What is Paroxysmal Atrial Fibrillation?
A normal heartbeat works in a pattern, with the upper chambers of the heart (the atria) contracting first, followed by the lower chambers (the ventricles). This pattern should continue in the same way at a steady rhythm. The signal that tells the heart to beat usually starts in the right atria at a place called the sinus node, hence we call a regular, normal heartbeat a sinus rhythm. Arrhythmia is when your heartbeat doesn’t follow a regular rhythm and isn’t in response to anything natural (like exercise). Most types of arrhythmias are harmful, but there is one called sinus arrhythmia that is a normal response to your breathing changing.
Arrhythmia is categorized based on your heart rate: tachyarrhythmia is when your heart beats too fast, bradyarrhythmia is when it beats too slow, and tachy-brady is when it alternates between too fast and too slow.
Tachyarrhythmia that start above the ventricles (like in atria or the atrioventricular node, or AV node), is a type of arrhythmia known as supraventricular tachycardia (SVT). There are many types of SVTs including atrial flutter, atrial fibrillation (AF), paroxysmal supraventricular tachycardia, atrioventricular reentrant tachycardia, and multifocal atrial tachycardia.
Atrial fibrillation (AF) is the most common type of sustained arrhythmia, causing the heart to have a disorganized, rapid, and irregular rhythm. With AF, the atria can’t contract properly, leading to a risk of blood clots forming.
The American Heart Association and American College of Cardiology have classified AF into four categories:
1. Paroxysmal AF: an irregular heartbeat that comes and goes, often resolving within 7 days of treatment.
2. Persistent AF: This type of AF lasts for longer than 7 days.
3. Long-lasting AF: This AF lasts for over 12 months.
4. Permanent AF: This is when the AF becomes long-lasting, and doctors stop trying to get the heart back into a regular rhythm.
There are two other special types of AF:
1. Lone AF: This happens in people under 60 who have no other heart disease and their heart looks normal on a heart ultrasound.
2. Non-Valvular AF: This describes an AF that isn’t related to a problem with the heart valves. A Non-Valvular AF is harder to convert back into a regular rhythm.
What Causes Paroxysmal Atrial Fibrillation?
Atrial fibrillation, a type of irregular heartbeat, often happens because of conditions that change the heart’s structure. There are various causes and risk factors associated with atrial fibrillation, including:
Cardiac (heart-related) causes:
* Hypertensive heart disease: when high blood pressure leads to heart problems
* Coronary artery disease: when the blood vessels that supply the heart get narrow
* Valvular heart disease: problems with one or more of the four heart valves
* Heart failure: when the heart can’t pump blood as well as it should
* Congenital heart disease: heart problems present at birth
* Cardiomyopathy: the heart muscle becomes enlarged or thick
* Infiltrative cardiac disease: when substances not usually found in the heart build up in the heart tissue
* Sick sinus syndrome: an irregular heartbeat caused by a problem with the heart’s natural pacemaker
* Pre-excitation syndrome: an extra electrical pathway between the upper and lower chambers of the heart
Non-cardiac (not directly related to the heart) causes:
* Chronic lung disease: long-term diseases that affect the lungs and other parts of the lung system
* Pulmonary embolism: a sudden blockage in a lung artery
* Electrolyte abnormalities: imbalances in the levels of minerals in the body
* Acute infections: sudden and severe infections
* Thyroid disorders: conditions that affect the thyroid gland
* Pheochromocytoma: a rare tumour of the adrenal glands
* Hypothermia: when body temperature drops too low
* Post-surgical: seen in 35% to 50% of patients after a procedure to improve blood flow to the heart
Risk factors, which are conditions or habits that make someone more likely to develop the disease, include:
* Age-related fibrosis: changes in the heart’s structure due to age
* Diabetes
* Obesity
* Metabolic syndrome: a cluster of conditions including high blood pressure, high blood sugar levels, excess body fat around the waist, and abnormal cholesterol levels
* Obstructive sleep apnea: a sleep disorder where breathing repeatedly starts and stops
* Chronic kidney disease: long-term damage to the kidneys
* High-intensity exercise
* Genetic factors: inherited characteristics or conditions.
Risk Factors and Frequency for Paroxysmal Atrial Fibrillation
Atrial fibrillation (AF), a heart condition, is currently estimated to affect approximately 33.5 million people worldwide, according to a 2010 study. The number of people with AF has gradually increased in recent years.
