Should I perform an electrocardiogram (ECG) and a dipstick test after an electrical shock?

ECG and Dipstick Testing After Electrical Shock

Yes, you should perform a 12-lead ECG on all patients with electrical injury, but a urine dipstick is indicated only if you suspect renal injury from rhabdomyolysis or need to assess for myoglobinuria.

Mandatory ECG Assessment

A standard 12-lead ECG must be performed on all patients with electrical injury to detect cardiac abnormalities, regardless of symptoms. 1 This recommendation comes from the European Society of Cardiology and should be completed promptly as part of the initial evaluation.

Why ECG is Essential

• Electrical current can cause direct myocardial damage, arrhythmias, and conduction abnormalities even in asymptomatic patients 1
• The ECG serves both diagnostic and prognostic purposes, identifying high-risk features such as ventricular arrhythmias, conduction blocks, or ischemic changes 2, 1
• Cardiac complications may be delayed, making baseline documentation critical for comparison if symptoms develop later 1

Additional Cardiac Workup

Beyond the initial ECG, you should obtain:

• Cardiac biomarkers (troponin and CK/CK-MB) to assess for myocardial injury 1
• Continuous cardiac monitoring if any ECG abnormalities are present or if the patient has symptoms suggestive of cardiac involvement 2
• Echocardiography if there are suspected ventricular arrhythmias, structural heart disease, or persistent hemodynamic instability 2, 1

Urine Dipstick Indications

Perform urinalysis with dipstick only if you suspect rhabdomyolysis or need to screen for myoglobinuria. 1 This is part of the broader laboratory assessment that should include:

• Complete blood count 1
• Serum electrolytes (particularly potassium, which can be elevated from tissue injury) 1
• Renal function tests (creatinine, BUN) 1
• Creatine kinase levels (more specific than dipstick for muscle injury) 1

When Dipstick is Most Useful

The urine dipstick becomes particularly important when:

• There is concern for significant muscle injury or burns
• The patient has dark urine suggesting myoglobinuria
• You need rapid point-of-care assessment before formal lab results return 3
• Monitoring for acute kidney injury from myoglobin precipitation

Critical Timing Considerations

Obtain the ECG within 10 minutes of patient presentation if possible, following the same urgency as chest pain protocols 2. While electrical injury guidelines don't specify exact timing, the cardiac risk justifies this aggressive approach 1.

Common Pitfalls to Avoid

• Don't skip the ECG even in asymptomatic patients – electrical injury can cause occult cardiac damage that manifests later 1
• Don't rely solely on initial normal ECG – consider serial ECGs and continuous monitoring for at least 24 hours in moderate to severe exposures 2, 1
• Don't order routine dipstick without clinical indication – focus on targeted testing based on injury pattern and clinical suspicion 1, 3
• Don't delay ECG for other testing – cardiac assessment takes priority given the risk of life-threatening arrhythmias 2

Practical Algorithm

1. Immediate (within 10 minutes): 12-lead ECG 2, 1
2. Concurrent with ECG: Obtain blood for troponin, CK/CK-MB, electrolytes, renal function 1
3. If muscle injury suspected: Add urine dipstick and CK levels 1
4. If ECG abnormal or high-voltage exposure: Initiate continuous cardiac monitoring 2, 1
5. If hemodynamically unstable or persistent symptoms: Obtain echocardiography 2, 1

The ECG is non-negotiable for all electrical injuries, while the dipstick is a targeted test based on clinical suspicion of rhabdomyolysis or renal involvement 1, 3.