ECG of the Week - 12th December 2016 - Interpretation

The following ECG is from a 67 yr old male who was brought to the Emergency Department following an Out-of-Hospital Cardiac Arrest (OOHCA). Return of circulation was achieved pre-hospital following 8 mins of CPR. He has a history of 'heart muscle weakness', T2DM and 'kidney problems'. 

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Rate:

• 72 bpm

Rhythm:

• Irregular
• No organised atrial activity

Axis:

• Normal

Intervals:

• QRS - Prolonged (160 ms)

Segments:

• Minor ST depression leads V5-6

Additional:

• QRS prolongation without typical BBB pattern
• Very low voltage

Interpretation:

• Atrial Fibrillation
• QRS Prolongation
• Low voltage

Given the patient's history there are a very broad range of differentials for these ECG findings, including:

• Chronic cardiomyopathy
• Chronic atrial fibrillation
• Pericardial effusion - inflammatory, infective, uraemic
• ACS - chronic / acute
• Electrolyte abnormality - never forget K+ especially in patients with known renal impairment
• Drug toxicity - beta-blocker, calcium channel blocker, digoxin
• Environmental - hypothermia
• Multi-factorial

What happened ?

This patient had a combination of issues:

• Chronic atrial fibrillation
• Chronic dilated cardiomyopathy - EF 34%
• Acute on chronic renal - creatinine 235 from baseline 150 umol/L
• Hyperkalaemia - K 7.6 mmol/L
• Acidaemia - pH 7.15 HCO3 14 mmol/L
• Chronic digoxin toxicity

He required inotropic support, volume replacement, digifab/digibind therapy, correction of hyperkalaemia / acidaemia and renal replacement therapy.

References / Further Reading

Life in the Fast Lane

• Atrial fibrillation
• Digoxin toxicity
• Hyperkalaemia
• Low Voltage

Textbook

• Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.