Question

In rhythms originating from the AV junction, the QRS duration is typically _____ or less unless an intraventricular conduction delay exists.

Answer 1

In rhythms originating from the AV junction, the QRS duration is typically 100 ms or less unless an intraventricular conduction delay exists, which relates to the speed of electrical conduction through the heart's ventricles as seen on an ECG.

Step-by-step explanation:

In rhythms originating from the AV junction, the QRS duration is typically 100 ms or less, unless an intraventricular conduction delay exists. This statement is referencing the electrical activity within the heart's conduction system, particularly the atrioventricular (AV) node, and how it is represented on an electrocardiogram (ECG).

AV blocks can be classified by degrees, which describe the level of conduction delay between the sinoatrial (SA) and AV nodes. A first-degree AV block shows up on an ECG as a prolonged PR interval, whereas a second-degree block will have some P waves not followed by a QRS complex, and in a third-degree block, there is no correlation between the P waves and QRS complexes, demonstrating a complete disassociation of atrial and ventricular activities.

AV nodal rhythms typically produce a QRS duration that is narrow, reflecting the rapid conduction through the ventricles, unless there is an additional conduction anomaly such as a bundle branch block, which would result in a wider QRS complex.