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Effect of acetazolamide on chemosensitivity, Cheyne-Stokes respiration, and response to effort in patients with heart failure.

Author(s): Fontana M, Emdin M, Giannoni A, Iudice G, Baruah R, Passino C

Affiliation(s): Division of Cardiovascular Medicine, Fondazione G. Monasterio CNR-Regione Toscana, Pisa, Italy.

Publication date & source: 2011-06-01, Am J Cardiol., 107(11):1675-80. Epub 2011 Mar 21.

Publication type: Clinical Trial

Increased chemosensitivity to hypoxia and hypercapnia, together with a prolonged circulatory time, are the main determinants of Cheyne-Stokes (C-S) respiration in heart failure. To evaluate the effect of acetazolamide, a carbonic anhydrase inhibitor, on chemosensitivity and respiratory dynamics in patients with heart failure with C-S respiration, 12 patients (mean age 62 +/- 9 years, mean left ventricular ejection fraction 24 +/- 9%) and C-S respiration (mean apnea-hypopnea index 23 +/- 13) who underwent 4 consecutive days of oral acetazolamide treatment (250 mg twice daily) were enrolled in this study. Assessment of chemosensitivity to hypoxia and hypercapnia, cardiopulmonary stress testing, 24-hour cardiorespiratory polygraphy, and neurohormonal characterization were performed at baseline and at the end of treatment. Acetazolamide improved central apneas (apnea-hypopnea index 23 +/- 13 to 15 +/- 9, p = 0.012) and the percentage of time spent below an arterial oxyhemoglobin saturation of 90% (16 +/- 23% to 10 +/- 18%, p = 0.005). Chemosensitivity to hypoxia was blunted (1.03 +/- 0.69 to 0.78 +/- 0.55 L/min/mm Hg, p = 0.032), while chemosensitivity to hypercapnia increased after acetazolamide (1.27 +/- 0.71 to 1.54 +/- 0.78 L/min/% arterial oxygen saturation, p = 0.023); patients achieved a lower workload (90 +/- 30 to 81 +/- 30 W, p <0.001), with no differences in peak oxygen consumption, while there was an increment in the regression slope relating minute ventilation to carbon dioxide output (39 +/- 10 to 43 +/- 9, p = 0.010). In conclusion, in patients with heart failure, acetazolamide diminishes C-S respiration and improves oxyhemoglobin saturation, likely by decreasing chemosensitivity to hypoxia. However, it is associated with reduced maximal workload achieved during effort and increased chemosensitivity to hypercapnia, inducing a reduction in the ventilatory efficiency. Copyright (c) 2011 Elsevier Inc. All rights reserved.

Page last updated: 2011-12-09

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