How is the slow pathway defined?

How is the slow pathway defined?

• A. A pathway that naturally has slow conduction but repolarizes quickly
• B. A pathway that naturally has fast conduction but repolarizes slowly
• C. A pathway that naturally has slow conduction and slow repolarization
• D. A pathway that naturally has fast conduction and fast repolarization

Answer: (A)

The slow pathway is defined by slow conduction velocity but quick repolarization (short refractory period). In dual AV nodal physiology, this means impulses travel down the slow pathway slowly, yet the tissue recovers quickly enough to be ready for the next impulse sooner than the fast pathway. That combination—slow conduction with rapid recovery—distinguishes the slow pathway from the fast pathway, which conducts quickly but has a longer refractory period. The other descriptions don’t match these traits: pairing slow conduction with slow repolarization or fast conduction with fast repolarization describes the opposite properties or the fast pathway.

The slow pathway is defined by slow conduction velocity but quick repolarization (short refractory period). In dual AV nodal physiology, this means impulses travel down the slow pathway slowly, yet the tissue recovers quickly enough to be ready for the next impulse sooner than the fast pathway. That combination—slow conduction with rapid recovery—distinguishes the slow pathway from the fast pathway, which conducts quickly but has a longer refractory period. The other descriptions don’t match these traits: pairing slow conduction with slow repolarization or fast conduction with fast repolarization describes the opposite properties or the fast pathway.