The heart is a resilient organ. It is capable of pumping nearly 7,500 liters of blood in a single day. However, if the heart is put under undue stress from unhealthy diets and lack of exercise it will deteriorate. Drug use, disease, and other illnesses can all negatively affect the way the heart functions. In some cases this can manifest as irregular heartbeat and arrhythmia. One such complication is atrial flutter. We will discuss the causes of atrial flutter, complications of atrial flutter, atrial flutter management, as well as the physiology of the heart to help us understand and appreciate the various treatments for atrial flutter, and approaches to atrial flutter management.
Normal Physiology of a Heartbeat
The human heart is comprised of thousands of specialized cardiac muscle cells, cardiac fibers, valves and vessels all working in unison in order to effectively pump enough blood throughout the body. Our nervous system plays a vital role in providing stimulation to the heart via the sympathetic and parasympathetic pathways. It is through these nervous pathways the body can regulate how fast or how slow it wants the heart to beat. In a normal person, a resting heart rate falls between 60-100 beats per min. A heart rate below 60 beats per minute is termed Bradycardia while a heart rate over 100 beats per minute is termed tachycardia. If an illness or cardiac abnormality interferes with this regulated nervous stimulation, the blood pumping ability of the heart will become compromised and may lead to a possibly fatal outcome.
Located in the wall of the right atrium is the sinoatrial node (SA). It is a bundle of specialized cells that dictate the body’s heart rate. The SA node receives nervous input from the sympathetic and parasympathetic pathways setting both the heart rhythm and heart rate. Its main purpose is to contract the atria in order to push blood into the ventricles. This is why the sinoatrial node is commonly referred to as the natural pacemaker of the heart.
The signal from the SA node travels down the atria toward the ventricles, where it then passes by a second node called the atrioventricular node (AV). The atrioventricular node is located near the center of the heart, between the atria and ventricle, and delays the signal coming from the SA node. This is ensures that the atria contracts before the ventricle. In simpler terms, this process is the emptying of blood from the atria. The total delay time only amounts to about 0.16 seconds but is crucial insofar as it facilitates rhythmic pumping needed to send blood to the ventricles.
Once the signal passes through the AV node, it then travels through the His-Purkinje system located in the muscular walls of the ventricles. The His-Purkinje system consists of Purkinje fibers and specialized cardiac structures that pump blood out to the rest of the body. These specialized cardiac structures are known as a bundle of His, from which the system derives its name. After one complete pumping cycle is completed, the SA node receives a new impulse that begins the entire cycle all over again.
When the rhythmic homeostasis is disturbed, the heart begins pumping out of sync. That is to say that it is not contracting and filling when it’s supposed to which is potentially fatal. Atrial flutter, a type of supraventricular tachycardia (arrhythmia in the atria, over 100 beats per min) is primarily due a premature electrical impulse resulting in a re-entry circuit, perpetually moving in a circular pattern within the atria instead of to the rest of the heart, causing it to beat faster than the ventricles. This causes the heart to beat irregularly. In this state the heart is at increased risk of complications. Atrial flutter has a characteristic saw tooth pattern on an ECG. With the use of diagnostic testing, physicians are empowered to engage in effective atrial flutter management.
There are numerous causes of atrial flutter. These causes include, but are not limited to cardiac ischemia, hyperthyroidism, and changes in metabolism. In some cases substance abuse can be the cause of arrhythmias. These substances include alcohol, amphetamines, diet pills and caffeine. Any one of these substances can interrupt the way electrical impulses are transmitted through the heart. Identifying the underlying mechanism that drives the abnormal heart rhythm is essential to effective atrial flutter management. This information will dictate the type of medication for atrial flutter that will be used.
Other Causes and Risk Factors
Due to the abnormal heart rhythm, the conditions are not ideal for the heart to pump blood systemically through the rest of the body. It should come as no surprise that there are a number of complications of atrial flutter that can develop, and require a more strategic approach to atrial flutter management. For instance, due to the inadequate contraction within the heart, blood begins to collect and stagnate increasing the risk of thrombus formation. If steps are not taken to mitigate the clotting of blood, blood clots (thrombi) could break free (embolize) and travel to other parts of the body. In the event that a blood clot embolizes to the brain it causes a stroke whereas if it travels to the lungs it causes a pulmonary embolism. Due to the severity of these complications, approaches to atrial flutter management must address these concerns. Tantamount to effective management is adherence and compliance to medication for atrial flutter.
Treatment methodology for most arrhythmias revolves around rate and rhythm control. A normal rate and rhythm of contraction is vital for getting adequate amounts of blood to our organs. As such, the majority of atrial flutter management utilizes medication for atrial flutter that slows down the heart rate, and regulates rhythm in patients. Treatments for atrial flutter also include reducing the risk of complications such as mitigating the formation of thrombi through the use of blood thinners, a vital medication for atrial flutter management long-term.
Commonly Used Medications
Unfortunately, these treatments for atrial flutter aren’t always effective as some cases may become too advanced or unstable. In these instances, atrial flutter management becomes more specialized, as seen with the utilization of DC cardioversion (controlled electrical shock). DC cardioversion is performed in a hospital to help convert patients to a normal sinus rhythm. In some cases, the implantation of a pacemaker is required to regulate heartbeats, or catheter ablation, which is non-invasive surgical procedure using radiofrequency energy to destroy abnormally firing electrical impulses in the atria. These methods are used as needed to regain a normal sinus rhythm of the heart.