Clinical Electrophysiology

• Electricity moving towards an electrode is POSITIVE.

  Electricity moving away from an electrode is NEGATIVE.
• Fill in the blanks

  A) Limb

  B) Chest

  C) Rhythm Strip

  
• Fill in the blanks

  A) Inferior

  B) Anterior

  C) Lateral

  D) Lateral

  E) Lateral

  
• What do 5 small squares represent on an ECG?

  200 ms
• What do 5 big squares on an ECG represent?

  1 second
• What is a normal PR interval?

  120 - 200 ms (3-5 small squares)
• What does a prolonged PR interval indicate?

  1st degree heart block
• What is the normal width of a QRS complex?

  3 small squares (normal < 120 ms)
• What does a broad QRS indicate?

  Bundle branch block
• What does ST elevation indicate?

  Infarction

  Pericarditis
• What does ST depression indicate?

  Ischaemia (e.g. angina)
• What does T wave inversion indicate?

  Ischaemia, any structural heart problem, non-specific
• What does low K+ do to the T wave?

  Flat, prolonged T wave
• What does high K+ (& early MI) show on an ECG?

  High T wave (peaked)
• What is the normal range of of the QT interval?

  Males = 350 - 440 ms

  Females = 350 - 460 ms
• What is the approach to reading an ECG?

  Is the rhythm regular or irregular?

  Is the HR fast or slow?

  Is the axis in Lead I & II positive?

  Ratio; is there 1 P wave to each QRS?

  Is there any ST elevation or depression?

  Check intervals (PR, QRS, QT)
• What is normal HR?

  60-100 bpm
• How do you work out the rate of an ECG?

  Rate = 300/ number of large squares between R waves (for regular HR)

  OR

  Rate = total number of R waves x 6 (for irregular HR)
• What is a normal sinus rhythm?

  Normal looking P wave, always followed by a QRS, in regular fashion
• What is atrial fibrillation?

  Irregular heart rhythm.

  Irregularly irregular QRS complexes

  No P waves

  
• What is complete heart block?

  Condition where the electrical signals in the heart are completely blocked, resulting in a disruption of the normal rhythm and coordination of the heart's contractions.

  
• What is ventricular tachycardia?

  Tachycardia (120 - 250 bpm)

  Regular

  Broad QRS

  No P waves

  Potentially life-threatening

  Usually associated with structural heart disease

  
• What does the P wave represent?

  Atrial depolarisation
• What does QRS complex represent?

  Ventricular depolarisation
• What does the T wave respresent?

  Ventricular repolarisation
• What leads should be NORMALLY positive?

  Leads I & II

  
• What are the limb leads in an ECG?

  Lead I, II, III, aVR, aVL, aVF
• What are the chest leads in an ECG?

  V1 - V6
• T wave should be in the same axis as QRS complex.
• What is the length of a rhythm strip?

  10 seconds
• What is shown in the image?

  Normal sinus rhythm

  
• What is artial flutter?

  Regular atrial rhythm NOT a sinus rhythm

  Regularly irregular

  'Saw tooth' appearance

  
• What is complete heart block?

  Condition where the electrical signals in the heart are completely blocked, resulting in a disruption of the normal rhythm and coordination of the heart's contractions.

  Atria contract & ventricles contract BUT not in sync -> differing PR intervals

  
• What is the treatment of complete heart block?

  Pacemaker
• What is shown in the image?

  Ventricular tachycardia

  
• Fill in the blanks

  A) 2:1

  B) 3:1

  C) Variable

  
• What is a paroxysmal rhythm?

  A paroxysmal rhythm is an irregular heart rhythm that occurs suddenly and intermittently.
• What is a ventricular ectopic?


  An abnormal heartbeat originating from the ventricles.
• Ventricular ectopics in isolation is a normal finding.

  
• What is shown in the image?

  Left bundle branch block