Methods:

REVERT was a pragmatic, randomized, multicenter, parallel group trial conducted in 10 emergency departments in England. Patients with suspected supraventricular tachycardia (at emergency department or initial assessment) were screened for participation. Unstable patients and those in atrial fibrillation or flutter were excluded. For both groups, the Valsalva maneuver strain was standardized to a pressure of 40 mm Hg sustained for 15 seconds by forced expiration. In the modified Valsalva maneuver, participants performed the standardized strain in the same semi-recumbent 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. The primary outcome was the presence of sinus rhythm 1 minute after the Valsalva maneuver.