Atrial fibrillation (AF or Afib) is a condition of abnormal heart rhythm, typically characterized by rapid or irregular beating. Often staring as brief periods of abnormal beatings, patients with this condition experience longer and possibly constant irregular heart rhythms over time. Atrial fibrillation pathophysiology is characterized by disorganized electrical impulses typically originating in the roots of the pulmonary veins.
An arrhythmia is a disorder which affects the normal rate of the heart. With arrhythmia, the heart either beats too slowly, called bradycardia, too fast, called tachycardia, or irregularly. These conditions can have huge effects on the amount of blood being pumped by the heart. Atrial fibrillation pathophysiology produces irregular heartbeats in its patients.
Regular Heart Function
Normally the pumping of your heart is regulated by an electric impulse. This impulse starts in the sinoatrial (SA) node which then spreads to both atria like ripples overtaking a pond. This cause the atria to squeeze, contracting the blood into the ventricles. The electric impulses then travel down to the atrioventricular (AV) node which is in between and connecting both ventricles. The AV node then splits into two separate branches, allowing the spread of the electric impulses to reach both ventricles at the same time. This causes both ventricles to contract and squeeze the blood out to the vessels in your body. When a normal and healthy heart is working properly, this cycle repeats between 50 to 150 times per minute.
In atrial fibrillation pathophysiology, these electric impulses start firing from all over the atria in random patterns. It is these erratic electric impulses that cause the heart to beat randomly and, at times, too fast.
Atrial Fibrillation Prognosis
The largest threat to a good prognosis with atrial fibrillation is having a stroke. Unfortunately atrial fibrillation increases your risk of having a stroke considerably. This is because the atria (upper chambers) in your heart are beating quick and irregularly, forming clots which can travel to the brain. Your atrial fibrillation prognosis also depends on other variables including the type of Afib you have, other medical conditions and your age. No matter what treatment plan your healthcare provider decides on to reduce stroke and improve your atrial fibrillation prognosis, there are many important steps you can take. This includes controlling other atrial fibrillation risk factors such as high cholesterol, high blood pressure and diabetes. Maintaining a healthy weight and regular exercise will also help your prognosis along with having a healthy diet that avoids saturated fats and includes whole grains, fruits and vegetables.
Atrial fibrillation can be linked to different forms of cardiovascular disease but can also occur in normal and healthy hearts. Cardiovascular factors that have been known to be associated with the progression of atrial fibrillation include mitral stenosis, congenital heart disease, high blood pressure, coronary artery disease, left atrial enlargement, hypertrophic cardiomyopathy, pericarditis and previous heart surgery. Additionally, many lung diseases such as pneumonia, lung cancer, pulmonary embolism and sarcoidosis may also play a role in the development of atrial fibrillation. Obesity and excessive alcohol consumption is also a risk factor for atrial fibrillation. It has also been found that a family history of atrial fibrillation may increase the risk of getting the condition.
Atrial Fibrillation Pathophysiology
Atrial fibrillation pathophysiology can be better understood by looking at the mechanism or electrical impulses generated by the sinoatrial node. In a regular heart sinus rhythm conductions are organized and help the atria to release blood into the ventricles at an organized and efficient manner. The pathophysiology of a heart with atrial fibrillation does not have organized electrical impulses which leads to irregular conduction of ventricular impulses.
There is also a condition called nonvalvular atrial fibrillation which is restricted to cases where the rhythm irregularities occur in the absence of a prosthetic heart valve or rheumatic mitral stenosis.
Types of Atrial Fibrillation
Because Afib is the most common heart irregularity, or cardiac arrhythmia, there are many classes and types of atrial fibrillation. The symptoms of the different types of atrial fibrillation sometimes feel similar but how the condition is treated by your health care professional may be vary depending on the type. Generally, the types of atrial fibrillation can be classified by the duration of the arrhythmia and the underlying reason for the condition. It is essential that your health care professional be deeply involved throughout the diagnosis and treatment. The types of atrial fibrillation can be classified as:
Paroxysmal Fibrillation (PAF):
This type of atrial fibrillation is characterized by the heart going in and out of normal rhythm (called sinus rhythm) in its own. This explains why symptoms come and go and why your symptoms seem to disappear when you are in your doctor’s office. It is important to understand that your hearts spontaneous return the sinus rhythm does not mean it has returned to normal permanently. The problem may continue to come and go or may reoccur more frequently, as often as every day or two. Because of the risk of certain complications it is vital to seek medical assistance.
A specific type of atrial fibrillation in the Paroxysmal class is called “holiday heart syndrome.” It has this nickname because it tends to affect otherwise healthy individuals when under a bit more stress than usual. For example, during celebratory occasions (like Christmas, birthdays or a wedding) people tend to stay up later, eat unhealthy, drink alcohol and put themselves under stress. The heart, not used to this extra activity, may go into atrial fibrillation. Most cases of “holiday heart syndrome” are stabilized and corrected within 24 hours and patients are quickly released from medical care.
Sick Sinus Syndrome:
This type of atrial fibrillation occurs when the sinus node of the heart isn’t working effectively. This syndrome tends to worsen with age. To combat sick sinus syndrome the patient will typically be put on a pacemaker to assist the heart in beating at a normal sinus rhythm.
