How are ventricular premature complexes (VPCs) classified?

Updated: Nov 26, 2016
  • Author: Jatin Dave, MD, MPH; Chief Editor: Jose M Dizon, MD  more...
  • Print

VPCs can be classified in different ways. The Lown classification was introduced to gauge effects of antiarrhythmic drugs and widely assumed to encapsulate prognostic significance—it is not clear that it fulfills either of these goals, but this classification is still employed.

Table 1. Lown Classification (Open Table in a new window)






Unifocal; < 30/h


Unifocal; ≥ 30/h




2 consecutive


≥ 3 consecutive


R-on-T phenomenon


The Lown classification does not necessarily imply a continuum of increasing risk.

Clinical classification is as follows:

  • Benign

  • Potentially malignant

  • Malignant

Classification according to frequency is as follows:

  • Frequent - 10 or more VPCs per hour (by Holter monitoring) or 6 or more per minute

  • Occasional - Fewer than 10 VPCs per hour or fewer than 6 per minute

Classification according to relationship to normal beats is as follows:

  • Bigeminy - Paired complexes, VPC alternating with a normal beat

  • Trigeminy - VPC occurring every third beat (2 sinus beats followed by VPC)

  • Quadrigeminy - VPC occurring every fourth beat (VPC following 3 normal beats)

  • Couplet - 2 consecutive VPCs

  • Nonsustained VT - 3 or more consecutive VPCs (< 30 s)

Classification according to origin is as follows:

  • Number of foci: Unifocal/unimorphic (beats originate from 1 focus; ie, all VPCs have the same morphology) or multifocal/multimorphic (VPCs have more than one morphology and may originate from more than one site)

  • Site of origin: Left or right ventricular

  • Associated heart disease: None (idiopathic) or structural heart disease is present

Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!