Cardiac syncope is a specific form of syncope, or fainting, in which a person temporarily loses consciousness due to a brief reduction in blood flow to the brain.
Broadly speaking, syncope refers to the transient loss of consciousness and postural tone. Its causes can vary and include neurological, metabolic, orthostatic, and cardiovascular factors.
Due to its potential association with serious underlying conditions, cardiac syncope requires an accurate diagnosis and timely intervention.
What Is Cardiac Syncope?
Specifically, cardiac syncope or cardiogenic syncope refers to a brief loss of consciousness caused by a cardiovascular malfunction that reduces blood supply to the brain. It may result from various heart-related conditions:
- Arrhythmias: Irregular heart rhythms can cause prolonged pauses or rates that are too fast or too slow, leading to insufficient blood flow.
- Structural heart diseases: Conditions such as hypertrophic cardiomyopathy, aortic stenosis, or ventricular dysfunction can impair blood flow.
- Coronary anomalies: Diseases affecting the coronary arteries can reduce blood flow and trigger syncopal episodes.
- Conduction system disorders: Malfunctions of the sinus node or atrioventricular blocks can cause prolonged pauses in heart activity, leading to fainting.
Unlike other types of syncope, cardiac syncope may occur without prior warning and can sometimes be a sign of risk for sudden death.
Symptoms of Cardiac Syncope
Cardiac syncope is characterized by a sudden loss of consciousness and postural tone, followed by spontaneous recovery.
However, some warning or associated symptoms may appear due to the underlying cardiovascular issue, such as:
- Palpitations: A sensation of irregular or rapid heartbeats before the fainting episode.
- Chest pain: May indicate an underlying ischemic cause, such as a myocardial infarction.
- Shortness of breath (dyspnea): Can be a symptom of heart failure.
- Absence of prodromal signs: Unlike vasovagal syncope, which may present with dizziness or nausea, cardiac syncope often occurs without such early signs.
- Slow recovery: In some cases, the loss of consciousness may be prolonged, and the patient may take time to regain orientation.
- Syncope during physical activity: Fainting during exertion or exercise may indicate an underlying and potentially serious heart condition.
It’s essential to distinguish between the symptoms of vasovagal syncope and cardiac syncope, which is why rapid medical evaluation is crucial to prevent high-risk complications.
Vasovagal Syncope
Cardiac syncope is relatively uncommon; in contrast, vasovagal syncope is more frequent and results from an abnormal response of the autonomic nervous system, as opposed to a direct cardiovascular problem.
Vasovagal or neurocardiogenic syncope can be triggered by situations such as fear, pain, intense emotions, or standing for long periods. In these cases, the vagus nerve—which is the body’s longest nerve, originating in the brain and extending to the stomach—causes a temporary decrease in heart rate and blood pressure. This reduces cerebral blood flow and leads to fainting.
Unlike cardiac syncope, vasovagal syncope typically presents with prodromal symptoms such as dizziness, unsteadiness, sweating, blurry vision, nausea, or a feeling of heat.
It is important to identify the root cause of any fainting episode, as some arrhythmias can mimic vasovagal syncope, and patients with vasovagal syncope may also have underlying heart disease.
Proper evaluation and diagnosis require tests such as an electrocardiogram (ECG), Holter monitoring, echocardiogram, or tilt-table testing. These help differentiate between types of syncope and identify the exact cause.
Proper diagnosis of cardiac syncope must be a priority, as it is a potentially serious condition that requires detailed evaluation to rule out underlying cardiovascular diseases.
Early and accurate diagnosis is key to preventing adverse events, especially in patients with a history of heart disease.
At the ABC Medical Center’s Arrhythmia Clinic, we can provide you with specialized care. Contact us!
Fuentes:
MSD Manuals, Cigna, Fundación Española del Corazón
