The Valsalva maneuver (VM) is widely used in the assessment of adrenergic function, and provides valuable information about sympathetic vasomotor and cardiomotor adrenergic function. Dynamic alterations during both head-up-tilt and the VM are particularly important in detecting adrenergic failure.

The Valsalva Ratio is the ratio of the greatest heart rate to the lowest heart rate (within 30 seconds of the maneuver). This ratio is calculated by the WR TestWorks software and can be compared to statistical data, based on the patient’s age and gender.

The 4 phases of the VM

Phase 1 – A transient increase in BP occurs, which is caused by increased intrathoracic pressure, causing mechanical compression of the aorta.

Phase 2 (early) – A drop in BP is caused by venous return and reduced stroke volume, leading to a decrease in cardiac tone in spite of compensatory tachycardia.

Phase 2 (late) – The decrease in BP is stopped, as the total peripheral resistance increases.

Phase 3 – A mechanical phase of decreased BP, caused by decrease in intrathoracic pressure as the expiration stops.

Phase 4 – Overshoot of BP, dependent of cardiac adrenergic tone.

The VM is a simple and standardized test. The HRV Acquire can be programmed to provide patient feedback for a standardized test (40 mm Hg for 15 seconds) or any other protocol. Patients see their expiratory effort as well as a countdown of the length of time remaining in the maneuver. WR TestWorks software automatically marks the beginning and end of each maneuver, keeping technician focus on the patient.