In this section, we will provide you with a comprehensive overview on non-invasive atrial fibrillation treatments that are currently available. Specifically, we will be discussing what atrial fibrillation is, why detecting atrial fibrillation is important, how cardiac ablation (heart ablation) can be used as a treatment (specifically catheter ablations), how electrical cardioversion can be used, and the importance of seeking out atrial fibrillation treatment. We sincerely hope that our website helps to further your understanding on atrial fibrillation treatment. If you have further questions, please contact a healthcare professional.

What is atrial fibrillation?

afibAtrial fibrillation, one of the most common types of arrhythmias, is a heart condition characterized by an abnormal rhythm, a rapid heartbeat or a quivering of the atria (the upper chamber of the heart). According to the heart and stroke foundation, atrial fibrillation affects approximately 350,000 Canadians and at least 5 million Americans. While many of the people affected are over the age of 50 years old, a small percentage of cases (0.12-0.14% according to European population study in 2014) do occur in individuals under the age of 49 years old; it is believed that a large reason for this is because it remains undetected until too late in many patients. Importantly, most cases are asymptomatically harming the person and will not be detected until the person is tested with an electrocardiogram (a machine which detects electrical activity in the heart). It is important to be able to diagnose and undergo atrial fibrillation treatment as early as possible because a major complication that may result from it is stroke. Strokes create an insufficient amount of blood flow to the brain, which can lead to brain cell death. Moreover, the subsequent brain cell death in various regions of the brain may lead to debilitating conditions, such as paralysis, that cannot be reversed. Notably, atrial fibrillation is believed to increase the risk for stroke about 3 to 5 times.

How does the heart normally work?

Prior to discussing the various atrial fibrillation treatment options, it is important to have a general idea of how the heart works. The heart, a four chambered structure, consists of two upper chambers (the atria) and two lower ones (the ventricles), that are connected by valves. The right atrium is used to receive blood from the circulatory system (a system that circulates blood throughout the body) whereas the left ventricle is used to receive blood from the pulmonary system (blood from the lungs after oxygenation). Typically, a healthy heart pumps blood in several stages. In the first stage, the heart is in early diastole (a relaxed state), which allows blood to pool in the right atrium. Once the right atrium is sufficiently full it contracts in a stage called atrial systole. The contraction causes blood to be pushed into the right ventricle through a valve. The valve serves the important function of preventing backflow. Once the right ventricle is full it contracts and forces blood to flow to the lungs for oxygenation (adding oxygen to blood). The blood subsequently travels back to fill the left ventricle in a stage called diastole. The last stage, also called systole, is when the left ventricle contracts to push blood back into the circulatory system. Importantly, although the process has several stages for each chamber, the entire process occurs simultaneously; the ventricles are contracting together (two main stages of systole and diastole). This contraction is regulated by electrical impulses in a sinusoidal node, which is a section of nodal tissue located in the upper wall of the right atrium.

The sinusoidal node effectively functions as a pacemaker in the heart. Regulation of contractions is undeniably crucial in the overall functionality of the heart; it determines both the contraction rate and the efficiency of the heart. In atrial fibrillation the contraction is deregulated (often by electrical impulses originating from the roots of pulmonary veins), and therefore, the heart beats irregularly, quivers or has an abnormal rhythm.

What are the Signs of Atrial Fibrillation?

images_236As noted earlier, many cases of atrial fibrillation are undetected until it is too late. This is largely because the condition may be asymptomatic and/or the symptoms may be ignored or wrongly attributed to another condition. This is extremely problematic as a patient cannot undergo atrial fibrillation treatment without proper diagnosis. Some common symptoms to look out for that are associated with atrial fibrillation include:

• A persistent fast heartbeat or an irregular heartbeat
• Rapid thumping in the chest (heart palpations)
• Chest pressure, chest pain, chest discomfort
• Light headedness or fainting
• Nausea
• Dizziness
• Sweating
• Fatigue
• Shortness of breath (commonly with exertion or anxiety)

To reiterate, some people with atrial fibrillation do not exhibit symptoms or feel any discomfort. Nevertheless, because of the importance of controlling the condition and undergoing atrial fibrillation treatment promptly, your doctor may recommend a test called an electrocardiogram. This test simply records your heart rhythm and can determine if there are any abnormalities. If you notice any of these symptoms, please do not ignore it and contact your local healthcare professionals.

