title: Usefulness of nonlinear analysis of ECG signals for prediction of inducibility of sustained ventricular tachycardia by programmed ventricular stimulation in patients with complex spontaneous ventricular arrhythmias.
abstract: BACKGROUND
  The aim of our study was to assess the effectiveness of the nonlinear analysis (NLA) of ECG in predicting the results of invasive electrophysiologic study (EPS) in patients with ventricular arrhythmias.
  
  
  METHODS
  We evaluated 25 patients with history of cardiac arrest, syncope, sustained, or nonsustained ventricular tachycardia (VT). All patients underwent electrophysiologic study (EPS) and nonlinear analysis (NLA) of ECG. The study group was compared with a control group of 25 healthy subjects, in order to define the normal range of NLA. ECG was processed in order to obtain numerical values, which were analyzed by nonlinear mathematical functions. Patients were classified through the application of a clustering procedure to the whole set of functions, and the correlation between the results of nonlinear analysis of ECG and EPS was tested.
  
  
  RESULTS
  NLA assigned all patients with negative EPS to the same class of healthy subjects, whereas the patients in whom VT was inducible had been correctly and clearly isolated into a separate cluster. In our study, the result of NLA with application of the clustering technique was significantly correlated to that of EPS (P < 0.001), and was able to predict the result of EPS, with a negative predictive value of 100% and a positive predictive value of 100%.
  
  
  CONCLUSIONS
  NLA can predict the results of EPS with good negative and positive predictive value. However, further studies are needed in order to verify the usefulness of this noninvasive tool for sudden death risk stratification in patients with ventricular arrhythmias.
authors: Department of Cardiology, Ospedale Maggiore, Crema, Italy.
authors: Ornella
authors: O
authors: Durin
authors: Claudio
authors: C
authors: Pedrinazzi
authors: Giorgio
authors: G
authors: Donato
authors: Rita
authors: R
authors: Pizzi
authors: Giuseppe
authors: G
authors: Inama
mesh_terms: D000328:Adult; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000628:therapy; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D016022:Case-Control Studies; D016000:Cluster Analysis; D004562:Electrocardiography / Q000379:methods*; D015716:Electrocardiography, Ambulatory / Q000379:methods; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017711:Nonlinear Dynamics; D011237:Predictive Value of Tests; D011336:Probability; D012016:Reference Values; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D015996:Survival Rate; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000401:mortality / Q000628:therapy*; D016896:Treatment Outcome