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.