Dual-processing theory helps to explain delay in diagnosis of Stanford type A aortic dissection.

A woman in her 70s presented with chest pain, which was initially thought to be an acute coronary syndrome but subsequently felt to be pericarditis. Chest radiography and echocardiography demonstrated striking cardiomegaly and marked biatrial dilatation, likely secondary to undiagnosed restrictive cardiomyopathy. The patient remained well on the ward for some days with only mild discomfort and stable haemodynamics. CT of the thorax went on to unexpectedly demonstrate a Stanford type A aortic dissection. The patient was promptly transferred for emergent surgery but sadly died intraoperatively.Delayed or missed diagnosis of acute aortic dissection (AAD) is common. The dual-processing theory (DPT) of human judgement can be applied to medical decision making and used to explain this potential for diagnostic error in AAD diagnosis. A greater awareness of DPT and the role of heuristics and biases in medical decision making may help to reduce medical diagnostic error.