In a patient with severe left‑arm pain, a normal resting electrocardiogram, and documented vitamin D3 deficiency, how should the cardiac evaluation and overall management be approached?

Evaluation and Management of Severe Left Arm Pain with Normal ECG and Vitamin D3 Deficiency

Despite a normal resting ECG, acute coronary syndrome (ACS) must still be aggressively ruled out with immediate cardiac troponin measurement and serial ECGs, as more than 50% of patients with chronic stable angina have normal resting ECGs, and up to 6% of patients with evolving ACS are inappropriately discharged with normal ECGs. 1

Immediate Cardiac Evaluation Protocol

Initial Diagnostic Steps (Within 10 Minutes)

• Obtain cardiac troponin immediately and repeat at 6-12 hours, as troponin is the most sensitive test for myocardial injury and is essential for diagnosing NSTEMI even when the ECG appears normal 1, 2
• Perform serial ECGs every 15-30 minutes if symptoms persist or worsen, since a single normal ECG does not exclude ACS and ischemic changes may evolve over time 1, 2
• Obtain supplemental leads V7-V9 to evaluate for posterior wall MI, which is often "electrically silent" on standard 12-lead ECG and commonly missed with left circumflex occlusions 1

Risk Stratification for ACS

High-risk features requiring immediate admission (even with normal ECG): 1, 2, 3

• Left arm pain with diaphoresis (95% specificity, likelihood ratio 5.18 for ACS)
• Pain lasting >20 minutes at rest
• Hemodynamic instability (hypotension, pulmonary rales)
• Diabetes mellitus
• Known coronary artery disease

If troponin is elevated or serial ECGs show ischemic changes, admit immediately for ACS management per cardiology protocols, as this represents NSTEMI requiring antiplatelet therapy (aspirin 75-150 mg daily), anticoagulation (LMWH or unfractionated heparin), beta-blockers, and consideration for early invasive strategy 1, 2, 3

Chest Pain Observation Protocol

For patients with normal initial troponin and nondiagnostic ECG, implement a chest pain observation protocol including: 1

• Serial troponin measurements at 0,3, and 6 hours
• Continuous or serial ECG monitoring
• Stress testing or coronary CT angiography before discharge if troponins remain negative

This approach is safe and effective for risk stratification and reduces unnecessary admissions while maintaining safety 1

Alternative Cardiac Causes to Exclude

Aortic Dissection

• Evaluate for sudden, tearing pain radiating to the back, especially with hypertension history, bicuspid aortic valve, or Marfan syndrome 2, 4
• Obtain chest radiograph for mediastinal widening; if suspected, proceed immediately to contrast-enhanced chest CT 4

Pericarditis

• Assess for sharp, pleuritic chest pain that worsens supine and improves sitting forward 4
• If suspected and cardiac workup is negative, consider admission or close outpatient follow-up depending on hemodynamic stability 3

Non-Cardiac Differential Diagnosis

Musculoskeletal Pain

• Pain reproducible with palpation and worsening with specific arm movements suggests musculoskeletal origin, but this should only be considered after cardiac causes are excluded 3

Peripheral Vascular Causes

• Acute limb ischemia can present with severe arm pain, pallor, and absent pulses; requires urgent vascular surgery consultation 5

Vitamin D3 Deficiency Management

Vitamin D3 deficiency does not cause acute severe arm pain and should not delay cardiac evaluation 6, 7

However, vitamin D deficiency is associated with:

• Increased arterial stiffness and early cardiac dysfunction in patients with diabetes 8
• Potential cardiovascular risk factor that warrants correction

Supplementation approach: 6

• Daily oral vitamin D3 5,000-10,000 IU is safe for long-term use
• Higher doses (20,000-50,000 IU daily) have been used safely in specific clinical scenarios
• No cases of hypercalcemia reported with these dosing regimens in hospitalized patients

Critical Pitfalls to Avoid

Do not discharge based solely on a normal ECG – this is the most common error leading to missed ACS, as normal ECGs occur in >50% of patients with chronic stable angina and evolving ACS 1, 9

Do not delay troponin testing to obtain chest X-ray in unstable patients, as this causes treatment delays 2

Do not attribute left arm pain to vitamin D deficiency without first excluding life-threatening cardiac causes through serial troponins and ECGs 2, 3

Do not rely on pain characteristics alone – even atypical presentations require objective cardiac testing, particularly in patients with diabetes or other cardiac risk factors 1