Atrial fibrillation: Non-invasive afib treatments

Due to the fact that atrial fibrillation treatment aims to prevent stroke and circulatory instability, there are a variety of non-invasive treatment methods that can be used. Some atrial fibrillation treatments include: pulmonary vein ablation (PVA), electric cardioversion and anticoagulants. For the purposes of this discussion we will largely focus on how each of these treatments work and which patients they would typically be used in.

Pulmonary vein ablation (PVA) or pulmonary vein isolation ablation (PVI ablation)

Pulmonary vein ablation (also called pulmonary vein isolation ablation or PVI ablation), herein referred to as PVA, is a type of ablation that aims to prevent the propagation of unwanted electrical signals. Ablation, the removal or melting away of unwanted structure or tissue, is an important procedure that can be used to treat a variety of conditions throughout the body. When ablation is restricted to the heart, it is often referred to as cardiac ablation or heart ablation. Notably, cardiac ablation or heart ablation can be performed through various techniques including: radiofrequency ablation (uses heat energy) and cryoablation (uses very cold temperature). For the purposes of our discussion, we will focus on radiofrequency ablation as it is a well-established procedure.

To perform the cardiac ablation procedure (heart ablation procedure), a patient is first provided a sedative to help relax and an anesthetic to help numb an area on the skin of the neck, arm, or groin. Once numb, a catheter (a flexible, soft thin, tube that has the width of pencil lead and a match shaped electrode located on the tip) is inserted via a large vein into the respective area that was numb (normally the groin). Subsequently, this caterer is maneuvered into the heart and the tip of the catheter is directed to the area in the heart that is causing the atrial fibrillation. Importantly, the specific area may vary from person to person, depending on where the doctors discover the dysregulation is originating from. The shape of the tip and the preciseness of the procedure is important because it effectively helps with providing ablative energy to a specific location. This is an important consideration in cardiac ablation (heart ablation) because once heart cells (cardiomyocytes) are killed they do not regenerate.

As pointed out earlier, normal electrical impulses are typically generated by the sinoatrial node (in the right atrium) while the cause of disorganized, unwanted electrical impulses typically originate from the roots of pulmonary veins. These disorganized impulses cause the conduction of ventricular impulses, and thus, disrupt the normal heartbeat or heart rhythm. For this reason, ablation points typically target the roots of pulmonary veins and the procedure is referred to as PVA or pulmonary vein isolation ablation (PVI ablation). The entire idea of ablation is to establish a line of lesions to block the trigger points of atrial fibrillation and effectively prevent the arrhythmia from being transduced or propagating through the heart. Essentially, the line acts as a barrier to the signal. It is important to note that the lesions are targeted to the entrance of the pulmonary veins. Specifically, lesions are located in a region known as the pulmonary vein antrum, which is inside the left atrium and a few millimeters away from the pulmonary vein insertion. Overall, the main goal is to electrically isolate the pulmonary veins, which effectively completes the PVA procedure.

The techniques currently used in PVA are commonly described as achieving high success rates (70-85%) in paroxysmal atrial fibrillation patients. However, it is important to note that success is described as “restoring patients to normal sinus rhythm (NSR) for a period of one year.” Notably, the patient does not have to use medications but the patient may have to undergo more than one procedure to enjoy this success. Moreover, it is possible for the patient to revert to original conditions after this period of time.

Atrioventricular (AV) node ablation

AV node ablation is typically a “last resort” ablation method that is used on elderly patients or patients whose atrial fibrillation is untreatable by other means. Like the other ablation methods, AV node ablation involves an ablation energy source that precisely targets areas of the heart involved with electrical signal transmission. The areas doctors target in this procedure are specifically the AV node, which is responsible for sending signals from upper chambers of the heart to the lower chambers. The reason this procedure is typically avoided is because the patient continues to have atrial fibrillation, even though the signals are no longer transmitted, and it reduces the efficiency of the heart.

