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

From the Guidelines

Supraventricular tachycardia (SVT) should be initially managed with vagal maneuvers, such as the Valsalva maneuver or carotid sinus massage, as the first-line treatment to slow the heart rate, as recommended by the 2015 ACC/AHA/HRS guideline 1.

Initial Management

The initial management of SVT involves attempting to slow the heart rate using vagal maneuvers, which can be performed quickly and are recommended as the first-line intervention to terminate SVT 1.

• Vagal maneuvers, including Valsalva and carotid sinus massage, can be effective in terminating SVT, with a success rate of 27.7% in one study 1.
• The Valsalva maneuver is performed by having the patient raise intrathoracic pressure by bearing down against a closed glottis for 10 to 30 seconds, equivalent to at least 30 mm Hg to 40 mm Hg 1.
• Carotid massage is performed after absence of bruit has been confirmed by auscultation, by applying steady pressure over the right or left carotid sinus for 5 to 10 seconds 1.

Pharmacological Management

If vagal maneuvers are unsuccessful, the next step is to use pharmacological agents to convert the arrhythmia.

• Adenosine is recommended as the first-line medication for acute treatment of SVT, given as a rapid IV push starting at 6 mg, followed by 12 mg if needed, and another 12 mg dose if the arrhythmia persists 1.
• Adenosine has been shown to effectively terminate SVT in nonrandomized trials, with success rates ranging from 78% to 96% 1.
• Calcium channel blockers like verapamil or diltiazem, or beta-blockers such as metoprolol, can be used for longer-term management of SVT 1.

Catheter Ablation

For recurrent episodes of SVT, catheter ablation offers a definitive treatment with success rates exceeding 95% for most SVT types.

• EP study with the option of ablation is useful for the diagnosis and potential treatment of SVT, and can be considered as first-line therapy for treatment of symptomatic SVT 1.
• Catheter ablation can provide a definitive cure without the need for chronic pharmacological therapy, and is recommended for patients who prefer not to undergo long-term medication or have failed pharmacological therapy 1.

From the FDA Drug Label

Diltiazem Hydrochloride Injection is indicated for: Paroxysmal Supraventricular Tachycardia Rapid conversion of paroxysmal supraventricular tachycardias (PSVT) to sinus rhythm This includes AV nodal reentrant tachycardias and reciprocating tachycardias associated with an extranodal accessory pathway such as the WPW syndrome or short PR syndrome. Unless otherwise contraindicated, appropriate vagal maneuvers should be attempted prior to administration of diltiazem hydrochloride injection In domestic controlled trials, bolus administration of diltiazem hydrochloride injection was effective in converting PSVT to normal sinus rhythm in 88% of patients within 3 minutes of the first or second bolus dose

Diltiazem (IV) is indicated for the treatment of Paroxysmal Supraventricular Tachycardia (PSVT).

• The medication can rapidly convert PSVT to normal sinus rhythm.
• Vagal maneuvers should be attempted before administering diltiazem hydrochloride injection, unless contraindicated.
• In clinical trials, diltiazem hydrochloride injection was effective in converting PSVT to normal sinus rhythm in 88% of patients within 3 minutes of the first or second bolus dose 2.

From the Research

Definition and Types of Supraventricular Tachycardia

• Supraventricular tachycardia (SVT) is an abnormal rapid cardiac rhythm that involves atrial or atrioventricular node tissue from the His bundle or above 3.
• The common types of SVT include atrioventricular nodal reentrant tachycardia, atrioventricular reentrant tachycardia, and atrial tachycardia 3, 4.

Symptoms and Diagnosis

• Presenting symptoms of SVT may include altered consciousness, chest pressure or discomfort, dyspnea, fatigue, lightheadedness, or palpitations 3.
• Diagnostic evaluation may be performed in the outpatient setting and includes a comprehensive history and physical examination, electrocardiography, and laboratory workup 3.
• Extended cardiac monitoring with a Holter monitor or event recorder may be needed to confirm the diagnosis 3, 5.

Management and Treatment

• Acute management of paroxysmal SVT is similar across the various types and is best completed in the emergency department or hospital setting 3.
• In patients who are hemodynamically unstable, synchronized cardioversion is first-line management 3.
• In those who are hemodynamically stable, vagal maneuvers are first-line management, followed by stepwise medication management if ineffective 3, 6.
• Beta blockers and/or calcium channel blockers may be used acutely or for long-term suppressive therapy 3, 5, 6.
• Catheter ablation has a high success rate and is recommended as the first-line method for long-term management of recurrent, symptomatic paroxysmal SVT, including Wolff-Parkinson-White syndrome 3, 5.

Long-Term Management

• Long-term treatment is dependent on several factors including frequency of symptoms, risk stratification, and patient preference 4.
• Management can range from conservative, if symptoms are rare and the patient is low risk, to catheter ablation which is curative in the majority of patients 4, 5.
• Clinicians should use a patient-centered approach when formulating a long-term management plan for atrioventricular nodal reentrant tachycardia 3.