Final answer:
Beta blockers or calcium channel blockers are the recommended first-line medications for controlling ventricular rate in patients with rapid atrial fibrillation. They slow the heart rate by affecting how calcium and adrenaline interact with the heart.
Step-by-step explanation:
Beta blockers or calcium channel blockers are the preferred first-line agents for ventricular rate control in patients with rapid atrial fibrillation. The management of atrial fibrillation involves the control of ventricular rate to prevent hemodynamic instability and minimize symptoms. Beta blockers, such as propranolol, work by reducing the effects of adrenaline on the heart, which slows the rate at which the ventricles fill and thus lowers the heart rate.
On the other hand, calcium channel blockers, including drugs from the dihydropyridine, phenylalkylamine, and benzothiazepine classes, reduce the strength of heart contractions and slow the heart rate by blocking calcium from entering the cells of the heart muscle and the electrical conduction system.