Comparing Two Vagal Maneuvers for Paroxysmal Supraventricular Tachycardia

Reverse Vagal Maneuver Versus Modified Valsalva Maneuver for Paroxysmal Supraventricular Tachycardia: A Randomized Controlled Trial

The goal of this clinical trial is to compare two physical techniques for treating paroxysmal supraventricular tachycardia in adults. This condition causes a fast, regular heartbeat that starts and stops suddenly. Participants must be medically stable and have the condition confirmed by an electrocardiogram (ECG).

The main question is:

Does the reverse vagal maneuver restore normal heart rhythm more often than the modified Valsalva maneuver before rescue treatment is needed?

Researchers randomly assign participants to one of the two maneuvers.

Participants assigned to the modified Valsalva maneuver sit in a partly upright position. They blow into a 10-mL syringe for 15 seconds with enough force to move the plunger. They then lie flat while their legs are raised for 15 seconds.

Participants assigned to the reverse vagal maneuver sit upright and breathe out normally. They then close their nose and mouth and try to breathe in forcefully for 15 seconds.

All participants have an ECG before the maneuver and continuous heart rhythm monitoring. If normal rhythm is not restored, the assigned maneuver may be repeated up to three times. An ECG is recorded 45 seconds after each attempt. Participants receive standard rescue treatment if the assigned maneuver does not restore normal rhythm or if continuing becomes unsafe.

Researchers also record first-attempt success, rescue medication, electrical cardioversion, return of the fast heartbeat, hospital disposition, unwanted effects, repeat emergency department visits, and catheter ablation during one year of follow-up.

Inclusion Criteria:

• Age 18 years or older
• Presentation to the emergency department with symptoms consistent with paroxysmal supraventricular tachycardia (PSVT)
• Electrocardiogram-confirmed PSVT, defined as a regular narrow-complex tachycardia with a heart rate of 135 to 250 beats per minute and no clearly visible P waves
• Hemodynamically stable at enrollment, as determined by the treating emergency physician
• No acute antiarrhythmic medication received for the index episode before enrollment
• No electrical therapy received for the index episode before enrollment

Exclusion Criteria:

• Systolic blood pressure below 90 mm Hg
• Shock
• Evidence of hypoperfusion
• Altered mental status attributable to tachycardia
• Ischemic chest discomfort attributable to tachycardia
• Syncope attributable to tachycardia
• Acute heart failure attributable to tachycardia
• Pulmonary edema attributable to tachycardia
• Need for immediate cardioversion
• Need for another urgent treatment
• Inability to perform a vagal maneuver
• Pregnancy
• Body weight greater than 130 kg
• Comorbidity making performance of a vagal maneuver unsafe
• Previous operation making performance of a vagal maneuver unsafe
• Prior familiarity with either study maneuver together with the ability to self-perform it
• Reported acute use of a nonprescribed drug expected to affect heart rate or rhythm
• Reported acute use of a stimulant expected to affect heart rate or rhythm
• Reported acute exposure to another substance expected to affect heart rate or rhythm
• Reported recent consumption of a food expected to affect heart rate or rhythm
• Inability to provide informed consent
• Spontaneous conversion to sinus rhythm before the study intervention