Mr. Adams, a 68-year-old patient, has an ECG showing atrial fibrillation/flutter. Which medication could be used to treat his cardiac rhythm?

Diltiazem is a calcium channel blocker that is commonly used to treat atrial fibrillation and flutter. It works by slowing down the conduction through the atrioventricular (AV) node, which helps to control the heart rate and restore a more regular rhythm. This medication is particularly effective in managing rapid ventricular rates that can occur in atrial fibrillation or flutter.

In the context of a patient like Mr. Adams, who is 68 years old, controlling heart rate is crucial, especially since older patients may be more susceptible to complications arising from a rapid heart rate. Diltiazem can provide both rate control and some antiarrhythmic properties, making it an appropriate choice for managing his condition.

Other options, while they may affect heart function or blood pressure, do not specifically address the immediate need for rate control or rhythm management in atrial fibrillation and flutter as effectively as diltiazem does.