Which two drug classes are first-line for rate control in stable atrial fibrillation with preserved LV function?

• A. Beta-blockers and non-dihydropyridine calcium channel blockers
• B. ACE inhibitors and diuretics
• C. Nitrates and hydralazine
• D. Digoxin and amiodarone

Answer: (A)

The main idea is that rate control in atrial fibrillation aims to slow the heart’s ventricular response by reducing AV nodal conduction, and in patients with normal LV function the safest and most reliable way to do this is with drugs that directly slow AV nodal activity without depressing myocardial contractility. Beta-blockers achieve this by blocking sympathetic input to the AV node, lowering both heart rate and AV conduction. Non-dihydropyridine calcium channel blockers, such as diltiazem or verapamil, slow AV nodal conduction through calcium channel blockade, also reducing the ventricular rate during AF.

These approaches are preferred here because they effectively control rate while preserving or even supporting stable pumping function. Other options either don’t target AV nodal conduction as directly (ACE inhibitors and diuretics), are not used for rate control (nitrates and hydralazine), or are less ideal first-line in this scenario (digoxin is slower and less reliable with activity; amiodarone is more toxic and reserved for when rhythm control is needed or LV dysfunction is present).

So, slowing AV node conduction with beta-blockers or non-dihydropyridine calcium channel blockers is the best first-line strategy for rate control in stable AF with preserved LV function.