A modified version of the Valsalva maneuver more than doubled the rate of conversion from acute supraventricular tachycardia to normal sinus rhythm when compared with the standard maneuver, said authors of a randomized, controlled trial published Oct. 31 in the Lancet.
In all, 93 of 214 (43%) emergency department patients with acute supraventricular tachycardia (SVT) achieved cardioversion a minute after treatment with the modified Valsalva maneuver, compared with only 37 (17%) of patients treated with standard Valsalva (adjusted odds ratio, 3.7; 95% confidence interval, 2.3-5.8; P less than .0001), reported Dr. Andrew Appelboam of Royal Devon and Exeter (England) Hospital NHS Foundation Trust and his associates.
Standard Valsalva is safe, but achieves cardioversion for only 5%-20% of patients with acute SVT. Nonresponders usually receive intravenous adenosine, which causes transient asystole and has other side effects, including a sense of “impending doom” or imminent death, the investigators noted (Lancet 2015;386:1747-53). For the modified Valsalva maneuver, patients underwent standardized strain at 40 mm Hg pressure for 15 seconds while semirecumbent, but then immediately laid flat while a staff member raised their legs to a 45 ° angle for 15 seconds. They returned to the semirecumbent position for another 45 seconds before their cardiac rhythm was reassessed. The control group simply remained semirecumbent for 60 seconds after 15 seconds of Valsalva strain.
The adapted technique should achieve the same rate of cardioversion in community practice, and clinicians should repeat it once if it is not initially effective, said the investigators. “As long as individuals can safely undertake a Valsalva strain and be repositioned as described, this maneuver can be used as the routine initial treatment for episodes of supraventricular tachycardia regardless of location,” they said. Patients did not experience serious adverse effects, and transient cardiac events were self-limited and affected similar proportions of both groups, they added.
The National Institute for Health Research funded the study. The researchers declared no competing interests.