Which of the following rhythms is characterized by QRS complexes that are the same shape, size, and direction?

Monomorphic ventricular tachycardia is defined by its consistent appearance of QRS complexes that are identical in shape, size, and direction. This uniformity helps to distinguish it from other types of arrhythmias, where the QRS complexes may vary in morphology.

In monomorphic ventricular tachycardia, the origin of the electrical impulses is from a single ectopic focus within the ventricles, leading to these uniform complexes. This can result in rapid heart rates, typically over 100 beats per minute, but the regularity and uniformity give healthcare providers a clear picture of the underlying rhythm.

Recognizing this rhythm is crucial in the clinical setting as it often necessitates immediate treatment, especially if the patient is experiencing hemodynamic instability. Understanding the distinct nature of monomorphic ventricular tachycardia helps differentiate it from other rhythms such as ventricular fibrillation, where there is chaotic electrical activity leading to varied QRS complexes without any discernible pattern. Other rhythms like junctional escape rhythms and idioventricular rhythms also exhibit different characteristics, such as differing QRS morphologies or slower rates respectively.