Which condition is NOT an indication for Diltiazem?

Diltiazem is a calcium channel blocker commonly utilized in the management of various cardiovascular conditions. It effectively slows down the heart rate and can help control the rhythm in conditions like atrial fibrillation and atrial flutter, where abnormal electrical activity in the atria can lead to rapid heart rates. The drug is also useful in treating certain types of tachycardia by decreasing heart rate and lowering blood pressure through vasodilation.

Hypertension, or high blood pressure, is indeed a condition that Diltiazem can treat, rather than not being an indication for it. In this case, the other three conditions are more specifically related to its role in rate control for fast atrial rhythms and tachycardic states, but hypertension is also a recognized indication, making the provided answer not correct in context.

Therefore, while hypertension serves as a valid indication for Diltiazem, it works well for conditions such as atrial fibrillation, atrial flutter, and tachycardia due to its mechanism of action.