What Is Stokes-Adams Syndrome?

Introduction

Stokes-Adams syndrome (SAS), which can also be referred to as Stokes-Adams attacks or Adams-Stokes disease, is characterised as a sudden episode of fainting, which is caused by a change in the heart rate (rhythm) due to a complete heart block. Because of this change, the heart is unable to pump sufficient oxygenated blood to the brain, which results in fainting. Consciousness is usually restored quite quickly, typically a few seconds after the attack. However, there is a treatment available for this condition which can vastly improve your quality of life if you suffer from SAS. These will be explained further in this article to potentially answer any questions you might have. 

Causes and risk factors

SAS can be slightly more prevalent in certain groups; it is commonly seen in the elderly population that have pre-existing heart conditions and also in the young population which suffers from congenital heart blockages.¹ There might also be some evidence suggesting that SAS can be inherited in families, which was first recognised in 1903.² 

A complete heart block is defined as a total absence of transmission between the atria and the ventricles, which will be explained in more detail in the next section of this article. Since SAS is mostly caused by complete heart blocks, the causes for this syndrome are similar to the causes of heart blockages:

• Heart attacks
• Myocarditis (inflammation of heart muscle)
• Structural heart disease
• Atrioventricular (AV) nodal disease
• Fibrosis (scarring or thickened tissue) of the heart 
• Electrolyte imbalance 
• Certain drugs such as digitalis, quinidine and procainamide
• Certain pre-existing conditions, including arthritis, amyloidosis, and multiple myeloma 

Pathophysiology 

The heart consists of four chambers in total, two of which are the upper chambers called atria, whereas the other two are the lower ventricles. Normally, electrical impulses travel from the atria to the ventricles. These impulses cause the ventricles to contract and pump blood all over the body, including the brain. When there is a blockage in this transmission of electrical impulses, the communication between the atria and the ventricles is disrupted. Therefore, the ventricles are unable to perform their normal function of pumping oxygenated blood around the body. This results in a hampering of the blood flow to the brain. This hampering of blood flow to the brain is responsible for causing fainting in SAS.

SAS is usually caused by a complete or incomplete atrioventricular heart block. This involves A blockage of the conduction pathway from the atria to the ventricles, which disrupts the flow of electrical impulses, as discussed earlier. Another blockage, known as a sino-atrial block, might also cause SAS, although the incidence of this is lower than that of atrioventricular heart block. 

An attack of SAS could also be brought about when the heart beats too slowly (bradycardia) or too fast (tachycardia). In both conditions, there is an insufficient amount of blood being pumped to the brain. A normal heart rate is considered to be between 60-100 beats per minute, and anything above or below this value is typically abnormal.³ 

At times, the presence of an abnormal rhythm (fibrillation) in the atria or the ventricles might also precipitate an SAS episode. The abnormal rhythm would prevent the heart from pumping oxygenated blood around the body. It is important to note that ventricular fibrillation is life-threatening and needs immediate medical intervention. 

Symptoms

• The classic symptom of SAS is sudden fainting, which occurs without warning.
• The skin would appear pale before fainting due to decreased blood flow.
• The fainting spell usually only lasts a few seconds, and recovery is quick, although the patient might be confused upon awakening.
• The heart rate may be very fast or very slow (more or less than 60-100 beats per minute).
• Upon recovery, the face may appear flushed.
• There may be multiple episodes of fainting in one day, which can be quite disruptive to daily life.
• There is no aura before fainting, but there might be some twitching seen during the fainting episode.

Diagnosis

To properly diagnose SAS, the underlying abnormalities of heart rhythm must also be identified. 

As a first step, your doctor might ask you for a detailed medical history., This will involve asking several questions about your attack. They will most likely want to know which medications you are currently taking if you have any previous history of heart disease, and they will also ask you to describe your attack in more detail. This will also include describing any previous attacks you may have had. A list of what questions you can expect about your fainting episode may be found here. A detailed and precise history is imperative for an accurate diagnosis. 

