The applicability of guideline recommendations for management of diseases (including heart failure) in primary care has recently been questioned as this research is rarely conducted in representative populations.13 This question is important in heart failure because the effectiveness of treatment may depend on the severity of disease, and beta-blockers and ACE inhibitors carry significant morbidity risk, accounting for approximately one in seven emergency hospital admissions due to adverse drug reactions.15 This evidence concerns the gene ACE and heart failure.