Right ventricular impairment in patients with chronic respiratory failure on home oxygen therapy--non-invasive assessment using a new Doppler index.

We evaluated the usefulness of the newly defined Doppler index combining systolic and diastolic myocardial performance, in assessing right-heart dysfunction in 29 patients with chronic respiratory failure caused by old tuberculosis who were on 24-h home oxygen therapy. We measured tricuspid inflow velocity, right-ventricular outflow velocity, late/early diastolic peak velocities (A/E), the ratio between pre-ejection period and ejection time (PEP/ET), and the new index of systolic and diastolic myocardial performance (SDMP) calculated as (isovolumetric contraction time + isovolumetric relaxation time)/ejection time. The calculated A/E, PEP/ET and SDMP in our patients were significantly higher than those in age-matched healthy subjects (n = 37, mean age 67 +/- 8 years). There was no overlap in the SDMP index between healthy subjects and patients and the index was not influenced by heart rate. Our results suggest that SDMP index is a better marker than A/E and PEP/ET for the assessment of right-ventricular impairment.