This is a plain English summary of an original research article
A simple postural change to the Valsalva manoeuvre (see Definitions) improves the effectiveness of this cheap, non-invasive means of treating supraventricular tachycardia - an abnormally fast heart rate over 100 beats per minute. The NIHR funded a pragmatic trial of the promising technique in ten hospital emergency departments in England. The trial found that laying people flat and raising their legs, just after the Valsalva blowing, or ‘strain’ phase, was three times more effective at bringing their heart rhythm back to normal than performing the whole manoeuvre in the usual semi-reclining position. The findings add to existing guidance and have the potential to reduce the need for more interventional treatments, such as intravenous adenosine, which may have unpleasant side effects.
Why was this study needed?
Supraventricular tachycardia occurs in just over 2 in 1,000 people and involves periods of abnormally fast heart rate (over 100 heartbeats a minute) often followed by a rapid return to a normal heart rate. Most episodes are harmless, don't last long and settle on their own without treatment, but some can last for longer causing dizziness, fainting, chest pain and difficulty breathing, particularly if there is an underlying heart condition. In these cases hospital treatment might be needed. Some people find the heart rate can be returned to normal using the “Valsalva manoeuvre” (see Definitions), but the success rate is quite low, ranging from 19% to 54%. It involves forcefully blowing out against resistance, similar to blowing up a balloon. This trial was the first to test whether a simple modification to the Valsalva manoeuvre could improve its success rate in the hospital emergency room setting. A randomised trial against current practice, in real life practice, is the best way to reliably test a new intervention.
What did this study do?
The REVERT trial was a randomised controlled trial of a modification to the Valsalva manoeuvre in real-life practice in 10 emergency departments in the South West of England. The trial included 428 participants with supraventricular tachycardia who did not have very low blood pressure or need immediate treatment to return their heart rates to normal. Participants were randomly allocated to receive the standard Valsalva manoeuvre or its modification, which could be repeated if the first attempt was unsuccessful. The main outcome was success rate at achieving normal heart rhythm, as measured one minute after the manoeuvre, using an electrocardiogram. The trial was designed rigorously, and carefully ensured that an independent expert checked each electrocardiogram, so we can be confident in the results.
What did it find?
- Those receiving the modified Valsalva manoeuvre were more likely to regain normal heart rhythm (43% success) compared with those receiving the standard Valsalva manoeuvre (17% success). The odds ratio was 3.7, 95% confidence interval 2.3 to 5.8.
- There was no difference between the groups in terms of the amount of time spent in the emergency department or need for hospital admission.
- There were no serious adverse events, and no significant difference between minor adverse events in either group.
What does current guidance say on this issue?
The Resuscitation Council UK 2010 guidelines recommend that vagal manoeuvres such as the Valsalva manoeuvre are the first line intervention for people with uncomplicated supraventricular tachycardia. Another vagal manoeuvre is carotid sinus massage but they advise this should only be performed by medical personnel with access to defibrillators. If these techniques do not return the heart back to a normal rhythm within seconds, then treatment with intravenous adenosine is recommended.
What are the implications?
The modification improves the effectiveness of the original Valsalva manoeuvre for treating supraventricular tachycardia. It is cheap, safe, quick and easy to apply in the emergency department, and potentially more acceptable to people with supraventricular tachycardia than drug treatments such as intravenous adenosine. The authors noted potential for clinicians to teach the modified manoeuvre to eligible patients, which could enable them to treat themselves at home. Overall, the modification has the potential to challenge existing guidance and practice, may save resources and improve patient satisfaction.
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 DOI: 10.1016/s0140-6736(15)61485-4.
This project was funded by the National Institute for Health Research programme Research for Patient Benefit (grant number PB-PG-0211-24145).
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