5. Diagnosis of NYHA Class II - III heart failure. 6. No evidence of significant obstructive CAD on invasive coronary angiography or noninvasive stress imaging 7. Resting LV ejection fraction <40% on noninvasive imaging within 30 days of research cardiac MIBG imaging 8. Current stable treatment regimen of medications including a betablocker and either an ACE inhibitor or ARB unless documented to be intolerant to these classes of drugs.