Diagnostic criteria

  Depolarization of the ventricles occurs by an impulse originating from an ectopic ventricular focus.

  There is
no causally related preceding P wave since the impulse originates from the ventricles.

  Since the impulse originates from an ectopic ventricular focus, depolarization wave does not propagate

      over the fast Purkinje fibers but by the cardiac myocytes which results in
slow conduction and hence

wide QRS complex (>120ms).

Clinical significance

  Observation of VPS in a subject without organic heart disease is not significant.

  VPS is the most common type of arrhythmia.

  VPS is not specific for a certain disease.

Not all wide QRS complexes are due to VPC:

      Ventricular pacemeker stimulation results in wide QRS.

      Aberrant conduction of a supraventricular impulse to the ventricles (aberrancy) causes wide QRS.

  Sometimes, artifacts may look like VPCs.

Click on the links below to see various types of VPCs:

            End-diastolic VPC

            Interpolated VPC

            Interpolated ventricular couplet

            R-on-T VPC

            Rule of bigeminy

            VPC-like artifact