Electric cardioversion

pic-defibrillatorCardioversion, an attempt to help switch an irregular heartbeat to a normal heart beat, can be performed by either electrical or chemical means. In electrical cardioversion the heart rhythm is restored using a DC electric shock. Essentially, a cardioverter, a defibrillator or a pacemaker machine will be connected to pads placed on a patient’s chest while a jolt of energy will be sent to the heart. Although it may take several tries, electrical cardioversion should restore the patient’s rhythm to a normal sinus rhythm. However, it is important to note that although the electrical cardioversion procedure is effective at converting the rhythm back to normal, it is not very successful in keeping it there. This is an important consideration because if a patient has persistent atrial fibrillation, electrical cardioversion can be used early as a quick “fix” but it is only temporary. Likewise, for those on medications, the procedure can help as a temporary solution but they will likely have to seek out other solutions.

In contrast to electrical cardioversion, the other cardioversion procedure is chemical cardioversion. Chemical cardioversion also attempts to bring the heart back into normal rhythm but involves the use of medications such as: dofetilide, amiodarone, flecainide, dronedarone and ibutilide. This procedure will be further discussed in the “medications” sections.

Why is atrial fibrillation treatment important?

As elucidated earlier, although atrial fibrillation may not sound like a serious condition, it is extremely important to diagnose and undergo atrial fibrillation treatment if you have it. A large part of the reason for this is because it may increase the risk for stroke and other heart conditions, such as heart failure. Specifically, because blood is not properly flowing from the atria into the ventricles, it can eventually starve the body from oxygen rich blood. This may cause the individual to feel sick, tired, and even incapacitated. It can be even more serious if the blood that remains in the atria pools and creates blood clots. Part of the reason for this is because the clots can travel throughout the body, and effectively, clog an important vein or artery (such as in the brain or heart). Notably, stroke is the number one cause of permanent disability and a major cause of death. Moreover, the prevalence of detected atrial fibrillation is currently high and it has the potential of becoming even higher if more people undergo an electrocardiogram test; it is often not detected until too late.

For any additional information on atrial fibrillation treatment options or catheter ablations please contact your local healthcare professional.

Atrial fibrillation: surgery

As elucidated earlier, atrial fibrillation (afib) patients have a few options with their afib treatment. One important option includes atrial fibrillation surgeries. Though less popular, atrial fibrillation surgeries come in different forms and confer some advantages that medications and non-invasive procedures do not, such as being a more permanent afib treatment.

What atrial fibrillation surgeries are available?

There are few different types of atrial fibrillation surgeries available including: the Cox maze (III) procedure, the maze procedure, the mini maze procedure and pacemaker surgery. The following discussion will outline what each type of surgery is and the advantages they present.

How does the Cox maze (III) procedure work?

The Cox maze (III) procedure, also called the “cut-and-sew-Maze,” is an afib treatment option that, as the name suggests, involves “cutting and sewing of tissue.” Specifically, this open heart maze procedure takes advantage of the ability of incisions to scar tissues, and thus, prevent their abnormal function. In another words, the surgeon makes a maze like pattern through a complicated set of incisions on the right and left atria, which effectively interrupts the electrical signals that are causing the abnormal heartbeat in that tissue. Because scars tissue is dead tissue, the erratic electrical impulses are blocked permanently in the tissue which has been purposefully damaged, while normal electrical signals from the sinusoidal node continue working. Interestingly, a study conducted by Washington University suggests that this procedure may have a greater than 96% cure rate for a 10 year period, and effectively, can reduce the risk for stroke more than 99%. The amazing results that this open heart maze procedure can produce is the reason it is commonly considered the “gold standard” procedure. However, it is important to recognize it is an open heart maze procedure that is very complex, and most surgeons are not willing to perform it. For this reason, two variants of this procedure, the maze procedure and the mini maze procedure, were developed.

