Ventricular Premature Complex

1. What is a Ventricular Premature Complex (VPC)?

A. A premature beat originating from the atria
B. A premature beat originating from the AV node
C. A premature beat originating from the ventricles
D. A pause following a normal sinus beat

Correct Answer: C

Explanation:
VPCs (also called PVCs – Premature Ventricular Contractions) are early depolarizations originating in the ventricles. They bypass the normal conduction pathway, resulting in abnormal, widened QRS complexes without preceding P waves.


2. Which of the following ECG features is characteristic of a VPC?

A. Narrow QRS complex
B. P wave before each QRS
C. Wide, bizarre QRS complex
D. Long PR interval

Correct Answer: C

Explanation:
Because VPCs originate in the ventricular myocardium, the impulse takes longer to travel, producing a wide (>120 ms) and often bizarre-looking QRS complex.


3. What usually follows a VPC on the ECG?

A. Atrial fibrillation
B. A compensatory pause
C. Shortened QT interval
D. PR prolongation

Correct Answer: B

Explanation:
VPCs are usually followed by a full compensatory pause, as the sinus node timing is unaffected, and the next normal sinus beat arrives on schedule.


4. Which of the following is NOT typically associated with VPCs?

A. Hypokalemia
B. Myocardial ischemia
C. Digoxin toxicity
D. Hyperthyroidism

Correct Answer: D

Explanation:
While VPCs can occur in various conditions, hyperthyroidism is more commonly linked with atrial arrhythmias like atrial fibrillation. VPCs are typically associated with ischemia, electrolyte imbalance, and digitalis toxicity.


5. A pattern where a VPC occurs after every normal beat is known as:

A. Trigeminy
B. Bigeminy
C. Couplet
D. Quadrigeminy

Correct Answer: B

Explanation:
Bigeminy is a rhythm in which every second beat is a VPC — a normal beat followed by a VPC repeatedly.


6. What defines a couplet in the context of VPCs?

A. Two VPCs from different foci
B. Two VPCs in a row
C. VPC with a supraventricular beat
D. Two VPCs with compensatory pauses

Correct Answer: B

Explanation:
A couplet refers to two consecutive VPCs. It’s important as it may indicate increased ventricular irritability.


7. Three or more consecutive VPCs at a rate >100 bpm are termed:

A. Ventricular fibrillation
B. Supraventricular tachycardia
C. Ventricular tachycardia
D. Paroxysmal atrial tachycardia

Correct Answer: C

Explanation:
Ventricular tachycardia (VT) is defined as three or more VPCs in a row at a rate >100 bpm. It may be sustained (>30 sec) or non-sustained.


8. What is a fusion beat?

A. Simultaneous atrial and ventricular beat
B. Beat with features of both sinus and VPC
C. Two VPCs fused together
D. Ventricular beat with a hidden P wave

Correct Answer: B

Explanation:
A fusion beat is when a sinus beat and a VPC occur simultaneously, producing a hybrid QRS complex. It’s a sign of ventricular origin during arrhythmia.


9. Which of the following is an appropriate first-line treatment for symptomatic frequent VPCs?

A. Amiodarone
B. Digoxin
C. Beta-blockers
D. Calcium channel blockers

Correct Answer: C

Explanation:
Beta-blockers are the first-line for symptomatic VPCs, especially in post-MI patients or those with structural heart disease. Antiarrhythmics like amiodarone are used in resistant or high-risk cases.


10. Why are frequent VPCs concerning in patients with structural heart disease?

A. They improve cardiac output
B. They indicate AV nodal reentry
C. They may degenerate into ventricular fibrillation
D. They resolve spontaneously with rest

Correct Answer: C

Explanation:
In patients with underlying cardiomyopathy or ischemic heart disease, frequent VPCs can be a warning sign and may lead to ventricular tachycardia or ventricular fibrillation, both of which are life-threatening.


