Causes
Syncope falls into three broad groups:- Reflex (vasovagal) syncope: The most common type. A nervous-system reflex abruptly slows the heart and drops blood pressure, triggered by prolonged standing, heat, pain, emotional distress, or even the sight of blood. In Florida's heat and humidity, dehydration is a frequent contributor.
- Orthostatic syncope: Blood pressure falls on standing because of dehydration, blood loss, or medications such as blood pressure drugs, diuretics, and some antidepressants.
- Cardiac syncope: The most concerning group. Rhythm problems — very fast rhythms such as supraventricular tachycardia or very slow rhythms — and structural problems such as severe valvular heart disease can abruptly cut the heart's output.
Symptoms and Warning Signs
Reflex fainting usually announces itself: lightheadedness, warmth, nausea, sweating, "graying out" or tunnel vision, and muffled hearing in the seconds before consciousness is lost. Bystanders may notice pallor. Recovery is rapid once the person is lying flat. Fainting with no warning at all, or during physical exertion, points toward a cardiac cause and is treated far more seriously.Diagnosis
The most valuable tools are a careful history — what you were doing, what you felt beforehand, how quickly you recovered — a physical examination, blood pressure measurements lying and standing, and an electrocardiogram. Depending on the findings, your physician may add blood tests, an echocardiogram, a wearable heart monitor to catch intermittent rhythm problems, or a tilt-table test to reproduce reflex fainting under controlled conditions. Routine brain imaging is usually unnecessary unless the story suggests a seizure or head injury, because true syncope is a circulation problem rather than a brain problem.Treatment
Treatment is aimed at the underlying cause:- Reflex syncope: Staying well hydrated, recognizing warning symptoms, and sitting or lying down promptly. Physical counter-maneuvers — crossing the legs and tensing the muscles — can abort an episode.
- Orthostatic causes: Reviewing and adjusting medications, increasing fluid and salt intake when appropriate, and rising slowly from sitting or lying positions.
- Cardiac causes: Treating the specific rhythm or valve problem, which may involve medication changes, a pacemaker for slow rhythms, or valve intervention.