As a medical professional with expertise in cardiology, I can provide insight into the significance of a notch in the P wave on an electrocardiogram (ECG). A notched P wave, also known as a "double hump" or "biphasic P wave," can be indicative of certain cardiac conditions. When the notches are one small box width or more apart, it can be diagnostic of Left Atrial Enlargement (LAE). This enlargement of the left atrium is often a response to conditions that increase the workload on the heart, such as high blood pressure or mitral valve disorders. The P wave on an ECG represents the electrical activity of the atria during atrial contraction. A normal P wave is smooth and rounded, but in the case of LAE, the P wave may appear wider and notched, reflecting the increased distance the electrical impulse has to travel through the enlarged atrium. It's important to note that while a notched P wave can suggest LAE, it is not definitive proof. Other diagnostic tests and a comprehensive patient history are necessary 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 >>