Certified Rhythm Analysis Technician (CRAT) Practice Exam 2026 - Free CRAT Practice Questions and Study Guide

The correct answer is the ventricular pacemaker. This type of pacing is necessary when the heart’s intrinsic conduction system is unable to generate an effective enough rhythm. In this situation, a pacemaker is placed in the ventricles, which sends an electrical impulse that prompts the ventricles to contract.

When this occurs, the pacing spike appears on the electrocardiogram (ECG) before the QRS complex. The QRS complex represents the depolarization of the ventricles, indicating that the ventricles are contracting. The presence of the pacing spike before the QRS signifies that the pacemaker is actively stimulating the ventricles directly, bypassing any intrinsic conduction pathways that may be compromised.

In contrast, atrial and atrioventricular pacemakers would produce a pacing spike prior to the P wave or at times pause until they are initiated by the atria, thus not coinciding with the waveforms associated with ventricular depolarization as seen in the QRS. The atrioventricular pacemaker's pacing may lead to a slight delay due to the additional AV node interaction before the ventricles are stimulated. Therefore, it's key to recognize that the timing of the pacing spike is a significant indicator of which part of the heart is being stimulated