MARKED EXPRESSION OF PLASMA BRAIN NATRIURETIC PEPTIDE IS A SPECIAL FEATURE OF HYPERTROPHIC OBSTRUCTIVE CARDIOMYOPATHY

Objectives. We examined whether plasma brain natriuretic peptide level s are abnormally elevated in hypertrophic obstructive cardiomyopathy c ompared with other cardiac diseases. Background. We previously reporte d that plasma brain and atrial natriuretic peptide levels mere elevate d in hypertrophic cardiomyopathy. Methods. We compared plasma concentr ations of brain and atrial natriuretic peptide and hemodynamic and ech ocardiographic data in 50 patients with hypertrophic obstructive cardi omyopathy (n = 15, mean [+/-SD] intraventricular pressure gradient 37 +/- 16 mm Hg), hypertrophic nonobstructive cardiomyopathy (n = 15), ao rtic stenosis (n = 10, mean pressure gradient 41 +/- 18 mm Hg) and hyp ertensive heart disease (n = 10, mean systolic/diastolic blood pressur e 203 +/- 16/108 +/- 11 mm Mg, respectively) and 10 normal subjects. R esults. Plasma brain natriuretic peptide levels were higher in the hyp ertrophic obstructive cardiomyopathy group (397.1 +/- 167.8 pg/ml) th an in the hypertrophic nonobstructive cardiomyopathy (60.0 +/- 48.1 pg /mldagger), hypertensive heart disease (53.9 +/- 31.4 pg/ml*dagger), aortic stenosis (75.4 +/- 54.3 pg/mldagger) and normal groups (9.8 +/ - 6.4 pg/ml dagger [p < 0.05 vs. normal group, dagger p < 0.05 vs. hyp ertrophic obstructive cardiomyopathy group]). Although plasma atrial n atriuretic peptide levels mere higher in the hypertrophic obstructive cardiomyopathy group than the other patient groups, the brain/atrial n atriuretic peptide ratio in the hypertrophic obstructive cardiomyopath y group mas higher (4.5 +/- 2.3) than those in the other three patient groups (1.1 to 1.4) and the normal group (0.7 +/- 0.5). Left ventricu lar end diastolic pressure and left ventricular end-diastolic volume i ndex mere similar among the four patient groups. The interventricular septal thickness and the ratio of interventricular septal thickness to left ventricular posterior wall thickness mere similar between the hy pertrophic obstructive and nonobstructive cardiomyopathy groups. Concl usions, Abnormal elevations of plasma brain natriuretic peptide levels are difficult to explain oa the basis of hemodynamic and echocardiogr aphic data and are a special feature of hypertrophic obstructive cardi omyopathy.