of the Week:
Sinus rhythm with blocked PAC's (in a trigeminal pattern).
Note the long
pause identified by the blue horizontal line. Look at the T wave
on the beat prior to each pause...the T wave has a notch or buried P wave
(identified by red arrow). The P wave of this premature atrial
contraction has come too early in the cycle to be conducted, resulting
in a blocked QRS or non-conducted PAC.