title: Prediction of QTc length as function of BMI: a clinical tool to establish arrhythmias risk in obesity.
abstract: OBJECTIVE
  Among the electrocardiographic alterations used for stratifying the cardiovascular risk of life threatening arrhythmias (LFA) and sudden death (SD) there is the increment of the corrected QT(QTc). This increment is usually observable in obese patients (OP). Therefore, a study has been planned to investigate the possibility to predict QTc values in OP simply by detecting the best fitting regression method that represents the relationship between QTc and Body Mass Index (BMI).
  
  
  METHODS
  The study has been carried on 144 individuals classified as a function of their BMI in normoponderal subjects (NPS, No. 24; F/M=15/9; BMI=21.8± 1.7 kg/m(2)), Class I OP (No. 24; F/M=17/7; BMI=32.5± 1.1 kg/m(2)); Class II OP (No. 24; F/M=17/7; BMI=37.7± 1.5 kg/m(2)). Class IIIa (No. 24, F/M=15/9; BMI=44.4± 27 kg/m(2)), Class IIIb (No. 24; F/M=14/10; BMI 54.3± 2.7 kg/m(2)); Class IIIc (No. 24; F/M=14/10; BMI=63.3± 4.5 kg/m(2)). Both linear and non-linear fitting modes have been tested.
  
  
  RESULTS
  While the BMI progressively increases in classified OP, the QTc shows an intergroup difference that is not only not constant but also declining in Class IIIc obesity. The optimal regressive model was found to be the following fourth order degree polynomial: QTc=317,15+(7,47xBMI)+(-0,28*BMI(2))+(0,005xBMI(3))+ (-0,00003xBMI(4)).
  
  
  CONCLUSIONS
  By entering the BMI of a given OP into the above-cited formula, the QTc can be easily predicted and compared to that of NPS. Importantly, to have the possibility for a pre-electrocardiographic estimation of QTc allows all the medical and paramedical personnel, involved in the multidisciplinary treatment of obesity, to immediately establish the cardiovascular risk in the OP under observation.
authors.affiliation: Department of Internal Medicine and Medical Specialities, University of Rome Sapienza, Italy. mario.curione@uniroma1.it
authors.forename: M
authors.initials: M
authors.lastname: Curione
authors.forename: A
authors.initials: A
authors.lastname: Tego
authors.forename: D
authors.initials: D
authors.lastname: Capoccia
authors.forename: M
authors.initials: M
authors.lastname: Varrenti
authors.forename: E
authors.initials: E
authors.lastname: Baiocco
authors.forename: S
authors.initials: S
authors.lastname: Salvatore
authors.forename: C
authors.initials: C
authors.lastname: Maglio
authors.forename: F
authors.initials: F
authors.lastname: Leonetti
mesh_terms: D000328:Adult; D001145:Arrhythmias, Cardiac / Q000453:epidemiology / Q000209:etiology*; D015992:Body Mass Index; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications* / Q000503:physiopathology*; D011237:Predictive Value of Tests; D012044:Regression Analysis; D018570:Risk Assessment