| Type | MGI:General | Description | homozygotes initiate heart contractions at the 3-somite stage but display a conduction block within 24 hrs after the first contractions from E9.5 onward, atrial contractions or transmission of the atrial impulses through the AV canal, or both, are severely impaired in addition, the outflow tract fails to expand and contract in accordance with the ventricular contractions |
