M-A of randomized trials: Effectiveness of the modified Valsalva maneuver in adults with supraventricular – “The meta-analysis demonstrated a significantly higher success rate for reconversion to sinus rhythm when using the modified VM compared to the standard VM in patients with an SVT (odds ratio = 4.36; 95% confidence interval, 3.30–5.76; P < 0.001)”.

Effectiveness of the modified Valsalva manoeuvre in adults with supraventricular tachycardia: a systematic review and meta-analysis – European Journal of Emergency Medicine (link to abstract – $ for full-text)

Related: Randomized Trial: Standard Valsalva vs. Modified Valsalva for Cardioversion of SVT (studies and commentaries on the subject)

Video: Modified Valsalva manoeuvre for supraventricular tachycardia – The Lancet