Enhanced parasympathetic activity in Chagas disease still stands in need of proof

Antonio Luiz P Ribeiro, Antonio Carlos Campos de Carvalho, Federico Lombardi, Mauro Martins Teixeira, Manoel Otávio Costa Rocha

Research output: Contribution to journalArticlepeer-review


Cardiac vagal modulation impairment is a typical feature of Chagas disease (ChD) and is correlated to antagonistic anti-M2 autoantibodies activity. In this letter, we analyze the hypothesis that, in ChD, anti-muscarinic antibody activity could simultaneously increase parasympathetic tonus (decreasing heart rate) and decrease vagal modulation over cardiac sinus node (reducing heart rate variability - HRV). Although attractive, this hypothesis is not supported by empirical data, since reduction of vagal-specific HRV indexes has been demonstrated in the absence of bradycardia. Moreover, anti-muscarinic antibody levels correlate with HRV indexes, but not with heart rate. In the absence of reduced heart rate and, consequently, of tonic vagal enhancement, it is impossible to explain the reduction of vagal-mediated HRV by continuous and strong muscarinic activity of autoantibodies in ChD.

Original languageEnglish
Pages (from-to)406-408
Number of pages3
JournalInternational Journal of Cardiology
Issue number3
Publication statusPublished - Jul 10 2009


  • Autonomic nervous system
  • Chagas disease
  • Heart rate variability

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine


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