Falling heels over head: you make my heart skip a beat
Resident Clinical Pearl (RCP) November 2019
Patricia Marks – PGY1 (FRCPC) Dalhousie University, Halifax, NS
Reviewed by Dr David Lewis
Introduction:
Supraventricular tachycardias (SVT) is a common presentation to the emergency room, and most patients will require treatment with adenosine or electrical cardioversion, as vagal maneuvers are less than 20% of the time in clinical practice. Adenosine and electrical cardioversion both require additional hospital resources, and adenosine is poorly tolerated by patients.
The REVERT trial published in 2015 in the Lancet by Appelboam et al. proposed a modified Valsalva maneuver in the treatment of SVT. The study was a multicentre randomized control trial in England involving 433 patients with stable SVT. According to an intention to treat analysis, the authors found a 43% success rate of conversion to sinus rhythm with the modified Valsalva maneuver compared to 17% with standard Valsalva. No significant dangerous adverse effects occurred in this study.
Modified Valsalva: The How-To
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Patient identification:
- Is my patient eligible for Valsalva?
- Stable SVT
- Age > 18 years
- Able to perform Valsalva
- Able to lie flat and have legs lifted
- Contraindications:
- Unstable or indication for immediate cardioversion
- Atrial fibrillation, atrial flutter, sinus tachycardia
- Recent MI
- Aortic stenosis
- Glaucoma
- Retinopathy
- Third trimester of pregnancy
- Is my patient eligible for Valsalva?
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Materials
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- 10cc syringe
- Manometer (optional)
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Performing the modified Valsalva maneuver
- Position the patient in a semi-recumbent position (45º)
- Instruct the patient to blow into the tip of a 10cc syringe for 15 seconds. The patient should be targeting a pressure reading on the manometer of 40mmHg, or blowing hard enough to move the plunger tip*
- Lower the patient flat and passively raise their legs to a 45º angle for 15 seconds
- Return the patient to a semi-recumbent position for an additional 45 seconds
- Assess the rhythm
- Repeat x1 if unsuccessful before moving on to adenosine or electrical cardioversion (provided the patient remains stable)
*The REVERT trial used a manometer to measure 40mmHg of pressure, however Smith and Boyle have demonstrated that 40mmHg of pressure is generated when a patient is instructed to blow into a 10cc syringe until the plunger moves
Image obtained from https://www.ecgmedicaltraining.com/wp-content/uploads/2016/06/REVERT-Trial-SVT.jpg on February 21, 2020.
Watch the REVERT authors perform the maneuver:
Benefits of this method:
- Easy to instruct patients; can try at home
- Higher success rate than standard Valsalva
- Similar ED length of stay compared to standard Valsalva
- Less patients require adenosine or cardioversion
Additional considerations
- No formal studies exist for pediatric patients, however a recent case report by Rayburn and Wagers did demonstrate successful conversion to sinus rhythm with this maneuver
Bottom Line
In adults with stable SVT, the modified Valsalva maneuver as published in the REVERT trial achieves a high rate of conversion to sinus rhythm with a NNT of 3.8 and without significant adverse effects. In patients without contraindications, the modified Valsalva maneuver is a low-cost and easy to teach strategy that should be trialled to convert patients in SVT prior to adenosine or electrical cardioversion.
References
- Appelboam A, Reuben A, Mann C, Gagg J, Ewings P, Barton A, Lobban T, Dayer M, Vickery J, Benger J; REVERT trial collaborators. Postural modification to the standard Valsalva manoeuvre for emergency treatment of supraventricular tachycardias (REVERT): a randomised controlled trial. Lancet. 2015 Oct 31;386(10005):1747-53. doi: 10.1016/S0140-6736(15)61485-4.
- Rayburn D, Wagers B. Modified Valsalva Maneuver for Pediatric Supraventricular Tachycardia. Pediatr Emerg Care. 2020 Jan;36(1):e8-e9. doi: 10.1097/PEC.0000000000002023
- Smith G, Boyle MJ. The 10 mL syringe is useful in generating the recommended standard of 40 mmHg intrathoracic pressure for the Valsalva manoeuvre. Emerg Med Australas. 2009 Dec;21(6):449-54. doi: 10.1111/j.1742-6723.2009.01228.x
- Smith GD, Fry MM, Taylor D, Morgans A, Cantwell K. Effectiveness of the Valsalva Manoeuvre for reversion of supraventricular tachycardia. Cochrane Database of Systematic Reviews 2015, Issue 2. Art. No.: CD009502. DOI: 10.1002/14651858.CD009502.pub3