- In 2017, the Centers for Disease Control and Prevention estimated that between 2.6 to 6.1 million people in the United States have AF.
- The prevalence of AF goes up with age; about 9% of all adults over 80 years have this condition.
- Europe sees a higher prevalence of AF compared to the United States.
- Likewise, the incidence of AF (new cases) also increases with age.
- In all age groups, males are more likely to have AF than females.
- Interestingly, African Americans, despite having a high prevalence of risk factors, tend to have lower AF incidence compared to Caucasians.
Signs and Symptoms of Paroxysmal Atrial Fibrillation
Atrial Fibrillation (AF) can present in many ways. Some people may not have any obvious symptoms, and AF is only noticed during a routine health check. In more serious cases, AF can result in a stroke due to an irregular heartbeat that hasn’t been diagnosed. Common symptoms include a racing or irregular heartbeat, shortness of breath at rest or during physical activity, chest pain, tiredness, feeling faint or dizzy, excessive sweating, and fainting or near fainting. AF can sometimes present as symptoms of worsening heart failure, such as weight gain, swelling in the legs and feet, and heavy breathing.
Anyone who presents with these symptoms should have a thorough medical history taken, including any previous heart or medical problems. During a physical examination, medical professionals will look for a pulse that does not have a regular rhythm, signs of heart failures such as a swollen neck vein, swollen legs and feet, and abnormal lung sounds. In cases where AF is caused by heart valve issues, a specific type of heart murmur can sometimes be heard. It’s also crucial to know if the patient has undergone tests to identify the cause of their AF, what blood thinning medications they are taking, and what methods have been used to manage their heart rate or rhythm.
- Racing or irregular heartbeat
- Shortness of breath
- Chest Pain
- Tiredness
- Feeling faint or dizzy
- Excessive sweating
- Fainting or near fainting
- Heart failure symptoms like weight gain, leg and feet swelling, and heavy breathing
Testing for Paroxysmal Atrial Fibrillation
If your doctor suspects that you have atrial fibrillation (AF), a kind of irregular heartbeat, they will need to do a thorough check-up and take a detailed medical history from you. An electrocardiogram (ECG) will be needed to confirm the diagnosis which is a test that measures the electrical activity of your heart.
The ECG can show some specific signs when someone has AF:
- The ‘P’ waves, which represent the electrical signal that starts each heartbeat usually seen on an ECG readout, are missing.
- The time between each heartbeat (called R-R interval) becomes irregular.
- There is a fast heart rate typically between 110 and 160 beats per minute.
- The ‘QRS’ complex, another wave seen on ECG that represents the electrical signals causing your heart’s lower chambers to contract, remains narrow unless there are other heart issues or conditions present.
- Sometimes ‘fibrillatory waves’ are present, which can look like ‘P’ waves but are actually due to the irregular contractions in AF.
In some cases, the shape of the QRS wave can change in AF. This is known as the Ashman phenomenon and happens due to sudden changes in the heart’s rhythm. These changes can sometimes lead to a condition known as a bundle branch block, which affects the heart’s ability to distribute electrical signals properly.
Once AF has been identified, it’s important to understand why it developed. The doctor will perform additional tests to check your levels of bodily salts (called electrolytes), rule out hormone-related illnesses (like overactive thyroid) or causes due to certain medications, infections, or withdrawal from certain substances. They may also use an echocardiogram, a type of ultrasound, to check if your heart’s structure is normal. If you’ve had a stroke, but there’s no known history of AF, a special heart monitor called a Holter monitor may be used for 72 hours to check for AF that comes and goes (paroxysmal AF).
Treatment Options for Paroxysmal Atrial Fibrillation
When treating irregular heart rhythms such as atrial fibrillation, doctors usually follow two main strategies: preventing blood clots (antithrombotic therapy) and controlling the heart rate or rhythm. Research has not found one of these methods to be clearly better than the other.
Atrial fibrillation can increase the risk of stroke up to five times. Therefore, doctors often prescribe medications to prevent blood clots (anticoagulants). This approach aims to lower the risk of stroke, but it’s important to balance it against the chance of causing excessive bleeding. Physicians use certain risk models to determine whether a patient needs this type of therapy. For instance, the CHA2DS2-VASc score evaluates overall stroke risk by considering factors like congestive heart failure, hypertension, age, diabetes, prior stroke, vascular disease, and sex. Another score – the HAS-BLED – is used to calculate the risk of bleeding caused by anticoagulation.
