The case is presented of a 66 year old woman who attended the emergency department with severe abdominal pain subsequent to a bout of coughing, following a week's history of productive cough. She was known to have chronic obstructive pulmonary disease and was also on warfarin for recurrent deep vein thromboses. She had no history of ischaemic heart disease. She was found to have a rectus sheath haematoma and an international normalised ratio of 7.7, and admission was arranged for coagulation control and analgesia. However, a routine electrocardiograph (ECG) demonstrated an ST elevation pattern consistent with an acute inferior infarction. Subsequent ECGs showed no ST elevation, although the axis and chest lead QRS morphology remained the same throughout the first 12 hours. Over the next three days, R wave progression decreased in the chest leads. Troponin I at admission and 24 hours later were both <0.2 ng/ml. ECG changes compatible with acute myocardial infarction have been reported in association with a number of non-cardiac presentations; however, to our knowledge, it has never been reported in relation to a rectus sheath haematoma. We speculated on the possible mechanism of such "pseudo myocardial infarction" and the importance of treating the patient, not the ECG.