Spontaneous left main coronary artery dissection in pregnancy.

Spontaneous coronary artery dissection (SCAD) is a rare cause of acute myocardial ischaemia [1] whose aetiology and pathogenesis have not been fully elucidated. It is defined as hemorrhagic separation of the coronary artery media with creation of a false lumen in the absence of precipitating factors [2]. It has also been associated with intense physical exercise, oral contraceptives and connective tissue disorders [2]. Pregnancy related spontaneous coronary dissection is thought to be related to an excess of progesterone, leading to biochemical and structural changes to the vessel wall (e.g., loss of normal corrugation in elastic fibers, fragmentation of reticular fibers, and decreases in the amount of acid mucopolysaccharides). The physiologic increase in blood volume and cardiac output may magnify shear forces of the blood column in large vessels, resulting in a greater propensity for dissection [3]. SCAD is often fatal and the mortality rate for pregnant patients presenting with SCAD is reported to be as high as 38% [4]. However, the prognosis is favourable for patients who survive the initial event [4,5]. A 33-year-old female 36 weeks into her 3rd pregnancy (Gravida 3, Para 2) was admitted to hospital with left sided pleuritic chest pain, shortness of breath and tachycardia. Her pregnancy had been uncomplicated. There were no known cardiac risk factors. On presentation she was haemodynamically stable and her clinical examination was unremarkable with normal fetal monitoring. Initial 12 lead ECG was