title: Weight loss and P wave dispersion: a preliminary study.
abstract: BACKGROUND
  The aim of this study is to investigate if therapeutic weight loss reduces P wave dispersion.
  
  
  METHODS
  20 obese patients (10 males and 10 females), part of a randomized clinical trial, were examined over a 6 month period. They were treated with a diet, aiming at 5% weight loss at the 6th month. After physical examination, they underwent laboratory tests, bioelectrical impedance analysis and a electrocardiogram (ECG). ECGs were transferred to a personal computer via a scanner and then magnified 400 times. We examined at baseline and at the 6th month, maximum and minimum P-wave duration, P-wave dispersion and heart rate.
  
  
  RESULTS
  Comparing responders (patients who lost 5% of weight at t6) and not responders (who lost less than 5%), responders showed a significant reduction of P wave dispersion value (-0.38 [SD: 0.35] mm equal to -32.3 [SD: 11.3] % p=0.00001). All responders present a reduction of P wave dispersion, while for not-responders this is no longer evident. Finally, a good degree of correlation (r=0.54) between P wave dispersion difference and the decrease of weight was noticed. Females have a better response in P dispersion reduction strictly connected with their weight loss with a good correlation, (r=0.7, p=0.002), versus a moderate correlation evidenced in males (r=0.5, p=0.011).
  
  
  CONCLUSIONS
  P wave duration and dispersion are significantly reduced in patients who lost more than 5% of weight and this decrease is highly related to the extent of weight loss.
authors.affiliation: Department of Internal Medicine and Therapeutics, Clinica Medica II, Vascular and Metabolic Diseases, IRCCS Policlinico San Matteo Foundation, Pavia, Italy. Electronic address: a.falchi@smatteo.pv.it.
authors.forename: Anna Giulia
authors.initials: AG
authors.lastname: Falchi
authors.affiliation: Department of Internal Medicine and Therapeutics, Clinica Medica II, Vascular and Metabolic Diseases, IRCCS Policlinico San Matteo Foundation, Pavia, Italy.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Grecchi
authors.affiliation: Department of Internal Medicine and Therapeutics, Clinica Medica II, Vascular and Metabolic Diseases, IRCCS Policlinico San Matteo Foundation, Pavia, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Muggia
authors.affiliation: Clinical Epidemiology and Biometric Unit, IRCCS Policlinico S. Matteo Foundation, Pavia, Italy.
authors.forename: Carmine
authors.initials: C
authors.lastname: Tinelli
mesh_terms: D000328:Adult; D001823:Body Composition / Q000502:physiology; D017097:Electric Impedance; D004562:Electrocardiography; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000178:diet therapy / Q000503:physiopathology*; D017678:Sex Distribution; D016896:Treatment Outcome; D015431:Weight Loss / Q000502:physiology*
keywords: Obesity; P wave dispersion; Weight loss