Left Atrial Abnormality
- Prolonged P wave duration of >120 msec in lead II
- Prominent notching of the P wave, usually most obvious in lead II, with an interval between the notches of >40 msec (p mitrale)
- Ratio between the duration of the P wave in lead II and the duration of the PR segment of >1.6
- Increased duration and depth of the terminal negative portion of the P wave in lead V1 (the P terminal force) so that the area subtended by it exceeds 0.04 mm-sec (Morris index)
- Leftward shift of the mean P wave axis to between -30 and +45 degrees
Right Atrial Abnormality
- Peaked P waves with amplitudes over 250 muV in lead II (p pulmonale)
- Rightward shift of the mean P wave axis to above 75 degrees
- Increased area under the initial positive portion of the P wave in lead V1 to >0.06 mm-sec
References:
- Edhouse J, Thakur RK, Khalil JM. ABC of clinical electrocardiography. Conditions affecting the left side of the heart. BMJ. 2002 May 25;324(7348):1264-7. [Medline]
- Harrigan RA, Jones K. ABC of clinical electrocardiography. Conditions affecting the right side of the heart. BMJ. 2002 May 18;324(7347):1201-4. [Medline]
Created: Jan 04, 2006
