atrial ectopics
Last reviewed 01/2018
Atrial ectopics have the following characteristics on the ECG:
- premature P waves
- abnormal shaped P waves
- incomplete compensatory pause before next sinus beat
Most atrial ectopic beats will be conducted through the AVN, hence the QRS complex is normal.
Ectopic P waves occurring early in the cardiac cycle may encounter components of the conducting system which are still refractory:
- blocked atrial ectopic - the AVN is refractory
- prolonged P-R interval - the AVN is partially refractory
- phasic aberrant ventricular conduction - a bundle branch, usually the right, is refractory. The QRS may resemble that of a ventricular ectopic