Heart failure remains an increasing cause of morbidity and mortality in the United States even in the face of recent advances in the treatment of cardiovascular disease. There is an urgent need to reevaluate the treatment of heart failure. Shifting substrate utilization used in energy metabolism from fatty acids to glucose is beneficial to the heart presumably by increasing the efficiency of ATP production. Several new drugs for the treatment of cardiac ischemia work by this mechanism. There is increasing evidence that patients with heart failure may also benefit by the same type of intervention. Patients with heart failure are known to have low serum thiamine levels because of poor dietary intake and increased urinary excretion. Inadequate thiamine will deleteriously shift substrate utilization from glucose to fatty acids.

We hypothesize that thiamine supplementation will be beneficial for patients with heart failure by increasing glucose and decreasing fatty acid utilization. This will be initially tested in a pilot double-blinded placebo controlled study of thiamine supplementation in diabetic and non-diabetic patients presenting to the emergency department with acute decompensated heart failure.

Inclusion Criteria:

1. History of heart failure on a loop diuretic.
2. Worsening dyspnea over the past 24 hours.
3. Currently dyspneic sitting or supine, on or off oxygen.
4. Radiographic cephalization of vessels. This criteria is not needed if the patient has no other reason for being dyspneic after being evaluated in the emergency department.
5. Elevated NT pro-BNP (>450).
6. Able to communicate in English or Spanish.
7. Able and willing to provide informed consent.
8. Age > 18 years.
9. A primary admitting diagnosis of acute decompensated heart failure.

Exclusion Criteria:

1. Renal failure on dialysis.
2. Severe valvular disease.
3. EKG criteria for acute myocardial infarction (ST segment elevation > 1mm on two contiguous leads).
4. Initial troponin elevated.
5. Ventricular arrhythmia (ventricular tachycardia or fibrillation).
6. Supraventricular arrhythmia (atrial fibrillation / flutter) with a ventricular rate >120 beats per minute.
7. Taking a daily thiamine supplementation (any multivitamin or specific thiamine supplementation within the past 2 weeks. Fortified foods, such as cereals, are acceptable
8. Taking a daily fatty acid supplement.
9. Pregnancy as determined by standard serum or urine b-HCG assay.