Very good. Valsalva has excellent specificity and sensitivity (90–99% and 70–95%, respectively) for
detecting left ventricular dysfunction, either systolic or diastolic. It also has significant likelihood ratios (both
negative and positive—the latter being 7.6). To perform the test, inflate the blood pressure cuff 15
mmHg above the patient’s resting systolic pressure, and then maintain this value throughout the 10 seconds
of strain and the 30 seconds of release. While doing so, auscultate over the brachial artery, looking for
Korotkoff’s sounds. When the patient starts straining, a normal response consists of an initial increase in
systolic pressure with clear-cut sounds (phase I); this is then followed by a drop in systolic pressure with
disappearance of sounds (phase II) and then, after release of straining, by an overshooting in pressure
with reappearance of sounds (phase IV).
Note that Korotkoff’s sounds should always be heard during phase I. If not, the patient has failed to adequately increase intrathoracic pressure. Patients with heart failure have instead a quite different response: they either maintain sounds throughout the entire 40 seconds of the maneuver (as a result of an increase in systolic pressure that matches the increase in intrathoracic pressure—square wave response), or they fail to gain them back after strain release (because of the failing ventricle’s inability to produce a systolic pressure overshoot after the hypotension induced by straining—absent overshoot). In fact, the degree of overshoot is directly related to left ventricular ejection fraction, and thus provides a marker for systolic dysfunction. Note, however, that an abnormal Valsalva response may also reflect high filling pressures (and thus provide a marker for diastolic dysfunction)
detecting left ventricular dysfunction, either systolic or diastolic. It also has significant likelihood ratios (both
negative and positive—the latter being 7.6). To perform the test, inflate the blood pressure cuff 15
mmHg above the patient’s resting systolic pressure, and then maintain this value throughout the 10 seconds
of strain and the 30 seconds of release. While doing so, auscultate over the brachial artery, looking for
Korotkoff’s sounds. When the patient starts straining, a normal response consists of an initial increase in
systolic pressure with clear-cut sounds (phase I); this is then followed by a drop in systolic pressure with
disappearance of sounds (phase II) and then, after release of straining, by an overshooting in pressure
with reappearance of sounds (phase IV).
Note that Korotkoff’s sounds should always be heard during phase I. If not, the patient has failed to adequately increase intrathoracic pressure. Patients with heart failure have instead a quite different response: they either maintain sounds throughout the entire 40 seconds of the maneuver (as a result of an increase in systolic pressure that matches the increase in intrathoracic pressure—square wave response), or they fail to gain them back after strain release (because of the failing ventricle’s inability to produce a systolic pressure overshoot after the hypotension induced by straining—absent overshoot). In fact, the degree of overshoot is directly related to left ventricular ejection fraction, and thus provides a marker for systolic dysfunction. Note, however, that an abnormal Valsalva response may also reflect high filling pressures (and thus provide a marker for diastolic dysfunction)