Circadian variation in the effects of aldosterone blockade on heart rate variability and QT dispersion in congestive heart failure

Kok-Meng Yee, Stuart D. Pringle, Allan D. Struthers

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    143 Citations (Scopus)

    Abstract

    OBJECTIVES

    The study was designed to comprehensively evaluate the circadian effects of aldosterone blockade on autonomic tone and QT dispersion in chronic heart failure (CHF).

    BACKGROUND

    Spironolactone therapy given in addition to angiotensin-converting enzyme inhibitors improved survival in CHF, but the mechanism of its benefit is uncertain. Experimental evidence suggests that aldosterone may have detrimental effects on the autonomic nervous system, especially during the morning hours.

    METHODS

    Twenty-eight patients with New York Heart Association class II to IV CHF received spironolactone 50 mg daily and placebo for four weeks each in a double-blind crossover fashion. After each treatment phase, a full circadian assessment was undertaken of spironolactone’s autonomic effects. The assessment included monitoring heart rate, QT dispersion, continuous Holter recordings, heart rate variability (HRV) and norepinephrine kinetics.

    RESULTS

    Spironolactone significantly reduced all indices of QT dispersion. The reductions in QTcmax, QTd and QTcd were greatest at 6 am. In addition, spironolactone had favorable autonomic effects, which were limited to the morning (6–10 am), including heart rate reduction and an improvement in HRV.

    CONCLUSIONS

    Spironolactone reduced heart rate and improved HRV and QT dispersion in CHF. Its effects were particularly prominent during the morning hours.
    Original languageEnglish
    Pages (from-to)1800-7
    Number of pages8
    JournalJournal of the American College of Cardiology
    Volume37
    Issue number7
    DOIs
    Publication statusPublished - 1 Jun 2001

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