Anatomic correlates that serve as memory aids for atrial patterns are that the normal two humps to the P wave are comprised of a right and left atrial component:

q      The left atrial notch is second following the right atrial notch with the subsequent depolarization of the left atria. The P wave can have a negative component in V1/V2 because the left atria makes up the posterior border of the heart.

q      Left atrial abnormality or P-mitrale: broad, notched P waves in II and AVF (greater than 2.5 millimeters wide or 100 milliseconds duration) with a negative component in V1 or V2 (that exceeds one millimeter by one millimeter, e.g., 40 milliseconds by 0.I millivolt) - associated with mitral regurgitation, congestive heart failure or any clinical condition that elevates LV filling pressure. It can even be transient with the occurrence of CHF.

These changes from the normal P wave morphology are called abnormalities since it is not clear if they are due to hypertrophy, dilation or altered electrical activation.

Left atrial abnormality not present on prior ECGs: If the Left atrial abnormality or P-mitrale is new when comparing to previous tracings, consider the clinical presentation for congestive heart failure and/or mitral valvular insufficiency. The Framingham Criteria for congestive heart failure consist of a listing of historical and physical findings; a definitive diagnosis of congestive heart failure relies on the concurrent presence of two major or one major and two minor criteria.

q      The major criteria include PND or orthopnea, neck vein distention, rales, cardiomegaly, acute pulmonary edema, S3, and hepatojugular reflux.

q      The minor criteria include ankle edema, night cough, DOE, hepatomegaly, pleural effusion, and tachycardia greater than 120 bpm.

Mitral valvular insufficiency is confirmed by a holo-systolic murmur radiating to the axilla and if necessary, by echocardiography.

Left atrial abnormality on prior ECG: If the Left atrial abnormality or P-mitrale is old when comparing to previous tracings, consider the ECG for the other left ventricular hypertrophy criteria. This can be an ominous marker for future events including CHF, stroke or death. Physical exam and an echocardiogram can confirm these possible diagnoses. If a dilated cardiomyopathy is confirmed by documenting systolic dysfunction (decreased ejection fraction or fractional shortening) an ACE inhibitor or vasodilators (long acting nitrates and hydralazine) is indicated to improve patient survival. ACE inhibitors can cause a cough, hyperkalemia and renal dysfunction requiring a switch to a long acting nitrate and hydralazine.