Premature Ventricular Contractions

A relatively common event where the ventricle initiates its own contraction instead of the sinoatrial node.

Determining PVCs on a cardiac monitor using the analytical approach:

QRS Complex: WIDE ≥0.12 seconds
P Waves: If present, they have no relation to the ventricular beat
Rate: Dependent on underlying rhythm
Rhythm: Generally this ectopic beat is an interruption of a regular underlying rhythm
PR Interval: Since any P wave wouldn't be connected to the V-beat, there is no PR interval

Wikipedia Entry: A PVC may be perceived as a "skipped beat" or felt as palpitations in the chest. In a normal heartbeat, the ventricles contract after the atria have helped to fill them by contracting; in this way the ventricles can pump a maximized amount of blood both to the lungs and to the rest of the body . In a PVC, the ventricles contract first, which means that circulation is inefficient. However, single beat PVC arrhythmias do not usually pose a danger and can be asymptomatic in healthy individuals.

Symptoms

  • Chest pain;
  • Faint feeling;
  • Fatigue;
  • Hyperventilation (after exercise)

Frequent episodes of continuous PVCs becomes a form of ventricular tachycardia (VT), which is a rapid heartbeat, because there is an extra electrical impulse, causing an extra ventricular contraction.

Treatment

Isolated PVCs with beginning characteristics require no treatment. In healthy individuals, PVCs can often be resolved by restoring the balance of magnesium, calcium and potassium within the body. The most effective treatment is the elimination of triggers (particularly the cessation of the use of substances such as caffeine, and illegal drugs.)

  • Pharmacological agents
    • Antiarrhythmics: Lidocaine, Amiodarone
    • Beta blockers
    • Calcium channel blockers
  • Electrolytes replacement
    • Magnesium supplements (e.g. magnesium citrate, orotate, Maalox, etc.)
    • Potassium supplements
  • Radiofrequency catheter ablation treatment
  • Lifestyle modification
    • Frequently stressed individuals should consider therapy, or joining a support group.
    • Heart attacks can increase the likelihood of having PVCs.

In the setting of existing cardiac disease, however, PVCs must be watched carefully, as they may cause a form of ventricular tachycardia (rapid heartbeat).

Recent studies have shown that those subjects who have an extremely high occurrence of PVCs (several thousand a day) can develop dilated cardiomyopathy. In these cases, if the PVCs are reduced or removed (for example, via ablation therapy) the cardiomyopathy usually regresses.

 

 


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