Syncope: When is it a sign of a heart condition?

Syncope, also known as fainting, can sometimes signal a serious heart condition requiring thorough evaluation and appropriate management.

Dr Mohamed Al-Obaidi, renowned consultant cardiologist, explains what syncope is, how it is assessed, and when more advanced cardiac treatments are needed.

What is syncope?

Syncope is a brief, sudden loss of consciousness caused by a temporary decrease in blood flow to the brain. This episode often lasts only seconds to minutes, with the person experiencing it typically regaining consciousness within moments.

Syncope can stem from various causes, including dehydration, sudden changes in position, or neurological issues. From a cardiac perspective, syncope can result from structural heart problems or abnormal heart rhythms that disrupt normal blood circulation. When the heart can’t pump effectively, blood flow to the brain may drop suddenly, resulting in fainting.

Conditions such as arrhythmias (irregular heartbeats), heart valve disorders, and cardiomyopathies (heart muscle diseases) are among the heart-related issues that can lead to syncope. For this reason, special attention is given to patients experiencing recurrent fainting, especially if the episodes occur during physical exertion or without warning.

How is syncope assessed?

Assessment of syncope begins with a thorough medical evaluation to determine whether it has a benign or potentially life-threatening cause. Your cardiologist will review your medical history and take note of any related symptoms, such as palpitations, chest pain, or shortness of breath, which could point toward a heart-related cause.

An electrocardiogram (ECG) is often the first test performed in cases of syncope. This quick, non-invasive test measures the heart’s electrical activity, helping your cardiologist identify abnormalities in heart rhythm that could explain fainting episodes.

In some cases, further cardiac tests will be necessary, such as Holter monitoring, which records the heart’s rhythm over a longer period, or an echocardiogram, which uses ultrasound to capture images of the heart's structure and function.

A tilt-table test will be performed for patients whose syncope appears related to posture changes. During this test, you will be secured to a table that tilts at various angles while your heart rate and blood pressure are closely monitored. This will help identify issues related to blood pressure regulation and can confirm conditions such as vasovagal syncope.

In more complex cases, an electrophysiological study will be recommended. During this invasive procedure, thin, flexible wires will be inserted into the heart to record electrical activity. This will help reveal abnormalities in the heart's electrical system that aren’t detectable through external monitoring.

How is syncope managed?

Treatment for syncope depends on the underlying cause. If the cause is benign, lifestyle changes may be sufficient to prevent future episodes. You will be advised to stay well-hydrated, avoid standing for long periods, or learn physical techniques, such as leg-crossing or tensing the leg muscles, which can help stabilise blood pressure and improve circulation.

When syncope is related to heart conditions or other medical conditions, medications will be prescribed to regulate blood pressure, heart rate, or blood volume. Drugs such as beta-blockers or anti-arrhythmics are useful in preventing syncope in patients with specific types of arrhythmias. Other medications, like fludrocortisone, can help increase blood volume, which is beneficial for patients prone to syncope due to low blood pressure.

Patients with recurrent vasovagal syncope, where fainting is triggered by stress, dehydration, or prolonged standing, may benefit from cognitive-behavioural therapy to help manage triggers. In cases where medical treatment doesn’t prevent syncope, more invasive options will be advised, especially if the episodes are dangerous or affecting quality of life.

When is the use of a pacemaker or implantable cardioverter defibrillator (ICD) indicated?

In certain cases, your cardiologist will recommend the implantation of a pacemaker or an ICD. Both devices help regulate heart function and can prevent dangerous drops in blood flow that may lead to syncope.

Pacemaker

A pacemaker is a small, battery-powered device implanted under the skin, usually near the collarbone, with wires that connect to the heart. This device helps manage slow heart rates by sending electrical impulses to stimulate the heart, ensuring it maintains a steady rhythm.

Pacemakers are typically recommended for patients with bradycardia (an abnormally slow heart rate) or advanced atrioventricular block, and for elderly patients who may experience syncope due to age-related heart rate slowing.

Implantable cardioverter defibrillator (ICD)

An ICD is similar to a pacemaker but has the additional capability to detect and correct life-threatening arrhythmias, such as ventricular tachycardia or ventricular fibrillation, which can lead to sudden cardiac arrest if untreated. When the ICD detects an abnormal, potentially dangerous rhythm, it delivers a high-energy shock to restore normal heart rhythm, preventing both syncope and sudden death.

ICDs are recommended for patients at high risk of severe arrhythmias, particularly those with a history of heart failure, previous heart attacks, or low ejection fraction (a measurement of how well the heart pumps blood). In patients with these conditions, an ICD serves as a critical safeguard, constantly monitoring heart rhythm and delivering life-saving therapy if needed.

If you would like to book an appointment with Dr Mohamed Al-Obaidi, head on over to his Top Doctors profile today.