Table 2.

Calibration factor calculations from the aorta

Specific Aortic Pressure Phases	Catheter, mmHg	Subharmonic Amplitude, dB	Calibration Factor, mmHg/dB
Canine 1
Peak systolic	74.8 ± 1.2	53.0 ± 1.1
Minimum diastolic	49.6 ± 0.4	65.5 ± 1.3
Systemic pulse	25.2 ± 1.0	−12.5 ± 1.0	−2.0
Canine 2
Peak systolic	81.0 ± 1.1	48.6 ± 0.2
Minimum diastolic	59.9 ± 1.0	54.1 ± 0.3
Systemic pulse	21.1 ± 0.3	−5.5 ± 0.1	−3.8
Canine 3
Peak systolic	76.7 ± 1.8	61.6 ± 2.4
Minimum diastolic	45.3 ± 3.0	71.6 ± 1.9
Systemic pulse	31.4 ± 3.5	−10.0 ± 3.1	−3.1
Canine 4
Peak systolic	79.3 ± 0.6	47.6 ± 0.9
Minimum diastolic	51.7 ± 0.8	59.3 ± 1.3
Systemic pulse	27.6 ± 1.0	−11.7 ± 1.6	−2.4
Canine 5
Peak systolic	122.8 ± 0.8	46.9 ± 1.7
Minimum diastolic	81.0 ± 1.0	57.3 ± 1.1
Systemic pulse	41.8 ± 1.3	−10.4 ± 2.0	−4.0

Values are means ± 1 SD. Subharmonic signal amplitudes at optimum incident acoustic power setting are indicated. Systemic pulse values are calculated as the difference between the systolic and diastolic values. The calibration factor values are calculated by dividing the systemic pulse pressures by the systemic pulse subharmonic amplitudes.