Dizziness and loss of consciousness: cardiovascular causes
BACKGROUND: Dizziness and loss of consciousness are common clinical problems presenting in general practice. OBJECTIVE: This article aims to provide the practitioner with a pragmatic and logical approach to identifying the cardiovascular causes of dizziness and loss of consciousness. DISCUSSION: A range of disorders with varying pathology cause a transient loss of consciousness associated with postural collapse (syncope) by interruption of blood flow to the brain. Syncope and seizures are the only common causes of recurrent episodes of loss of consciousness. The vasovagal reaction or 'common faint' and postural hypotension are both common and benign causes of syncope. Syncope can also result from cardiac causes that include disorders of cardiac rhythm and mechanical obstruction to cardiac output. Cardiac causes of syncope are associated with much higher morbidity and mortality than postural hypotension or fainting. Specific treatment is available for the various cardiac causes of syncope and thus accurate diagnosis is imperative.