What is the Valsalva Maneuver
The Valsalva maneuver is a forced expiratory effort against a closed airway (closed glottis or mouth) that generates intrathoracic pressure of 30-40 mmHg for 10-30 seconds, primarily used to terminate supraventricular tachycardia by increasing vagal tone and slowing AV nodal conduction. 1
Definition and Technique
The maneuver consists of the following key components:
The patient bears down forcefully against a closed glottis (similar to straining during a bowel movement or blowing into a closed tube) while maintaining intrathoracic pressure equivalent to at least 30-40 mmHg 1
Duration should be 10-30 seconds, with most standardized protocols using 15 seconds 2, 3
Patient positioning matters: The American College of Cardiology and American Heart Association recommend performing the maneuver with the patient in the supine position for optimal effectiveness 1
Supporting the patient's cheeks during the expiratory effort helps prevent air leaks and ensures true intrathoracic pressure generation rather than merely using buccal muscles 3
Physiologic Mechanism
The maneuver produces complex cardiovascular changes:
Increases vagal tone, which slows conduction through the AV node and can interrupt reentrant circuits in supraventricular tachycardia that involve the AV node as a requisite component 4
Increases intrathoracic and intra-abdominal pressure, leading to decreased venous return to the heart and peripheral venous pressure elevation during the strain phase 5, 6
Triggers baroreceptor-mediated reflexes that produce a sequence of hemodynamic changes, including initial blood pressure drop followed by compensatory increases in heart rate and peripheral vascular resistance 5, 6
Primary Clinical Application
The Valsalva maneuver is recommended as first-line treatment for acute termination of hemodynamically stable supraventricular tachycardia, particularly AV nodal reentrant tachycardia (AVNRT) and orthodromic AV reentrant tachycardia (AVRT) 2, 4
Modified Valsalva Technique
The modified Valsalva maneuver is 2.8-3.8 times more effective than the standard technique, achieving approximately 43% conversion to sinus rhythm compared to 17% with standard technique 2
Success is defined as complete conversion to sinus rhythm within one minute of the intervention, not merely rate control 2
Important Clinical Considerations
Explicit coaching is necessary because most patients are unfamiliar with the technique; clear instruction combined with strong encouragement markedly improves performance 3
The maneuver will not be effective if the rhythm does not involve the AV node as a requisite component of a reentrant circuit (e.g., it will not work for sinus tachycardia or atrial fibrillation) 2, 4
All patients with SVT should be educated on how to perform this maneuver for self-termination of episodes, potentially avoiding prolonged tachycardia and reducing the need for emergency medical attention 1
Management Algorithm When Valsalva Fails
If the Valsalva maneuver does not achieve conversion:
Second-line: Adenosine 6 mg IV rapid push, which yields 90-95% success rates in terminating AVNRT 2, 4
Third-line: IV calcium channel blockers or beta blockers, achieving 80-98% success rates when adenosine fails 2
Rescue: Synchronized cardioversion for hemodynamically unstable patients or when pharmacologic therapy fails 2
Other Medical Applications
Beyond SVT management, the Valsalva maneuver has applications in:
Otolaryngology: Testing patency of eustachian tubes and expelling fluid from the middle ear 7
Intraoperative use: During specific surgical procedures to assist with visualization or hemostasis 8
Diagnostic testing: Evaluating autonomic nervous system function and detecting heart problems based on abnormal blood pressure and heart rate responses 5
Historical Context
The maneuver was originally described by Italian anatomist, physician, and surgeon Antonio Maria Valsalva (1666-1723), though its cardiovascular applications were first described later by German physiologist Eduard Friedrich Weber 9, 7