Supraventricular Tachycardia (SVT) is a rapid heart rhythm that originates in the upper chambers of the heart, or the tissue connecting the upper and lower chambers. This condition involves a malfunction in the heart’s electrical signaling system, causing the heart rate to suddenly increase significantly. Determining whether an episode can be managed at home or requires immediate emergency medical attention is a decision based entirely on the severity and nature of the symptoms.
Understanding SVT Symptoms
A typical SVT episode begins and ends abruptly, often characterized by a sudden onset of a very fast, regular heart rate. The heart rate during an episode usually ranges from 150 to 220 beats per minute, which is often perceived as intense palpitations or a racing heart. Many individuals also experience a pounding sensation in the chest or neck.
Along with the rapid heart rate, common symptoms include mild lightheadedness, shortness of breath, and a feeling of anxiety. These symptoms occur because the heart’s rapid beating reduces the time available for the chambers to fill, temporarily lowering the efficiency of blood flow.
Episodes of SVT can be triggered by common factors like high caffeine intake, alcohol consumption, emotional stress, or intense physical exertion. For many people, these episodes are paroxysmal, meaning they start and stop spontaneously, often lasting only a few minutes before the heart returns to a normal rhythm.
Immediate Self-Management Steps
When an SVT episode begins, the first course of action for a stable patient is to attempt to slow the heart rate using non-pharmacological techniques known as vagal maneuvers. These maneuvers work by stimulating the vagus nerve, which helps regulate the heart rate.
The most commonly recommended technique is the Valsalva maneuver, which involves trying to exhale forcibly against a closed airway, similar to bearing down during a bowel movement. A patient should hold this straining for about 10 to 15 seconds while lying down. Another method is the diving reflex, which can be accomplished by splashing ice-cold water on the face or immersing the face in a basin of cold water.
These simple actions can successfully disrupt the abnormal electrical circuit causing the SVT and restore a normal heart rhythm in many cases. These self-management steps should be attempted promptly in a patient who feels stable and is not experiencing any severe warning signs. If these maneuvers do not stop the episode, or if symptoms worsen, a higher level of care is required.
Critical Symptoms Requiring Hospital Care
The presence of certain severe symptoms indicates that the heart rhythm is significantly compromising the body’s circulation and necessitates immediate emergency care. The threshold for seeking emergency care is lower for those with a known history of heart disease, such as coronary artery disease or heart failure, as they are at higher risk for complications.
Call emergency services immediately if you experience any of the following:
- New or severe chest pain or pressure, which signals that the heart muscle is not receiving enough oxygen due to the rapid rate.
- Syncope (complete loss of consciousness) or near-syncope (feeling like you are about to faint).
- Severe, sudden shortness of breath that is significantly worse than a typical episode.
- Signs of poor circulation, such as pale, clammy, or ashen skin, which indicate the body may be going into a state of shock.
- A rapid heart rate, typically over 150 beats per minute, that persists for more than 30 minutes despite having attempted vagal maneuvers.
Follow-Up and Long-Term Management
Even if an SVT episode resolves quickly and completely with self-management, it is important to schedule a follow-up consultation with a healthcare provider, ideally a cardiologist or an electrophysiologist. This is necessary to confirm the diagnosis and assess the specific type of SVT, which guides long-term strategy. The specialist can use tests like a Holter monitor or event recorder to capture the rhythm and identify potential triggers.
Long-term management options are discussed based on the frequency and severity of symptoms. These options range from taking medications, such as beta-blockers or calcium channel blockers, to prevent future episodes. Another option is a curative procedure called catheter ablation. Catheter ablation is a minimally invasive procedure that targets and destroys the small electrical pathway in the heart responsible for the abnormal rhythm.