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Jason's Blog: ECG Challenge for the month of July, 2013.

jer5150's picture

No information available about this patient.  What is your interpretation?

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Submitted by mjross on

Sinus rhythm with blocked PACs resulting in assistance from pacemaker.

Submitted by wrmedic82 on

I see a sinus rhythm with a normal axis, with a pause following a ventricular paced beat. V1, V2 have a RBBB morphology with poor r wave progression in the precordial leads.'s picture

As per my "subject heading" - this NEAT tracing by Jason has a number of interesting findings on it.

  • Agree with mjross - there is underlying sinus rhythm with a blocked PAC (best seen in leads II,III ). This results in a pause that is ended by paced escape beats. Of note is that a sinus P wave is seen to occur just before the paced escape beat - so there might be some fusion in the paced complex.
  • Otherwise - there is complete RBBB. While the ST-T depression in leads V1,V2 are consistent with the RBBB - the J-point is depressed in lead V3 - and ST depression persists throughout the remaining precordial leads which is not normal for RBBB. In addition - there is inferior ST depression. This suggests possible ischemia that could be acute.
  • No clinical information is given. One should keep in mind that RBBB and inferior and/or anterior ST-T wave depression are two ECG signs that IF the clinical setting was right - might suggest acute pumonary embolus. One would expect tachycardia .... but clinical correlation would be key.
  • The P wave in lead II is relatively tall. It is not quite "pointed" enough to qualify for RAE - but again, IF the clinical context was new-onset dyspnea - one might contemplate PE ...

NICE tracing! THANKS for posting - : )

Ken Grauer, MD   [email protected] 

jer5150's picture
Submitted by jer5150 on

(1.)  Sinus rhythm (rate about 79/min) interrupted twice by . . .
(2.)  . . . nonconducted atrial premature beats (APBs; arrows).
(3.)  Ventricular demand pacemaker presumably pacing the right ventricle (RV) at a rate of 50/min.
(4.)  Right bundle-branch block (RBBB).
(5.)  Primary ST-T changes.

If not for the nonconducted APBs, we would have no direct way of knowing this patient had any device implanted.  As Ken stated, the pacemaker is serving as an artificial analogue for a ventricular escape beat.  Playing the part of devil's advocate, my only question would be if a pacemaker was implanted solely because of the nonconducted APBs.  Was a pacemaker really necessary?  In some patients, it is actually less risky to implant a permanent pacemaker than it is to medically treat the APBs. 

Jason E. Roediger - Certified Cardiographic Technician (CCT)
[email protected]

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