The heart’s rhythmic contractions are orchestrated by a complex electrical system, ensuring efficient circulation. Malfunctions can lead to irregular heartbeats, known as arrhythmias. This article explores paroxysmal atrial tachycardia (PAT), a specific type of abnormal heart rhythm that can manifest suddenly and disrupt the heart’s normal function.
Understanding Normal Heart Rhythm
A healthy heart beats in a synchronized manner, driven by electrical signals. The process begins in the sinoatrial (SA) node, the heart’s natural pacemaker, located in the upper right chamber (atrium). This node generates electrical impulses that spread across the atria, causing them to contract and push blood into the lower chambers, the ventricles.
The electrical signal then travels to the atrioventricular (AV) node, which delays the impulse slightly to allow the ventricles to fill with blood. From there, the signal rapidly propagates through specialized pathways to the ventricles, prompting them to contract and pump blood out to the lungs and the rest of the body. A typical adult resting heart rate usually ranges between 60 and 100 beats per minute. This coordinated electrical activity ensures a steady and effective heartbeat, called normal sinus rhythm.
What is PAT?
Paroxysmal Atrial Tachycardia (PAT) is an abnormal heart rhythm characterized by a sudden onset of a rapid heartbeat originating in the atria. The term “paroxysmal” means these episodes begin and end abruptly. During a PAT episode, the heart rate can significantly increase, often ranging from 100 to 250 beats per minute.
PAT is a form of supraventricular tachycardia (SVT), meaning the irregular rhythm originates above the ventricles. This condition arises when an area in the atria, outside the natural pacemaker, generates rapid electrical impulses. While the heart muscle and valves may be healthy, the electrical system experiences a temporary malfunction. The rapid contractions can reduce the time available for the heart to fill with blood, potentially leading to various symptoms.
Common Causes and Triggers
Several factors can contribute to or trigger PAT episodes. While the precise cause is not always fully understood, PAT often involves abnormalities in the heart’s electrical pathways, sometimes including extra pathways. Stimulants like excessive caffeine, alcohol, and nicotine can induce episodes. Certain over-the-counter medications, such as cold and sinus remedies and diet pills, can also overstimulate the heart.
Stress and anxiety are also triggers that can influence the heart’s electrical system. Underlying health conditions like heart valve disorders, an overactive thyroid, or chronic lung disease may also play a role. While PAT can occur in individuals with healthy hearts, it is sometimes associated with existing heart disease or prior heart surgery.
Recognizing Symptoms and When to Seek Medical Attention
Individuals experiencing a PAT episode often notice a sudden, rapid heartbeat or palpitations. Other common symptoms include shortness of breath and dizziness or lightheadedness, as the heart’s rapid beating might prevent it from filling adequately with blood. Some may also report chest discomfort or pain, anxiety, or fatigue during an episode.
While PAT is generally not life-threatening, especially if short-lived, seek medical attention if symptoms are severe or prolonged. Call emergency services if you experience a very fast heartbeat lasting more than a few minutes, or if accompanied by severe chest pain, fainting, extreme dizziness, or significant weakness. These symptoms could indicate a more serious issue.
Diagnosis and Treatment Approaches
Healthcare professionals employ various methods to diagnose PAT. An electrocardiogram (ECG or EKG) records the heart’s electrical activity, capturing the rapid heart rate and the arrhythmia’s origin within the atria. However, because PAT episodes are paroxysmal, a routine ECG might appear normal if an episode is not occurring.
A doctor may recommend a Holter monitor, a portable device that continuously records heart activity for 24 to 48 hours or longer, to capture an episode. Event monitors, worn for several weeks and activated by the patient during symptoms, are another option.
Treatment for PAT often begins with lifestyle modifications, such as reducing caffeine, alcohol, and nicotine intake. Vagal maneuvers, simple techniques like holding one’s breath and bearing down, can sometimes slow the heart rate by stimulating the vagus nerve. Medications like beta-blockers and calcium channel blockers are commonly prescribed to control heart rate and rhythm. For persistent cases, catheter ablation may be considered to eliminate the area causing the abnormal signals.