What is the appropriate workup for a patient presenting with premature ventricular contractions (PVCs) and bigeminy?

Workup for Premature Ventricular Contractions (PVCs) and Bigeminy

The appropriate workup for a patient with PVCs and bigeminy should include a 12-lead ECG, 24-hour Holter monitoring, echocardiography, and exercise stress testing to assess for underlying structural heart disease and quantify PVC burden. 1

Initial Assessment

History and Focused Examination

• Assess for symptoms: palpitations, dizziness, presyncope, syncope, chest pain, dyspnea, or exercise intolerance
• Evaluate for risk factors of structural heart disease
• Check for family history of sudden cardiac death or inherited arrhythmias
• Medication history (QT-prolonging medications, stimulants)
• Physical exam focusing on cardiac findings (murmurs, gallops, signs of heart failure)

Basic Testing

1. 12-lead ECG during sinus rhythm 1

   • To identify underlying heart disease
   • Document PVC morphology and coupling intervals
   • Look for other conduction abnormalities

2. 24-hour Holter monitoring 1, 2

   • Quantify PVC burden (percentage of total beats)
   • Document pattern (bigeminy, trigeminy, couplets)
   • Identify non-sustained VT episodes
   • Critical threshold values:
     • <2,000 PVCs/24h: Very low risk
     • 10-15% burden: Intermediate risk

     • 15% burden: High risk

     • 24% burden: Very high risk for cardiomyopathy

3. Echocardiography 1, 2

   • Assess for structural heart disease
   • Evaluate ventricular function (LVEF)
   • Rule out valvular disease
   • Look for early signs of PVC-induced cardiomyopathy

4. Exercise stress testing 1

   • Evaluate if PVCs increase or decrease with exercise
   • Assess for exercise-induced ventricular arrhythmias
   • Help exclude ischemia as a cause

Advanced Testing (Based on Initial Findings)

For Patients with Abnormal Initial Evaluation or High PVC Burden

1. Cardiac MRI 2

   • Indicated for patients with:
     • High PVC burden (≥15% of total beats)
     • Non-sustained VT
     • Abnormal findings on initial evaluation
   • Evaluates for subtle structural abnormalities
   • Identifies areas of fibrosis or scarring
   • May help localize PVC origin in preparation for ablation 3

2. Electrophysiologic Study

   • Consider for patients with:
     • Symptomatic PVCs refractory to medical therapy
     • High PVC burden (>15%)
     • Evidence of PVC-induced cardiomyopathy
     • Suspected arrhythmogenic focus amenable to ablation

For Specific Clinical Scenarios

1. Coronary evaluation (stress test, coronary CT, or angiography)

   • For patients with risk factors for coronary artery disease
   • When ischemia is suspected as trigger for PVCs

2. Signal-averaged ECG

   • If arrhythmogenic right ventricular cardiomyopathy (ARVC) is suspected 2

3. Genetic testing

   • When family history suggests inherited arrhythmia syndromes 2

Risk Stratification Based on Findings

Low Risk

• Asymptomatic or mildly symptomatic
• PVC burden <10%
• Normal cardiac structure and function
• PVCs suppress with exercise
• No family history of sudden death

Intermediate to High Risk

• Symptomatic despite therapy
• PVC burden >15%
• Evidence of structural heart disease
• PVCs increase with exercise
• Presence of non-sustained VT
• Evidence of declining LV function

Common Pitfalls to Avoid

1. Misdiagnosis of bigeminy

   • Blocked atrial bigeminy can mimic sinus bradycardia; examine T waves carefully for hidden P waves 1
   • Ensure proper differentiation between ventricular and supraventricular bigeminy with aberrancy

2. Inadequate quantification of PVC burden

   • Short-term monitoring may underestimate true PVC burden
   • Consider extended monitoring (>24 hours) if clinical suspicion is high

3. Missing underlying structural heart disease

   • Up to 30% of patients with ≥2,000 PVCs/24h may have underlying structural heart disease 1
   • Comprehensive imaging is essential even with seemingly benign PVCs

4. Overlooking PVC-induced cardiomyopathy

   • Can occur with PVC burden ≥10%, with higher risk at ≥24% 2
   • Follow-up echocardiography may be needed in patients with high PVC burden

By following this systematic approach to evaluating patients with PVCs and bigeminy, clinicians can identify those at risk for adverse outcomes and determine appropriate management strategies based on risk stratification.