At today’s report Dr. Dixit took us through the complicated world of SVT’s and how to better incorporate our understanding of the electrophysiology into the assessment of each patient.
The VA team discussed initial maneuvers to break an SVT including carotid massage and Valsalva which lead us to the REVERT trial summarized below (3).
Valsalva maneuver is a safe first line treatment in ED’s for SVT with roughly the same efficacy between Valsalva and carotid massage (2). Cardioversion is rarely successful in clinical practice (5-20%) (1-2) and patients who remain in an SVT are usually treated with adenosine which is associated with substantial side effects. The REVERT researchers proposed to compare a modified Valsalva (15 second Valsalva + passive leg raise) to a standard Valsalva with a primary outcome of return to sinus rhythm at 1 minute.
- Randomized controlled, multicenter parallel group trial
- N = 433
- Modified Valsalva (n=216)
- Standard Valsalva (n=217)
- Analysis: Intention-to-treat
- Primary Outcome: Return to sinus rhythm at 1 minute
- Secondary Outcomes: Use of adenosine, use of any emergency treatment for SVT (including adenosine), the need and reason for admission to the hospital, length of time participants spent in the ED, adverse events.
- Inclusion Criteria: >18 yo, presented to ED with SVT (regular, narrow complex tachycardia with QRS duration <0.12s on ECG)
- Exclusion Criteria: unstable SBP <90mmHg, suspected aflutter requiring adenosine trial, contraindication to Valsalva maneuver (AS, recent MI, glaucoma retinopathy), inability to lay flat or raise legs.
- Standard Valsalva: pressure of 40 mmHg sustained for 15 seconds by forced expiration measured by manometer while SITTING at 45 degrees + standardized verbal instructions
- Modified Valsalva: pressure of 40 mmHg sustained for 15 seconds by forced expiration measured by manometer while SITTING at 45 degrees + standardized verbal instructions + THEN laying flat and had their legs lifted by staff member to 45 degrees for 15 seconds
- Primary Outcome: 43% of participants in modified Valsalva maneuver group vs. 17% in standard Valsalva group achieved sinus rhythm at 1 minute. The absolute difference was 26.2% therefore 3 patients needed the modified Valsalva maneuver to avoid one case of further treatment.
This simple cost-free postural change to a standard Valsalva returns more people to sinus rhythm within 1 minute AND results in a substantial reduction in the number of patients needing other emergency treatments including adenosine.
** To do a Valsalva of about 40 mmHg you can use a 10mL syringe blown to just move the plunger **
- Smith G et al. Use of valsalva manoeuvre in the prehospital setting: a review of the literature. Emerg Med J 2009; 26:8-10.
- Lim SH et al. Comparison of treatment of supraventricular tachycardia by valsalva manoeuvre and carotid sinus massage. Ann Emerg Med 1998; 31: 30-25.
- Appelboam A et al. Postural modification to the standard Valsalva manoeuvre for emergency treatment of supraventricular tachycardias (REVERT): a randomised controlled trial. Lancet 2015; 386: 1747-53.