A 41 year old man with previous cardiac history and ablation presents with palpitations and shortness of breath. On presentation his blood pressure and other observations are within normal limits and he is pain free.
ECG is as follows.
Interpretation:
- Rate: 132
- Rhythm: atrial tachycardia
- Axis: normal 0-90
- Morphology: intermittent normally and aberrantly conducted complexes
- Intervals: Normal complexes QRS 100 Aberrant complexes QRS 160
- Summary: Could this be Ashman phenomenon?
What is Ashman phenomenon:
when a long RR interval is followed by a short RR interval and then terminated by an aberrant QRS complex (which normally has a RBBB pattern)
most commonly seen in AF but can also be seen in other atrial tachycardias
a long RR interval will cause a long refractory period of the myocardium as the two are proportional. This means that if a short RR interval (ie a premature electrical stimulus) follows a long RR interval the His bundle will still be in refractory state, meaning that you will get an abnormally conducted beat. They often have a RBBB morphology, as the right BB has a longer refractory period than the left.
from a practical perspective they are benign and require no intervention. Some patients may experience palpitations none the less.
for this patient the AF was his acute pathology and the reason for his symptoms.