Hammock mitral valve in a 12-day-old female: pathophysiology, management and legal issues

Hammock mitral valve (HMV), or mitral arcade (MA), is an extremely rare congenital mitral anomaly characterized by absent fibrous chordae and hypertrophic papillary muscles directly inserting into the leaflets. This rare valve structure can trigger severe mitral regurgitation and overwhelm a newborn's heart and lungs within days. Because symptoms often resemble those of more common respiratory or cardiac issues, early diagnosis is difficult - but vital. Recognizing the anomaly in time and referring the infant to a specialized center can make the difference between life and death.

We report the case of a 12-day-old female who died suddenly from acute heart failure secondary to undiagnosed HMV/MA. We conducted a comprehensive forensic investigation by analyzing medical records, autopsy findings, and the clinical course as inferred from the available documentation. Gross pathology examination showed congenital mitral arcade. Histological examination highlighted massive pulmonary congestion, diffuse alveolar damage, and signs of circulatory overload. Imaging and gross anatomical findings ruled out other congenital heart defects.

This case illustrates the challenges of diagnosing HMV/MA in newborns, particularly when symptoms resemble more common heart or lung conditions. Recognizing the condition early requires a sharp clinical eye, expert echocardiography, and prompt referral to a specialized center. Delays in recognizing the condition or referring the patient to a specialized center may raise liability concerns. From a medico-legal standpoint, thorough documentation of pre- and perinatal care and complete autopsy with targeted cardiac examination are crucial for determining the cause of death and assessing standard-of-care compliance.