Which plasma lipoprotein level is most concerning when considering the risk of coronary atherosclerosis?

Choice A reason:
Nifedipine is a dihydropyridine calcium channel blocker that primarily affects vascular smooth muscle, leading to vasodilation. While it can lower blood pressure, it does not significantly affect cardiac conduction or rhythm, which is why it is not used as an antidysrhythmic.

Choice B reason:
Verapamil and Diltiazem are calcium channel blockers that affect the movement of calcium into the cells of both the heart and blood vessels. They have a significant impact on cardiac conduction and can be used to treat arrhythmias by slowing down the heart rate and reducing the conduction through the atrioventricular node.

Choice C reason:
Not all three medications have antidysrhythmic properties. Only Verapamil and Diltiazem are effective as antidysrhythmic agents due to their effects on cardiac conduction. Nifedipine does not share these properties and is therefore not used to manage arrhythmias.

Choice D reason:
Nifedipine primarily affects the movement of calcium into the cells of vascular smooth muscle, not the heart. Its main use is in the treatment of hypertension and angina, where its vasodilatory effects are beneficial. It does not significantly impact cardiac rhythm or conduction like Verapamil and Diltiazem do.

Choice A reason:
The onset of warfarin is delayed, meaning it takes longer to achieve a therapeutic effect. Warfarin requires several days to adjust to effective anticoagulation levels because it works by inhibiting the synthesis of clotting factors that are already present and active in the bloodstream. In contrast, heparin has an immediate anticoagulant effect when administered, which is crucial for patients with acute conditions like deep vein thrombosis.

Choice B reason:
Warfarin does not prevent platelet aggregation. Instead, it works by inhibiting vitamin K-dependent clotting factors, which are essential for blood coagulation. Platelet aggregation is primarily inhibited by antiplatelet drugs like aspirin or clopidogrel, not anticoagulants like warfarin.

Choice C reason:
Heparin does not necessarily have fewer adverse effects compared to warfarin. Both anticoagulants have their specific risks and side effects. Heparin is preferred in acute settings due to its rapid onset of action, but it can cause complications like heparin-induced thrombocytopenia (HIT), which requires careful monitoring.

Choice D reason:
Heparin does not have a longer half-life than warfarin. In fact, heparin's half-life is relatively short, which is why it is often administered via continuous infusion or frequent subcutaneous injections. Warfarin has a longer half-life, but its delayed onset of action makes it less suitable for immediate anticoagulation needs.