Daniel Kim, MD FRCPC (biography, no disclosures)
What I did before
Supraventricular tachycardia (SVT) is a dysrhythmia characterized by abrupt onset, regular rate that usually exceeds 150 beats/minute, and lack of identifiable P waves on ECG. SVT is caused by an abnormal circuit that allows a wave of depolarization to repeatedly travel in circular fashion in cardiac tissue via a reentry circuit that may reside in the atrioventricular (AV) node or outside the AV node in an accessory pathway. The goal of treatment is to terminate this circular depolarization.
The American Heart Association (AHA) Guidelines suggest that vagal maneuvers are the preferred initial therapy to terminate stable SVT. <1> The literature shows that cardioversion is rarely successful with vagal maneuvers (<20%), <2> and my personal success rate with vagal maneuvers was so low I didn’t even bother attempting them.
My initial treatment for stable SVT was a rapid intravenous push of adenosine because of its high efficacy in terminating SVT. However adenosine results in transient asystole and a feeling of imminent death that many patients find unpleasant and frightening. <1>
What changed my practice
In August 2015, Appelboam and colleagues published the results of the REVERT trial (Randomized Evaluation of modified Valsalva Effectiveness in Re-entrant Tachycardias). <3> They studied the effectiveness of a modified Valsalva maneuver that involved a 15-second Valsalva strain to a pressure of 40 mm Hg followed immediately by being laid flat and having ones legs raised to 45° for 15 seconds.
They performed a pragmatic, randomized controlled study in adult patients presenting with SVT. They randomly assigned patients to undergo either this modified Valsalva maneuver, or a standard semi-recumbent Valsalva strain to a pressure of 40 mm Hg without any postural modification afterwards.
During a 2-year period, 433 patients were randomly assigned to either a standard Valsalva group or a modified Valsalva group. After excluding repeat visits by 5 patients, 214 patients in each group were included in the intention-to-treat analysis. Only 37 (17%) patients in the standard Valsalva group achieved sinus rhythm compared with 93 (43%) patients in the modified Valsalva group. Adenosine use was significantly higher in the standard Valsalva group (69% vs 50%). There were no serious adverse events in either group.
What I do now
My initial treatment for stable SVT is now the modified Vasalva maneuver. We don’t have a manometer to ensure a measurable 40 mm Hg Valsalva strain, but a 10-ml syringe blown to just move the plunger generates similar pressures. I have the patient blow on a 10-ml syringe for 15 seconds, then lay them supine and raise their legs in the air for 15 seconds. I’ve successfully cardioverted more than one-third of my SVT patients using this technique.
This intervention is free, safe, effective, does not require an intravenous, and can be taught to patients. There are very few treatments in medicine that are free, safe, and effective.
References
- Neumar RW, Otto CW, Link MS, et al. Part 8: Adult advanced cardiovascular life support: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation 2010; 122:S729-67. (View with CPSBC or UBC)
- Lim SH, Anantharaman V, Teo WS, et al. Comparison of treatment of supraventricular tachycardia by Valsalva maneuver and carotid sinus massage. Ann Emerg Med 1998; 31:30-5. (View with CPSBC or UBC)
- Appelboam A, Reuben A, Mann C, 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. (View with CPSBC or UBC)
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Glad to see this article. I have been doing a modification to the sad old feeble yet standard vagal maneuver for about 18yrs. Once I have a sense that the patient is stable, I do 3 things – 1) 30-45deg of trendelenberg as explain to the patient what is going on,what will be going on,and why, 2) then after a couple of minutes I get the patient to do the valsalva and 3) immediately post valslava carotid sinus massage. My success rate is in the 40-50%. Anecdotely, patients that have a slight slowing of the heart rate when put into trendelenberg seem to be the most likely responders to the other vagal maneuvers.
By the way I always check out these “This Changed my Practice” emails. Unusual not to find something useful.
Most interesting. Like most I have been unimpressed by the valsalva technique to date, so this sounds very promising, a definite positive advance to be tried.
I agree this does sound promising but I am going to experiment on myself to determine an easier measure of achieving a 40mm strain.
I also have combined the Valsalva with carotid massage and gotten better results than valsava alone.
This is such an interesting low cost and low risk intervention! For fun, today on rounds at the hospital I tried to see if healthy young nursing staff, residents, medical students and an attending could actually MOVE the 10cc syringe plunger. None of us could actually do it (even after breaking the seal, manually moving the plunger a few times or with water in the syringe). It definitely produces a strong vasalva so the goal of the effort is achieved but I’m not sure if we can expect patients to actually MOVE the plunger. Anyone else try to move the plunger themselves?
Again, the method seems very useful and I’m looking forward to trying for SVT in the future!
it is safe and effective and free, it is definitely good to use. excellent approach to the treatment no side effect.
After being told about this modification,we tried to blow the syringe. Not easy. Lot of dizzy people. Sustained pressure seems to work. Was succesful on firs t patient we tried!
I have not tried the syringe method, but get my patients to blow into a drinking straw and pinch the straw closed for the duration of exhalation, followed by trendelenburg positioning for about 30 seconds. I find this converts SVT in ~40% patients and works especially well in kids with SVT. (More fun for kids to have them try to blow bubbles in cup of water as you pinch straw, and gets them to blow longer.)
THIS IS GREAT I AM HAPPY TO LEARN YOU CAN TREAT USING THIS SIMPLE MODIFIED METHOD WELL DONE DOCTOR