Extended Matching Questions - Broad Complex Tachyarrhythmias

For each of the following ECGs select the most appropriate finding(s) from the list below. Each option may be used once, more than once or not at all.

  1. Accessory pathway - Wolff Parkinson White
  2. Axis deviation - left
  3. Axis deviation - right
  4. Bundle branch - left
  5. Bundle branch - right
  6. Concordance - negative
  7. Concordance - positive
  8. Conduction Delay -  intraventricular
  9. Idioventricular rhythm - escape
  10. Idioventricular rhythm - accelerated
  11. Rhythm - sinus
  12. Rhythm - supraventricular tachycardia
  13. Rhythm - atrial fibrillation
  14. Rhythm - atrial flutter
  15. Rhythm - ventricular tachycardia
  16. Rhythm - ventricular fibrillation
  17. Rhythm - capture beats
  18. Rhythm - fusion beats
  19. Supraventricular tachycardia - aberrant conduction
  20. Wide complex tachycardia - mechanism not clear

Question 1A

+ Question 1A. Palpitations and dyspnoea in a 84 year old woman

A: 3; 5; 15; 18.
The irregularity in the R-R intervals seen between the 9th and 14th QRS beats in the rhythm strip suggest atrial fibrillation (the R-R interval between the other complexes is constant at 320 msec). A small deflection is seen emerging from the T wave that precedes the 9th, 12th and 14th QRS complexes - this is (most likely) a P wave. The 9th, 12th and 14th QRS complexes have a similar shape but a smaller amplitude than the other complexes in the rhythm strip. The 9th, 12th and 14th complexes are thus fusion beats. The R wave in Lead avR, the frontal plane axis of - 900 and the rS morphology in Lead V6 also support the diagnosis of ventricular tachycardia.

Question 1B

+ Question 1B. Rhythms strips recorded by the ambulance paramedics in a 72 year old man with sudden onset of crushing central chest pain and diaphoresis, followed by the onset of palpitations while being transported to hospital

15; 16; 11 (after cardioversion).

Question 1C

+ Question 1C. Sixty seven year old man with a past history of hypertension, elevated cholesterol, gastro-oesophageal reflux and insertion of a stent into the left anterior descending artery 12 months ago at another hospital. While having a meal he had sudden onset of central chest pain, dyspnoea and sweating. These symptoms initially responded to glyceryl trinitrate, but the chest discomfort returned 15 minutes later. This ECG was obtained upon arrival at the Emergency Department, when he still had mild chest pain. There was no alteration in his conscious state or blood pressure. There were no previous ECGs available for comparison.

3; 5; 7; 10.
The morphology of the complexes in the precordial leads (Rsr' in Leads V1 to V3) and the positive concordance favour a ventricular origin for the rhythm, and the ventricular rate of about 103 beats per minute is more likely to be caused by an accelerated idioventricular rhythm than a (slow) ventricular tachycardia.

Question 1D (Initial ECG)

Question 1D. The initial ECG of a 104 year old man with palpitations and a systolic blood pressure of 110 mmHg. The patient did not have any chest pain (taken at 1747).

2; 8; 20.
The shape of the complexes in Lead I and Lead V1 resembles those seen in left bundle branch block, but Lead V6 has a RS configuration that does correspond to left bundle branch block.

The working clinical diagnosis of the rhythm in this case was "wide QRS complex tachycardia - consider ventricular tachycardia". There was no previous ECG for comparison, so we do not know if the intraventricular conduction disorder is a new finding.

There are no ECG features of ventricular tachycardia apart from possible negative concordance: Leads V1 to V4 have a QS/rS shape, and Leads V5 and V6 have deep S waves but the associated R wave amplitude exceeds that of the S wave

Question 1D (Subsequent ECG)

+ Question 1D. The ECG of the 104 year old man after cardioversion. (1828)

2; 6; 8; 11.
The similarity between the QRS complexes in this second ECG and the initial ECG indicate that the underlying mechanism of the tachycardia was a supraventricular tachycardia