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This Article Full Text Full Text (PDF) All Versions of this Article: 287/2/H878    most recent 00007.2003v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Grossman, P. M. Articles by Starling, M. R. Search for Related Content PubMed PubMed Citation Articles by Grossman, P. M. Articles by Starling, M. R.

Cardiac-specific norepinephrine mass transport and its relationship to left ventricular size and systolic performance

Divisions of ¹Cardiology and ²Geriatric Medicine, Department of Internal Medicine, and the ³Horace H. Rackham School of Graduate Studies, University of Michigan; and ⁴Geriatric Research, Education, and Clinical Center and ^2,4Cardiology Section of Veterans Affairs Ann Arbor Healthcare System, Ann Arbor, Michigan 48105

Submitted 7 January 2003 ; accepted in final form 1 April 2004

Objectives of this study were to develop a technique for quantifying cardiac-specific norepinephrine (NE) mass transport and determine whether cardiac NE kinetic modeling parameters were related to physiological variables of left ventricular (LV) size and systolic performance in nine patients with chronic mitral regurgitation. Biplane contrast cineventriculograms were used to determine LV size and ejection fraction (EF), micromanometer LV pressures and radionuclide LV volumes from a range of loading conditions to calculate LV end-systolic elastance, and [³H]NE infusions with LV and coronary sinus sampling for [³H]NE and endogenous NE during and after termination of infusions to model NE mass transport. Total NE release rate into cardiac interstitial fluid (_IF^R) averaged 859 ± 214 and NE released de novo into cardiac interstitial fluid (_IF^u,r,en) averaged 546 ± 174 pmol/min. Both _IF^R and correlated directly with LV end-systolic volume (r = 0.84, P = 0.005; r = 0.86, P = 0.003); inversely with LV EFs (r = –0.75, P = 0.02; r = –0.81, P = 0.008); and inversely with LV end-systolic elastance values, optimally fit by a nonlinear function (r = 0.89, P = 0.04; r = 0.96, P = 0.01). We conclude that total and newly released NE into interstitial fluid of the heart, determined by regional mass transport kinetic model, are specific measures of regional cardiac-specific sympathetic nervous system activity and are strongly related to measures of LV size and systolic performance. These data support the concept that this new model of organ-specific NE kinetics has physiological relevance.

mitral regurgitation; left ventricle; ejection fraction; contractility