rss
Heart 1999;81:297-302 doi:10.1136/hrt.81.3.297
  • Paper

QT dispersion in patients with chronic heart failure: β blockers are associated with a reduction in QT dispersion

  1. C E Bonnara,
  2. A P Daviec,
  3. L Caruanac,
  4. L Fennd,
  5. S A Ogstonb,
  6. J J V McMurrayc,
  7. A D Struthersa
  1. aDepartment of Clinical Pharmacology and Therapeutics, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK, bDepartment of Epidemiology and Public Health, Ninewells Hospital and Medical School, cDepartment of Cardiology, Western Infirmary, Glasgow, UK, dDepartment of Cardiology, Western General Hospital, Edinburgh, UK
  1. Dr Bonnar. email:c.e.bonnar{at}clinpharm.dundee.ac.uk
  • Accepted 9 October 1998

Abstract

OBJECTIVE To compare QT dispersion in patients with impaired left ventricular systolic function and in matched control patients with normal left ventricular systolic function.

DESIGN A retrospective, case-control study with controls matched 4:1 for age, sex, previous myocardial infarction, and diuretic and β blocker treatment.

SETTING A regional cardiology centre and a university teaching hospital.

PATIENTS 25 patients with impaired left ventricular systolic function and 100 patients with normal left ventricular systolic function.

MAIN OUTCOME MEASURES QT and QTc dispersion measured by three methods: the difference between maximum and minimum QT and QTc intervals, the standard deviation of QT and QTc intervals, and the “lead adjusted” QT and QTc dispersion.

RESULTS All measures of QT/QTc dispersion were closely interrelated (r values 0.86 to 0.99; all p < 0.001). All measures of QT and QTc dispersion were significantly increased in the patients with impaired left ventricular systolic functionv controls (p < 0.001): 71.9 (6.5) (mean (SEM)) v 46.9 (1.7) ms for QT dispersion, and 83.6 (7.6) v 54.3 (2.1) ms−1−2 for QTc dispersion. All six dispersion parameters were reduced in patients taking β blockers (p < 0.05), regardless of whether left ventricular function was normal or impaired—by 9.4 (4.6) ms for QT dispersion (p < 0.05) and by 13.8 (6.5) ms−1−2 for QTc dispersion (p = 0.01).

CONCLUSIONS QT and QTc dispersion are increased in patients with systolic heart failure in comparison with matched controls, regardless of the method of measurement and independently of possible confounding factors. β Blockers are associated with a reduction in both QT and QTc dispersion, raising the possibility that a reduction in dispersion of ventricular repolarisation may be an important antiarrhythmic mechanism of β blockade.

Footnotes

    This Article

    1. Abstract
    2. Full text
    3. PDF

    Responses

    1. Submit a response
    2. No responses published

    Register for free content

    The full back archive is now available for all BMJ Journals. Institutional subscribers may access the entire archive as part of their subscription. Personal subscribers will also have access to all content when logged in. Non-subscribers who register have free access to all articles published before 2006 right back to volume 1 issue 1. Register here to access the free archive of all BMJ Journals.

    Don't forget to sign up for content alerts so you keep up to date with all the articles as they are published.