Association of serum triiodothyronine with B-type natriuretic peptide and severe left ventricular diastolic dysfunction in heart failure with preserved ejection fraction.

There are well-documented changes in thyroid hormone metabolism that accompany heart failure (HF). However, the frequency of thyroid hormone abnormalities in HF with preserved ejection fraction (HFpEF) is unknown, and no studies have investigated the association between triiodothyronine (T(3)) and markers of HF severity (B-type natriuretic peptide [BNP] and diastolic dysfunction [DD]) in HFpEF. In this study, 89 consecutive patients with HFpEF, defined as symptomatic HF with a left ventricular ejection fraction >50% and a left ventricular end-diastolic volume index <97 ml/m(2), were prospectively studied. Patients were dichotomized into 2 groups on the basis of median T(3) levels, and clinical, laboratory, and echocardiographic data were compared between groups. Univariate and multivariate linear regression analyses were performed to determine whether BNP and DD were independently associated with T(3) level. We found that 22% of patients with HFpEF had reduced T(3). Patients with lower T(3) levels were older, were more symptomatic, more frequently had hyperlipidemia and diabetes, and had higher BNP levels. Severe (grade 3) DD, higher mitral E velocity, shorter deceleration time, and higher pulse pressure/stroke volume ratio were all associated with lower T(3) levels. T(3) was inversely associated with log BNP (p = 0.004) and the severity of DD (p = 0.039). On multivariate analysis, T(3) was independently associated with log BNP (β = -4.7 ng/dl, 95% confidence interval -9.0 to -0.41 ng/dl, p = 0.032) and severe DD (β = -16.3 ng/dl, 95% confidence interval -30.1 to -2.5 ng/dl, p = 0.022). In conclusion, T(3) is inversely associated with markers of HFpEF severity (BNP and DD). Whether reduced T(3) contributes to or is a consequence of increased severity of HFpEF remains to be determined.