The ECG of a patient with an artificial pacemaker in the right ventricle shows –
**Core Concept**
The question is testing the understanding of the ECG changes associated with artificial pacemakers, specifically those implanted in the right ventricle. The underlying principle involves the abnormal electrical activity generated by the pacemaker, which affects the cardiac rhythm.
**Why the Correct Answer is Right**
The ECG of a patient with an artificial pacemaker in the right ventricle typically shows a wide QRS complex with a normal P wave, as the pacemaker is stimulating the ventricle directly. This results in a ventricular-paced rhythm, characterized by a wide QRS complex without a preceding P wave. The pacemaker is set at a specific rate, and the ECG will show a regular rhythm with a consistent interval between beats.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because a narrow QRS complex would suggest that the pacemaker is not stimulating the ventricle directly, and the rhythm is likely to be sinus in origin.
**Option B:** This option is incorrect because a right bundle branch block (RBBB) pattern with a wide QRS complex would not be a typical ECG finding in a patient with a ventricular-paced rhythm from a right ventricular pacemaker.
**Option C:** This option is incorrect because a left ventricular pacemaker would not typically show a wide QRS complex with a normal P wave, as the pacemaker is stimulating the left ventricle, which has a different electrical conduction pathway.
**Clinical Pearl / High-Yield Fact**
In patients with artificial pacemakers, it is essential to check the pacemaker's settings and function regularly, as changes in the pacemaker's rate or mode can affect the patient's cardiac rhythm and lead to complications.
**Correct Answer:** B.