ECG of the Week – 4th June 2018 – Interpretation

The following ECG is from an 81 yr old female who presented with a 4 day history of RUQ pain on a background of known gallstones. 

Click to enlarge

Rate:
  • Mean ventricular rate 114 bpm
Rhythm:
  • Irregular
  • No p wave visible
Axis:
  • Normal
Intervals:
  • QRS - Normal (90ms)
  • QT - 340ms (QTc Bazette 430 ms)
Additional:
  • Low voltage QRS
  • Flat T lead avL
  • T waves in inferior leads relatively large in relation to QRS voltage
  • No ST depression / elevation
Interpretation:
  • Atrial fibrillation with rapid ventricular response
  • Low voltage QRS

Clinical Factors in Atrial Fibrillation

There are several features to establish on assessment of the patient in atrial fibrillation that will influence both the immediate and long-term management strategies, including:
  • Onset and duration of symptoms
  • Likelihood of paroxysmal episodes
  • Evidence of compromise from AF
    • Chest pain, cardiac failure, hypotension etc.
  • Current medications
    • Especially anti-coagulation and anti-arrhythmics
  • Potential precipitant / cause
    • E.g. sepsis, electrolyte abnormality, endocrine disease
  • Suitability and contra-indications to management options
    • E.g. fasting status, anaesthetic risk, drug allergy / intolerance, bleeding risk
Management Options in Atrial Fibrillation

There are several considerations in the management of AF which include:
  • Rate vs. rhythm control
    • Electrical vs Chemical rhythm control
  • Anti-coagulation
    • Risk vs Benefit
    • Drug to use
  • ? Underlying precipitant
    • Infection / ischaemia / structural / endocrine / metabolic etc.
  • Follow-up / disposition
  • Ablation suitability
Despite being one of the commonest arrhythmia encountered in medicine there is considerable variability in the clinical management of atrial fibrillation. There are a number of international guidelines and protocols regarding AF management, including:
AF Related Calculators (links to MDCalc)
Low Voltage QRS

Differentials include:

  • Increased distance between heart and ECG leads
    • Obesity
    • Emphysema
    • Pleural effusion
    • Pericardial effusion
  • Inflammatory / infiltrative disease
    • Sarcoid
    • Amyloid
    • Myxoedema
    • Scleroderma
  • Structural
    • Cardiomyopathy

What happened ?

This patient was commenced on metoprolol and digoxin for rate control as their time of onset was unknown. Their underlying cholecystitis was treated with fluids and antibiotics.

References / Further Reading

Life in the Fast Lane


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