What is the maze procedure?

Contrary to the open heart maze procedure described earlier (the Cox maze (III) procedure), the maze procedure (also called Cox maze IV) takes less time and uses an ablation procedure. Ablation, as described previously, is the burning or melting of tissue using either heat or extremely cold temperatures. The importance of using a surgical ablation energy source lies in the idea that it enables the cardiothoracic surgeon to proceed without continuously having to make incisions to kill off the tissue; it is faster to direct energy through an ablation energy source than it is to weave in and out of tissue. Other than the source, this open heart maze procedure uses essentially the same open heart procedure as the Cox maze III procedure and has been shown to be almost as effective. Once again, however, because it is an open heart procedure, it is typically combined with another open heart surgery, such as pacemaker surgery.

Risks associated with Cox III procedure and maze procedure:

As stated earlier, both the Cox III maze procedure and the maze procedure are open heart surgeries. While the Cox III procedure has a higher amount of risks due to its complexities, it is important to note that the maze procedure also shares many of the same risks. Some include:

• Need for pacemaker
• Bleeding
• New arrhythmias
• Lung damage
• Infection
• Pneumonia
• Death

What is the mini maze procedure?

The mini maze procedure, also a derivative of the Coz maze III procedure, is like the maze procedure as it uses surgical ablation as an energy source. One major difference between the maze procedure and the mini maze procedure is that the mini maze procedure is not an open heart maze surgery. To perform the mini maze procedure a cardiothoracic surgeon makes 3 or 4 small incision on each side of the chest. These incisions are then used to place surgical instruments through, including an ablation device and a thoracoscope (endoscope), which is a camera to allow the surgeon to see the heart. Once the surgeon has maneuvered the ablation device to the precise location, the surgical ablation energy source is used to cause a conduction block in the electrical signals. It does this in a similar manner to the catheter; it kills cells, and effectively, causes scar tissue. This scar tissue is an important result of healing in the area and does not allow the disruptive electrical signals that cause atrial fibrillation from propagating their signal. Notably, the mini maze surgery is minimally invasive because it doesn’t require opening the chest and has a shorter recovery time. Moreover, it is commonly used if the patient doesn’t require a concomitant surgery, such as pacemaker surgery, for the heart.

Risks associated with mini maze procedure:

Like any heart surgery, the mini maze procedure has a minor chance of risks including:

• Vein inflammation
• Heart damage
• Blood vessel damage
• Collapsed lung
• Death

Pacemaker surgery

In contrast to maze heart surgery, pacemaker surgery is an option often used to help alleviate afib symptoms but does not constitute as an afib treatment option. The procedure involves inserting a sophisticated device that listens to your heartbeat and responds accordingly to resemble the natural pacemaker found in the heart. The actual device, called a pacemaker, is a small device that helps control abnormal heart rhythms by using low energy electrical pulses to override abnormal signalling in the heart. Importantly, this is not the same as having a defibrillator implanted because a pacemaker cannot deliver shocks to the body during dangerous rhythms. However, it can effectively be used to cause the heart to:

• Speed up
• Ensure ventricles contract instead of quiver
• Control fast heart rhythm or abnormal rhythm
• Coordinate electrical signalling (between ventricles and between lower and upper chambers of the heart)
• Avoid the disorder called long QT syndrome (associated with dangerous arrhythmias)

It is important to recognize that installing a pacemaker may be for permanent or temporary use depending on the individual’s circumstances. Typically, however, temporary pacemakers are used for short term problems and emergency situations. For example, a temporary pacemaker may be used to speed up a slow heartbeat. On the contrary, a permanent pacemaker is typically used to treat long term conditions, such as damage to the heart as a result of a heart attack. There are two basic types of pacemakers that may be used: single chamber pacemakers and dual chamber pacemakers. The important difference between the two is that the former stimulates one chamber of the heart (often a ventricle) while the latter functions by sending electrical impulses to both the atrium and ventricle, which effectively synchronizes their rhythm.

