How does Lidocaine affect cardiac conduction?

Lidocaine primarily affects cardiac conduction by blocking sodium channels in the cardiac tissue. This action reduces the influx of sodium ions during the depolarization phase of the cardiac action potential, which is essential for initiating the impulse that leads to heart contraction. By inhibiting sodium permeability, lidocaine decreases the excitability of the cardiac cells and slows down conduction velocity in the heart. This is particularly useful in managing certain types of ventricular arrhythmias, as it helps stabilize the cardiac membrane and prevent abnormal electrical activity.

Understanding the role of sodium channels in cardiac conduction is crucial. The normal cardiac action potential relies on the proper functioning of these channels to facilitate rapid depolarization. When lidocaine or other sodium channel blockers are used, they modulate this process, leading to clinical effects that can help control irregular heart rhythms.