What arrhythmia is characterized by a sudden increase in heart rate that can last from seconds to hours?

Paroxysmal supraventricular tachycardia (PSVT) is characterized by a sudden increase in heart rate that can last from seconds to hours. This arrhythmia originates above the ventricles and is typically a result of abnormal electrical pathways in the atria or the AV node, which leads to rapid heartbeats. The term “paroxysmal” indicates that the episodes can start and stop abruptly, which aligns with the description of a sudden increase in heart rate.

In PSVT, patients may experience palpitations, dizziness, or even chest pain during episodes. The heart rate often exceeds 100 beats per minute and can be much higher, making it a clear-cut example of a rapid arrhythmia that can resolve itself spontaneously.

Other arrhythmias listed, such as ventricular fibrillation and atrial flutter, have distinct characteristics and mechanisms that differentiate them from PSVT. Ventricular fibrillation is typically a chaotic and life-threatening condition that can lead to cardiac arrest, while atrial flutter features a more stable, but still rapid, heart rhythm that usually does not have the same abrupt onset and offset as PSVT. Bradycardia, on the other hand, refers to a slower heart rate, which is fundamentally different