Vagal Maneuvers (Modified Valsalva)

Vagal maneuvers slow AV-node conduction and can end AVNRT or AVRT. In the REVERT trial, the modified maneuver returned sinus rhythm in 43% of adults vs 17% with the standard maneuver at 1 minute.

A vagal maneuver pushes up parasympathetic (vagal) tone at the AV node, and the node slows down. In AVNRT or AVRT, that can break the re-entry circuit (AVRT here includes orthodromic AVRT in WPW). Use it as a first step in a stable patient. It is not a treatment for AF or flutter.

How It Works

• Strain: the patient breathes out hard against a closed airway. Intrathoracic pressure climbs, and that reflex slows AV conduction.
• Release: pressure drops and the vagal brake comes off. The modified version raises the legs at that same moment to boost venous return.
• Result: if it works, the re-entry rhythm stops. You see an abrupt return to sinus rhythm on the strip.

Where It Fits

Stable and regular, narrow complex: vagal maneuver first, then adenosine. Still in SVT? Move to the AV-nodal blockers on their own pages. Unstable? Cardiovert.

Indications

• Stable regular narrow-complex tachycardia: AVNRT or orthodromic AVRT on a regular rhythm with a narrow QRS.
• Adults first: REVERT enrolled adults with SVT. AF and flutter were left out.

Absolute Contraindications

• Unstable patient: hypotension, altered mental status, ischemic chest pain or acute heart failure with the tachycardia. Cardiovert instead.
• Irregular or wide-complex tachycardia: don't use the maneuver on it. Wide and regular is VT until proven otherwise.

Relative Contraindications & Cautions

• Cannot follow the strain instruction: use the protocol's alternative for that patient.
• Pre-excited rhythm (WPW) with AF: no AV-nodal blockers. A vagal maneuver doesn't treat pre-excited AF.

Team Roles During the Procedure

• Operator: explains the maneuver, coaches the strain and leads the leg raise.
• Monitor reader: watches the rhythm strip and calls the time of the release.
• Medication clinician: prepares adenosine with a flush and a second check of the dose.
• Recorder: documents the time, pressure and response.

Rhythm Check

• Regular and narrow: the usual target. Confirm with a 12-lead where the protocol allows it.
• Irregular: not a vagal maneuver candidate. Treat per the atrial fibrillation pathway.
• Wide: treat it as VT unless proven otherwise. Adenosine only for a regular monomorphic rhythm, under expert guidance or protocol. No other AV-nodal blocker (verapamil, diltiazem, beta-blocker).

Physiologic Risk

• Hypotension: SBP <90 mmHg with the tachycardia is an unstable pattern. Cardiovert.
• Mental status and chest pain: either one pushes you toward cardioversion.
• Baseline: record SpO₂ and blood pressure before the maneuver. Without them, a later change is hard to see.

Equipment

• Cardiac monitor: continuous ECG with a rhythm strip you can save or print.
• 12-lead ECG: when the protocol allows, before the maneuver.
• Pulse oximeter and blood pressure cuff: baseline and during the maneuver.
• Defibrillator with pads: set for synchronized cardioversion and ready for the unstable path.
• Adenosine: 6 mg and 12 mg rapid-bolus vials with a saline flush, per your stock.
• Pressure device: the manometer or other method your protocol uses to hold the strain near 40 mm Hg.

Patient Positioning & Preparation

• Start semi-recumbent: sitting up, upper body reclined, so the leg raise can be done immediately.
• Explain the sequence: blow out against the closed mouth and nose for 15 seconds, then lie back as directed.

Typical adult and pediatric references only. Verify them against local protocol and current drug labeling. Doses vary by protocol; follow local protocols and medical direction.

Adenosine Cautions

• Contraindicated: second- or third-degree AV block, or sick sinus syndrome, without a pacemaker (FDA label).
• Avoid: asthma or bronchospasm (FDA label).
• Central line or heart transplant: the label dosing is for peripheral IV. Central venous use has not been systematically studied. Some protocols start lower, at 3 mg here. Follow your protocol.
• Interactions: caffeine and theophylline blunt the effect. Dipyridamole boosts it, so a smaller dose may be enough. Carbamazepine can deepen heart block (FDA label).

