Interpolated VPC

  Does not have a compensatory pause.

  The RR interval of the 2 sinus beats encompassing the VPC is slightly longer than

      the RR interval of the 2 sinus beats not including the VPC.

 
The first PR interval following the VPC MAY be longer than the PR interval of other beats.

      Sometimes, the prolongation of PR interval may even be observed in the second sinus beat following

      the VPC.

  Generally seen during bradycardia.




Reference

  J Electrocardiol 2006;39:377-379.





ECG 1. Interpolated VPC. RR intervals are almost the same.

Click here for a more detailed ECG





ECG 2. In the ECG above, the
PR interval of the first sinus P wave following the VPC is prolonged.
In lead C3, the
T wave of the second sinus beat preceding the VPC looks similar to the T wave following the first sinus beat:
there is no aberrantly conducted supraventricular beat since the interpolated VPC has no embedded P wave before itself.

Click here for a more detailed ECG





ECG 3. The ECG from a 60 years-old man with acute inferior myocardial infarction (
ST segment elevation in inferior leads).
PR interval of the first sinus P wave following the VPC is prolonged.
Compare it with the
PR interval of the preceding sinus beats.

Click here for a more detailed ECG





ECG 4. The above ECG is from a 67 years-old man and shows ventricular trigeminal rhythm with interpolated
VPCs.
The
PP interval containing the VPC is shorter than the PP interval not encompassing it.
Also, the first
PR interval following the VPC is relatively prolonged when compared with the preceding PR interval.

Click here for a more detailed ECG