• Serial ECGs if the initial ECG is nondiagnostic but clinical suspicion remains high or symptoms persist. 4

Life-Threatening Conditions to Rule Out

Beyond myocardial infarction, your symptoms require exclusion of:

• Aortic dissection: Sudden tearing pain radiating to the back, particularly with hypertension history, bicuspid aortic valve, or Marfan syndrome. This requires immediate blood pressure control and contrast-enhanced chest CT. 2, 3
• Pulmonary embolism: Pleuritic chest pain with dyspnea and tachycardia in >90% of patients. 3
• Acute pericarditis: Sharp, pleuritic chest pain worsening when lying flat and improving when sitting forward. 3

If Cardiac Workup is Negative

Only after comprehensive cardiac evaluation excludes ACS should alternative diagnoses be considered:

• Gastroesophageal reflux disease (GERD): Can mimic cardiac pain with burning substernal discomfort radiating to the left arm, often occurring after meals or at night. However, GERD typically does not cause isolated arm tingling. 4, 5, 6
• Musculoskeletal causes (costochondritis): Pain reproducible with palpation of the chest wall and worsening with specific movements. This is unlikely given your burning quality and arm symptoms. 4
• Esophageal causes: May require upper endoscopy if symptoms persist despite acid suppression therapy. 4

Critical Pitfalls to Avoid

• Never assume this is "just heartburn" or muscle strain without cardiac evaluation—10-30% of patients with recurrent chest pain have GERD, but cardiac causes must be excluded first. 5, 6
• Do not delay ECG and troponin testing to obtain chest X-ray in unstable patients, as this causes treatment delays. 2
• Do not drive yourself to the hospital—EMS transport allows for earlier treatment initiation and direct routing to appropriate facilities. 4

Disposition Based on Test Results

• If troponin elevated or ECG shows ischemic changes: Immediate admission for ACS management per cardiology protocols. 1, 2
• If cardiac workup completely negative: Consider evaluation for gastrointestinal causes (GERD, esophagitis) or referral to cognitive-behavioral therapy if recurrent presentations with consistently negative cardiac workup. 4

The bottom line: Your symptoms warrant immediate emergency evaluation. Call 9-1-1 now, take aspirin if available and not contraindicated, and await EMS transport. 4