<prompt> Base of the heart is formed by-Rt. ventricleLVLV RVRA LA  <response>: Left Auricle. The left auricle, also known as the left atrial appendage LAA, is a flap of heart wall on the anterior surface of the left atrium of the heart.The name auricle comes from the Latin word auricula, which means ear and refers to the floppy dog-ear shape of the auricle 