ECG of the Week - 23rd April 2018 - Interpretation

The following ECG is from a 41yr old male who was referred to telehealth from a rural center ~1500 km  (930 miles) from the nearest major hospital.

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Rate:

• 48 bpm

Rhythm:

• Sinus arrhythmia
• Sinus rhythm

Axis:

• Normal

Intervals:

• PR - Normal (~200ms)
• QRS - Normal (80ms)
• QT - 410ms (QTc Bazette 370ms)

Additional:

• Early R wave transisition
• Borderline voltage criteria LVH
• V1 S + V5 R ~35mm
• No non-voltage criteria present

Interpretation:

• Sinus bradycardia with sinus arrhythmia

Considerations with sinus bradycardia

I get asked to review many ECG's that show sinus bradycardia and there are a few considerations in these cases including:

• Is the patient symptomatic ?
• Is this 'normal' for the patient ?
• What is / could be the cause ?

Regarding symptoms these may be the reason for an Emergency Department attendance or more insidious and can include:

• Syncope
• Dizziness
• Light headedness
• Dysponea
• Decreased exercise tolerant
• Lethargy
• Palpitations
• Chest pain

There are multiple potential causes of bradycardia including:

• Physiological - athletes or during sleep
• Increased vagal tone - nausea, vomiting, pain
• Ischaemia
• Drug effect / toxicity - inc, digoxin, beta-blockers, calcium channel blockers
• Environmental - hypothermia
• Endocrine - hypothyroid
• Myocarditis
• Sinus node dysfunction
• Sleep apnoea

References / Further Reading

Life in the Fast Lane

• Left Ventricular Hypertrophy

Textbook

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