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EXETER, UK – The Valsalva maneuver, while effective in some patients with supraventricular tachycardia, has a low success rate. That often necessitates an adenosine injection, which can cause side effects such as an uncomfortable sense of doom.
A simple modification to the physical technique improves its effectiveness by more than 25%, however, according to a study published recently in The Lancet.
During the Valsalva maneuver, patients are instructed to forcibly exhale or strain while keeping the nose and mouth closed, which changes the rate and volume of blood returning to the heart and causes a reflex slowing of the heart. Ideally, that returns the heart rhythm to a normal rate.
Yet, that is not usually the case because the technique has a success rate of between 5% and 20%. To try to improve effectiveness, a British research team, led by the Royal Devon and Exeter NHS Foundation Trust, embarked on a study across 10 UK National Health Service emergency departments involving more than 400 patients.
Results indicate that repositioning patients immediately after the strain – i.e., laying them flat with legs lifted by staff to increase blood flow back to the heart -- the Valsalva maneuver was much more successful in returning the heart rhythm to a normal rate.
The study reported that, while heart rate returned to normal in only 17.5% of patients using the traditional posture, the percentage rose to 43.5% in patients using the modified posture.
"While supraventricular tachycardia is rarely life threatening, it can be extremely distressing for patients. We thought that the Valsalva maneuver had potential to be yet more effective as a treatment option and our study has borne this out,” Andrew Appelboam, FRCEM, consultant in emergency medicine at the Royal Devon and Exeter NHS Foundation Trust, told The Lancet. “What it means is that more patients can benefit from it without the need for further treatments with significant side effects. It also means that, because the postural modification is cost-free with no identified disadvantages, it could be easily adopted worldwide."
Study authors recommend widespread adoption of the modified technique, noting, “In patients with supraventricular tachycardia, a modified Valsalva maneuver with leg elevation and supine positioning at the end of the strain should be considered as a routine first treatment, and can be taught to patients."