Formation of cardiac loop

The folding of the heart tube to firm the cardiac loop starts on day 22 and ends on day 28. The heart tune first lengthens. If this lengthening fails to occur then anomalies like DORV (Double Origin Right Ventricle where both aorta and pulmonary artery arise from the right ventricle), tetralogy of Fallot, etc. occur. This loop formation occurs inside the pericardial cavity. Another anomaly of abnormal cardiac looping is dextrocardia.