What is PVC (Premature Ventricular Contraction)?

Premature Ventricular Contraction (PVC)

A premature ventricular contraction (PVC) is an early heartbeat that originates from the ventricles rather than from the sinoatrial node, resulting in an irregular heart rhythm that can range from asymptomatic to causing significant cardiac dysfunction depending on frequency and underlying cardiac conditions. 1

Definition and Characteristics

• PVCs are a type of ventricular arrhythmia (VA) that represent early beats originating in the ventricles rather than following the normal electrical conduction pathway 1
• PVCs are common and increase in frequency with age, with longer-term monitoring showing PVCs in approximately 50% of all people with or without heart disease 1
• PVCs can present with a spectrum of clinical manifestations ranging from no symptoms to palpitations, dizziness, or in rare cases, contributing to cardiac dysfunction 2

Epidemiology

• PVCs were found in only 0.6% of healthy individuals <20 years of age and 2.7% of those >50 years of age on standard 12-lead ECGs 1
• In the general population, frequent PVCs (defined as at least 1 PVC on a 12-lead ECG or >30 PVCs per hour) are associated with increased cardiovascular risk and mortality 1
• PVC burden is classified as low risk at approximately 2.1% of total heartbeats in patients without structural heart disease 2

Risk Stratification

• The risk of underlying structural heart disease increases with PVC burden:
  • 0% for <100 PVCs/24h 2
  • 3% for <2,000 PVCs/24h 2
  • Up to 30% for ≥2,000 PVCs/24h 2
• Multifocal PVCs are associated with increased risk of death and nonfatal cardiovascular adverse outcomes in patients without sustained VT or structural heart disease 1
• PVCs have been associated with increased risk of stroke in population studies 1

Clinical Significance

• Most isolated PVCs in structurally normal hearts are benign 3
• Very frequent PVCs (>10,000 to 20,000 per day) can be associated with depressed left ventricular function 1
• When PVCs constitute >10% of total heartbeats, patients may experience fatigue and exertional dyspnea 4
• When PVCs exceed 20% of total heartbeats, patients may develop cardiomyopathy and heart failure 4
• PVC-induced cardiomyopathy can develop in susceptible individuals with frequent PVCs, though not all patients with high PVC burden will develop cardiomyopathy 5

Evaluation

• Determine if a patient has symptoms related to PVCs, such as palpitations, dizziness, or syncope 2
• Evaluate for underlying structural heart disease with an echocardiogram to assess cardiac function and structure 2
• Exercise stress testing can help determine if PVCs suppress with exercise (benign) or increase (potentially concerning) 2
• The morphology of PVCs is important - those originating from the right ventricular outflow tract are generally benign, but QRS duration exceeding 160ms may indicate early arrhythmogenic right ventricular cardiomyopathy 2

Management

• For asymptomatic patients with normal ventricular function, clinical surveillance without specific treatment is recommended 2
• No antiarrhythmic therapy is indicated for asymptomatic patients with normal ventricular function 2
• Treatment is indicated for:
  • Frequent and symptomatic PVCs 6
  • Cases with worsening of left ventricular function 6
  • When PVCs trigger polymorphic ventricular tachycardia 5
• Treatment options include:
  • Catheter ablation, which is often effective for reducing PVC frequency and resolving left ventricular dysfunction 5
  • Antiarrhythmic medications, which may provide reduction in PVC frequency and resolution of left ventricular dysfunction 5

Important Considerations

• In the post-MI population, treatment of PVCs with class I sodium channel–blocking medications (e.g., quinidine, flecainide) increases the risk of death despite suppression of ventricular arrhythmias 1
• In patients with reduced left ventricular ejection fraction, class I sodium channel–blocking medications and d-sotalol increase the risk of death 1
• Further evaluation is warranted if PVCs increase during exercise rather than suppress 2
• If episodes of non-sustained ventricular tachycardia are present, additional evaluation including cardiac MRI may be indicated 2