Ophthalmologists can play a pivotal role in detection and treatment of life-threatening disorders by recognizing syndromes associated with retinal tumors. Ophthalmologists can play a pivotal role in detection and treatment of life-threatening disorders by recognizing syndromes associated with retinal tumors.
The P wave in the ECG represents atrial depolarization, which results in atrial contraction.
The portion of the ECG that corresponds to atrial depolarization is  called the P wave. The P wave is the first wave on the ECG.