Risks associated with pacemaker surgery

Although pacemakers confer the advantage of having a device to replace the natural pacemaker found in the body, they also confer some risks (rare). Some risks during surgery may include:

• Infection
• Collapsed lung
• An allergic reaction to the anesthetic
• Blood vessel or nerve damage near the pacemaker
• Bleeding, bruising or swelling at the generator site

Comparing Afib Treatment Options

There are many considerations that must be made when comparing the various surgical afib treatment options, such as how long the patient has had afib, the extent of afib damage on the heart, other comorbidities and the age of the patient. With that being said, Cox maze III is undoubtedly the gold standard afib treatment option, but because not many surgeons are willing to take on such a complex procedure or high risk level, the other forms are more common. Like the Cox maze III procedure, the maze procedure is an open heart procedure, and thus, also tries to be avoided in patients that are not being treated for other heart conditions. However, research has found that the maze procedure has comparable results with the Cox maze III procedure; freedom from stroke was also in excess of 99%. Notably, the rate of afib free patients is largely dependent on the surgical ablation energy source and the specific type of afib they were suffering. For example, a report by the American Association for Thoracic Surgery (AATS) found that using bipolar radiofrequency ablation allowed 90% of patients to be afib free after 12 months. On the contrary, a worldwide multicenter study reported that 85% of epicardial patients were afib free after six months when a high intensity focused ultrasound (HIFU) ablation source was used. The other possible ablation sources considered in afib treatment include: cryoablation, microwave, irrigated bipolar radiofrequency, irrigated unipolar radiofrequency and non-irrigated unipolar radiofrequency. This difference in efficacy can also be observed in the mini maze procedure, but because the results were much more inconsistent from center to center it is difficult to accurately differentiate between the efficacy of the sources. One thing that the reports strongly suggest, however, was that the success rates of afib patients was lower (80%–90% for paroxysmal atrial fibrillation patients and 50%–75% for persistent afib patients) than the other maze procedures.

In contrast to the maze procedures, pacemaker surgery does not attempt to burn off or kill off cells in the heart; it tries to overcome the abnormal electrical impulses though its own electrical impulses. This effectively means that it cannot be directly compared to the maze procedures in terms of efficacy but rather must be considered by itself. Prior to elaborating on the merits of installing a pacemaker, it is important to recognize that research suggests that pacemakers themselves do not actually treat atrial fibrillation, and therefore, must be used in conjunction with another afib treatment option. Additionally, it is important to note that it does not confer the advantage that a defibrillator implant does: to help control life threatening arrhythmias that may cause sudden cardiac arrest. This is significant because a surgery is typically considered a large undertaking and the risks must be worth the benefits. With that being said, the primary purpose of a pacemaker is essentially to regulate heart rhythm in a patient when it is beating too slowly or too fast. Due to the fact that a pacemaker is surgically implanted into the chest and requires routine check up, doctors will always try to rule out other possible options first.

Why are Surgeries Important to Atrial Fibrillation Treatment?

Surgery is an extremely important treatment option for atrial fibrillation patients because it confers the advantage of a “permanent” or “nearly permanent” treatment regime. By destroying the cells responsible for erratic electrical signals or destroying their path of signal transmission, surgeons are effectively able to reduce the detrimental effects of atrial fibrillation on the heart. This is significant because when the heart is responding to abnormal electrical signals, it can be overworked to the point of inefficiency. A core issue with this is that the rest of the body may not receive sufficient oxygenated blood or the blood may not be circulating out of the heart fast enough, and thus, start clotting. The clots can then lead to a multitude of other health issues that may permanently affect the way an individual can live their life.

For more information of atrial fibrillation surgeries, or more specifically maze heart surgery, please contact your local healthcare professional.

Atrial fibrillation medications as a treatment

Atrial fibrillation medications are an important treatment regime that offer a non-invasive method of controlling atrial fibrillation. They are important because they provide patients with a flexible, non-invasive treatment option that can help patients deal with the symptoms of atrial fibrillation, and more importantly, reduce their risk of stroke. Notably, many people worldwide are currently prescribed atrial fibrillation medications for other related conditions with the same overall aim: to prevent heart problems and stroke.

