What is the diagnosis and treatment for Supraventricular Tachycardia (SVT)?

From the Guidelines

For the management of supraventricular tachycardia (SVT), oral beta blockers, diltiazem, or verapamil is recommended as the first-line treatment for ongoing management in patients with symptomatic SVT who do not have ventricular pre-excitation during sinus rhythm. This approach is based on the 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia, which suggests that these medications are useful for reducing the frequency and duration of SVT episodes 1. The guideline recommends the following options for ongoing management:

• Oral beta blockers, diltiazem, or verapamil for patients with symptomatic SVT who do not have ventricular pre-excitation during sinus rhythm
• EP study with the option of ablation as a first-line therapy for treatment of symptomatic SVT, providing the potential for definitive cure without the need for chronic pharmacological therapy
• Patient education on how to perform vagal maneuvers, such as the Valsalva maneuver or the diving reflex, to help terminate SVT episodes
• Flecainide or propafenone as a reasonable option for ongoing management in patients without structural heart disease or ischemic heart disease who have symptomatic SVT and are not candidates for, or prefer not to undergo, catheter ablation. Key points to consider when managing SVT include:
• The importance of educating patients on how to perform vagal maneuvers to help manage SVT episodes
• The potential benefits and risks of catheter ablation, including its high success rate and low risk of complications
• The need to individualize treatment based on patient preferences and medical history, including the presence of structural heart disease or ischemic heart disease. Overall, the goal of SVT management is to reduce symptoms, prevent recurrent episodes, and improve quality of life, while also minimizing the risk of complications and mortality 1.

From the FDA Drug Label

ADENOSINE INJECTION, USP is indicated as an adjunct to thallium-201 myocardial perfusion scintigraphy in patients unable to exercise adequately The most common adverse reactions are flushing, chest discomfort, and shortness of breath. SVT (Supraventricular Tachycardia) is not mentioned in the provided drug label for adenosine (IV) as an indication.

• However, adenosine is often used for the treatment of SVT.
• The provided label does not directly support the use of adenosine for SVT.
• Verapamil (PO) label does mention atrial fibrillation and atrioventricular block, but does not directly address SVT.
• Given the information provided in the labels, adenosine (IV) may be considered for SVT, but the label does not directly support this use 2.
• Verapamil (PO) is not directly indicated for SVT based on the provided label 3.

From the Research

Definition and Causes of SVT

• Supraventricular tachycardia (SVT) refers to rapid rhythms that originate and are sustained in atrial or atrioventricular node tissue above the bundle of His 4
• The condition is caused by reentry phenomena or automaticity at or above the atrioventricular node, and includes atrioventricular nodal reentrant tachycardia, atrioventricular reciprocating tachycardia, and atrial tachycardia 4

Symptoms of SVT

• Sudden onset of an accelerated heart rate can cause palpitations, light-headedness, chest discomfort, anxiety, dyspnea, or fatigue 4
• The history is important to elicit episodic symptoms because physical examination and electrocardiography findings may be normal 4

Diagnosis of SVT

• A Holter monitor or event recorder may be needed to confirm the diagnosis 4
• In many cases, the underlying mechanism can be deduced from electrocardiography during tachycardia, comparing it with sinus rhythm, and assessing the onset and offset of tachycardia 5

Treatment of SVT

• Vagal maneuvers may terminate the arrhythmia; if this fails, adenosine is effective in the acute setting 4, 6
• Calcium channel blockers (diltiazem or verapamil) or beta blockers (metoprolol) can be used acutely or as long-term therapy 4
• Class Ic antiarrhythmics (flecainide or propafenone) can be used long-term 4
• Catheter ablation has a success rate of 95% and recurrence rate of less than 5%, and causes inadvertent heart block in less than 1% of patients 4
• Nondihydropyridine calcium channel blockers, such as verapamil and diltiazem, may be as effective as adenosine, without the negative short-term side effects 7

Comparison of Adenosine and Calcium Channel Antagonists

• Moderate-quality evidence shows no differences in the number of people reverting to sinus rhythm who were treated with adenosine or CCA (89.7% vs 92.9%; OR 1.51,95% confidence interval (CI) 0.85 to 2.68; participants = 622; studies = 7; I2 = 36%) 8
• Low-quality evidence suggests no appreciable differences in major adverse event rates between CCAs and adenosine 8
• Calcium channel blockers are a viable option for treatment for AVNRT, especially in refractory states 7