Which of the following best describes an idioventricular rhythm?

Which of the following best describes an idioventricular rhythm?

• A. A rhythm originating from the atria
• B. A rhythm without any P wave activity
• C. A rhythm originating from the ventricles
• D. A rhythm with a normal sinus origin

Answer: (C)

An idioventricular rhythm is characterized by its origin from the ventricles rather than the atria or the sinoatrial (SA) node, which is responsible for initiating the normal heartbeat. In this type of rhythm, the intrinsic pacemaker of the ventricles takes over when higher pacemaker sites are not functioning, resulting in a heart rate that typically ranges from 20 to 40 beats per minute. This is a protective mechanism that allows the heart to continue beating even when the upper chambers fail to generate a rhythm.

The presence of a broad QRS complex on the EKG is another hallmark feature of idioventricular rhythms, further supporting its ventricular origin. In contrast to rhythms where atrial activity or a normal sinus rhythm may be present, the idioventricular rhythm will lack atrial depolarization, leading to the absence of P waves, which can help distinguish it from other rhythms. Thus, identifying an idioventricular rhythm involves recognizing these specific characteristics indicating that the ventricular tissue is the primary pacemaker.