Dx Extrasystoles

• Extrasystoles are contractions which occur when there is electrical discharge from somewhere in the heart other than SA node.
• Extrasystoles can be seen in ECG as premature QRS complex which is followed by delay before next QRS.
• Extrasystoles can be classified as atrial, junctional or ventricular.
• Atrial and junctional extrasystole appears as narrow QRS complexes (<120msec or 3 small squares) while ventricular extrasystoles are wide QRS complexes (>120msec).
• Atrial extrasystoles have P waves that have different morphology compared with sinus P wave, while junctional extrasystoles do not have P wave.