title: [Antiarrhythmic drug effectiveness. Proposal for a new approach based on pharmacological hourly effects].
abstract: OBJECTIVE
  To use a new approach in order to assess the antiarrhythmic drugs, based in the hourly autonomic effects and antiarrhythmic efficacy of sotalol.
  
  
  METHODS
  Sixteen patients were evaluated in a randomized double-blind placebo-controlled study. Patients were classified in group 1 (anti-arrhythmic efficacy) and group 2 (no antiarrhythmic efficacy). The following parameters were analyzed: 1) clinical variables as age, gender, cardiac disease and ventricular ectopies density; 2) drug effects on pNN50 in 24-hour and on mean hourly cardiac cycle length; 3) percentage of hourly ventricular ectopies distribution and its correlation with pNN50 and with mean hourly cardiac cycle length in all patients; 4) drug effects on mean hourly cardiac cycle length in groups 1 and 2; 5) correlation between hourly pNN50 and ventricular ectopies density after sotalol administration in groups 1 and 2; 6) hourly drug efficacy in groups 1 and 2 and correlation with pNN50.
  
  
  RESULTS
  Efficacy of the drug was present in 8 (50%) patients. Sotalol significantly increased 24-hour pNN50 (placebo 5.01 +/- 2.02%; after drug, 11.70 +/- 5.59%-p < 0.001), also increasing mean hourly cardiac cycle length during the day and night, in all patients (placebo 758.25 +/- 75.68 ms; after drug 967.71 +/- 80.17 ms-p < 0.000). It was noted that patients under placebo had different autonomic tonus; group 1 showed higher sympathetic activity as compared to group 2. Hourly drug efficacy was seen in 23 of 24-hour recordings in group 1 while it was not seen at any time in group 2.
  
  
  CONCLUSIONS
  Sotalol significantly increased parasympathetic cardiac activity. The anti-arrhythmic response was related to the autonomic tonus seen before and after drug administration.
authors.affiliation: Hospital Pró-Cardíaco/Pró-Ritmo, Rio de Janeiro.
authors.forename: I G
authors.initials: IG
authors.lastname: Maia
authors.forename: T N
authors.initials: TN
authors.lastname: Seixas
authors.forename: A M
authors.initials: AM
authors.lastname: Costa
authors.forename: A K
authors.initials: AK
authors.lastname: Perez
authors.forename: P A
authors.initials: PA
authors.lastname: Alves
mesh_terms: D000328:Adult; D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001145:Arrhythmias, Cardiac / Q000188:drug therapy*; D001341:Autonomic Nervous System / Q000502:physiology; D002940:Circadian Rhythm / Q000187:drug effects; D004311:Double-Blind Method; D015716:Electrocardiography, Ambulatory; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013015:Sotalol / Q000494:pharmacology / Q000627:therapeutic use*
chemical_list: D000889:Anti-Arrhythmia Agents; D013015:Sotalol
vernacular_title: Efficácia das drogas antiarrítmicas. Proposta para uma nova forma de avaliação baseada nos efeitos farmacológicos horários.