These are a series of electrocardiograms (ECGs) obtained from a patient with tricyclic antidepressant overdose. The first (above) shows the initial ECG demonstrating QRS interval prolongation and characteristic changes in AVR. The second (Severe cardiac toxicity) shows worsening changes consistent with progression of cardiac toxicity. Note the increases in the QRS interval and the R wave in AVR. The third (After treatment) shows narrowing of the QRS complex but persistent right axis deviation of the terminal 40 milliseconds following the initiation of treatment. The final ECG (Resolution) shows complete resolution of interval changes related to toxicity.
