"Water Gun:" A New Morphology of Left Atrial Appendage.

An 86-year-old patient with non-valvular atrial fibrillation was referred to our institution to undergo a left atrial appendage (LAA) closure for recurrent gastrointestinal bleeding on direct oral anticoagulants. The transesophageal echocardiogram (TEE) performed the previous day evaluated the morphology and dimensions of the LAA and ruled out any thrombus. During the procedure, a pigtail catheter was inserted into the LAA, observing an unusual image we describe as a culde- sac, without an anomalous connection with any drainage in other vessel or cavity. After additional imaging studies, we concluded that it was morphology related to LAA, which we have termed the "water-gun" morphology. Four morphologies have been described based on the shape of the central and secondary lobes. To the best of our knowledge, this is the first description of a fifth type, which was shown to be effectively closed with current closure devices.