Introduction The coexistence of congenital cardiovascular anomalies provides valuable insights into the intricate nature of human cardiac anatomy and its potential interactions with underlying health conditions. This case report presents an autopsy analysis of a diabetic patient manifesting both a patent foramen ovale and a Chiari network. Case presentation A 26-year-old male with a history of type 2 diabetes mellitus was admitted with post cardiac arrest. He died despite resuscitative efforts. Autopsy revealed notable findings including a patent foramen ovale and a Chiari network. Post-mortem biochemical markers indicated elevated HbA1c level and hyperglycaemia. The absence of cryptogenic strokes or paradoxical embolism prompted exploration into potential relationships between these anomalies and metabolic disturbances, and prompts a discussion about whether the observed anatomical variations could potentially serve as risk factors contributing to the patient's death due to complications of diabetes. Conclusion The co-occurrence of a patent foramen ovale and a Chiari network within a diabetic patient, accompanied by elevated HbA1c level and hyperglycaemia, offers a unique perspective on the convergence of congenital cardiovascular variation and metabolic health. The juxtaposition of these anomalies with biochemical markers underscores the intricate interplay between cardiac morphology and metabolic conditions.