How do atrial fibrillation medications work?

Due to the fact that the main goals of treatment are to prevent circulatory instability and stroke, there are a variety of different types of atrial fibrillation medications that may be used. More specifically, there are groups of medication to treat irregular heart rhythm, abnormal heart rate and to prevent clot formation (blood thinner medications). This is partially because electrical impulse production and propagation is a complex stepwise process that involves many molecules. Moreover, there are many ways in which the heart is regulated, such as various hormones. For the purposes of this discussion we will focus on two important heart rate medications (afib beta blockers and afib calcium channel blockers), two important heart rhythm medications (sodium channel blockers and potassium channel blocker) and commonly used oral and injectable anticoagulants.

Medication that lowers heart rate

Medication that lowers heart rate normally slow the heart rate to about 100 beats per minute. It is important to control the heart rate because errant electrical signals can overwork the heart, and consequently, cause irreversible heart damage. To understand this assertion, it is important to recognize that the heart, like all other organs, requires oxygen and is capable of being overworked like all other muscles are. However, because the heart has such an important function (to pump oxygenated blood throughout the body), it has to constantly be working to ensure all of the other organs in the body are not deprived of oxygen; this is in stark contrast to leg muscles or arm muscles, which get a break after strenuous exercise. For this reason, and the fact that cardiac muscle does not regenerate (once muscle cells in the heart die they cannot be replaced), it is important to make every effort to prevent the heart from being damaged. As stated earlier, two important common types of medication that lowers heart rate are: afib beta blockers and calcium channel blockers, and a third, less favorable type, are cardiac glycoside.

1)

Beta blocker drugs

: these are drugs that slow the heart rate by blocking the effects of the hormone epinephrine. Epinephrine, also known as adrenaline, is commonly associated with the fight/ flight response. By blocking the receptors of this hormone, the body can effectively prevent the heart rate from rapidly increasing and reduce blood pressure. It is important to recognize that the main type of beta blockers used in atrial fibrillation are ones that block the beta-1 receptor.

2)

Calcium channel blockers

: the calcium channel blockers list contain drugs that prevent calcium from entering the cells of blood vessel walls and cells of the heart. Ultimately, this relaxes blood vessels and reduces the heart workload, which effectively also lowers blood pressure. Notably, they may be available as either short acting drugs or long term drugs and can be referred to as calcium antagonists.

3)

Cardiac glycosides

: caridiac glycosides are very effective drugs that improve cardiac output. Despite their efficacy, however, they are often avoided because they can also be toxic. One important example of a cardiac glycoside is Digoxin (Lanoxin®).

Beta blocker drugs list:
• acebutolol (Sectral)
• atenolol (Tenormin)
• betaxolol (Kerlone)
• labetolol (Trandate)
• bisoprolol (Zebeta)
• carvedilol (Coreg)
• metoprolol tartrate (Lopressor)
• metoprolol succinate (Toprol-KL)
• nebivolol (Bystolic)
• penbutolol (Levatol)
• propranolol
• sotalol hydrochloride (Betapace)
• timolol
• nadolol (Corgard)
• pindolol (Visken)

Calcium channel blockers list:
• verapamil hydrochloride (Calan SR, Verelan)
• diltiazem hydrochloride (Cardizem CD, Dilacor XR)

With that being said, it is important to note that there is considerable debate in the medical community about whether medication that lowers heart rate or medication that regulates heart rhythm is better for atrial fibrillation patients. Specifically, some studies suggest that if rate control medications are combined with clot control medications, they are as good as rhythm control medications. The question then becomes: why not just use rhythm control medications? Well, while rhythm control medications are effective, they tend to be riskier to use than rate control medications. For example, while rate control medications have risks, such as a small possibility to promote cardiac arrhythmias, rhythm control medications may have major side effects, such as lung toxicity in some patients. Importantly, some side effects of using rate controlling medications may include: dizziness, fatigue or shortness of breath while the side effects of rhythm control medications are typically more severe. The doctor must essentially weigh the risks vs the benefits for each patient prior to prescribing any medications. Furthermore, it is typical for a doctor to recommend starting with medication that lowers heart rate then subsequently changing over to medication that controls heart rhythm if the heart rate- anticoagulant combo no longer works.

