Cardinal ECG Features and Treatment
The cardinal ECG features treatment:
- Rate over 100
- P waves present, before QRS (antegrade) but shape may be abnormal (Fig 1) (distinguishes it from sinus tachycardia)
- In focal atrial tachycardia there will be a consistent abnormal P wave, whilst multifocal atrial tachycardia will have multiple different P wave morphologies
- R-P baseline isoelectric (distinguishes it from AF)
Treatment
DC cardioversion is likely to terminate the tachycardia, but some rhythms may recur.
Evidence for specific drug therapy is poor, with beta-blockers, calcium channel blockers and most anti-arrhythmic drugs having potential roles. Adenosine may diagnose the rhythm but is unlikely to terminate it.
Beta-blockers & calcium channel blockers may be used first-line for chronic therapy of recurrent episodes, with catheter ablation the definitive treatment of choice.