title: QRS analysis using wavelet transformation for the prediction of response to cardiac resynchronization therapy: a prospective pilot study.
abstract: BACKGROUND
  Wider QRS and left bundle branch block morphology are related to response to cardiac resynchronization therapy (CRT). A novel time-frequency analysis of the QRS complex may provide additional information in predicting response to CRT.
  
  
  METHODS
  Signal-averaged electrocardiograms were prospectively recorded, before CRT, in orthogonal leads and QRS decomposition in three frequency bands was performed using the Morlet wavelet transformation.
  
  
  RESULTS
  Thirty eight patients (age 65±10years, 31 males) were studied. CRT responders (n=28) had wider baseline QRS compared to non-responders and lower QRS energies in all frequency bands. The combination of QRS duration and mean energy in the high frequency band had the best predicting ability (AUC 0.833, 95%CI 0.705-0.962, p=0.002) followed by the maximum energy in the high frequency band (AUC 0.811, 95%CI 0.663-0.960, p=0.004).
  
  
  CONCLUSIONS
  Wavelet transformation of the QRS complex is useful in predicting response to CRT.
authors.affiliation: First Department of Cardiology, AHEPA University Hospital, Aristotle University Medical School, Thessaloniki, Greece.
authors.forename: Vassilios P
authors.initials: VP
authors.lastname: Vassilikos
authors.affiliation: First Department of Cardiology, AHEPA University Hospital, Aristotle University Medical School, Thessaloniki, Greece; Cardiology Department, Royal Brompton Hospital, London, UK. Electronic address: lmantziari@yahoo.com.
authors.forename: Lilian
authors.initials: L
authors.lastname: Mantziari
authors.affiliation: First Department of Cardiology, AHEPA University Hospital, Aristotle University Medical School, Thessaloniki, Greece.
authors.forename: Georgios
authors.initials: G
authors.lastname: Dakos
authors.affiliation: First Department of Cardiology, AHEPA University Hospital, Aristotle University Medical School, Thessaloniki, Greece.
authors.forename: Vasileios
authors.initials: V
authors.lastname: Kamperidis
authors.affiliation: Laboratory of Medical Informatics, Aristotle University Medical School, Thessaloniki, Greece.
authors.forename: Ioanna
authors.initials: I
authors.lastname: Chouvarda
authors.affiliation: First Department of Cardiology, AHEPA University Hospital, Aristotle University Medical School, Thessaloniki, Greece.
authors.forename: Yiannis S
authors.initials: YS
authors.lastname: Chatzizisis
authors.affiliation: First Department of Cardiology, AHEPA University Hospital, Aristotle University Medical School, Thessaloniki, Greece.
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Kalpidis
authors.affiliation: First Department of Cardiology, AHEPA University Hospital, Aristotle University Medical School, Thessaloniki, Greece.
authors.forename: Efstratios
authors.initials: E
authors.lastname: Theofilogiannakos
authors.affiliation: First Department of Cardiology, AHEPA University Hospital, Aristotle University Medical School, Thessaloniki, Greece.
authors.forename: Stelios
authors.initials: S
authors.lastname: Paraskevaidis
authors.affiliation: First Department of Cardiology, AHEPA University Hospital, Aristotle University Medical School, Thessaloniki, Greece.
authors.forename: Haralambos
authors.initials: H
authors.lastname: Karvounis
authors.affiliation: First Department of Cardiology, AHEPA University Hospital, Aristotle University Medical School, Thessaloniki, Greece.
authors.forename: Sotirios
authors.initials: S
authors.lastname: Mochlas
authors.affiliation: Laboratory of Medical Informatics, Aristotle University Medical School, Thessaloniki, Greece.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Maglaveras
authors.affiliation: First Department of Cardiology, AHEPA University Hospital, Aristotle University Medical School, Thessaloniki, Greece.
authors.forename: Ioannis H
authors.initials: IH
authors.lastname: Styliadis
mesh_terms: D000368:Aged; D000465:Algorithms; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006333:Heart Failure / Q000175:diagnosis* / Q000517:prevention & control*; D006801:Humans; D008297:Male; D010865:Pilot Projects; D011379:Prognosis; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D058067:Wavelet Analysis
keywords: Biventricular pacing; Heart failure; Morlet wavelet transform; QRS complex; Signal processing