A set of actions performed to decrease the heart rate through physical stimulation of the vagus nerve. Common maneuvers are the Valsalva maneuver and carotid massage. The stimulated vagus nerve then acts on the sinoatrial and atrioventricular nodes, which slows the heart rate and reduces conduction velocity.
Valsalva maneuver
- Definition: forceful exhalation against a closed airway
- Technique: four phases
- Phase I (Onset)
- Transient ↑ BP (due to aortic compression).
- Phase II (Strain) – High Yield
- ↓ Preload → ↓ BP.
- Reflex ↑ HR (Sympathetic activation).
- Murmur maneuvers rely on this phase.
- Phase III (Release)
- Transient ↓ BP (blood pools in expanded pulmonary vessels).
- Phase IV (Recovery)
- Venous return surge against vasoconstriction → ↑ BP (Overshoot).
- Reflex ↓ HR (Vagal activation).
- Phase I (Onset)
- Applications
- Treatment of supraventricular tachycardia (e.g., AVNRT)
- Evaluate conditions of the heart
- Augments heart sounds on physical exam (e.g., earlier click in mitral valve prolapse and louder murmur in hypertrophic obstructive cardiomyopathy)
- Decreases heart sounds intensity (most valve stenosis or regurgitation murmurs)
- Test for hernia or varicocele (increased intraabdominal pressure → bulging)
- Diagnosis of urinary stress incontinence (urine leakage during the maneuver)