From the Guidelines
The initial treatment for a patient presenting with Paroxysmal Supraventricular Tachycardia (PSVT) should be to attempt vagal maneuvers, such as the Valsalva maneuver or carotid sinus massage, as recommended by the 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia 1.
Rationale for Vagal Maneuvers
Vagal maneuvers are recommended as the first-line treatment for PSVT because they can terminate the arrhythmia by increasing parasympathetic tone, and they are quick, easy, and non-invasive. The Valsalva maneuver and carotid sinus massage are the most commonly used vagal maneuvers, and they should be performed with the patient in the supine position.
Next Steps if Vagal Maneuvers Fail
If vagal maneuvers fail to convert the patient to a normal sinus rhythm, the next step is to administer intravenous adenosine, typically starting with a 6 mg rapid bolus followed by a saline flush, as supported by the 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care 1. Adenosine works by temporarily blocking AV nodal conduction, interrupting the reentry circuit responsible for PSVT.
Alternative Treatments
For patients with contraindications to adenosine, such as severe asthma or those taking dipyridamole, intravenous calcium channel blockers like verapamil (5-10 mg IV) or diltiazem (0.25 mg/kg IV) can be used instead, as recommended by the 2015 ACC/AHA/HRS guideline 1. Beta-blockers such as metoprolol (5 mg IV) are another alternative.
Importance of Continuous Monitoring
During treatment, continuous cardiac monitoring is essential, and equipment for potential cardioversion should be available in case the patient becomes hemodynamically unstable. For hemodynamically unstable patients with PSVT, immediate synchronized cardioversion at 50-100 joules is indicated rather than pharmacological management.
Key Points to Consider
- Vagal maneuvers are the first-line treatment for PSVT
- Adenosine is the next step if vagal maneuvers fail
- Calcium channel blockers and beta-blockers are alternative treatments
- Continuous cardiac monitoring is essential during treatment
- Synchronized cardioversion is indicated for hemodynamically unstable patients
From the FDA Drug Label
For patients with PSVT and patients with PAF the recommended starting dose is 50 mg every 12 hours. The initial treatment for a patient presenting with Paroxysmal Supraventricular Tachycardia (PSVT) is flecainide 50 mg every 12 hours 2.
- The dose may be increased in increments of 50 mg bid every four days until efficacy is achieved.
- The maximum recommended dose for patients with paroxysmal supraventricular arrhythmias is 300 mg/day.
From the Research
Initial Treatment for PSVT
The initial treatment for a patient presenting with Paroxysmal Supraventricular Tachycardia (PSVT) depends on their hemodynamic stability.
- For hemodynamically stable patients, the first-line acute therapy includes vagal maneuvers such as the modified Valsalva maneuver 3 and intravenous adenosine 3, 4, 5.
- Vagal maneuvers increase vagal tone and can include the traditional carotid sinus massage, Valsalva maneuver, head-down tilt, activation of the diving reflex, and use of the pneumatic antishock garment 6.
- Adenosine is the drug of choice for treating PSVT, with a high efficacy rate of 91% 3.
- Calcium channel blockers, such as verapamil and diltiazem, can also be used to treat PSVT, especially if adenosine is contraindicated or not available 6, 5.
Hemodynamically Unstable Patients
- For hemodynamically unstable patients, emergent cardioversion is recommended 3, 4.
- Synchronized electrical countershock is the treatment of choice for hemodynamically unstable patients 6.