Next, your blood pressure, as well as your heart rate, will be recorded. Some routine blood tests, as well as some cardiac blood tests, might also be conducted to assess heart function. A full cardiovascular examination will also be carried out, which will involve the practitioner asking some more questions, carrying out a physical examination, and listening to your heart with a stethoscope.⁴ 

A 12-lead electrocardiogram (ECG) examination will also need to be conducted. During this examination, 12 ECG leads will be placed at various locations on your chest, and a monitor will provide information about your heart rhythm. However, this might not show any abnormal changes in heart rhythm, as it could have returned to normal after the attack. Therefore,  your doctor might provide you with a Holter monitor, which will record your heart rhythm for 24 hours. This monitor can be simply worn on the body and is easily carried around as you go about your day. Due to the 24-hour monitoring, your doctor will be able to see any heart changes occurring throughout the day, especially during any SAS attacks you might have. 

Your doctor might also decide to undertake some electrophysiology tests if they need to determine the underlying cardiac cause of your fainting. These tests involve passing a narrow tube through your veins to your heart to try and see where your abnormal heart rhythms are originating from. This can help determine the cause of your heart irregularities and, hence, aid in treatment. 

Treatment and management 

The first step in the management of SAS would involve stabilising the patient so that this condition is no longer a threat to their life. Managing SAS involves treating the underlying disorder. Any drugs, electrolyte abnormalities and underlying heart conditions which are precipitating this disorder need to be promptly addressed. 

If the SAS is being caused by heart abnormalities, a pacemaker might be required.⁵ A pacemaker is a small device that is installed inside or outside your body. It sends electrical impulses to your heart, which can help it to beat in a normal rhythm. This will ensure that a good and constant supply of oxygenated blood is being pumped out of your heart and all over your body. A pacemaker is usually required if there is a complete heart block presence or heart failure. The pacemaker can:

• Keep your heart beating within the normal range and rhythm
• Prevent your heart from stopping
• Prevent any fainting episodes 

After you have had your pacemaker installed, you should be able to go home the same day or the day after, barring any complications. Usually, installing a pacemaker is a very safe procedure, but there is a small risk of some complications, such as:

• Infections 
• Malfunction of the pacemaker device
• Puncture of the heart (very rare)⁶

Prognosis

SAS needs to be treated as soon as possible, and if left untreated, it could potentially be fatal. It is also disruptive to normal life, as consciousness could be lost several times a day. There is also a risk of injuring yourself during a fainting episode. 

However, after undergoing treatment, the prognosis is good. There are lower chances of experiencing another attack, and it also reduces the incidence of sudden cardiac arrest. 

After treatment, you will still need to be vigilant about your health and immediately report any associated symptoms to your doctor. Lifelong follow-up appointments will also be required to monitor your health. Despite this, it might still be possible to live a relatively normal life. 

Summary 

SAS is a disorder in which your heart is unable to pump sufficient oxygenated blood to the brain, and therefore, it results in episodes of fainting. This fainting can be differentiated from other causes of fainting, as in SAS, there is no warning, and the fainting episode usually lasts only for a few seconds. There is pallor in the skin before fainting, and the face might appear flushed upon regaining consciousness. 

This condition is usually caused by an underlying heart condition, which causes a complete heart block. This means that the usual transmission pathway of electrical impulses from the atria to the ventricles is disrupted, and thus, the ventricles are unable to pump sufficient oxygenated blood around the body. 

Apart from being disruptive to the daily life of the affected individual, it can also be a dangerous condition which needs to be treated as soon as possible. Thankfully, there is a treatment available for this condition, which requires the installation of a pacemaker in the affected individual. A pacemaker can reduce the frequency of SAS attacks and prevent heart failure. This is a simple procedure, and the person can then go on to live a relatively normal life. However, regular check-ups with your doctor will be required and you will need to keep a close eye on any new symptoms that might appear.