Full list: Adenosine.

Phase 1: Prepare

1. Confirm the rhythm and stability: regular, narrow, and no hypotension, altered mental status, chest pain or heart failure.
2. Record the baseline: rate, BP, SpO₂ and the time on the strip.
3. Position the patient: sitting semi-recumbent, with the legs ready to lift.
4. Explain the maneuver: one long, forced breath out for 15 seconds, then lie back as you direct.

Phase 2: Perform

5. Start the strain: the patient exhales against a closed airway, holding about 40 mm Hg for 15 seconds.
6. Lie back and raise the legs immediately: do not wait after the strain ends.
7. Watch the strip: keep the rhythm running through the minute.

Phase 3: Confirm & Secure

8. Read the rhythm at 1 minute: sinus rhythm is success. Record the time.
9. If still tachycardic: go to adenosine per protocol (6 mg, then 12 mg in adults).
10. Reassess after each step: rate, BP and rhythm, and stop for any new hypotension.

Alternative Technique: Infants and Children

Many children and infants can't perform the strain. This page doesn't give a pediatric vagal technique. Use the protocol-approved maneuver in your PALS SVT algorithm (see Pediatric Tachycardia and SVT). REVERT tested the maneuver in adults only.

Primary Confirmation

Sinus rhythm on the strip at 1 minute is success. It is the outcome REVERT used. Confirm with a 12-lead when the protocol allows.

Secondary Confirmation

• Heart rate drops and stays steady after the return to sinus rhythm.
• Blood pressure recovers once the leg raise is released.
• No new ectopy or pauses on the strip.

Ongoing Monitoring

• Continuous ECG: until the rhythm has held and the patient is handed off.
• BP and SpO₂: at baseline, after the maneuver and after each drug push.

Pediatrics

• Scope: This page covers adults. The REVERT trial enrolled adults only. For infants and children, use the protocol-approved vagal technique in your PALS SVT algorithm and the Pediatric Tachycardia and SVT page.
• Adenosine by weight: 0.1 mg/kg (max 6 mg), then 0.2 mg/kg (max 12 mg), per the PALS dosing on the adenosine page. Use the weight-based dosing and pediatric vital signs references.
• Unstable child: synchronized cardioversion at 0.5–1 J/kg, then 2 J/kg. See the pediatric shock page.

Older Adults

• Baseline BP matters: A lower baseline makes hypotension from the strain or leg raise more likely. Monitor closely.

Pregnancy

• Protocol and obstetric input: The trial did not study pregnancy. Follow the local protocol. Bring in obstetric and cardiology care as the situation requires.
• Adenosine: the FDA label says no pregnancy studies were done. Use it in pregnancy only if clearly needed.

Immediate Aftercare

• Keep monitoring: the rhythm can recur after the maneuver.
• Document the response: time, pressure, rhythm and any drug given.

Ongoing Maintenance

• Rhythm strip: keep it through transfer of care.
• Recurrence plan: a repeat maneuver or drug per protocol; ongoing care for recurrent SVT.

Transport Considerations

• Reassess after each move: the leg raise and position change can drop BP.
• Movement and noise: rely on the monitor, not on feel, for rhythm.

Pearls

• Modified beats standard: the leg raise after the strain converted 43% vs 17% in REVERT.
• Regular and narrow only: aim it at the rhythm it can break. Not AF, not wide complexes.
• Time the release: write the clock time on the strip. Then the one-minute check is a fact, not a guess.
• Stable first, shock if not: a maneuver never delays cardioversion for an unstable patient.

Common Pitfalls

• Standard strain only, no leg raise: use the modified sequence when the patient is stable.
• Pausing the strip for the drug: keep the rhythm running through the push.
• Calling a brief slowing a success: confirm sinus rhythm at 1 minute.
• Repeating the maneuver on an unstable patient: cardiovert.

Skill Maintenance

• Practice the 15-second strain and the leg raise on a simulator or a partner.
• Rehearse the one-minute strip check and the time documentation.
• Review the adenosine dosing and the rapid-push technique once a year.