Impact of a modified Valsalva manoeuvre in the termination of paroxysmal supraventricular tachycardia.

BACKGROUND: Paroxysmal supraventricular tachycardia (SVT) is a relatively common problem presented to the emergency department. Most sources advocate the use of vagal manoeuvres as first-line management, including Valsalva manoeuvre. Despite this, there is lack of standardisation as to how the technique is performed. There is currently no 'gold standard' Valsalva manoeuvre. We propose a modified Valsalva manoeuvre, based on techniques described in small-scale electrophysiological studies, but no large clinical trials.

OBJECTIVE: The study was designed to assess the impact of introducing this modified Valsalva manoeuvre as the departmental standard for non-pharmacological reversion of SVT.

METHODS: A retrospective audit reviewing the preceding 6-month presentations of SVT was performed, and a questionnaire assessing techniques used and anticipated success rates was completed by a representative sample of emergency department doctors. Finally, a prospective trial of the impact of the modified Valsalva manoeuvre on patients presenting in SVT to the emergency department was performed. After meeting the study criteria and giving consent, the patients were instructed to perform the modified Valsalva manoeuvre, that is, while lying supine on the bed in a Trendelenberg position, they forcefully expire into a section of suction tubing and pressure gauge for at least 15 s and at a pressure of at least 40 mm Hg.

RESULTS: The retrospective 6-month audit revealed only one successful reversion with Valsalva from a sample of 19 patients. Thirty-two doctors completed the questionnaire describing a variety of different Valsalva techniques highlighting a lack of consensus. 27 patients were recruited to the prospective trial, of whom 19 were correctly diagnosed as having paroxysmal SVT. Of these 19 patients, 6 reverted with the modified Valsalva manoeuvre.

CONCLUSION: Our findings support previous observations that there is lack of standardisation as to how Valsalva is performed, and an apparent reliance on adenosine. The impact of introducing this technique as our departmental standard was a raise in non-pharmacological reversion from 5.3% to 31.7% with no reported significant adverse effects.