Contraindications to prehospital thrombolysis | Reduced level of consciousness (The patient must be able to give consent to thrombolytic therapy). |
| Dementia (increased risk of stroke1). |
| Age greater than 75 years (increased risk of stroke2). |
| Continuous symptoms for less than 30 minutes or more than 6 hours (Myocardial salvage is limited beyond 6 hours3). |
| Suspected aortic dissection (risk of severe bleeding). |
| Pericarditis. |
| Bradycardia of 50 beats per minute (bpm) or less (patient may require pacing). |
| Tachycardia of 140 bpm or more (arrhythmia may be mimicking ECG changes synonymous with AMI). |
| Systolic blood pressure (SBP) 80 mm Hg or less (risk of further hypotension if streptokinase administered). |
| SBP 160 mm Hg or more (increased risk of stroke4). |
| Pregnancy, or delivery within past two weeks (there are no data on fetal safety when thrombolytic therapy is administered during pregnancy, and there is also a risk of maternal bleeding in the first week postpartum). |
| Peptic ulcer within the last 6 months (increased risk of bleeding). |
| Previous stroke, or disability from a previous stroke (increased risk of stroke). |
| Cerebral tumour (increased risk of bleeding). |
| Active bleeding or known bleeding disorder (increased risk of severe bleeding). |
| Recent blood loss, except for normal menstruation (menstrual bleeding that is not due to haematological abnormalities5). |
| Anticoagulant therapy (risk of severe bleeding). |
| Surgical operation, tooth extractions, significant trauma, or head injury within the past 4 weeks (increased risk of bleeding). |
| Previous administration of streptokinase (antigenic and allergenic properties of streptokinase will reduce efficacy6). |
| Chest compression for resuscitation for a period of longer than 5 minutes during the presenting incident (increased risk of bleeding due to traumatic injury). |
| Liver failure, renal failure, or any other severe systemic illness (for example, chemotherapy for cancer) (increased risk of bleeding). |
Indications to prehospital thrombolysis: | ST segment elevation of 2 mm or more (0.08s after the J point) in at least two standard leads or at least two contiguous precordial leads, not including V1. |
| QRS width 0.14 mm or less, and bundle branch block absent from the tracing. |
| NO atrio-ventricular block greater than 1st degree (if necessary after treatment with intravenous atropine). |