Women may be more aware of PVCs at the time of the menstrual period.Premature ventricular contractions may be associated with underlying heart disease, and certain characteristics are therefore elicited routinely: the presence of signs of heart disease or a known history of heart disease (e.g. previous myocardial infarction), as well as heart disease or sudden cardiac death in close relatives. PVCs and palpitation associated with syncope (transient loss of consciousness) or provoked by exertion are also concerning. Physical examination is focused on identifying evidence of underlying heart disease. Causes
Premature ventricular contractions occur in healthy persons of any age, but are more prevalent in the elderly and in men. In a very significant proportion of people they occur spontaneously with no known cause.Some possible underlying causes of PVCs include:

Non-cardiac causes
Adrenaline excess
Anemia
Catecholamine excess
Certain medicines such as tricyclic antidepressants, digoxin, sympathomimetics, aminophylline
Chemical (electrolyte) abnormalities in the blood (for example hypokalemia (low blood potassium), which can occur in those taking diuretics ("water pills") and hypomagnesaemia (magnesium deficiency)). Contact with the carina (trachea/bronchi) when performing medical suctioning stimulates vagus nerve
Drugs/substances such as:Amphetamines
Alcohol
Caffeine
Cocaine
Nicotine
Theobromine
Hypercapnia (CO2 poisoning)
Hypertension (high blood pressure)
Hyperthyroidism
High blood calcium
Hypoxia and/or hypercapnia
Lack of sleep/exhaustion
Sarcoidosis
Smoking
Stress
Anxiety

Cardiac causes
Any structural heart disease which alters electrical conduction pathways due to tissue alterations
Cardiomyopathy, hypertrophic or dilated
Myocardial infarction
Myocarditis
Myocardial contusion
Mitral valve prolapse

Pathophysiology
Normally, impulses pass through both ventricles almost at the same time and the depolarization waves of the two ventricles partially cancel each other out in the ECG.
- Hyperthermia — elevated body temperature
- Autonomic instability (e.g. tachycardia, high blood pressure, diaphoresis, diarrhoea, etc. )Urinary retention — the inability to pass urine despite having urine to pass. Blood dyscrasias e.g. agranulocytosis (a potentially fatal drop in white blood cell count), leukopaenia (a drop in white blood cell counts but not to as extreme an extent as agranulocytosis), neutropaenia (a drop in neutrophil [the cells of the immune system that specifically destroy bacteria] count), thrombocytopaenia (a dangerous drop in platelet [a cell found in the blood that plays a crucial role in the blood clotting process] counts), purpura (the appearance of red or purple discolourations of the skin that do not blanch when pressure is applied), eosinophilia (raised eosinophil [the cells of the immune system that specifically fights off parasites] count)
Hepatitis — inflammation of the liver
Jaundice
Pigmentary retinopathy
Anaphylactoid reactions
Oedema — the abnormal buildup of fluids in the tissues
Asthma
Coma
Seizures
Confusional states
Disorientation
Incoordination
Ataxia
Tremors
Peripheral neuropathy — nerve damage
Numbness, tingling and paresthesias of the extremities
Dysarthria
Syndrome of inappropriate antidiuretic hormone secretion (SIADH)
Tinnitus — falsely hearing ringing in the ears. Alteration in EEG patterns
Paralytic ileus — cessation of the peristaltic waves that propel partially digested food through the digestive tract. Hyperpyrexia (elevated body temperature)
Disturbance of accommodation
Increased intraocular pressure
Mydriasis

Pharmacology
Binding affinities (Ki[nM]; for human cloned receptors when available)

See also
Flupentixol/melitracen
Olanzapine/fluoxetine
Tranylcypromine/trifluoperazine


== References ==