Medication that control heart rhythm (antiarrhythmic drugs)

As mentioned earlier, antiarrhythmic drugs are often riskier than heart rate medications. This is largely because the target of antiarrhythmic drugs is not as “defined” and these molecules need to be in a precise balance in the body. In other words, sodium and potassium channels are widely used throughout the body by various organs and processes, and thus, disturbing their activity may greatly affect many aspects of the body. This is an important consideration because it increases the likelihood of toxicity and may impact the pharmacokinetics (how the drug is metabolized in the body). Nevertheless, it is equally important to recognize that antiarrhythmic drugs are very important atrial fibrillation medications because they are often prescribed if heart rate medications do not work. Moreover, they are often the medication used in chemical cardioversion (an attempt to help switch an irregular heartbeat to a normal heart beat). If a doctor believes that a patient will benefit from antiarrhythmic drugs, they often prescribe the drug that they believe is best for the type of atrial fibrillation and the patient’s medical history. Two important basic types are sodium channel blockers and potassium channel blockers.

Sodium channel blockers

: sodium channel blocking drugs impair the conduction of sodium ions through their respective channels (sodium channels). This effectively affects the rapid depolarization of fast response cardiac action potentials in the heart. In other words, it affects the ability for non-nodal cardiomyocytes to send the erratic signals that they do. The sodium channel blocking drugs used in the heart comprise of Class I antiarrhythmic compound (based on the Vaughan- Williams classification scheme).

Potassium channel blockers

: potassium channel blockers are drugs that interfere with conduction through potassium channels. They work by binding and blocking potassium channels which are responsible for repolarization (phase 3). Ultimately, this delays repolarization (an essential step in being able to transmit electrical signals), increases the action potential duration and increases the effective refractory period. In simpler terms, it prevents the abnormal electrical signals from being fired by “non-designated” cells. Like sodium channel blocker drugs, potassium channel blocker drugs can be classified by the Vaughan William classification scheme; they comprise the Class III antiarrhythmic compounds.

List of sodium channel blockers:
• disopyramide
• mexiletine
• quinidine
• procainamide
• propafenone
• flecainide

List of potassium channel blockers:
• amidodarone
• dronedarone
• sotalol

Due to the risks associated with many of heart rhythm control medications, it may be necessary to have heart monitoring when starting them. Notably, some may take up to a year or more to start getting a continuous normal sinus rhythm. With this in mind, it is also important to note that the medications may not necessarily be effective for all patients (studies suggest some drugs have an efficacy of only about 50%) and some have major side effects. For example, while amiodarone is very effective, it is often a last resort because it has the potential to cause long term consequences and it is known to be associated with lung toxicity. These considerations, and the fact that the medications often work in the beginning and then stop working, are all important factors that affect a doctor’s decision when prescribing.

In addition to efficacy, it is also important to note that many patients have reported that rhythm control drugs left them feeling persistently tired, and overall, “bad.” If the extent of “feeling bad” is significant doctors may suggest that the patient considers catheter ablation or surgical ablation- which are used to directly treat the problem at its root by killing cells that are causing it.

While conventional wisdom in the medical community suggests that if a patient’s sinus rhythm returns to normal their risk of stroke is reduced; recent studies have suggested otherwise. More specifically, these studies found that patients whose normal sinus rhythm was restored were at a greater risk for stroke if they stopped taking anticoagulants. Although this phenomenon is not well understood, it makes a considerable difference in a doctor’s willingness to take on some of the risks that rhythm medications confer.

