Premature Ventricular Contractions (PVCs)

• Premature ventricular complexes (PVCs) are defined by early electrical firing from a focal region of the ventricle, leading to ventricular contraction before adequate coordination and filling of these chambers.¹
• In contrast to a normal beat, the electrical conduction with a PVC does not generally use the specialized conduction system. Instead, it occurs from depolarization of myocardial cell to myocardial cell, which have slower conduction properties than the specialized conduction system and thus results in a wider QRS (longer duration).¹
  • “sinus beats use a highway (specialized conduction system) to quickly get from point A to point B; PVCs use the back roads (myocardial cell to cell) and take longer to reach their destination”
• Premature ventricular complexes can be both a cause of and a consequence of an undiagnosed cardiomyopathy and progression of congestive heart failure.¹
• Some PVCs can also increase a patient’s risk for ventricular arrhythmias, syncope, and SCD.¹
• A PVC disrupts the normal filling of the ventricles.
• Three main mechanisms are used to explain the generation of PVCs:¹
  • triggered activity
  • enhanced automaticity
  • reentry
  • 
• Why may patients be symptomatic 😰? ¹
  • The symptoms are likely to be related to the early contraction and the dyscoordination of ventricular contraction. Because diastolic filling of the ventricle is interrupted, this results in reduced ventricular filling. The resultant cardiac output from the PVC-related ventricular contraction is thus diminished. It may lead to patients having a myriad symptoms, such as shortness of breath, lightheadedness, and fatigue.
  • left atrial pressures can be significantly elevated, leading to dyspnea due to higher pulmonary pressures

Work-up

Figure source: ¹

• Family history
  • screen for heart failure, coronary artery disease, arrhythmias, history of cardiomyopathy, and sudden unexplained deaths, particularly in young family members
• Social history
  • detailed account of caffeine, alcohol use, supplements, drug use, and psychological stressors
  • exercise and sports engagement
• Medication review
  • beta-agonists (such as albuterol inhalers for asthma or chronic obstructive pulmonary disease), alcohol, caffeine, and stimulants such as amphetamine derivatives
• ECG
  • note the following: PVC burden (generally presented as a percentage during a period of time); PVC morphology and axis to help localize the PVC origination site; PVC coupling interval; and, most important, if the patient is symptomatic, correlation of PVCs at the exact time of symptoms¹
• Event monitor
  • characterize PVC frequency, morphology and complexity
• Echocardiogramecho
  • to assess for structural heart disease, e.g. Cardiomyopathies or valvular disorders
• Cardiac MRI
  • even if Echo normal
  • particularly useful for patients with PVCs/VT and a non-idiopathic origin
• Exercise ECG
  • ↓/resolution of PVCs with exercise →
    • monomorphic PVCs that ↓/resolve during exercise are generally considered benign
    • may be d/t heightened sympathetic tone (↑ HR) suppressing abnormal automaticity that sometimes causes PVCs
  • ↑/persistent PVCs during exercise or recovery →
    • high-grade PVCs (frequent, multifocal, R-on-T, or VT) during recovery are associated with an ↑ long-term risk of CV mortality, even in the absence of known heart disease.
      • thought to be d/t insufficient vagal reactivation post-exercise
    • exercise-induced PVCs (esp. if high-grade) may reflect underlying structural heart disease or subclinical ischemia
  • In a study of asymptomatic individuals, ² found that “high-grade PVCs occurring during recovery were associated with long-term risk of cardiovascular mortality in asymptomatic individuals, whereas PVCs occurring only during exercise were not associated with increased risk.”
    • 

PVC Localization

• Outflow tract PVCs
  • Outflow tract PVCs are the most common.
  • Characteristically dominant R waves (tall positive deflections) in the inferior leads of II, III, and aVF (termed inferior axis).
  • Common outflow tract PVCs in isolation are not prognostically significant unless there is a high burden or associated cardiomyopathy.

