How is AF diagnosed? How does it progress?

Due to the numerous causes of AF, diagnosing the disease may include several factors, including family history, signs and symptoms (palpitations, rapid heart rate, shortness of breath, etc...), physical exams, and most accurately an electrocardiogram or ECG. An ECG is a test which interprets and provides an illustration of the electrical rhythm of the heart. As we know, AF is an electrical disturbance in the heart, therefore this test provides the physician with the best presentation for determining a diagnosis. (1)

The disease typically progresses as aging progresses. Through early diagnoses, AF can usually be well controlled through lifestyle and medication. If those with AF follow their treatment plan and live a healthy life (eating well and exercising) to keep blood pressure in a healthy range and cholesterol/fat to a minimum, AF is less likely to progress into complications. The other factor influencing disease progression depends on which type of AF the person has (paroxysmal, persistent, or permanent) which we learned about last week. (2)

It is important to understand that you could have AF without knowing it. Not everyone experiences the symptoms and this can cause the disease to progress undetected. Be sure to visit your doctor for wellness and physical exams to assess your heart and promote the chance of early detection and treatment if required.

Here is an illustration of what an ECG would look like with AF in comparison to a normal rhythm. (3)

 References:

1.     How Is Atrial Fibrillation Diagnosed? (2014, September 18). Retrieved January 29, 2015, from http://www.nhlbi.nih.gov/health/health-topics/topics/af/diagnosis
2.     Long-Term Progression and Outcomes With Aging in Patients With Lone Atrial Fibrillation. (2007, March 30). Retrieved January 28, 2015, from http://circ.ahajournals.org/content/115/24/3050.short
3.     Illustration of the electrocardiogram (ECG or EKG) in atrial fibrillation [Motion picture]. (2012). YouTube.

Etiology: What causes AF?

Referencing week one's post, we know AF is an electrical problem with the heart's pacemaker. This impulse can progress to AF from a few different causes. Chronic hypertension is very common, as long-term high blood pressure places an increased workload on the heart muscle, causing it to grow in size. Unfortunately, bigger is not always better, especially regarding the heart. Overtime, this leads to heart disease As the muscle grows, the neurons (electrical cells) are unable to deliver an adequate impulse to stimulate an efficient contraction of the muscle. This can eventually cause the pacemaker (SA node) to perform out of sequence, causing misfires. Another cause may be a problem with the actual structure of the heart, predisposing the individual to a greater risk of having the abnormal rhythm. This may be caused by family history and involve the valves of the heart or actual pacemaker. (2)

AF may present in three different categories; paroxysmal, persistent, and permanent. Paroxysmal AF may last up to a few days but stops on its own. This may progress to a more chronic type or could acute and triggered by over stimulation of the vagus nerve (affects the nervous system and blood vessels involved in heart rate and rhythm). Persistent AF is less common than paroxysmal but requires medical intervention in order to restore the hearts normal rhythm. Cardioversion is often used, this is electroshock therapy, a treatment which is intended to reset the heart back into its regular rhythm. Permanent AF is exactly what it sounds like. Cardioversion will not be effective for restoring the rhythm back to normal. This can occur over time with chronic episodes and poor controlled AF or failure to treat early onset AF. Lifelong treatment will be required. (1)

The biggest concern of being in an AF rhythm is the risk of blood clot formation. Because the atrial chambers are not distributing all their blood into the ventricle chambers, the risk of blood pooling inside the atria increases. If this is not resolved, the blood will clot and depending on which chamber the clot forms, the result could be either a pulmonary embolism (clot in the lung) or stroke (clot in the brain). 

Some of the Several Causes

References:

1.     Pathophysiology and Prevention of Atrial Fibrillation. (2001, January 1). Retrieved January 20, 2015, from http://circ.ahajournals.org/content/103/5/769.full#cited-by

2.     Kannel, W., & Benjamin, E. (2008, February 15). Final Draft Status of the Epidemiology of Atrial Fibrillation. Retrieved January 15, 2015, from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2245891/#FN2

3.     Atrial Fibrillation, What Causes It? [Motion picture]. (2010). United States: EmpowHer.

Epidemiology: How common is it? Who is at risk? Morbidity and mortality.

I tend to think of an epidemic as a problem like the recent Ebola outbreak, or the influenza of 1918, or even the ever so popular idea of a zombie apocalypse. It is easy for every day morbidity's to become a normal part of life which we forget may be preventable to some extent. I think AF is one of these diseases.

When recognizing the statistical data it is obvious that AF is becoming more prevalent and we need to appreciate this. Today, approximately 2.3 million people in the US are diagnosed with AF, that's more than the population of King County! Estimated projections show this increasing to 5.6 million by 2050. Several factors are involved in the increasing prevalence of AF; chronic high blood pressure (hypertension), obesity, diabetes, cardiovascular disease, and advancements in diagnoses should be considered. (1) Most of these morbidity's are problems related to poor lifestyle habits with the exception of genetic predisposition and congenital heart defects. 

Sorry guys, we have a 1.5-fold greater likelihood of developing AF than women. (1) Though there is little research to explain why this is it suggests some relation to male genetics and/or lifestyle. 

Family history of AF also plays a role as it increases the risk for children whose parents have AF by 2-3-fold. (1)

As age increases, the occurrence and severity of AF increases. We know the risk factors include many chronic problems which may take years before causing complications with AF. The wear and tear of high blood pressure (hypertension) and fat accumulation on the heart over many years promotes AF. The disease can be controlled in many cases, preventing mortality with medication and lifestyle changes is most successful. Once diagnosed, the condition is a morbidity which usually requires attention for the remainder of life.

References:

1.     Kannel, W., & Benjamin, E. (2008, February 15). Final Draft Status of the Epidemiology of Atrial Fibrillation. Retrieved January 15, 2015, from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2245891/#FN2

 A-Fib is certainly not a lie, in fact it is a very real concern and unfortunately common disorder among many people. I'll bet you heard of this term, but perhaps you don't have an understanding of what it means. This is where I come in. Join me each week to gain an understanding of one of the world's most common heart disorders.

Atrial Fibrillation or A-fib is a heart disorder. Our heart's have four chambers, two of which are called atria. Fibrillation is a fast, disordered pattern of muscle contraction within these atria. Since our heart is a large muscle, this compromises the hearts ability to contract efficiently. Our hearts function by electricity and this problem is caused by a malfunction in the electrical signals in the heart.

Atrial fibrill...

The atria are small collection chambers for returning blood from the body to enter the heart. They contract and squeeze blood into the two larger chambers, the ventricles. It is the electrical stimulus causing this contraction which becomes disturbed. The cycle begins at the atria, in the electrical center and hearts pace maker, the SA node (a bundle of neurons). This node begins the contraction cycle and maintains a regular heart beat. When this node malfunctions, the heart muscle and blood flow suffer. The atria attempt to contract with each electrical impulse but because the rate can be greatly increased, the heart fails to adequately perform its vital function, transporting blood. This effects the ventricles as well. The SA node transmits its impulse to another node the AV node, then along the borders of the ventricle muscle to contract them. When the SA node is firing irregularly and too fast, not each impulse can be received by the AV node and thus fail to reach the ventricles. This prevents the heart from working in sync.

If this problem persists it can lead to more serious complications. Fortunately the disorder can usually be well controlled if discovered in time.