A syncopal episode, the medical term for fainting, is a temporary loss of consciousness accompanied by a loss of muscle tone. This results from a sudden decrease in blood flow to the brain. This experience is common, affecting all ages, although it occurs more frequently in older adults. The loss of consciousness is short-lived, with awareness returning within minutes as blood flow is restored.
The Syncopal Episode Experience
The moments leading up to a faint, the pre-syncopal phase, have distinct warning signs. A person may feel lightheaded, dizzy, or that the room is moving. Vision can become blurry or narrow into “tunnel vision,” and sounds may seem distant or muffled. Other sensations include a sudden clammy sweat, nausea, and appearing pale to others.
The faint itself is characterized by a brief loss of consciousness and muscle control, causing the person to fall or slump over. This change in position helps restore blood flow to the brain, which is why the period of unconsciousness is very short. The person will not be responsive during this time and their breathing may be shallow.
Upon regaining consciousness, a person enters the post-syncopal phase. It is common to feel confused, groggy, or tired for a short period. Some people may experience a headache or feel weak. While alertness often returns within minutes, a feeling of fatigue can linger.
Underlying Causes of Syncope
The most frequent cause of a syncopal episode is vasovagal syncope, often called the “common faint.” This is a reflex response to triggers such as the sight of blood, intense emotional distress, pain, fear, or prolonged standing. These triggers cause a sudden drop in both heart rate and blood pressure, reducing circulation to the brain and leading to fainting.
Another cause is orthostatic hypotension, which is fainting that occurs when standing up too quickly. When a person stands, gravity pulls blood into the legs and lower body. The nervous system counteracts this by increasing heart rate and constricting blood vessels to maintain blood pressure. In orthostatic hypotension, this response is inadequate, causing blood pressure to drop and leading to fainting. Dehydration, certain medications, and some neurological conditions can contribute.
Less common, but more serious, are syncopal episodes caused by underlying heart conditions. Cardiac syncope can occur if the heart beats too quickly or too slowly (an arrhythmia), preventing it from pumping blood effectively. Structural problems with the heart, such as diseased valves or weakened heart muscle, can also obstruct blood flow. These causes require prompt medical investigation.
Medical Evaluation and Diagnosis
Determining the cause of a syncopal episode begins with a medical evaluation. A healthcare provider will take a detailed medical history and ask for a precise description of the event. Information about the circumstances, such as the patient’s position, activity, and any potential triggers, is important for diagnosis.
A physical examination is a standard part of the evaluation. This includes measuring blood pressure and heart rate, sometimes in different positions to check for orthostatic hypotension. Listening to the heart can help detect murmurs or other sounds that might suggest a structural heart problem. This assessment helps guide further testing.
An electrocardiogram (ECG or EKG) is a common diagnostic tool that records the heart’s electrical activity and can identify arrhythmias. If a cardiac cause is suspected but not captured on a standard ECG, more specialized monitoring may be used. A Holter monitor is a portable device worn for 24 hours or longer to record the heart’s rhythm. For infrequent faints, a tilt-table test may be performed to simulate changing positions and monitor the body’s response.
Treatment and Prevention Strategies
The approach to managing syncope is tailored to its underlying cause. For vasovagal syncope, a common recommendation is to recognize warning signs and avoid known triggers. When symptoms appear, performing counter-pressure maneuvers can help. These include crossing the legs, tensing muscles in the arms and legs, or gripping an object tightly to raise blood pressure.
For orthostatic hypotension, lifestyle adjustments are often effective. Increasing the intake of fluids and sometimes salt can help maintain blood volume. It is also advised to change positions slowly, for instance, by sitting on the edge of the bed for a moment before standing. Wearing compression stockings can also improve blood circulation from the legs.
When syncope is due to a cardiac condition, treatment focuses on the specific heart problem. This might involve medications to control an irregular heartbeat, known as antiarrhythmics. In other cases, a procedure or an implantable device, such as a pacemaker or an implantable cardioverter-defibrillator (ICD), may be necessary to prevent future episodes.