Never Been to Spain

Well I never been to Spain
But I kinda like the music
Say the ladies are insane there
And they sure know how to use it

Well I never been to heaven
But I've been to Oklahoma
Well they tell me I was born there
But I really don't remember

Never Been to Spain: Written by Hoyt Axton, and sung by Three Dog Night

The patient is a 32 year old man with a past history of non Hodgkins lymphoma diagnosed 10 years ago and treated with chemotherapy and a stem cell transplant. Three years ago he had a splenectomy following an accident.  Two months ago, while travelling in Spain, he had several episode of marked tachycardia.  One week ago he had another episode of tachycardia, and was treated in another hospital. His arrhythmia did not respond to cardioversion, and he was sent home on oral flecainide.
He presented with a ninety minute history of palpitations and feeling dizzy. There was no chest pain nor sweating nor dyspnoea. The blood pressure was 120/80 mm Hg,  and examination of the cardiovascular system was normal.

+ What are the main findings on the initial ECG taken at 2156 hours?

Enlarged view of the rhythm strip of ECG_0012

The rhythm strip shows two different types of QRS complexes:

  • Upright complexes with a qRs or Rs shape and a width of about 0.08 seconds
  • Complexes with a rS or RS shape and a width of about 0.2 seconds. Some of these complexes show a delta wave (e.g. the eighth complex in the top panel of the rhythm strip).

The RR interval is irregular, and there are no P waves (apart from one possible P wave preceding the eighth complex in the top panel) The ventricular rate is about 140 beats per minute.

There are two distinct families of QRS complexes in ECG-0012.
ECG-0012-A shows the family of narrow QRS complexes from ECG-0012.

These complexes have a large amplitude and a normal axis. There is T wave inversion in Leads II, III and aVF and ST depression in Lead I and Leads V2 to V6. There is slight ST elevation in Lead aVR and Lead aVL.

ECG-0012-B shows the family of wide QRS complexes from ECG-0012. These complexes have a right bundle branch block morphology and left axis deviation. Delta waves are seen in many of the complexes e.g. Leads V4 - V6

The diagnosis is atrial fibrillation in a person with Wolf Parkinson White syndrome. The ventricular rate is relatively slow because the patient is on flecainide. The narrow QRS complexes are due to conduction through the AV node, and the wide QRS complexes are due to conduction through the accessory pathway and the AV node.

The plan was to treat the patient with intravenous flecainide, but the atrial fibrillation reverted to sinus rhythm before this was done (ECG-0012-C below).*

ECG0012C showing sinus rhythm