RADIONUCLIDE VENTRICULOGRAPHY FOR DIAGNOSING IMPAIRMENT OF RIGHT-VENTRICULAR FUNCTION IN PATIENTS WITH OBSTRUCTIVE SLEEP-APNEA SYNDROME

To investigate right ventricular burden in patients with obstructive s leep apnea syndrome (OSAS), 20 patients after exclusion of significant pulmonary or primary heart disease were evaluated. The investigations included patients with all OSAS stages. After confirmation of diagnos is by polysomnography; pulmonary artery pressure under rest and worklo ad with 75 W was measured. Ventricular function was evaluated by gated radionuclide ventriculography. Pulmonary artery pressure was increase d in one patient at rest and in three patients during exercise. A path ological difference between right and left ventricular ejection fracti on or an absolutely impaired right ventricular ejection fraction was f ound in ten patients. Between these parameters and the pulmonary arter y pressure at workload there was no correlation, with pulmonary artery pressure at rest only a weak correlation. There was no reference betw een hemodynamic values and the severity of the OSAS. The results demon strate that right ventricular burden, caused by the pathophysiology of OSAS, is to be expected in 50% of patients. It is not necessarily ass ociated with pulmonary hypertension. The patients' hazard to develop a cor pulmonale can be better evaluated with radionuclide ventriculogra phy than with pulmonary pressure measurement alone.