Persistent (Chronic) Atrial Fibrillation:
This condition is characterized by atrial fibrillation that lasts longer than seven days. Medical intervention will be performed to try to restore and maintain the heart to a normal sinus rhythm. A physician will use either appropriate medication or a shock to the heart (electrical cardioversion) to bring normal rhythm back to the heart. Atrial fibrillation patients who have persistent problems and are at a high risk of stroke may have procedures done that target the source of the arrhythmia.
Permanent Atrial Fibrillation (long-lasting persistent):
In some patients atrial fibrillation lasts indefinitely. The main goal for any individual with persistent atrial fibrillation is to control the heart rate as much as possible with medication. Many times blood thinner medications are taken to reduce the risk of stroke.
Atrial Fibrillation Risks
There are many atrial fibrillation risks that need to be taken into consideration. The most common atrial fibrillation risk is having abnormalities or damage to the heart’s structure. Other atrial fibrillation risks include having an overactive thyroid gland or other metabolic imbalances, viral infections, sleep apnea, and emotional stress. It is important to note that use of stimulants (either prescription or illegal) puts you at a high risk for atrial fibrillation. Heavy tobacco and alcohol consumption are also thought to put an individual at a high risk for atrial fibrillation. Age is also a factor as the older you are, the great your risk is of developing atrial fibrillation. People who are obese or have a family history of atrial fibrillation also have a higher chance of getting this condition.
Some patients who have atrial fibrillation but don’t have any abnormalities or heart damage have a condition called lone atrial fibrillation. In this condition, the cause is unclear. However, serious complications are rare.
Atrial fibrillation itself is typically not life threatening. However, if left untreated the complications of atrial fibrillation can potentially be life threatening. Atrial fibrillation makes it harder for the heart to pump oxygenated blood effectively throughout the body. With blood moving slowly atrial fibrillation complicationswill include the formation of blood clots. If a clot is pumped out of the heart it can potentially travel to the brain and cause a stroke; another complication of atrial fibrillation. Without treatment, atrial fibrillation can also cause a fast pulse rate for extended periods of time. This means the ventricles are beating much too quickly. When ventricles beat too fast over a long time, the cardiac muscles can become weaker in a condition called cardiomyopathy. This condition can lead to long term disability and heart failure.
Medications for Atrial Fibrillation
Atrial fibrillation medications, for most patients, are the most effective form of treatment. However, it is widely studied that patients often stop taking medication because they no longer believe they need it or because their side effects diminish. Discontinuing medication can be extremely harmful and conversation between the patient and health care provider is key. Both taking and tracking your medication is one of the best things you can do for your health.
Typically medications for atrial fibrillation are prescribed to treat and prevent the formation of blood clots which can lead to stroke. Because blood is moving slower in the system due to atrial fibrillation it is easier for buildup of plaque to occur cause blood clots.This is why atrial fibrillation and anticoagulant medication go hand in hand. Some examples of antiplatelet and anticoagulants are aspirin, warfarin, dabigatran and apixaban. Warfarin has also become a standard treatment for reducing strokes and emboli in patients with nonvalvular atrial fibrillation.
It is very important, when talking about atrial fibrillation and blood clot medication,that the patient call their healthcare provider right away if any unusual bruising or bleeding occurs. Both antiplatelets and anticoagulants increase the risk of bleeding. It is also important to consistently take your daily dose of anti-clotting medication, however, if you forget, don’t take an extra dose to catch up.
Always talk to your healthcare provider when switching from one anti-clotting medication to another. Even changing to a generic version, small variations of the dose in the medication can cause much bigger problems. It is also smart to take extra precaution and care with contact sports or any situations where trauma could occur. Thing to specifically watch for and report to your physician include having an accident of any kind, frequently finding bruises or blood blisters, bleeding gums, dark or off coloured stool, feeling sick or dizzy, and bad headaches or stomach aches that won’t go away.
There are also medications for atrial fibrillation and nonvalvular atrial fibrillation that are used to slow the heart rate. These medications are classified as beta blockers. Because most patients can function and feel better if their heart rate is controlled it is important for your healthcare provider to set you up with the proper medication that will combat your atrial fibrillation pathophysiology. Some example of beta blockers include atenolol, nadolol and timolol. Calcium channel blocker medications also have positive effects on the heart for atrial fibrillation patients. They are used to both reduce the strength of the cardiac muscle cell contraction and slow heart rate down significantly. Some examples include dilitiazem and Verapamil.
Once your heart rate is completely under control and your healthcare provider is happy with the progress in controlling your heart rate, management to restore the heart rhythm back to normal is the next step. Heart rhythm controlling medications have a significant effect however some side effects may occur, so close monitor of a health care provider is key. One type of heart rhythm controlling medications are sodium channel blockers which help the hearts rhythm by slowing its ability to conduct electricity. Another type of heart rhythm controlling medication include potassium channel blockers which help the hearts rhythm by slowing down the electrical signals from the sinus node that cause atrial fibrillation.
There are also non-surgical and surgical approaches in the treatment of atrial fibrillation which your healthcare provider can discuss and talk about.
Atrial fibrillation is the most common arrhythmia problem among residents in the US and Canada. With the right treatment plan, however, you can live a long and healthy life. It is important to understand atrial fibrillation pathophysiology, know the symptoms and learn to reduce the risk of stroke. Working side by side with your health care professional is the most important thing you can do to ensure a good prognosis with atrial fibrillation.