Objective: Both brain natriuretic peptide (BNP) and cardiac sympathetic activity are useful surrogate markers of congestive heart failure. BNP is known to be secreted in response to sympathetic tone. This study examined the relationship between the cardiac sympathetic system and BNP.
Patients and methods: Sixty patients with chronic ischemic heart failure (mean age,72 years-old; 46 males and 14 females) who had undergone cardiac catheterization and were classified as NYHA II underwent resting (99m)Tc-sestamibi quantitative gated imaging (MIBI) and (123)I-metaiodobenzylguanidine imaging (MIBG). MIBI was used to obtain left ventricular (LV) dimension. MIBG was used to obtain the washout rate and the H/M ratios as well as the extent of LV washout rate abnormality (RSNA), which was defined as the number of regions with a regional washout rate of more than mean+2SD of 15 normal subjects on a two-dimensional polar map divided into 20 regions. Blood samples were obtained to measure neurohormones such as BNP, renin activity, noradrenaline, and angiotensin II.
Results: Simple linear regression analysis showed that BNP had significant correlations to age, LVEF, LV end diastolic volume, LV end systolic volume, RSNA, global washout rate, myocardial ischemia, and LV end diastolic pressure. Among them, multiple linear regression analysis showed that only RSNA (partial regression coefficient =0.618, p<0.002) had a significant positive correlation with BNP.
Conclusion: This study suggested that the extent of cardiac sympathetic overactivity in the LV could enhance BNP release.