Atrial flutter is a type of abnormal heart rhythm that originates in the upper chambers of the heart, known as the atria. The atria beat very rapidly. When atrial flutter occurs in episodes that begin and end suddenly, it is referred to as paroxysmal atrial flutter (PALS).
Understanding Atrial Flutter
In atrial flutter, an electrical impulse circulates repeatedly within the atria, creating a rapid, regular electrical circuit. This continuous loop causes the atria to contract at a very fast rate.
While the atria beat quickly, not all of these rapid impulses are conducted to the ventricles. The atrioventricular (AV) node acts as a gatekeeper, blocking some signals to prevent the ventricles from beating dangerously fast. This results in the ventricles beating at a slower, but still accelerated, rate compared to the atria. This rapid, regular atrial activity is characteristic of atrial flutter.
Recognizing the Symptoms
Individuals experiencing paroxysmal atrial flutter may notice various symptoms. A common sensation is palpitations, a pounding, racing, or fluttering feeling in the chest. These episodes can start abruptly and may resolve spontaneously, aligning with the paroxysmal nature of the condition.
Other symptoms include shortness of breath, which can occur due to the heart’s reduced ability to pump enough blood to meet the body’s demands. Fatigue is also frequently reported, as the rapid heart rate can decrease the heart’s efficiency in circulating oxygenated blood. Some individuals might also experience dizziness, lightheadedness, or occasional chest discomfort.
Identifying Paroxysmal Atrial Flutter
Healthcare professionals diagnose paroxysmal atrial flutter primarily by assessing the heart’s electrical activity. The electrocardiogram (ECG) is a standard diagnostic tool that records these electrical signals. A characteristic “sawtooth” pattern, representing the rapid atrial contractions, is often visible on the ECG, particularly in certain leads.
Because paroxysmal atrial flutter episodes are intermittent, a standard ECG taken during a symptom-free period might not capture the abnormal rhythm. In such cases, portable heart rhythm recorders, like Holter monitors or event recorders, are used. A Holter monitor continuously records the heart’s electrical activity over 24 to 48 hours, while an event recorder can be activated by the patient when symptoms occur, allowing for the capture of transient episodes.
Factors Associated with Paroxysmal Atrial Flutter
Several underlying conditions and lifestyle elements can contribute to the development of paroxysmal atrial flutter. Heart conditions such as coronary artery disease, heart failure, and high blood pressure are frequently linked to its occurrence. Structural heart issues, including heart valve problems or prior heart surgery, can also predispose individuals to atrial flutter.
Beyond cardiovascular factors, other health issues may play a role. Thyroid disorders, particularly an overactive thyroid, can increase the risk of developing this arrhythmia. Lifestyle factors such as excessive alcohol consumption, obesity, and untreated sleep apnea are also associated with a higher likelihood of experiencing paroxysmal atrial flutter.
Distinguishing Paroxysmal Atrial Flutter
Paroxysmal atrial flutter shares similarities with other heart rhythm disorders, but it possesses distinct characteristics. It is frequently compared to atrial fibrillation (AFib), another common arrhythmia, due to overlapping symptoms like palpitations and shortness of breath. However, a key difference lies in the regularity of the atrial electrical activity.
In atrial flutter, the atrial rhythm is typically regular and organized, albeit very fast, creating a more consistent pattern of electrical impulses. In contrast, atrial fibrillation involves highly disorganized and irregular electrical signals in the atria, leading to a chaotic and irregular ventricular response. While both conditions can cause rapid heart rates and increase the risk of complications, their underlying electrical mechanisms and ECG patterns differentiate them. It is possible for an individual to experience both atrial flutter and atrial fibrillation.