Premature ventricular contraction

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**Premature ventricular contraction**
*Classifications and external resources*

Premature ventricular contraction in an ECG (arrows)
ICD-10	I 49.3
ICD-9	427.69
DiseasesDB	32412
eMedicine	emerg/773

Premature ventricular contraction (PVC), also known as ventricular premature beat (VPB) or extrasystole, is a form of irregular heartbeat in which the ventricle contracts prematurely. This results in a "skipped beat" followed by a stronger beat. Individuals with the condition may report feeling that his or her heart "stops" after an attack. PVCs are also called heart palpitations (although there are many other forms of arrhythmia). The depolarization begins in the ventricle instead of the usual place, i.e. the sinus node. PVCs can be a useful natural probe, since they induce Heart rate turbulence whose characteristics can be measured, and used to evaluate cardiac function.

1 Frequency
2 Causes
3 Diagnosis
4 Possible triggers
5 Possible remedies
6 See also

[edit] Frequency

PVCs are a very common form of arrhythmia, and can occur in both individuals with and without heart disease. They can also occur in otherwise healthy athletes (e.g. in the days following a major effort such as a marathon). Estimates of the prevalence of PVCs vary greatly, but in large, population-based studies African Americans are known to have an increased occurrence of almost 30% compared with individuals of the Caucasian race.

In children, PVCs occur less frequently than in adults, although healthy children are known to have episodes of PVC. In fact, on routine monitoring of children aged 10-13 years with a Holter monitor, about 20% of healthy boys had occurrences of PVC. In otherwise healthy newborns, PVCs will oftentimes resolve on their own by the 12th week of life, and almost never require treatment.

[edit] Causes

Some possible causes of PVC in adults include the use of cocaine, amphetamines, alcohol, and tobacco. Medicines including digoxin, sympathomimetics, tricyclic antidepressants, and aminophylline have also been known to trigger attacks of PVC.

Heart conditions or a previous history of heart attack, ischemia, myocarditis, dilated or hypertrophic cardiomyopathy, myocardial contusion, atrial fibrillation and mitral valve prolapse may cause PVC. Patients with hypomagnesemia, hypokalemia, and hypercalcemia may also present with PVC.

PVCs in young children are thought to be associated with developmental factors of the autonomic nervous system. In older children, sympathomimetic drugs, such as cold or asthma medication may cause PVCs, along with mild cases of viral myocarditis, and excessive caffeine.

[edit] Diagnosis

PVCs are diagnosed by an ECG but some patients will need to wear a Holter monitor to record PVCs that occur outside the doctor's office or hospital. PVCs are often benign but may be a sign of a heart condition. PVCs may be unifocal (coming from the same part of the heart and having the same shape on the ECG) or multifocal (coming from several parts of the heart and having various shapes on the ECG). On the ECG, PVCs are diagnosed by: 1. prematurity 2. wide QRS 3. the presence(usually) of a compensatory pause.

In healthy individuals, PVCs can often be resolved with continuous rehydration and by repleting the balance of magnesium, calcium and potassium within the body.