Syncope (Fainting)

The categories of syncope

Reflex (neurally mediated) syncope

The largest category. The autonomic nervous system over-responds to a trigger — long standing, heat, dehydration, emotional stress, sight of blood, pain, micturition, defecation, post-meal — causing a brief drop in heart rate and blood pressure. The classic pattern: prodrome (warmth, nausea, sweating, dimming vision) → collapse → rapid recovery. Vasovagal syncope is the most common subtype.

Orthostatic syncope

Fainting from a drop in blood pressure on standing. Can be from volume depletion (dehydration, blood loss), medications (especially antihypertensives, alpha blockers, diuretics), or autonomic dysfunction (diabetes, Parkinson's, pure autonomic failure). Diagnosed by checking BP supine and at 1 and 3 minutes standing.

Cardiac syncope

The category most worth identifying. Subtypes:

• Arrhythmic — from bradycardia (heart block, sinus node dysfunction) or tachycardia (ventricular tachycardia, supraventricular tachycardia, AFib with rapid response). Often abrupt with no prodrome.
• Structural — aortic stenosis, hypertrophic cardiomyopathy, pulmonary hypertension, pulmonary embolism. Often exertional.
• Ischemic — acute coronary syndrome occasionally presents with syncope.

Non-syncope mimics

Worth keeping in mind: seizures, hypoglycemia, drop attacks, cataplexy, and psychogenic spells can look like syncope but are not.

What an evaluation looks like

History — most diagnostic

A detailed account of the event answers most of the question: circumstances, posture, triggers, prodrome, duration of loss of consciousness, witness observations (eye-rolling, twitching, tongue-biting, urinary incontinence — point toward seizure; pallor and rapid recovery — toward syncope), recovery, and associated symptoms (chest pain, palpitations, breathlessness). Family history of sudden death is critical. Medication list and recent changes also matter.

ECG

A 12-lead ECG is part of almost every syncope workup. Looks for arrhythmias, conduction blocks, evidence of structural heart disease, Long-QT syndrome, Brugada pattern, and other signals that point toward cardiac syncope.

Echocardiogram

Ordered in most cases to assess heart structure and rule out structural causes (aortic stenosis, hypertrophic cardiomyopathy).

Rhythm monitoring

For unexplained syncope, monitoring during the episode is diagnostic. Picked by frequency:

• Holter monitor for daily symptoms (rarely enough — episodes are usually less frequent than syncope workups suggest).
• Patch monitor (1-2 weeks) for episodes a few times a week.
• Event monitor (30 days) for less frequent episodes.
• Implantable loop recorder for infrequent but recurrent unexplained syncope — months to years of continuous monitoring.

Tilt-table testing

Reserved for selected cases where vasovagal syncope is suspected but the diagnosis is not clear from history. The patient is monitored on a table that tilts upright; the test attempts to reproduce the symptoms under controlled conditions.

Stress testing

Added when syncope occurs with exertion — to look for exertional arrhythmias or ischemic causes.

Treatment by cause

• Reflex syncope — education on triggers, counter-pressure maneuvers, adequate hydration and salt, sometimes fludrocortisone or midodrine for refractory cases.
• Orthostatic syncope — medication review, volume management, compression stockings, sometimes medications to raise standing BP.
• Cardiac syncope — directed at the cause: pacemaker for severe bradyarrhythmia, antiarrhythmic medication or ablation for tachyarrhythmias, ICD for high-risk ventricular arrhythmias, valve intervention for severe structural disease.

How virtual cardiology handles syncope

1. First visit by video. Detailed history of the episode(s), review of any prior workup, screening for high-risk features.
2. Initial workup ordered to facilities near you. ECG, echocardiogram, monitor as indicated.
3. Follow-up visit to interpret results and finalize the plan.
4. Coordination with local cardiology for procedural interventions when needed (pacemaker, ablation, ICD).

Syncope with high-risk features (exertional, with prodrome of chest pain or severe SOB, in known structural heart disease, family history of sudden cardiac death) is escalated to urgent workup rather than routine outpatient evaluation.