We undertook our study in order to evaluate right ventricular function and perfusion by conventional and contrast echocardiography in adults with congenitally corrected transposition who had not undergone cardiac surgery, comparing the echocardiographic findings with those obtained using equilibrium radionuclide ventriculography and gated single-photon emission computed tomography with Technetiumc-99 m sestamibi.
We discovered severe tricuspid regurgitation in 8 patients (61%). Right ventricular ejection fraction, as calculated by nuclear medicine, had a correlation of 0.67 (p = 0.059) with area fractional shortening and 0.84 (p = 0.01) with ejection fraction calculated by the method depending on descent of the tricuspid ring. All patients with severe tricuspid regurgitation also had right ventricular dysfunction. Of these 8 patients, 7 had persistent perfusion defects, while 6 also had ischemic perfusion defects.
Echo contrast had a high sensitivity, at 91%, and also specificity and positive predictive value, both at 100%, for persistent defects, and a negative predictive value of 66% compared to methods depending on nuclear medicine. The sensitivity of contrast echocardiography for detection of ischemic defects was 66%, the specificity 100%, the positive predictive value 100%, and the negative predictive value 77% compared to the methods involving nuclear medicine.
The method depending on descent of the tricuspid ring had the highest correlation with equilibrium radionuclide ventriculography in evaluation of right ventricular function in patients with congenitally corrected transposition.
We conclude that contrast echocardiography is extremely valuable when assessing right ventricular myocardial perfusion, having high sensitivity and specificity for detecting persistent defects, although sensitivity was less for detection of ischemic defects than that of gated single-photon emission computed tomography with Technetium-99 m Sestamibi.
Persistent and ischemic perfusion defects, together with chronic volume overload from tricuspid regurgitation, are the determining factors of right ventricular dysfunction.