The rate of ventricular conduction can be best determined by examining what on an EKG?

The rate of ventricular conduction is best assessed by examining the number of QRS complexes on an EKG. Each QRS complex represents one complete depolarization of the ventricles, which is crucial for understanding how quickly the ventricles are contracting and pumping blood. By counting the number of QRS complexes in a set period, typically over one minute, you can calculate the ventricular rate, which is fundamental in diagnosing various cardiac conditions.

The other options do not directly indicate the rate of ventricular conduction. For instance, the length of the P-wave primarily pertains to atrial depolarization, while the PR interval reflects the time taken for electrical impulses to travel from the atria to the ventricles but does not gauge the conduction rate within the ventricles themselves. The ST segment is associated with the period between ventricular depolarization and repolarization and is crucial for evaluating myocardial ischemia or infarction, but it does not relate to the conduction rate. Thus, examining the number of QRS complexes is the clearest method for determining ventricular conduction rate on an EKG.