HOLEY HEARTS AND HAZY HISTORIES: A CASE OF MISTAKEN CAUSALITY

Introduction: Patent foramen ovale (PFO) is a common condition seen in approximately 20% to 25% of the general population. In populations exposed to decompression sickness (DCS)-causing environments (aviators and divers) the risks of PFO is largely unknown. Clinical Case: A 19 y/o airman basic was referred to the USAF School of Aerospace Medicine Aeromedical Consult Service because of a finding of a presumptively symptomatic patent foramen ovale (PFO). The member had been involved in water training exercises to become an USAF Combat Controller (CCT). During one exercise he reportedly had symptoms of dyspnea and fatigue and per report became confused. He was referred for an echocardiogram secondary to the dyspnea, which suggested a PFO. This finding was subsequently confirmed on transesophageal echocardiography (TEE). A presumptive diagnosis of decompression sickness with paradoxical bubble embolism and CNS involvement was made. Secondary to the presumptive CNS involvement, the member was disqualified from further training. Evaluation: CCT involves multiple high-risk activities such as High-Altitude Low-Open jumps (HALO jumps) and SCUBA diving to depths of > 100 feet. As such, repeated exposures to DCS-causing environments are routine, and progression in this type of training was thought to be contraindicated. However, subsequent history challenged the diagnosis of DCS and any CNS involvement. After an exhasutive literature review, consultation with the Naval Undersea Medical Institute (NUMI), and a more thorough history, recommendation was made to proceed with CCT training. Discussion: This case highlights the difficulties in attributing causality of symptoms to the common anatomic variant of a PFO, while also illustrating the importance of an accurate history in assessing the significance of PFO's in aviators and divers.