Table 3

Detection of serum anti-M2 mAChR antibodies in chagasic patients subjected to different tests for dysautonomia

TestsAnti-M2mAChR antibodies (number of antibody positive patients/total)
Basal heart rateTiltingCoughingHyperventilationValsalva
Normal7/3018/5012/3520/553/40
Altered49/55* 3-151 22/35 32/50§ 25/30 45/45*
Sensitivity (%)89.162.864.083.3100.0
Specificity (%)76.764.065.763.692.5
Youden index65.826.829.746.992.5
  • Chagasic patients (group I, n = 55; group II, n = 30) were subjected to a variety of tests for detection of cardiovascular dysautonomia. The presence of circulating anti-M2 mAChR antibodies in every patient was determined at 1/50 serum dilution byelisa as described in Methods.

  • Prevalence of antibodies in patients with normalv abnormal tests for dysautonomia were compared by χ2 test with Yates’ correction. Significantly different from normal test: *p < 0.00001;p < 0.02637; §p < 0.01322; p< 0.00009.

  • 3-151 Altered basal heart rate = bradycardia (< 55 beats/min).