Final answer:
Verapamil and Diltiazem are non-DHP CCBs used for heart rate control in the management of narrow QRS complexes, owing to their effects on cardiac conduction tissue.
Step-by-step explanation:
Non-DHP CCBs that can be used in the management of narrow QRS complexes include Verapamil (Calan, Verelan) and Diltiazem (Cardizem, Tiazac). These drugs are part of the class of medications known as Calcium Channel Blockers or Calcium Antagonists, which help reduce heart rate and blood pressure. Unlike the Dihydropyridines (DHPs) such as Amlodipine (Norvasc, Lotrel) and Nifedipine (Adalat, Procardia), which primarily affect vascular smooth muscle and have limited effects on the heart, Verapamil and Diltiazem can be used to slow down the heart rate in conditions such as supraventricular tachycardia (SVT), due to their more significant effects on the cardiac conduction tissue.