As a medical professional with expertise in cardiology, I can provide you with an explanation of a notched P wave. A notched P wave is a type of P wave that has an indentation or notch in its contour. This can be observed on an electrocardiogram (ECG) and is indicative of certain cardiac conditions. When the notch is one small box width or more away from the peak of the P wave, it is considered significant and can be diagnostic of Left Atrial Enlargement (LAE). This enlargement of the left atrium is often due to conditions that increase the workload on the left side of the heart, such as high blood pressure or mitral valve disease. Additionally, a biphasic P wave, which is a P wave that has two opposite deflections (positive followed by negative or vice versa), can also indicate LAE if the downward portion of the P wave is one box or larger in both depth and length. This biphasic nature is another sign that the left atrium may be enlarged. It's important to note that while a notched or biphasic P wave can suggest LAE, it is not definitive and other diagnostic tests are typically required to confirm the diagnosis. read more >>

A ��double hump�� or notched P wave is diagnostic of LAE if the peaks are one small box or more apart. A biphasic P wave indicates left atrial enlargement if the downward portion of the P wave is one box or larger in both depth and length.read more >>