ST elevation on a 12 lead ECG is one of the cardinal features of acute myocardial infarction (AMI), yet it also occurs with other clinical conditions such as spontaneous pneumothorax. Three cases are presented, all of whom had chest pain and ST elevation. All had pneumothoraces yet only one had an AMI. Thrombolysis was administered to one patient. With the current pressure on "door-to-needle" times, emergency physicians should take care to differentiate between these entities. F ollowing recent advances in AMI management, the 12 lead ECG has become the first part of the assessment of a patient with chest pain. With an ideal "door-to-needle" time of 20 minutes, ST elevation on ECG can easily determine a path of action for doctors. However, several clinical conditions produce these changes, one of which is spontaneous pneumothorax, for which thrombolysis is not standard therapy.
CASE REPORTS
Patient 1A 74 year old man presented complaining of chest pain for 1 hour that improved after sublingual glyceryl trinitrate. He also complained of numbness of his left arm, nausea, shortness of breath, and sweating. He had a history of hypertension. Pulse was120 beats/min, blood pressure 190/ 110 mm Hg, respiratory rate 30 breaths/min. A 12-lead ECG ( fig 1A) showed ST elevation of 2 mm in leads V1-V3 and a diagnosis of AMI was made. The patient was thrombolysed with reteplase. A chest radiograph ( fig 1B) showing a left sided pneumothorax was then obtained. A chest drain was inserted and the ST elevation resolved. Subsequently, troponin I was 7.6 ng/ml.
Patient 2A 25 year old man presented complaining of epigastric tightness for 9 hours, with some shortness of breath. He had no known risk factors for ischaemic heart disease and had never used cocaine. ECG showed 1 mm ST elevation in leads V2-V3 (fig 2A). He appeared well with normal vital signs, normal heart sounds, central trachea, and bilateral air entry. AMI was considered, but as the patient seemed so well, the cardiologist decided that neither percutaneous transluminal coronary angioplasty nor thrombolysis were appropriate. Subsequent chest radiograph ( fig 2B) showed a large left sided pneumothorax. Following aspiration, the ST elevation resolved. Serum troponin was never elevated.
Patient 3A 52 year old man presented as a priority call with severe difficulty in breathing. On arrival he was distressed, unable to speak, and using accessory muscles. His respiratory rate was 25 breaths/min, oxygen saturation 67% on air, and pulse 123 beats/min. Initial examination revealed bilateral resonant percussion and quiet breath sounds. On arrival, an ECG was performed ( fig 3A) which showed anterior ST elevation, right bundle branch block (RBBB), and right axis deviation. AMI was considered as a diagnosis but as the patient was so unwell, the senior house officer sought assistance. The consultant requested an immediate chest radiograph, which revealed a right sided pneumothorax ( fig 3B). A chest drain was immediately inserted, his respiratory rate and oxygen saturations improved,...