The work presented in this thesis has explored the hypotheses that three-dimensional echocardiography facilitates spatial recognition of intracardiac structures and therefore enhances the diagnostic confidence of echocardiography in congenital and acquired heart disease. The accuracy of three-dimensional reconstructions has been validated in vitro using two different phantoms and in vivo comparing the results with other established diagnostic techniques or surgical findings. Additionally, as the main limitation of transthoracic three-dimensional echocardiography is poor image quality in a substantial proportion of adult patients. Doppler myocardial imaging has been tested as a potentially superior method to conventional grey-scale imaging for transthoracic three-dimensional image acquisition. In vivo, the study was designed to compare the accuracy of grey-scale and Doppler myocardial imaging three-dimensional left ventricular volume measurements and cineventriculography. The differences were significantly smaller for the Doppler technique during both end-diastole and end-systole. A series of congenital heart lesions has also been studied. It has been shown that dynamic surgical reconstruction of the secundum atrial septal defect is feasible from the transthoracic approach in all patients. However, in adults, Doppler myocardial imaging proved more effective than grey-scale imaging in the accuracy of three-dimensional defect reconstruction. In patients with sinus venous atrial septal defect, transthoracic three-dimensional echocardiography was more accurate than standard echocardiography in diagnosing the defect including a detailed description of the abnormal pulmonary venous drainage. Finally, in children with atrio-ventricular septal defects, the 'unroofed' atrial reconstruction of the common valve accurately displayed dynamic valve morphology en face and the mechanism of valve reflux.