Table 7.
Effects of IMT on Blood Flow, Cardiac Output, and Ejection Fraction Measured by CMRI
| Parameter | Before IMT, Mean±SD | After IMT, Mean±SD | P Value | Changea |
|---|---|---|---|---|
| Resting heart rate, beats/min | 73.3±15.1 | 75.7±14.4 | 0.41 | 2.33 (−3.66 to 8.33) |
| Peak heart rate, beats/min | 121.0±20.0 | 118.8±19.6 | 0.53 | −2.25 (−9.88 to 5.38) |
| Resting aortic flow, mL/beat | 58.5±19.2 | 60.0±14.3 | 0.64 | 1.45 (−5.20 to 8.11) |
| Peak aortic flow, mL/beat | 55.3±14.6 | 59.3±11.5 | 0.17 | 4.03 (−2.06 to 10.11) |
| Resting cardiac output, L/min | 4.2±1.2 | 4.5±1.0 | 0.03 | 0.29 (0.03 to 0.54) |
| Peak cardiac output, L/min | 6.6±1.5 | 7.0±1.4 | 0.16 | 0.36 (−0.22 to 0.95) |
| Resting pulmonary flow, mL/beat | 52.2±11.2 | 55.1±12.2 | 0.37 | 2.82 (−3.82 to 9.45) |
| Peak pulmonary flow, mL/beat | 55.4±11.6 | 54.8±6.5 | 0.81 | −0.52 (−5.29 to 4.24) |
| Resting stroke volume, mL | 60.6±7.6 | 63.7±10.4 | 0.10 | 3.08 (−0.65 to 6.81) |
| Peak stroke volume, mL | 70.5±11.5 | 68.2±9.0 | 0.26 | −2.33 (−6.70 to 2.03) |
| Resting ejection fraction, % | 50.1±4.3 | 52.8±6.1 | 0.03 | 2.67 (0.41 to 4.92) |
| Peak ejection fraction, % | 57.6±6.0 | 55.3±5.1 | 0.14 | −2.25 (−5.40 to 0.90) |
| Resting APC flow, mL/beat | 9.4±9.4 | 6.9±6.0 | 0.24 | −2.45 (−6.79 to 1.89) |
| Indexed resting APC, % | 13.8±11.9 | 10.9±8.8 | 0.32 | −2.90 (−9.02 to 3.23) |
| Peak APC flow, mL/beat | 4.2±5.8 | 6.0±6.1 | 0.25 | 1.80 (−1.47 to 5.07) |
| Indexed peak APC, % | 6.3±7.7 | 9.0±8.6 | 0.23 | 2.71 (−1.97 to 7.40) |
| I+E ratiob | ||||
| Resting aortic flow, % | 48.6±6.5 | 48.4±7.6 | 0.94 | −0.18 (−4.76 to 4.41) |
| Peak exercise aortic flow, % | 54.5±7.3 | 55.1±4.8 | 0.81 | 0.99 (−4.81 to 6.78) |
| Resting pulmonary flow, % | 55.1±10.2 | 56.1±10.2 | 0.84 | 1.07 (−10.1 to 12.2) |
| Peak exercise pulmonary flow, % | 47.1±10.1 | 54.1±16.2 | 0.06 | 6.98 (−0.40 to 14.36) |
APC indicates aortopulmonary collateral; CMRI, cardiac magnetic resonance imaging; I, inspiratory; E, expiratory; IMT, inspiratory muscle training.
a
Calculated as post‐IMT values minus pre‐IMT values; expressed as mean change (95% confidence interval).
b
Inspiration percentage of aortic and pulmonary blood flow at rest and at peak exercise.