An aberration correction algorithm has been implemented and demonstrated in an echocardiographic clinical trial using 2D imaging. The method estimates and compensates arrival time errors between different sub- aperture processor signals in a matrix array probe in post processing. Five standard views of channel data cineloops were recorded from 22 patients. Using a coherence metric, the aberration correction algorithm was shown to improve image quality in all 7380 processed frames. In a blinded and left-right-randomized side-by-side evaluation, four cardiologists (two experienced and two in training) preferred the aberration corrected image in 97% of the cases. The feedback from the clinicians was that the images appeared sharper with better contrast and less noise. Many structures like valve leaflets, chordae, endocardium, and endocardial borders appeared narrower and more clearly defined in the aberration corrected images. An important finding is that aberration correction improves contrast between the endocardium and ventricle cavities for all processed images. This was confirmed by the cardiologists in their feedback, and quantified with a median global gain difference estimate between the aberration-corrected and non- corrected images of 1.2 dB.