Premature Ventricular Contraction

Aka: Premature Ventricular Contraction, PVC

1. See Also
   1. Extrasystole
2. Physiology
   1. PVCs have been historically thought to be benign
   2. More recently, data suggests increased risk
      1. In underlying cardiac disease, PVCs increase arrhythmia risk
      2. In otherwise normal hearts, PVCs are still typically benign
         1. However, longstanding frequent PVCs, increase risk of Cardiomyopathy
3. Definitions
   1. Bigeminy
      1. Extrasystole follows every sinus beat
   2. Trigeminy
      1. Extrasystole follows every other sinus beat
      2. Every third beat is ectopic
   3. Couplet
      1. Extrasystole and preceding beat
4. Causes
   1. Occasional PVCs are normal finding in healthy patient
   2. Cardiac causes
      1. Ischemic Heart Disease
      2. Cardiomyopathy
      3. Valvular heart disease
      4. Mitral Valve Prolapse
   3. Stimulants
      1. Caffeine
      2. Cocaine
      3. Alcohol
      4. Ephedrine or Pseudoephedrine
   4. Electrolyte Abnormalities
      1. Metabolic Acidosis
      2. Hypoxemia
      3. Hyperkalemia
      4. Hypokalemia
      5. Hypomagnesemia
   5. Medications
      1. Digoxin
      2. Theophylline
      3. Antipsychotic Medications
      4. Tricyclic Antidepressants
      5. Antiarrhythmics (Flecainide, Sotalol, Quinidine)
5. Signs: EKG Findings
   1. Unusual and Wide QRS with bizarre axis
   2. Large T Wave with opposite polarity as QRS
   3. Full compensatory pause
   4. No P Wave included in Extrasystole
   5. Associated with left bundle branch pattern
6. Evaluation: Lown Criteria to distinguish pathologic PVCs
   1. Low risk of degenerating into ventricular dysrhythmia
      1. Class 0: No PVCs
      2. Class 1: <30 PVCs per hour
   2. Intermediate risk of degeneration
      1. Class 2: 30 or more PVCs per hour
   3. High risk of degeneration
      1. Class 3: Multifocal PVCs
      2. Class 4a: Two consecutive PVCs
      3. Class 4b: Three consecutive PVCs
      4. Class 5: R on T Phenomena
7. Management
   1. No heart disease (normal left ventricular function)
      1. Avoid provocative factors
      2. Mild asymptomatic PVCs
         1. No management required
      3. Symptomatic PVCs accounting for <20% of total beats
         1. Consider Beta Blocker for disabling symptoms
      4. PVCs account for >20% of total beats
         1. Consider Cardiac Catheter Ablation
         2. Associated with increased risk of developing a Cardiomyopathy
            1. See physiology above regarding risk
   2. Heart disease (with Left Ventricular Dysfunction)
      1. PVCs increase risk of morbidity and mortality
      2. Consider management for Lown Class 3-5
         1. Consider Cardiac Catheter Ablation
8. References
   1. Baman (2010) Heart Rhythm 7(7): 865-9 [PubMed]