Which condition is NOT an FDA label indication for Diltiazem Hydrochloride?

Diltiazem Hydrochloride is a calcium channel blocker primarily indicated for the management of certain cardiovascular conditions. One of its main uses is in the treatment of hypertension, where it helps relax blood vessels to lower blood pressure. It is also indicated for stable, chronic angina, as it helps to reduce the heart's workload and improve blood flow to the heart muscle. Additionally, it is utilized for managing atrial arrhythmias and paroxysmal supraventricular tachycardia, being effective in controlling heart rate.

However, heart failure is not an FDA-approved indication for Diltiazem. In clinical practice, while some calcium channel blockers may be used cautiously in heart failure patients, particularly dihydropyridines, Diltiazem is generally not recommended as a treatment option for this condition. This is likely due to its negative inotropic effects, which can potentially exacerbate heart failure symptoms rather than alleviate them. Thus, in the context of the FDA labeling and typical uses in clinical settings, the condition that is not indicated for Diltiazem Hydrochloride is indeed heart failure.