Answer :
Final answer:
In AVNRT ablation, typically the slow pathway is targeted to prevent tachycardia while preserving the heart's normal electrical conduction. Regarding the heart conduction system's slowest firing rate, it is the atrioventricular node which serves to delay the electrical signal for optimal heart function.
Explanation:
In the treatment of Atrioventricular Nodal Reentrant Tachycardia (AVNRT), the ablation procedure typically targets the slow pathway. This is the more common strategy as it poses a lower risk of interfering with the normal conduction system of the heart compared to ablation of the fast pathway. Destroying the slow pathway prevents the reentrant circuit from initiating the tachycardia without disrupting the primary electrical route from atria to ventricles. However, occasionally the fast pathway may be targeted, depending on specific cardiac anatomy and the electrophysiologist's judgment.
When considering the component of the heart conduction system with the slowest rate of firing, the correct answer is atrioventricular node (a). The atrioventricular node is designed to delay the electrical signal before it passes to the ventricles, providing adequate time for the atria to contract and for blood to fill the ventricles. This natural delay establishes the atrioventricular node as having the slowest rate of firing among the options provided.
