Those at Risk
About 90 percent of people who faint have cardiovascular syncope, the most serious type of fainting disorder. The risk of cardiovascular syncope increases with age, and those at greatest risk are people who have:
- Coronary artery disease, or CAD (clogged blood vessels to the heart), angina (chest pain caused by reduced blood flow to the heart) or a prior heart attack (myocardial infarction).
- Ventricular dysfunction, a weakness in the ventricles, the heart's major pumping chambers.
- Structural heart disease, such as problems with the heart valves or muscles (cardiomyopathy).
- An abnormal electrocardiogram (ECG). An ECG is a common test that prints out a graph that shows how the heart is beating and records its electrical activity.
- Recurrent episodes of fainting that come on suddenly and without warning.
Signs of Cardiovascular syncope
Cardiovascular syncope usually is sudden. There may be no warning signs that an individual is about to faint. People sometimes feel tightness in the chest, shortness of breath, apprehension or an unusual awareness of the heartbeat (palpitations). Palpitations may feel as if the heart is fluttering, racing, skipping beats or pounding with unusual force in the chest. If syncope occurs after palpitations that end abruptly, a heart rhythm disorder often is the cause.
Fainting during physical exercise or a history of unexplained fainting in childhood may be signs that syncope is related to a heart problem.
Orthostatic (Postural) Hypotension is a condition in which the blood pressure drops suddenly when a person stands up. Sometimes the underlying cause is a cardiovascular condition called "pump failure." This means that the heart pump sometimes "fails" to maintain normal blood pressure. This may be due to muscle damage from a prior heart attack, inflammation of the heart, structural defects in the heart's valves or muscle (cardiomyopathy) or medications. Disorders of the electrical system that regulates the rate and strength of the heartbeat can cause pump failure. Heart rhythm disorders (arrhythmias) include bradycardia (a too-slow heartbeat), tachycardia (a rapid heartbeat) and fibrillation (a rapid heartbeat that also is chaotic, or irregular).
Cardiovascular Syncope and Long QT Syndrome
Fainting is the primary symptom - and may be the only warning sign - of Long QT Syndrome (LQTS), an inherited electrical disorder of the heart.
LQTS is believed to be a common cause of sudden and unexplained death in children and young adults. It may occur in as many as 1 in 5,000 individuals and causes up to 4,000 deaths in children and young adults each year in the United States.
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