Oral vitamin C improves carotid baroreflex sensitivity in chronic heart failure

D. J. Blackman*, J. A. Morris-Thurgood, G. R. Ellis, J. R. Cockcroft, M. P. Frenneaux

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Baroreflex sensitivity (BRS) is reduced in chronic heart failure (CHF) and is associated with an adverse prognosis. Oxidative stress may be implicated via reduced arterial compliance and/or direct effects on bare-receptor nerve endings. We investigated the effects on baroreflex sensitivity of treatment with the antioxidant vitamin C in CHF. 10 patients with CHF were studied. Integrated BRS was measured using spontaneous sequence analysis of a 10 minute recording of blood pressure and ECG, and arterial BRS evaluated using a carotid neck collar. BRS was recorded at baseline, 1 month after treatment with oral vitamin C 2g bd, and in a subset of 5 patients repeated 6 weeks after stopping treatment. Baseline BRS was measured in 10 age-matched controls for comparison. Both spontaneous and carotid BRS were significantly reduced in the patients compared to the controls (7.3±3.0 vs 13.3±5.2 ms/mmHg, p=0.005, and 0.9±0.6 vs 2.9±2.1 ms/mmHg, p=0.01 respectively). After treatment with vitamin C there was a significant improvement in carotid BRS (0.9±0.6 to 1.7±1.1, p=0.04) but no change in spontaneous BRS (7.3±3.0 to 7.8±3.3, p=0.54). In the subgroup re-evaluated after discontinuing treatment, carotid BRS deteriorated (1.7±0.8 to 1.1±0.7, p=0.02), but spontaneous BRS remained unchanged (8.5±4.9 to 10.1±8.8. p=0.68). Treatment with the antioxidant vitamin C results in an improvement in carotid arterial baroreflex sensitivity in patients with CHF which is reversed 6 weeks after stopping therapy. There is no effect on integrated BRS assessed by spontaneous sequence analysis.

Original languageEnglish
JournalHeart
Volume81
Issue numberSUPPL. 1
Publication statusPublished - May 1999
Externally publishedYes

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