title: [Pacemaker with sensor of contractility regulated by autonomic nervous system variations in chronic Chagas cardiomyopathy].
abstract: OBJECTIVE
  To analyse the performance of the artificial cardiac stimulation with the VVIR pacemaker whose sensor is adjusted by the variations of the autonomic nervous system in Chagas disease patients with deficiency of the conduction system.
  
  
  METHODS
  Forty-seven Chagas disease patients have been studied, 28 male between 24 and 68 years old, 36 patients had complete AV block, 8 had 2nd degree AV block and the other 3 had sinusnode disease. The patients were in class I (4), II (15), III (16) and IV (12) according to the NYHA. A 12-month-follow-up with constant clinical evaluations was carried out after pacemaker implantation. Patients were divided in 2 different groups according to the HR at rest--group 1: > 65 beats per minute (bpm) and group 2: < or = 65 bpm, for a comparative study considering: 1) HR at stress test after the implantation; 2) arterial blood pressure at rest after the implantation and, 3) evaluation of the identified electrodes such as TIR-60-UP and others.
  
  
  RESULTS
  The group 1 had greater HR at rest, and a smaller variation of values at stress than group 2. This shows that with this type of stimulation system it is possible to control each patient separately. The values of blood pressure at rest and during stress were not different between groups. According to the factors analysed the TIR-60-UP electrode had the same performance as the others.
  
  
  CONCLUSIONS
  The VVIR pacemaker with the sensor adjusted by the ANS variations has provided the Chagas patients with a restoration of their physiological mechanisms. 74% of them had the improvement of either one or 2 functional classes.
authors.affiliation: Instituto de Moléstias Cardiovasculares, São José do Rio Preto.
authors.forename: O T
authors.initials: OT
authors.lastname: Greco
authors.forename: R V
authors.initials: RV
authors.lastname: Ardito
authors.forename: D R
authors.initials: DR
authors.lastname: Souza
authors.forename: M
authors.initials: M
authors.lastname: Schaldach
mesh_terms: D000328:Adult; D000368:Aged; D001341:Autonomic Nervous System; D002598:Chagas Cardiomyopathy / Q000601:surgery*; D002908:Chronic Disease; D015444:Exercise / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D010138:Pacemaker, Artificial; D012146:Rest / Q000502:physiology