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.
12-lead electrocardiographic tracing demonstrating sinus atrial rhythm, total AV block with narrow QRS complex, with two sinus capture beats (4th and 5th QRS complexes of the D2 lead tracing at the bottom). (A higher resolution / colour version of this figure is available in the electronic copy of the article).
