Thiamin is also known as vitamin B1. The named disease of thiamin deficiency is beriberi; one symptom of which is an enlarged heart. A study appearing in the Journal of the American College of Cardiology (2006; 47: 354-61) looked at the prevalence of thiamin deficiency in patients with congestive heart failure. In 100 patients with congestive heart failure, 33% were found to be thiamin deficient. This was much higher than the level of thiamin deficiency found in 50 control subjects without congestive heart failure; only 12% of those subjects were found to be thiamin deficient. Diuretics, which are commonly prescribed to patients with heart failure, deplete thiamin.