Which rhythm is described as lethal and often caused by multiple PVCs in a diseased heart?

• A. Atrial Fibrillation
• B. Ventricular Tachycardia
• C. Ventricular Fibrillation
• D. Asystole

Answer: (B)

Premature ventricular contractions originate in the ventricles, and when many of them occur in succession they can produce a rapid, organized ventricular rhythm known as ventricular tachycardia. In a diseased heart, scar tissue or ischemia creates abnormal conduction pathways and supports reentry circuits, making the ventricles more likely to fire rapidly in response to PVCs. Ventricular tachycardia typically runs at a rate above 100 beats per minute and presents with wide QRS complexes and a usually regular rhythm. Because the ventricles are beating so fast, filling time and cardiac output drop, leading to hypotension, dizziness, or even loss of consciousness. If VT continues, it can deteriorate into ventricular fibrillation, where the heart quivers instead of pumping, a state that is immediately life-threatening. For contrast, atrial fibrillation arises from the atria and isn’t driven by ventricular PVCs in the same way, while ventricular fibrillation is a chaotic, uncoordinated quivering of the ventricles and asystole is a flatline—both distinct from the orderly, rapid rhythm described here.