Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Schematic diagram showing ECG tracings. The letters P, Q, R, S, and T designate the respective waves. RR intervals: cardiac cycle; P wave: atrial depolarization; PR intervals: atrioventricular conduction; QRS intervals: ventricular depolarization; QT intervals and T wave: ventricular repolarization.