Anticoagulants(blood thinner medications)

Anticoagulant medications, also referred to as blood thinner medications, are substances that inhibit coagulation of blood. In other words, anticoagulants are drugs that somehow effect the clotting cascade to prevent the formation or reduce the formation of blood clots. They are very important to atrial fibrillation patients because a major risk associated with disrupted heart function is stroke. This is partly because when the heart is not pumping blood at a normal rate or with a normal rhythm, there are opportunities for clots to form. The importance of clots, particularly in stroke, is that they can become lodged in important arteries, and thus, prevent sufficient oxygen from reaching vital organs. Moreover, hypoxia (lack of oxygen) in organs can lead to significant cell death, and depending on the organ, permanent debilitating consequences.

There are many different types of anticoagulant medications that may be prescribed including orally administered anticoagulants, injectable anticoagulants and antiplatelet drugs. Notably, anticoagulants are widely prescribed, even if a patient does not have atrial fibrillation. This is because they tend to be very effective at preventing clot formation.

In general, there are two main types of oral anticoagulants: traditional anticoagulants and NOACs (novel oral anticoagulants). While traditional anticoagulants, such as warfarin, have been prescribed for many years, NOACs, such as rivaroxaban, have only recently started to be prescribed. Notably, both NOACs and traditional anticoagulants have similar efficacies but there are some important differences amongst them that must be taken into account. Some of the important advantages that NOACs confer are: the advantage of having a short half-life, a rapid onset and a fairly predictably pharmacokinetics. In contrast to this, traditional anticoagulants typically require monitoring to reach appropriate dosage and take time to start having an effect on the patients. Nevertheless, a major advantage traditional anticoagulants, such as warfarin, provide is the ability to reverse its effects through an antidote. This is important because clotting is a natural process in the body and is often used to fix cuts, prevent infections and stop bleeding. A patient on anticoagulants is often prone to hemorrhage and uncontrollable bleeding.

List of commonly used anticoagulants:
• warfarin (Coumadin)
• dabigatran (Pradaxa)
• edoxaban (Savaysa)
• rivaroxaban (Xarelto)
• apixaban (Eliquis)

Like oral anticoagulants, injectable anticoagulants can also cause hemorrhage and uncontrollable bleeding. One advantage they confer, however, is they can be directly released into the bloodstream in cases of emergency or when a patient is allergic to any part of the capsule formation.

List of injectables:
• enoxaparin (Lovenox)
• dalteparin (Fragmin)
• fondaparinux (Atrixtra)

Antiplatelet drugs are slightly different from anticoagulants because they prevent tiny cells in the blood (called platelets) from becoming “sticky.” These platelets are important to clot formation because they normally clump together during the clot formation cascade, which effectively helps produce a blood clot. The key difference between anticoagulants and antiplatelets is that anticoagulants affect molecules in the chemical reaction while antiplatelets affect the platelet cells. However, it is important to note that they still are considered blood thinner medications.

List of antiplatelets:
• anagrelide (Agrylin)
• aspirin
• clopidogrel (Plavix)
• prasugrel (Effient)
• ticagrelor (Brilinta)
• tirofiban (Aggrestat)
• vorapaxar (Zontivity)
• dipyridamole (Persantine)

Why are Atrial Fibrillation Medications Important?

Atrial fibrillation medications, such as blood thinner medications, are especially important to the treatment of atrial fibrillation because they provide an easy, non-invasive way for patients to take control of their atrial fibrillation symptoms. This is important because many patients do not want to resort to surgery or other procedures that may impact their daily living. Moreover, because the condition can lead to a multitude of other health issues, such as stroke and its associated consequences, it is crucial to be able to provide a treatment regime that can practicably be used by a large number of people. With that being said, recent research has discerned a link between the prevalence of other comorbidities, such as obesity, and atrial fibrillation. Unfortunately, these comorbidities are on the rise and not enough patients are being screened for atrial fibrillation until it is too late. If you suspect that you may have atrial fibrillation, please contact your health care professional to get screened today. Simple treatment regimens like atrial fibrillation medications are available and can help you prevent unfortunate health issues in the future.

For any further information on any of the atrial fibrillation medications, please contact your local health care professionals.