Although two-dimensional echocardiography (2DE) was a major step forward for the noninvasive assessment of cardiac structure and function, the diagnosis of complex disorders remained a difficult mental conceptualization process. In addition, the measurement of left ventricular volume and function, the most common referral reason for echocardiography, required important geometric assumptions about its shape causing inaccuracy and significant variability. Also, quantitative assessment of the right ventricle and left atrium with their peculiar shape continued to be elusive. Consequently, imaging methods to display cardiac structures in relationship to each other in the three spatial dimensions were investigated soon after the introduction of 2DE in the 1970s.