In this algorithm, the authors used the Veterans Affairs EHR system to identify a cohort of HFpEF using an inclusion criterion of any ICD-9 code of HF (428.xx) and either BNP or aminoterminal pro-BNP (NT-proBNP) values recorded OR diuretic use within one month of diagnosis of HF. The gene discussed is NPPB; the disease is hydrops fetalis.