Definition

  Occurrence of VPCs after long RR intervals and disapparence of them when the RR intervals shorten

      is called
the rule of bigeminy.

  The
rule of bigeminy is usually the explained by the reentry mechanism.

  The VPC
tends to perpetuate itself unless the RR interval shortens.



Reference

  Circulation 1955;11:422-430





ECG 1. The 3-channel ECG tracing above is from the Holter recording of a middle-aged woman.
As the heart rate progressively decreases (
as the RR interval progressively increases), a VPC is seen.

Click here for a more detailed ECG





ECG 2. The ECG above belongs to a 16 years-old male whose ECHOcardiogram was normal.
The long RR interval favors the occurrence of VPCs.
When the heart rate increases (
RR intervals shorten), the VPCs disappear.

Comment by Dr. Fred Kusumoto: These are PVCs that arise from the right ventricular outflow tract and are probably due to
triggered activity-this is the likely explanation for why they develop at slow heart rates and are suppressed at faster heart rates.
The fixed coupling interval argues against parasystole.

Pediatric Cardiologist Dr. Mahmut Gokdemir has donated this ECG to our website.


Click here for a more detailed ECG





ECG 3. The ECG above belongs to a 57 years-old woman with coronary artery disease and hypertension.
A VPC occurred only after
the cycle with the longest RR interval.
No additional VPC followed, probably due to the increase in heart rate.

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ECG 4. The ECG above is from another patient with coronary artery disease.
Ventricular bigeminy is seen on the left hand.
When the heart rate increases (
RR interval shortens) VPCs disappear.
When the heart rate decreases again (
RR interval lengthens), venticular bigeminal rhythm reappears.

Click here for a more detailed ECG