Management

• PVCs that occur during the day, during faster heart rates, or during exertion may respond better to medical therapy compared with those occurring at rest or during sleep
• Beta-blockers and Calcium Channel Blockers (CCBs) (diltiazem or verapamil)
  • If beta-blockers are prescribed first and are ineffective at suppressing PVCs, nondihydropyridine calcium channel blockers can then be trialed, and vice versa.
• Ablation
  • has 80-95% success rate
• Second-line: Anti-Arrhythmic Drugs (if hesitant about ablation)
  • Sotalol (class III antiarrhythmic), flecainide (class Ic antiarrhythmic), and propafenone (class Ic antiarrhythmic) can be well tolerated and effective in treating PVCs. Mexiletine (class Ib antiarrhythmic) is rarely used as a second- or third-line agent. Amiodarone is a highly effective medication but has the potential for significant long-term adverse effects that limit its use in younger patients.¹
  • Amiodarone trial: Whereas the long-term use of amiodarone should ideally be avoided, particularly in younger patients, a short-term (3-month) trial of amiodarone can be both diagnostic and therapeutic before consideration of catheter ablation.¹

Examples

Bigeminy

Figure source: ¹. Note the wide-complex beats that occur after every other sinus beat (narrow QRS, preceded by p wave). These premature ventricular contractions have a prominent inferior axis (positive II, III, and aVF and negative aVR and aVL), likely signifying outflow tract origin.

Short-coupled PVCs

A coupling interval <350 ms is considered a short coupling interval.³

Figure source: ¹. A, Electrocardiogram demonstrating a short-coupled premature ventricular complex (PVC). Note that these short-coupled PVCs fall on the T wave of the preceding sinus beat. B, Measurement of the PVC coupling interval should be taken at the end of the preceding QRS and the start of the PVC. C, Telemetry strip showing polymorphic ventricular tachycardia triggered by a close-coupled PVC in the same patient.

Outflow Tract PVCs

Figure source: ¹. A, Right ventricular outflow tract premature ventricular complex (PVC). Note the tall positive QRS beats in II, III, and aVF and negative aVR and aVL (signifying a superior structure, ie, outflow tract) and left bundle branch block morphology (generally signifying right ventricle). This is a high-yield pattern of a common PVC morphology. B, Anterolateral papillary muscle PVC. Note right bundle branch block morphology (signifying left ventricle), negative lead I (generally signifying left lateral location), and mildly positive II, III, and aVF (generally signifying superior/anterior location).

Footnotes

1. Tseng AS, Kowlgi GN, DeSimone CV. Management of Premature Ventricular Complexes in the Outpatient Setting. Mayo Clin Proc. 2023 Jul;98(7):1042-1053. doi: 10.1016/j.mayocp.2023.01.021. PMID: 37419573. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³

2. Refaat MM, Gharios C, Moorthy MV, Abdulhai F, Blumenthal RS, Jaffa MA, Mora S. Exercise-Induced Ventricular Ectopy and Cardiovascular Mortality in Asymptomatic Individuals. J Am Coll Cardiol. 2021 Dec 7;78(23):2267-2277. doi: 10.1016/j.jacc.2021.09.1366. PMID: 34857087; PMCID: PMC8720278. ↩

3. Sabbag A, Essayagh B, Barrera JDR, Basso C, Berni A, Cosyns B, Deharo JC, Deneke T, Di Biase L, Enriquez-Sarano M, Donal E, Imai K, Lim HS, Marsan NA, Turagam MK, Peichl P, Po SS, Haugaa KH, Shah D, de Riva Silva M, Bertrand P, Saba M, Dweck M, Townsend SN, Ngarmukos T, Fenelon G, Santangeli P, Sade LE, Corrado D, Lambiase P, Sanders P, Delacrétaz E, Jahangir A, Kaufman ES, Saggu DK, Pierard L, Delgado V, Lancellotti P. EHRA expert consensus statement on arrhythmic mitral valve prolapse and mitral annular disjunction complex in collaboration with the ESC Council on valvular heart disease and the European Association of Cardiovascular Imaging endorsed cby the Heart Rhythm Society, by the Asia Pacific Heart Rhythm Society, and by the Latin American Heart Rhythm Society. Europace. 2022 Dec 9;24(12):1981-2003. doi: 10.1093/europace/euac125. PMID: 35951656; PMCID: PMC11636573. ↩