title: Effects of subacute dietary salt intake and acute volume expansion on diastolic function in young normotensive individuals.
abstract: OBJECTIVE
  Chronic excess salt intake may have blood pressure-independent adverse effects on the heart such as myocardial hypertrophy and fibrosis. Effects of subacute sodium loading with excess dietary salt on diastolic function in normotensive individuals have been conflicting and the mechanisms are poorly understood.
  
  
  RESULTS
  Thirteen healthy normotensive subjects (age 24 ± 4 years) entered a 2-week crossover study with 1 week of a low-salt diet <10 mEq/day and 1 week of a high-salt diet >200 mEq/day. At the end of each study week, left ventricular dimensions, systolic, and diastolic function were assessed with echocardiography before and after 2 L of normal saline infusion. One week of high-salt and low-salt diets did not lead to differences in echocardiographic parameters of systolic or diastolic function, even after rapid volume expansion with saline infusion. The peak early diastolic strain rate (SR) increased after volume loading both after completion of low-salt (1.62 ± 0.23/s vs. 1.82 ± 0.14/s, P < 0.05) and high-salt diets (1.67 ± 0.16/s vs. 1.86 ± 0.22/s, P < 0.05). There was a positive correlation between the peak early diastolic SR and the cardiac index (r = 0.52, P = 0.017).
  
  
  CONCLUSIONS
  In healthy normotensive individuals, subacute excess dietary sodium intake does not affect diastolic function. The peak early diastolic SR, similar to other mitral Doppler and tissue Doppler parameters of diastolic function, appears to be strongly dependent on pre-load.
authors.affiliation: Cardiac Ultrasound Laboratory and Division of Cardiology, Massachusetts General Hospital and Harvard Medical School, 55 Fruit Street, Boston, MA 02114, USA.
authors.forename: Gary S
authors.initials: GS
authors.lastname: Mak
authors.forename: Heloisa
authors.initials: H
authors.lastname: Sawaya
authors.forename: Abigail May
authors.initials: AM
authors.lastname: Khan
authors.forename: Pankaj
authors.initials: P
authors.lastname: Arora
authors.forename: Andrew
authors.initials: A
authors.lastname: Martinez
authors.forename: Allicia
authors.initials: A
authors.lastname: Ryan
authors.forename: Laura
authors.initials: L
authors.lastname: Ernande
authors.forename: Christopher
authors.initials: C
authors.lastname: Newton-Cheh
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Wang
authors.forename: Marielle
authors.initials: M
authors.lastname: Scherrer-Crosbie
mesh_terms: D000328:Adult; D000886:Anthropometry; D001794:Blood Pressure / Q000187:drug effects*; D001835:Body Weight / Q000187:drug effects; D003971:Diastole / Q000187:drug effects; D015150:Echocardiography, Doppler / Q000379:methods; D005260:Female; D064368:Healthy Volunteers; D006334:Heart Function Tests; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D015588:Observer Variation; D012016:Reference Values; D012494:Sampling Studies; D012965:Sodium Chloride / Q000008:administration & dosage; D012982:Sodium, Dietary / Q000008:administration & dosage* / Q000009:adverse effects*; D013318:Stroke Volume / Q000187:drug effects; D016276:Ventricular Function / Q000187:drug effects*; D055815:Young Adult
chemical_list: D012982:Sodium, Dietary; D012965:Sodium Chloride
keywords: Diastolic function; Diastolic strain rate; Sodium