Determinants and clinical significance of natriuretic peptides in hypertrophic cardiomyopathy

Aims Atrial and brain natriuretic peptide levels closely reflect impaired l eft ventricular function in patients with heart failure. In the present stu dy we assessed the determinants and the clinical significance of atrial and brain natriuretic peptide plasma levels in hypertrophic cardiomyopathy. Methods and Results In 44 patients with hypertrophic cardiomyopathy (40 +/- 15 years) we evaluated: (a) atrial and brain natriuretic peptide plasma le vels; (b) left ventricular hypertrophy; (c) left ventricular ejection fract ion; (d) transmitral and pulmonary venous flow velocity patterns, arid left atrial fractional shortening; (e) left ventricular outflow tract gradient; (f) maximal oxygen consumption. Left ventricular hypertrophy influenced on ly brain natriuretic peptide levels (r=0.32; P<0.05). Atrial and brain natr iuretic peptide plasma levels did not correlate with left ventricular eject ion fraction, but correlated with left ventricular outflow tract gradient ( r=0.35; P<0.05; and r=0.40, P=0.022, respectively) and left atrial fraction al shortening (r= - 0.57; P<0.001, and r= - 0.35; P<0.05, respectively). At rial but not brain natriuretic peptide plasma levels were inversely related to maximal oxygen consumption (r= - 0.35: P<0.05). By stepwise multiple re gression analysis, left atrial fractional shortening and left ventricular o utflow tract gradient were the only predictors of atrial and brain natriure tic peptide plasma levels. respectively. Conclusions In hypertrophic cardiomyopathy, atrial natriuretic peptide plas ma levels are mainly determined by diastolic function: this explains the re lationship with exercise tolerance. In contrast, brain natriuretic peptide plasma levels are mainly determined by left ventricular outflow tract gradi ent.