Various toxic substances can cause distinct ECG changes:
- Prolonged QT Interval: A prolonged QT interval can be indicative of exposure to certain medications like antipsychotics, antiarrhythmics, and some antibiotics. This can increase the risk of Torsades de Pointes, a life-threatening arrhythmia. - QRS Complex Widening: Widened QRS complexes are often seen in poisonings with tricyclic antidepressants and other sodium channel blockers. This can lead to ventricular arrhythmias. - ST Segment Changes: Elevation or depression in the ST segment can be observed with substances like cocaine, which can cause myocardial ischemia and infarction. - Bradycardia and Tachycardia: Various toxins can cause either a slow (bradycardia) or fast (tachycardia) heart rate. For instance, beta-blockers and calcium channel blockers are known to cause bradycardia, while stimulants like amphetamines and cocaine can cause tachycardia.