ECG Characteristics

  1. Wide QRS complex (>120 ms)
  2. Bizarre morphology (different from normal QRS)
  3. No preceding P wave
  4. T wave direction opposite to QRS
  5. Usually followed by a full compensatory pause

Patterns of Occurrence

  • Isolated VPC: Single premature beat
  • Couplet: Two consecutive VPCs
  • Triplet: Three consecutive VPCs (may be nonsustained VT)
  • Bigeminy: VPC after every normal beat
  • Trigeminy: VPC after every two normal beats
  • Quadrigeminy: VPC after every three normal beats

Types Based on Morphology

  • Unifocal VPCs: All VPCs look the same (same origin)
  • Multifocal VPCs: Different morphologies (different origins) → higher risk

Clinical Relevance

  • Occasional VPCs in healthy individuals may be benign
  • Frequent VPCs (>10% of total beats or >30/hour) need evaluation
  • R-on-T phenomenon: VPC falling on preceding T wave → may trigger VT/VF
  • High burden VPCs can cause VPC-induced cardiomyopathy

Clinically significant

  • VPCs in presence of:
    • Structural heart disease (e.g. MI, cardiomyopathy)
    • Syncope or palpitations
    • Family history of sudden cardiac death
    • LVEF < 40%
      → Require urgent cardiology evaluation

Management

  • Asymptomatic + normal heart: Often no treatment
  • Symptomatic or frequent:
    • ✅ Lifestyle: avoid caffeine, stress, alcohol
    • ✅ Beta-blockers (1st line)
    • Calcium channel blockers (non-dihydropyridine) in some cases
    • Antiarrhythmics (e.g., Amiodarone) in selected cases
    • Catheter ablation for refractory or high-burden VPCs

Prognosis

  • Benign if infrequent and no structural heart disease
  • Concerning if:
    • High frequency
    • R-on-T phenomenon
    • Multifocal origin
    • Occur during exercise or recovery

Prognostic Implications Vary by Context

ContextPrognosis
Healthy heart, isolated VPCsUsually benign
Post-MI with frequent VPCsHigh risk for SCD
Dilated cardiomyopathy with VPCsWorsens prognosis
VPC-induced cardiomyopathyReversible if burden reduced

VPC-Induced Cardiomyopathy

  • Chronic high-burden VPCs (>10–15% of all beats) can cause:
    • LV dysfunction
    • Dilated cardiomyopathy
  • Reversible with:
    • Medical suppression (e.g., beta-blockers)
    • Catheter ablation (curative in many)

VPC falling on the preceding T wave can trigger malignant ventricular arrhythmias

Especially dangerous in:

  • Ischemia
  • Long QT syndromes
  • Electrolyte disturbances

VPCs During Exercise or Recovery

  • VPCs at peak exercise: May be benign
  • VPCs during recovery phase:
    • Strongly associated with increased cardiac mortality
    • Reflect autonomic imbalance and myocardial vulnerability

FeatureRisk Level
Isolated VPCs in healthy heartLow
Frequent VPCs with structural heart diseaseHigh
R-on-T, polymorphic, exercise-recovery VPCsVery high
VPC-induced cardiomyopathyReversible with treatment

VPCs in ECG – Risk Stratification (20 Key Points)

#ParameterHigh-Risk FeaturesLow-Risk Features
1Underlying heart diseaseStructural heart disease (e.g. MI, cardiomyopathy)Normal heart
2Frequency>10,000 VPCs/day or >10% burden<1% burden, rare
3PatternBigeminy, couplets, triplets, runsIsolated VPCs
4MorphologyPolymorphic, multifocalMonomorphic
5VPC timingR-on-T phenomenonOccurs after T wave
6Exercise stress testVPCs in recovery phaseVPCs at peak exercise or absent
7SymptomsSyncope, presyncope, palpitationsAsymptomatic
8Ejection fraction (EF)LVEF <40%LVEF >50%
9Response to exerciseIncrease in VPCsSuppression with exercise
1024-hr Holter monitoring>500 VPCs/hour<30 VPCs/hour
11Couplets/tripletsPresentAbsent
12Sustained VT historyPresentAbsent
13Family history of SCDPresentAbsent
14VPC burden effect on LVLV dysfunction (PVC-induced cardiomyopathy)No effect on LV
15Fusion beatsSeen (suggests re-entry)Absent
16QT intervalProlonged QT with VPCs → torsades riskNormal QT
17Presence of scar (MRI)Scar/fibrosis seenNormal myocardium
18Response to beta blockersPoor/no responseSymptom relief
19Inducibility on EP studyVT inducibleNot inducible
20ICD indicationMeets primary/secondary prevention criteriaNot indicated

Frequency:

The number of PVCs per minute or hour (PVC burden) is a crucial risk factor. More than 5 PVCs per minute or 10-30 per hour are generally considered frequent. 

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