VALUE OF ECHOCARDIOGRAPHY IN THE ASSESSMENT OF PULMONARY RESISTANCE (PR) IN D-TRANSPOSITION OF THE GREAT ARTERIES (DTGA)

Abstract

The reliability of echocardiography (EC) in predicting PR was Investigated in 20 DTGA (mean age: 20 months). Ten were simple DTGA, among them two had Eisenmenger reaction (ER). Three had VSD with PS, the rest either VSD, PDA or PS alone. All had an atrial septal defect. Three groups of parameters were studied: 10 EC pattern, of the pulmonary valve (PV). 20 Dimensions of cardiac structures: left ventricle (LV), pulmonary artery (PA) and aortic (Ao) diameters and posterior wall thickness of LV. 30 LV and right ventricular (RV) systolic and diastolic time intervals (SDTI). These parameters were correlated with the systolic, mean (MPA) and diastolic (DPA) pressure in the PA.Results show that: 1) EC patterns described in the PV with pulmonary hypertension (PH) are not seen in DTGA. 2) LV volume and thickness are poorly related to the PR. 3) Best correlations are found with the SDTI. The RV pre-ejection period (RVPEP) was always greater than LVPEP when PR and systemic resistance were within normal limits. Changes in the LVPEP over LV ejection time ratio were slightly more closely related to the DPA (r = 0.70) than the MPA (r = 0.65). More significant was the correlation between the LV isometric relaxation time (LVIRT) and the DPA (r = 0.90). All nine patients with an LVIRT lower than 20 msec had DPA lower than 20 mmHg. The two with ER had an LVIRT of 60 msec.