What does a wide QRS complex indicate?

A wide QRS complex indicates that there is a delay in the conduction of electrical impulses through the ventricles of the heart. This can occur due to various reasons, commonly associated with conditions such as a right bundle branch block (RBBB), as well as left bundle branch block and ventricular hypertrophy, among others. When the QRS complex exceeds a duration of 0.12 seconds, it signifies that the electrical impulse is not being conducted normally through the His-Purkinje system.

In the context of RBBB, the right ventricle's conduction pathway is obstructed, leading to delayed depolarization of the RV while the left ventricle depolarizes normally. This delayed depolarization is visually represented on an electrocardiogram (ECG) as a wider QRS complex.

Normal cardiac function would typically present with a narrow QRS complex, reflecting efficient and timely conduction of impulses through the ventricles. A wide QRS is not indicative of only atrial complications, which usually do not affect the width of the QRS complex but rather the P-wave morphology. Similarly, a low heart rate can occur with a wide QRS but is not a direct cause or correlation, as the heart rate may vary irrespective of Q