What is Atrial Fibrillation?
Atrial Fibrillation (Afib or AF) is the most common type of heart arrhythmia (or irregular heartbeat) and affects 350,000 Canadians and over 2 million Americans. This condition can dramatically increase the risk of stroke and general heart disease, especially for the elderly or those in poor health. Overall, 15% -20% of all strokes can be attributed to Afib. Nearly one-third of all strokes for those over the age of 60 can be linked to AF. Afib is primarily responsible for increasing the risk of an ischemic stroke. The key to managing this common heart arrhythmia is with regular check-ups and then following a doctorâ€™s prescribed plan for treatment, which may include medication, synchronized electrical cardioversion, and even surgical/ catheter-based ablation.
The heart pumps blood throughout the body with contractions of the atria (upper chambers) followed by the ventricles (lower chambers). The two actions are stimulated by electrical impulses generated within the heart and need to be completely in-sync for the heart to operate properly. The rhythm of these contractions is maintained by a system of electrical impulses generated in the sinoatrial (SA) node, which travels from the right to left atria and causes a contraction that forces blood to into the ventricles. The electrical impulse then travels from the atrioventricular (AV) node, which cause the walls of the ventricles to contract and push the blood out of the heart. The blood from the left ventricle delivers blood to the body while the right ventricle sends blood to the lungs. An atrial fibrillation occurs when many electrical impulses do not originate in the SA node but in another part of the atria and fire in an erratic manner, which produces a rapid and/ or irregular heartbeat. The two chambers of the heart, as a result, fall out of sync and cannot transport blood in and out of the heart in an efficient manner. A normal heart rate is typically 60- 100 beats per minute. An individual with Afib may have a heartbeat of 100-175 beats per minute.
Atrial fibrillation is the result of haphazard electrical signals that cause the atria of the heart to contract rapidly or in an irregular manner. These rapid electrical signals flood the AV node, which impedes the ability of the heartâ€™s lower chamber to respond by contracting the ventricles and sending blood to the body. A steady rhythmic heartbeat means that both the atria and ventricles are working together to pump blood in and out of the heart. The irregular electrical signals disrupt the connection between the two chambers in the heart. A stroke can occur if blood is not pumped to the ventricles and rather collects in the atria of the heart because when blood remains in the heart for extended periods of time due to abnormal rhythm it forms small clots. Â When the blood clot is released from the heart, it enters the blood stream and could then be directed to an artery that leads to the brain. If diagnosed with atrial fibrillation, there are ways to reduce the risk of stroke including medications like anticoagulants.
Symptoms Associated with Atrial Fibrillation
Atrial Fibrillation can be a silent threat as many individuals can appear completely healthy and exhibit no obvious symptoms. The key to identifying and treating Afib includes:
- Knowing the symptoms
- Talking to your doctor and following a treatment plan
- Lifestyle changes that lead to overall better heart health
- Heart palpitations / a rapid heartbeat
- Fluttering or thumpingÂ in the chest
- Chest discomfort, pain or pressure
- Shortness of breath or anxiety
- Dizziness or light headedness
- Fainting or confusion
In a case of chest pain or pressure, it is important to call 911 immediately as these could be signs of a heart attack.
Risk Factors for Atrial Fibrillation
In addition to age, there are combinations of risk factors related to the heart that contribute to this condition:
- Hypertension (high blood pressure)
- Heart valve disease
- Cardiomyopathies a disease in the heart muscle that can lead to congestive heart failure
- Left ventricular dysfunction when contractions in the heart are weak
- Coronary heart disease blockages that occur in the arteries
- Congenital heart disease
- Heart Surgeries a temporary cardiac arrhythmia can occur following a surgical procedure, especially if they were treated for a pre-existing heart condition. A heart arrhythmia is also possible due to post-operative scarring in the atria.
- Myocarditis inflamed heart muscle
- Pericarditis inflammation of the sac surrounding the heart
- Sick sinus syndrome malfunctioning SA node
- Supraventricular Tachycardia (SVT) for young people, a rapid contraction of the heartâ€™s upper chambers
Other Risk Factors Include:
- Sleep Apnea
- Overactive Thyroid
- Lung disease
- Smoking and alcohol consumption
- Diet an ideal diet for good heart health is low in saturated and trans fats and high in vegetables and lean proteins
- Family history
- Viral Infection
There is no single cause for AF and usually manifests as the result of a combination of risk factors. Treating underlying causes, like an overactive thyroid or high blood pressure, can help relieve the symptoms of AF though there is always risk of a future occurrence.
Assessing Risk of Atrial Fibrillation CHADS2:
Patients with atrial fibrillation often possess a large number of risk factors listed above that contribute to their diagnosis of atrial fibrillation and that compound the risks associated with an arrhythmia. The CHADS2 scoring system is a predictive tool that estimates the stroke risk of patients based on 6 criteria: congestive heart failure, hypertension, age, diabetes, stroke in the past or previous thromboembolism. The score out of 6 will assign an annual stroke risk percentage ranging from 1.9% to 18.2%. Based on these results, a physician can guide treatment with Baby Aspirin, or an oral anticoagulant such as Rivaroxaban, Apixaban or Warfarin. The CHADS2-Vasc is an extension of this model that includes additional risk factors to CHADS2 including: female sex, vascular disease and age range between 65-74. This provides a score out of 9. Any scores of 1 or greater require oral anti-coagulation in both CHADS2 and CHADS 2-Vasc groups.
Complications Associated with Atrial Fibrillation
The main threat of this condition is the risk of stroke. Blood clots created by this type of irregular heartbeat can also create blood clots that travel to other to other vital organs with serious implications including death. AF impacts the efficiency of your heartâ€™s ability to pump blood. Over time, this stress can weaken the heart and lead to congestive heart failure.
Is an Atrial Flutter the same as Atrial Fibrillation?
An atrial flutter is slightly different from an atrial fibrillation though it is still categorized as a heart arrhythmia. This condition occurs when the SA node fires a rapid but regular electrical impulse in the right atrium of the heart. These electrical impulses fire so quickly that they circulate within one upper chamber (typically the right) and only some travel to the lower chamber. This condition may or may not alter the normal rhythm of a heartbeat and does require medication to control it.
Prevention of Atrial Fibrillation
A lifestyle that supports good heart health is the key to preventingÂ atrial fibrillation. Common and easily implemented strategies include:
- Regular cardiovascular exercise
- A diet rich in vegetables and lean proteins; but low in saturated/ trans fats
- Limit the intake of alcohol and caffeine
- Quit smoking
Small changes like these will help you manage your weight as well as cholesterol levels and blood pressure, which will not only help with preventing the occurrence of AF but will have a positive impact on your overall health.