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This edition's critically appraised topic (CAT) looks at research into a new addition to an established technique to restore a steady rhythm to a rapidly beating heart.

 

CLINICAL BOTTOM LINE:

In patients with stable supraventricular tachycardia (SVT), using a modified Valsalva manoeuvre, involving leg elevation and supine positioning at the end of the usual strain, is a simple, no cost, well-tolerated procedure that is about 26 per cent more likely to restore sinus rhythm than the standard semi-recumbent Valsalva manoeuvre. It should be considered as a routine first treatment.

CLINICAL SCENARIO:

As a nurse working in the Emergency Department (ED), you frequently admit patients requiring emergency treatment for SVT. ED protocol recommends trying the standard Valsalva manoeuvre for initial treatment, which involves patients straining with force against a closed airway. However, successful reversion to sinus rhythm is uncommon and you decide to review the evidence for the effectiveness of this treatment option.

QUESTION:

In patients presenting acutely with supraventricular tachycardia, how effective is the Valsalva manoeuvre as the first-line treatment for restoring sinus rhythm?

SEARCH STRATEGY:

PubMed Clinical Queries (therapy, broad): Valsalva manoeuvre AND supraventricular tachycardia

CITATION:

Appelboam, A., Reuben, A., Mann, C., Gagg, J., Ewings, P., Barton, A., Benger, J. (2015). Postural modification to the standard Valsalva manoeuvre for emergency treatment of supraventricular tachycardias (REVERT): a randomised controlled trial. The Lancet.

STUDY SUMMARY:

The Randomised Evaluation of Modified Valsalva Effectiveness in Re-entrant Tachycardias (REVERT) study is a randomised, controlled, parallel group trial conducted in 10 emergency departments in England between 2013 and 2014. Inclusion criteria were patients older than 18 years presenting with SVT (regular, narrow complex tachycardia with QRS duration <0·12 s on ECG). Exclusion criteria were unstable patients with systolic blood pressure < 90mmHg or an indication for immediate cardioversion, atrial fibrillation or flutter (or suspected), contraindications to Valsalva manoeuvre, an inability to perform or tolerate the study procedure, third trimester pregnancy, or previous inclusion in this study. The 711 patients presenting to ED with suspected SVT were formally screened (241 did not meet eligibility criteria, 20 eligible were not enrolled, 17 declined consent); 433 were randomised and 428 analysed; five were excluded after randomisation as they were repeat enrolments.

• Standard care for both groups: All participants performed the initial straining component of the Valsalva manoeuvre in a semi-recumbent position. The Valsalva manoeuvre strain was standardised to a pressure of 40mmHg (measured by aneroid manometer) and sustained for 15 seconds (s). The Valsalva manoeuvre was repeated once if sinus rhythm was not restored. A 12-lead ECG was recorded if return to sinus rhythm was achieved at one minute after Valsalva manoeuvre, and one minute after the second manoeuvre even if unsuccessful.
• Interventions: (n = 214) Modified ‘lying down with leg lift’ Valsalva manoeuvre: participants performed the standardised strain in a semi-recumbent (at 45 degrees) position but immediately at the end of the strain were laid flat and had their legs raised to 45 degrees for 15 seconds. Participants were then returned to the semi-recumbent position for a further 45 seconds before re-assessment of cardiac rhythm.
• Control: (n = 214) Standard ‘sitting’ Valsalva manoeuvre: participants performed the standardised strain in a semi-recumbent (at 45 degrees) position. They remained in the semi-recumbent position for 60 seconds before reassessment of cardiac rhythm.
• Outcomes: Primary outcome – presence of sinus rhythm one minute after intervention. Secondary outcomes – use of adenosine or any other emergency SVT treatment, hospital admission, length of stay in ED and adverse events.

STUDY VALIDITY:

Randomisation was by an independent statistician. Allocation was concealed using serially numbered, opaque, sealed, tamper-evident envelopes. Investigators blinded to treatment allocation independently analysed all data. Clinicians and participants could not be blinded but trial paperwork and explanations didn’t indicate to participants which Valsalva manoeuvre was the intervention and which was the control. There was no loss to follow up. Analyses were performed on an intention-to-treat basis. Study groups were similar and groups were treated equally. Study quality was high.

STUDY RESULTS:

In both groups, around 85 per cent of participants achieved the desired strain pressure and duration. Significantly more participants reverted to sinus rhythm at one minute with the modified Valsalva manoeuvre than with the standard manoeuvre (table). Use of adenosine, or any emergency anti-arrhythmic treatment, was significantly lower in the modified Valsalva manoeuvre group (table). There was no significant difference between groups for rates of adverse events, time spent in ED or need for admission to hospital.

COMMENTS:

• This simple postural modification to the standard Valsalva manoeuvre reduced the need for unpleasant, higher risk anti-arrhythmic treatment (number needed to treat = 4).
• The procedure was well tolerated in the study population – adverse events were self-limiting and none were serious.
• The modified procedure can be easily taught to patients and staff; the open access publication has links to a training video and the authors advise that blowing into a 10ml syringe to just move the plunger generates a similar pressure to a 40mmHg strain 
• (no fancy equipment required).

Reviewer:

Cynthia Wensley RN, Honorary Professional Teaching Fellow, The University of Auckland and PhD candidate, Deakin University, Melbourne [email protected]