Certified Respiratory Therapist Practice Exam

What would a QRS complex wider than 0.12 sec indicate?

1. Normal heart function

2. Patient's peak flow

3. Bundle branch block or other conditions

4. Respiratory alkalosis

The correct answer is: Bundle branch block or other conditions

A QRS complex wider than 0.12 seconds typically indicates a disturbance in the heart's electrical conduction system. Specifically, this widening is often associated with conditions such as bundle branch blocks, which occur when there is a delay or blockage along the pathway that electrical impulses travel to the ventricles of the heart. This means that the ventricles may depolarize in a slower and less coordinated manner, leading to a longer duration of the QRS complex on an electrocardiogram (ECG). In addition to bundle branch block, other conditions that could result in a wide QRS complex include ventricular hypertrophy, certain types of arrhythmias, and intraventricular conduction delays. Thus, observing a wide QRS complex is clinically significant and often prompts further evaluation to determine the underlying cause. The other options do not relate directly to the interpretation of the QRS complex duration. Normal heart function would typically present with a QRS duration of 0.10 seconds or less. Peak flow measurements pertain to pulmonary function and are unrelated to cardiac electrical activity. Respiratory alkalosis pertains to acid-base balance in the blood and does not affect QRS duration directly.