Selecting the most suitable medication to prevent blood clots from forming is a personalised process, taking into account factors like cost, patient preference, and possible interactions with other medicines. Traditionally, warfarin has been a common choice, but its use requires frequent monitoring of blood clotting time. Newer drugs like apixaban, rivaroxaban, dabigatran and edoxaban do not require such monitoring and have been shown to be as effective as warfarin and may cause less bleeding in the brain. However, these newer drugs can be more expensive and may present challenges in quickly reversing their effects if needed.
Controlling the heart rate or rhythm is another approach to manage atrial fibrillation. Medications such as beta-blockers, calcium-channel blockers, and digoxin can help keep your heartbeat regular. If medicine is not sufficient or if the patient cannot tolerate medicine, a medical procedure called AV node ablation can achieve this goal.
Rhythm control can be achieved through drugs or through a procedure known as cardioversion, which involves using electricity or drugs to reset the heart’s rhythm to normal. However, drug therapy alone may carry potential side effects and is not always effective. Moreover, powerful medications used in rhythm control can cause other issues in patients with heart disease or heart failure. Cardioversion is used commonly in patients with new-onset atrial fibrillation and patients experiencing severe symptoms.
In some cases, doctors may recommend a procedure called catheter or surgical ablation to manage atrial fibrillation. This procedure aims to disrupt the electrical pathways causing the atrial fibrillation. It has been found to be highly successful and may improve symptoms and quality of life for patients. However, the decision between medication or procedures to maintain regular heart rhythm depends on the individual patient’s symptoms, their risk factors, and potential benefits of each therapy.
What else can Paroxysmal Atrial Fibrillation be?
When a doctor analyzes heart rhythms, they might identify several types, including:
- Sinus tachycardia
- Atrial flutter
- Atrial flutter with variable block
- Atrial tachycardia (AT)
- Multifocal atrial tachycardia (MAT)
- Wolff-Parkinson-White syndrome (WPW)
- Atrioventricular nodal reentry tachycardia (AVNRT)
- Atrioventricular reentry tachycardia (AVRT)
- Junctional ectopic tachycardia
What to expect with Paroxysmal Atrial Fibrillation
AF, or Atrial Fibrillation, is linked to an increased chance of heart-related death. Anticoagulants, which are medications that prevent blood clots, have proven to help improve overall outcomes for patients with a CHA2DS2-VASc score of 2 – this score assesses the risk of stroke in patients with Atrial Fibrillation.
Patients who are not receiving anticoagulation treatment are at a high risk of experiencing thromboembolic events, which are serious conditions caused by a blood clot blocking a blood vessel. Notably, 55% of AF patients are not receiving anticoagulant therapy, contributing to over 50,000 strokes annually. The consequences of a stroke related to AF tend to be more severe compared to other stroke types.
Patients who are suffering from heart failure have a higher risk of developing complications associated with AF. Furthermore, high levels of certain substances in the blood, such as C-reactive protein (a marker of inflammation) and troponins (proteins that are released when the heart muscle has been damaged), can lead to poor outcomes for patients with Atrial Fibrillation.
Possible Complications When Diagnosed with Paroxysmal Atrial Fibrillation
AF, or Atrial Fibrillation, can lead to several complications. These include:
- Blood clots that can cause a stroke
- New or worsening heart failure
- Heart muscle injury
- Unstable blood pressure leading to heart-related shock
- Sudden death due to Wolff-Parkinson-White syndrome, a rare heart condition
- Heart disease brought on by a rapid heartbeat
Preventing Paroxysmal Atrial Fibrillation
Atrial fibrillation is a common heart rhythm disorder that can greatly increase a person’s risk of having a stroke. Doctors should make sure to explain this risk to their patients, as well as discuss the pros and cons of blood thinning medication (anticoagulation). They need to understand that if they don’t use these drugs, their chance of having a stroke can go up a lot every year. The doctor should give the patient different medication options and ways to manage their condition so they can find the best fit for them and cut down on side effects.
A key part of using one common blood thinner, warfarin, is having regular blood tests (INR testing) to keep it working right. The doctor must also explain to the patient to pay close attention to worrisome symptoms like feeling breathless, heart racing (palpitations), feeling very tired, and gaining weight.
Patients can also help manage their condition without medicine by reducing the number of caffeinated drinks they have, not drinking alcohol, and working out regularly. These changes in lifestyle can help lower the chance of their atrial fibrillation coming back.
