The heart’s consistent beating is fundamental to overall health, ensuring blood circulates throughout the body. This rhythmic action is orchestrated by electrical signals, which dictate the heart’s rate and regularity. Sometimes these electrical signals can become disrupted, leading to an abnormal heart rhythm. When such irregularities originate in the upper chambers of the heart, they are referred to as a “supraventricular rhythm.” This article clarifies what a supraventricular rhythm signifies and its implications for heart health.
The Heart’s Electrical System
A normal heartbeat begins with a specialized cluster of cells located in the heart’s upper right chamber, known as the sinoatrial (SA) node. This SA node acts as the heart’s natural pacemaker, generating electrical impulses that initiate each beat. These impulses then spread across the atria, the two upper chambers of the heart, causing them to contract and pump blood into the lower chambers.
Following atrial contraction, the electrical signals converge at the atrioventricular (AV) node, positioned between the atria and the ventricles. The AV node briefly delays the impulse, allowing the ventricles to fill completely with blood before they contract. From the AV node, the signals travel rapidly into the ventricles, the heart’s powerful lower pumping chambers, prompting their contraction and propelling blood to the lungs and the rest of the body. This coordinated electrical pathway ensures efficient blood flow and a steady heart rhythm.
Understanding Supraventricular Rhythm
The term “supraventricular” literally means “above the ventricles,” with “supra” indicating above and “ventricular” referring to the heart’s lower chambers. Therefore, a supraventricular (SV) rhythm originates from electrical activity in the atria or the atrioventricular (AV) node. Essentially, any heart rhythm disturbance stemming from an area above the ventricles is classified as supraventricular.
While the word “rhythm” might suggest regularity, “SV rhythm” frequently pertains to an abnormal heart rhythm, also known as an arrhythmia, that begins in these upper heart regions. These rhythms can cause the heart to beat too fast, too slow, or irregularly. This is in contrast to ventricular rhythms, which arise from electrical disturbances directly within the lower chambers of the heart.
Common Types of Supraventricular Rhythms
Supraventricular rhythms encompass a variety of conditions, each with distinct characteristics:
- Atrial Fibrillation (AFib): A common type characterized by chaotic and irregular electrical signals in the atria, leading to a rapid and often very irregular heart rate. This disorganization causes the atria to quiver rather than contract effectively.
- Atrial Flutter: Involves electrical signals in the atria that are rapid but often more coordinated than in AFib, frequently causing the upper chambers to beat around 250 to 350 times per minute. This condition can also lead to a fast heart rate.
- Supraventricular Tachycardia (SVT): A general term for a fast heart rhythm that originates above the ventricles, often causing the heart to beat between 150 and 220 times per minute. SVT can result from faulty electrical signaling that causes early beats in the upper chambers.
- Premature Atrial Contractions (PACs): Extra heartbeats that originate in the atria earlier than expected, often perceived as a skipped beat or a flutter. While common and generally harmless, frequent PACs can sometimes indicate an underlying issue.
- Premature Junctional Contractions (PJCs): Extra heartbeats that originate from the AV junction, the area between the atria and ventricles. Like PACs, occasional PJCs are usually not harmful and may be felt as an extra or skipped beat.
Recognizing Symptoms and When to Seek Care
Abnormal heart rhythms can manifest through various symptoms. These may include a sensation of fluttering, pounding, or racing in the chest, often described as palpitations. Individuals might also experience dizziness, lightheadedness, or shortness of breath. Fatigue and a general feeling of weakness are also commonly reported.
While some of these symptoms can be benign, certain indicators warrant immediate medical attention. If palpitations are accompanied by chest pain or discomfort, severe dizziness, fainting, or prolonged shortness of breath, emergency care should be sought. New symptoms or those that worsen or last for several minutes also require prompt evaluation by a healthcare professional.
Diagnosis and General Management
Diagnosing a supraventricular rhythm typically involves an electrocardiogram (ECG or EKG), which measures and records the heart’s electrical activity. Since these rhythms may occur intermittently, a doctor might recommend ambulatory monitoring, such as a Holter monitor, to record heart activity over an extended period. Imaging tests like an echocardiogram, MRI, or CT scan may also be used to assess the heart’s structure and function.
Management approaches for supraventricular rhythms vary depending on the specific type of rhythm and its impact on the individual. Treatment may range from lifestyle adjustments, such as avoiding triggers like excessive caffeine, to medications that help control heart rate or rhythm. In certain instances, procedures like catheter ablation, which targets the abnormal electrical pathways, may be considered to restore a normal heart rhythm.