The supraventricular tachycardia emedicine
The supraventricular tachycardia emedicine Supraventricular tachycardia (SVT) is a common cardiac arrhythmia characterized by an abnormally rapid heart rate originating above the ventricles, primarily from the atria or the atrioventricular (AV) node. Typically, SVT causes a sudden onset and termination of rapid heartbeats, which can range from mild palpitations to severe symptoms such as chest discomfort, shortness of breath, dizziness, or even fainting. Understanding the pathophysiology, clinical presentation, diagnosis, and management of SVT is essential for healthcare providers and patients alike.
The supraventricular tachycardia emedicine SVT encompasses several arrhythmia types, including atrioventricular nodal reentrant tachycardia (AVNRT), atrioventricular reentrant tachycardia (AVRT), and atrial tachycardia. These arrhythmias share a common feature: an abnormally fast electrical circuit within the atria or the AV node. The abnormal electrical activity results in a rapid heart rate, often between 150 and 250 beats per minute, which can be sustained or episodic. The episodes may last from a few seconds to several hours, and triggers such as stress, caffeine, alcohol, or certain medications can precipitate episodes.
Clinically, patients with SVT often describe abrupt onset and cessation of palpitations. Some report a feeling of pounding or racing heart, while others might experience dizziness, chest discomfort, or shortness of breath. In severe cases, decreased cardiac output can lead to syncope or pre-syncope, especially in individuals with underlying heart disease. Physical examination during an episode typically reveals a rapid, regular pulse, and electrocardiogram (ECG) is the primary diagnostic tool for identifying SVT. The ECG often shows narrow QRS complexes with a regular rhythm, and specific features like a short RP interval can help distinguish among the different types.
The supraventricular tachycardia emedicine Diagnosis of SVT involves capturing the arrhythmia on a 12-lead ECG during an episode or using ambulatory monitoring such as Holter or event recorders if episodes are infrequent. Electrophysiological studies (EPS) can also be performed in selected cases to precisely identify the arrhythmia mechanism and to guide treatment options, especially when catheter ablation is considered.
The supraventricular tachycardia emedicine Management of SVT involves both acute and long-term strategies. For immediate relief during an episode, vagal maneuvers such as the Valsalva maneuver or carotid sinus massage are often effective. Pharmacologic agents like adenosine are the cornerstone of rapid termination due to their ability to transiently block AV nodal conduction. Adenosine acts quickly and has a short half-life, making it ideal for acute management. Other medications, including beta-blockers or calcium channel blockers, may be used for ongoing rate control or prophylaxis.
The supraventricular tachycardia emedicine In cases where episodes are frequent, recurrent, or refractory to medication, catheter ablation offers a highly effective definitive treatment. This procedure involves threading a catheter to the heart to ablate the abnormal electrical pathway responsible for the arrhythmia, often resulting in a cure rate exceeding 90%. Patients with SVT generally have a good prognosis, especially when appropriately diagnosed and managed.
In summary, supraventricular tachycardia is a common, often benign but occasionally symptomatic arrhythmia that requires prompt recognition and tailored treatment. Advances in electrophysiology have made catheter ablation a highly successful option, significantly improving quality of life for many patients. Understanding the mechanisms and management options ensures better outcomes and reduces the risk of complications. The supraventricular tachycardia emedicine
