Reversible airways obstructive disease, advanced heart block, or episodic decompensation. 

Vasodilators

Agents that dilate arteriolar smooth muscle and lower peripheral vascular resistance reduce left ventricular afterload and agents that diminish venous tone and increase venous capacitance reduce the preload of both ventricles as their principal effect.  

Nitrates

Intravenous vasodilators (sodium nitroprusside or nitroglycerin) are used primarily for acute or severely decompensated chronic heart failure, especially when accompanied by hypertension or myocardial ischemia.

Starting dosages of both agents are 10-20 μg/kg/min with upward titration by increments of 10 μg/kg/min as frequently as every 5-10 minutes. Dosages above 200 μg/kg/min are usually not required.

Isosorbide Dinitrate: 20-80 mg orally three times daily, has proved effective in several small studies.  

Side effects: headache, tolerance.