What is the target heart rate goal of a modified Valsalva maneuver for acute supraventricular tachycardia?

Target Heart Rate Goal of Modified Valsalva Maneuver

The modified Valsalva maneuver does not have a specific target heart rate goal—rather, the goal is complete termination of the supraventricular tachycardia and restoration of normal sinus rhythm. 1, 2

Understanding the Objective

The modified Valsalva maneuver is designed to induce a vagal response that terminates the reentrant circuit in SVT, not to achieve a specific heart rate target. 1 The success of the maneuver is defined as:

• Complete conversion to sinus rhythm within 1 minute of the intervention 3
• Termination of the tachyarrhythmia, not rate control 1, 2

Technique Parameters (Not Heart Rate Goals)

While there is no target heart rate, the technique itself has specific pressure and duration targets:

• Intrathoracic pressure goal: 30-40 mmHg during the strain phase 1, 2
• Duration of strain: 10-30 seconds (typically 15 seconds in standardized protocols) 1, 3
• Patient positioning: Supine with passive leg raise immediately after the strain 3, 4

Expected Physiologic Response

The maneuver induces a transient drop in heart rate through vagal stimulation, which may interrupt the AV nodal reentrant circuit. 5 Studies show:

• The modified VM produces a 3.8 bpm greater drop in heart rate compared to standard VM 5
• This vagal response is the mechanism of action, not the therapeutic endpoint 6

Success Rates and Clinical Endpoints

The modified Valsalva maneuver achieves sinus rhythm in 43% of patients with SVT, compared to only 17% with standard technique—representing a 2.8-3.8 fold improvement. 2, 3, 4 The clinical endpoint is binary:

• Success: Return to normal sinus rhythm (typically 60-100 bpm in adults) 3
• Failure: Persistent SVT requiring adenosine or other interventions 1, 2

Common Pitfall to Avoid

Do not confuse the modified Valsalva maneuver with rate control strategies. 1, 6 This is a rhythm conversion technique for SVTs involving the AV node (AVNRT, AVRT), not a method to slow sinus tachycardia or control ventricular rate in atrial fibrillation. 6 Vagal maneuvers will not work for sinus tachycardia caused by anxiety or other secondary causes. 6

Next Steps After Failed Conversion

If the modified Valsalva maneuver fails to restore sinus rhythm:

• Adenosine 6 mg IV rapid push is the next intervention, achieving 90-95% success in AVNRT 1, 2, 7
• IV calcium channel blockers or beta blockers if adenosine fails, with 80-98% success rates 2, 7
• Synchronized cardioversion for hemodynamically unstable patients or when pharmacologic therapy fails 1, 2