Question

In an ECG, the absence of P wave and widened QRS complex can indicate which of the following conditions?

1) Hyperkalemia
2) Tricyclic antidepressant (TCA) overdose
3) Both hyperkalemia and TCA overdose
4) None of the above

Answer 1

The absence of P waves and a widened QRS complex on an ECG would not typically indicate hyperkalemia or TCA overdose, which have different characteristic ECG changes. These ECG findings are more indicative of a third-degree heart block or another condition. Both conditions mentioned can cause a widened QRS complex, but not the complete absence of P waves, which suggests 'None of the above' (option 4 )is the correct choice.

Step-by-step explanation:

In an ECG, the absence of the P wave and a widened QRS complex can indicate several conditions, including a third-degree heart block where there is no correlation between atrial activity and ventricular activity. However, these specific changes are not typically associated with hyperkalemia or tricyclic antidepressant (TCA) overdose. Hyperkalemia often manifests as peaked T waves or a flattened P wave, while TCA overdose is characterized by a prolonged QT interval and widened QRS complex.

Neither hyperkalemia nor TCA overdose is known to cause the complete absence of P waves, which are associated with atrial depolarization. Instead, various forms of heart block, including third-degree (complete) heart block, can exhibit an ECG with no visible P waves, with the ventricles beating independently of the atria. It's essential to interpret ECG findings in conjunction with clinical findings to accurately diagnose the underlying condition.

Based on the information provided and standard ECG interpretations, the correct option indicating the absence of P waves and widened QRS complex would be 'None of the above' since neither condition mentioned perfectly fits these ECG changes.