Premature Ventricular Beats (PVCs) on ECG

Introduction

Premature ventricular contractions (PVCs), also known as premature ventricular beats, are extra heartbeats that originate from the ventricles. They are a common finding on an electrocardiogram (ECG) and may occur in healthy individuals or as a sign of underlying heart disease.

ECG Characteristics of PVCs

A PVC has distinctive features on an ECG: - Wide QRS complex (≥ 120 ms): This occurs because the impulse does not follow the normal His-Purkinje conduction system. - No preceding P wave: Since PVCs originate in the ventricles, they do not have an associated P wave preceding them. - Compensatory pause: Often, a PVC is followed by a longer-than-normal pause before the next normal beat. - Discordant T wave: The T wave is often in the opposite direction of the QRS complex.

Types of PVC Patterns

• Isolated PVCs: Occur sporadically.
• Bigeminy: Every normal beat is followed by a PVC.
• Trigeminy: Every two normal beats are followed by a PVC.
• Couplets: Two consecutive PVCs.
• Runs of PVCs: Three or more PVCs in a row, which may indicate nonsustained ventricular tachycardia.

Clinical Significance

• Benign PVCs: In people with a normal heart structure, occasional PVCs are usually harmless and do not require treatment.
• Pathological PVCs: Frequent or symptomatic PVCs can indicate structural heart disease, electrolyte imbalances, or ischemia.
• Risk of Arrhythmias: Frequent PVCs may increase the risk of developing dangerous arrhythmias, especially in patients with conditions like heart failure or a low ejection fraction.

Diagnosis and Management

• ECG and Holter Monitoring: Essential for assessing the PVC burden and pattern.
• Echocardiography: Helps rule out structural heart disease.
• Electrolyte and Thyroid Function Tests: To identify possible metabolic causes.
• Lifestyle Modifications: Reducing caffeine, alcohol, and stress can decrease PVC frequency.
• Medical Treatment: Beta-blockers or calcium channel blockers may be considered in symptomatic patients.
• Catheter Ablation: In cases of very frequent PVCs leading to heart dysfunction, ablation may be recommended.

Conclusion

While most PVCs are benign, frequent or symptomatic cases require further evaluation. If you experience palpitations, dizziness, or other symptoms, consult a cardiologist.

Source recommendations

1. American Heart Association Guidelines for the Evaluation and Management of Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death

1. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000549
2. https://professional.heart.org/en/science-news/2018-guideline-for-the-evaluation-and-management-of-bradycardia-and-cardiac-conduction-delay
3. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000548
4. https://www.heartrhythmjournal.com/article/S1547-5271(22)01946-4/fulltext
5. https://www.jacc.org/doi/abs/10.1016/j.jacc.2017.10.054

2. European Society of Cardiology Guidelines for the Management of Patients with Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death

1. https://academic.oup.com/eurheartj/article/43/40/3997/6675633
2. https://pubmed.ncbi.nlm.nih.gov/36017572/
3. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Ventricular-Arrhythmias-and-the-Prevention-of-Sudden-Cardiac-Death
4. https://pubmed.ncbi.nlm.nih.gov/26320108/
5. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000549