Muscarinic antibodies and heart rate responses to dynamic exercise and to the Valsalva maneuver in chronic chagasic patients

Revista do Instituto de Medicina Tropical de São Paulo

Barbara C. Das Neves²  Mey Lyn Bacilio²  Lisbeth Berrueta¹  Siham Salmen¹  Darrell L. Peterson¹  Jose H. Donis²  Tulio J. Nuñez²  Diego F. Davila² 

[1] ,Instituto de Investigaciones Cardiovasculares

关键词: Chagas disease;    Muscarinic receptors;    Cardiac muscarinic auto-antibodies;    Parasympathetic;    Dynamic exercise;    Valsalva Maneuver;   

DOI  :  10.1590/S0036-46652013000100006

来源: SciELO

【 摘 要 】

We have studied the cardiac chronotropic responses to the Valsalva maneuver and to dynamic exercise of twenty chronic chagasic patients with normal left ventricular function and no segmental wall abnormalities by two-dimensional echocardiogram. The absolute increase in heart rate of the patients (Δ = 21.5 ± 10 bpm, M±SD) during the maneuver was significantly diminished when compared to controls (Δ = 31.30 ± 70, M±SD, p = 0.03). The minimum heart rate (58.24 ± 8.90 vs. 62.80 ± 10, p = 0.68) and the absolute decrease in heart rate at the end of the maneuver (Δ = 38.30 ± 13 vs. Δ = 31.47 ± 17, p = 0.10) were not different from controls. The initial heart rate acceleration during dynamic exercise (Δ = 12 ± 7.55 vs. Δ = 19 ± 7.27, M±SD, p = 0.01) was also diminished, but the heart rate recovery during the first ten seconds was more prominent in the sero-positive patients (Median: 14, Interquartile range: (9.75-17.50 vs. 5(0-8.75, p = 0.001). The serum levels of muscarinic cardiac auto-antibodies were significantly higher in the chagasic patients (Median: 34.58, Interquartile Range: 17-46.5, Optical Density) than in controls (Median: 0, Interquartile Range: 0-22.25, p = 0.001) and correlated significantly and directly (r = 0.68, p = 0.002) with early heart rate recovery during dynamic exercise. The results of this investigation indirectly suggest that, the cardiac muscarinic auto-antibodies may have positive agonist effects on parasympathetic heart rate control of chagasic patients.

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