[Problems in the interpretation of changes in the ST segment after emergency cardioversion]

After cardioversion with continuous current (CV) we can find alterations in the ST segment and T wave, frequently associated with an increase in CPK total and CPKmB, which can lead us to the wrong diagnosis of acute myocardial infarction (AMI). We describe five cases of transitory alterations in ST after CV: four regular tachycardias with wide QRS and an atrial fibrillation with fast ventricular response. CPK, CPKmB and ECG were monitored being the CPK abnormal in all cases. AMI was discarded in all cases. When changes in ST following CV are observed, we believe that AMI should be discarded by ECG and enzymatic monitorization. If doubts persist technetium-99mm pyrophosphate must be used.