Advanced Cardiovascular Life Support (ACLS) Practice Exam

When persistent tachycardia is asymptomatic, what characteristic should be considered?

1. QRS duration less than 0.08 seconds

2. QRS duration greater than 0.12 seconds

3. Presence of ST elevation

4. Heart rate below 100 beats per minute

The correct answer is: QRS duration greater than 0.12 seconds

In the context of persistent tachycardia that is asymptomatic, it is crucial to consider the QRS duration as it helps in identifying the underlying mechanism of the tachycardia. A QRS duration greater than 0.12 seconds indicates a bundle branch block or possibly other forms of ventricular conduction delay, which may categorize the tachycardia as ventricular in origin or suggest the presence of a more complex arrhythmia. This characteristic can signify a more serious condition that may necessitate further evaluation and possibly intervention, despite the absence of symptoms. It is important to note that asymptomatic tachycardia may still require careful assessment of the QRS duration to understand risks and treatment options, differentiating between supraventricular and ventricular tachycardias. In contrast, a QRS duration less than 0.08 seconds would suggest a more benign and likely supraventricular origin. The presence of ST elevation could indicate myocardial ischemia or infarction, which may not be the primary concern in asymptomatic tachycardia. Lastly, a heart rate below 100 beats per minute does not pertain to the definition of tachycardia, since it signifies a normal heart rate. Thus, monitoring and evaluating the Q