Horm Metab Res 2009; 41(4): 302-307
DOI: 10.1055/s-0028-1112125
Humans, Clinical

© Georg Thieme Verlag KG Stuttgart · New York

N-Terminal-pro-B-type Natriuretic Peptide during Pharmacological Heart Rate Reduction in Hyperthyroidism

M. Schultz 1 , C. Kistorp 2 , P. Corell 1 , H. U. Andersen 1 , A. Jarlov 1 , J. Faber 2
  • 1Department of Cardiology and Endocrinology E, Frederiksberg University Hospital, Denmark
  • 2Department of Endocrinology J, Herlev University Hospital, Denmark
Further Information

Publication History

received 19.07.2008

accepted 24.11.2008

Publication Date:
12 January 2009 (online)

Abstract

We hypothesized that elevated N-terminal-pro-B-type natriuretic peptide levels in hyperthyroidism are mainly driven by increased metabolism due to excess thyroid hormones. Therefore, serum levels of N-terminal-pro-B-type natriuretic peptide were studied during reduced cardiac work load by means of pharmacologically induced heart rate reduction in untreated hyperthyroidism. We designed a noncontrolled interventional study. Eighteen women with newly diagnosed hyperthyroidism were evaluated (including an echocardiography) before and after pharmacological heart rate reduction with 360 mg verapamil daily for 6 days. Before treatment, N-terminal-pro-B-type natriuretic peptide was independently associated with thyroid function (free triiodothyronine-index, r=0.64, p=0.001) and the hemoglobin concentration (r=−0.36, p=0.031). The verapamil treatment induced a decrease in parameters reflecting cardiac function; resting heart rate [from mean 97 to 80 beats per min (17.5%), p<0.001] and mean arterial pressure (8.5%, p=0.001). Median N-terminal-pro-B-type natriuretic peptide increased insignificantly from 224 to 240 pg/ml (p=0.31). Thyrotrotrophin levels were totally suppressed (<0.001 mU/l), free thyroxine-index decreased from median 319 to 315 arbitrary units (p=0.039) and free triiodothyronine-index increased from 8.6 to 9.9 arbitrary units (p=0.010). No changes in echocardiographic parameters were observed. A decrease in resting heart rate in untreated hyperthyroidism due to verapamil treatment did not result in decreasing N-terminal-pro-B-type natriuretic peptide levels. Thus elevated N-terminal-pro-B-type natriuretic peptide in hyperthyroidism seems mainly a result of high metabolism due to excess thyroid hormones rather than increased cardiac work load.

References

Correspondence

M. Schultz, MD 

Department of Cardiology and Endocrinology E

Frederiksberg University Hospital

Ndr. Fasanvej 57

2000 Frederiksberg

Denmark

Phone: +45/2192 44 10

Fax: +45/3816 43 59

Email: [email protected]