Acute Treatment: Recommendations Recommendations for Acute Treatment of Orthodromic AVRT COR LOE Recommendations I B-R 1. Vagal maneuvers are recommended for acute treatment in patients with orthodromic AVRT.42,75,235,259 See Online Data and 12. For acute conversion of orthodromic AVRT, vagal maneuvers, including Valsalva and carotid sinus massage, can be performed quickly and should be the first-line intervention to terminate SVT. These maneuvers should be performed with the patient in the supine position. There is no gold standard for proper Valsalva maneuver technique, but in general, the patient raises intrathoracic pressure by bearing down against a closed glottis for 10 to 30 seconds, equivalent to at least 30 to 40 mm Hg.82,84 Carotid massage is performed after absence of bruit has been confirmed by auscultation, by applying steady pressure over the right or left carotid sinus for 5 to 10 Another vagal maneuver based on the classic diving reflex consists of applying an ice-cold, wet towel to the face85 ; in a laboratory setting, facial immersion in water at 10 C (50 F) has proved effective in terminating tachycardia, as well.86 One study involving 148 patients with SVT demonstrated that Valsalva was more successful than carotid sinus massage, and switching from 1 technique to the other resulted in an overall success rate of 27.7%.82 The practice of applying pressure to the eyeball is potentially dangerous and has been abandoned. I B-R 2. Adenosine is beneficial for acute treatment in patients with orthodromic AVRT.42,260,261 See Online Data and 12. Adenosine is effective for conversion of orthodromic AVRT in 90% to 95% of patients, with minor and brief (<1 min) side effects occurring in approximately 30% of patients.42,260,261 Patients often have atrial or ventricular premature complexes immediately after conversion that, on occasion, may induce further episodes of AVRT. 