Noninvasive diagnosis of latent pulmonary hypertension in COPD by exercise-load impedance rheopneumogram: a comparative study with right heart catheterization.

Impedance rheopneumogram (IRP) and right heart Swan-Ganz catheter examinations were simultaneously carried out in 63 patients. Two equations for calculating after-exercise-pulmonary-pressure (PAPm) were obtained by stepwise regression analysis: 1) PAPm (kPa) = -1.40-0.88.InHs+8.30.(B-F)+5.78.Q-B/B-Y (r = 0.730, IRP is measured at rest); 2) PAPm(kPa) = 6.46-5.04.Hs/square root of R-R +4.35.Q-B/B-Y-19.34.(Q-C) (r = 0.648, IRP is measured after exercise). This is a new method for diagnosing latent pulmonary hypertension noninvasively.