Measurement of right ventricular ejection fraction with krypton-81m in chronic obstructive pulmonary disease.

: Thirty patients with chronic obstructive pulmonary disease (COPD) and 15 healthy volunteers have been studied to assess the value of measuring right ventricular ejection fraction (RVEF) at rest with a perfusion of krypton-81m (81mKr). With this perfusion, equilibrium RVEF can be measured in a 30 degrees right anterior oblique projection, avoiding a superimposition of cardiac cavities. The average RVEF of the patients with COPD was significantly lower than that of the normal patients (36.3 +/- 9.3% vs 52.6 +/- 3.9%; p less than 0.001). An inverse linear relation was found between mean pulmonary artery pressure (Ppa) and RVEF (r = -0.543; p less than 0.01). The RVEF in a group of 15 patients with COPD and pulmonary hypertension (Ppa greater than 20 mmHg), averaged 30.4 +/- 7.26%, which was significantly lower than that of the other 15 COPD patients with normal Ppa, whose RVEF averaged 42.3 +/- 7.1% (p less than 0.01). Taking a RVEF value less than or equal to 35% as an indicator of pulmonary hypertension, the sensitivity was 80% and specificity was 75%, the predictive value for a positive test was 75%, and for a negative test was 80%. A positive but weak correlation was found between RVEF and PaO2 (r = 0.52; p less than 0.01), SaO2 (r = 0.41; p less than 0.05) and the forced expiratory volume in one second (FEV1) (r = 0.40; p less than 0.05). No correlation was found between RVEF and prior history of right cardiac insufficiency, PaCO2, pH, the ratio FEV1/vital capacity, ECG signs of cor pulmonale and left ventricular ejection fraction.(ABSTRACT TRUNCATED AT 250 WORDS)