We identifed three randomised controlled trials including 316 participants. All three studies compared the effectiveness of VM in
reverting SVT with that of other vagal manoeuvres in a cross-over design. Two studies induced SVT within a controlled laboratory
environment. Participants had ceased all medications prior to engaging in these studies. The third study reported on patients presenting
to a hospital emergency department with an episode of SVT. These patients were not controlled for medications or other factors prior
The two laboratory studies demonstrated reversion rates of 45.9 and 54.3 , whilst the clinical study demonstrated reversion success
of 19.4 . This discrepancy may be due to methodological differences between studies, the effect of induced SVT versus spontaneous
episodic SVT, and participant factors such as medications and comorbidities. We were unable to assess any of these factors further, nor adverse effects, since they were either not described in enough detail or not reported at all.
Statistical pooling was not possible due to heterogeneity between the included studies.