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.
Therefore, each small 1-mm square represents 0.04 sec (40 msec) in time and 0.10 mV in voltage. Because the recording speed is standardized, one can calculate the heart rate from the intervals between different waves. P wave (atrial depolarization) The P wave represents the wave of depolarization that spreads from the SA node throughout the atria, and is usually 0.08 to 0.10 seconds (80-100 ms) in duration. The brief isoelectric (zero voltage) period after the P wave represents the time in which the impulse is traveling within the AV node (where the conduction velocity is greatly retarded) and the bundle of His.