title: An Automatic Algorithm Based on Morphological Stability During Fast Ventricular Arrhythmias Predicts Successful Antitachycardia Pacing in ICD Patients: A Multicenter Study.
abstract: BACKGROUND
  Different types of ventricular arrhythmias (monomorphic ventricular tachycardia [VT], polymorphic VT, or ventricular fibrillation) can be detected by implantable cardiac defibrillators (ICDs) in fast VT zone. The efficacy of antitachycardia pacing (ATP) depends on the type of the treated arrhythmia. We hypothesized that an automatic algorithm based on morphological affinity of ICD far-field electrograms during tachycardia can predict ATP success and the need of shock.
  
  
  METHODS
  The algorithm was evaluated on ventricular arrhythmias recorded in CareLink ICD remote monitoring system (Medtronic Inc., Minneapolis, MN, USA). Patients were selected if first ATP programmed was a burst of eight pulses at 88% coupling interval and if a far-field electrogram was available. The algorithm calculated a stability coefficient (SC) for all their stored ATP-treated fast ventricular arrhythmia (VA) episodes (LC 200-300 ms), analyzing the morphology homogeneity of the last eight recorded far-field electrograms before ventricular arrhythmias detection.
  
  
  RESULTS
  Inclusion criteria were fulfilled by 717 patients from 29 centers. Three hundred and twenty fast VA were recorded in 103 patients. A higher SC was observed in episodes terminated with the first-ATP (0.78 [0.72-0.84] vs 0.74 [0.60-0.84]; P = 0.006). These differences were especially marked among the 62 episodes of very fast VA (CL ≤250 ms) (0.77 [0.74-0.85] vs 0.64 [0.51-0.8]; P = 0.006). In the multivariate analysis, a SC > 70% was independently associated with a higher likelihood of first-ATP success (odds ratio [OR] = 2.5; [95% confidence interval (CI) = 1.4-4.5], P = 0.001) and a lower need of shock (OR = 0.37; [95% CI = 0.2-0.7], P = 0.002).
  
  
  CONCLUSIONS
  This automatic algorithm (stability coefficient) shows that ATP therapy response can be predicted in fast ventricular arrhythmias through morphology evaluation.
authors.affiliation: Arrhythmia Unit, Cardiology Department, Ramón y Cajal Hospital, Madrid, Spain.
authors.forename: Roberto
authors.initials: R
authors.lastname: Matía
authors.affiliation: Arrhythmia Unit, Cardiology Department, Ramón y Cajal Hospital, Madrid, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Hernández-Madrid
authors.affiliation: Medtronic Ibérica, Madrid, Spain.
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Sánchez-Huete
authors.affiliation: Txagorritxu Hospital, Vitoria, Spain.
authors.forename: José Bautista
authors.initials: JB
authors.lastname: Martínez-Ferrer
authors.affiliation: Virgen de la Victoria Hospital, Málaga, Granada, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Alzueta
authors.affiliation: Santa Creu i Sant Pau Hospital, Barcelona, Spain.
authors.forename: Xavier
authors.initials: X
authors.lastname: Viñolas
authors.affiliation: Clinic of Valladolid Hospital, Valladolid, Spain.
authors.forename: Jerónimo
authors.initials: J
authors.lastname: Rubio
authors.affiliation: Donostia Hospital, Donostia, Spain.
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Porres
authors.affiliation: Canarias Hospital, Santa Cruz de Tenerife, Spain.
authors.forename: Aníbal
authors.initials: A
authors.lastname: Rodríguez
authors.affiliation: Vigo Hospital, Vigo, Spain.
authors.forename: Enrique
authors.initials: E
authors.lastname: García
authors.affiliation: Puerta de Hierro Hospital, Madrid, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Fernández-Lozano
authors.affiliation: Complejo Hospitalario Universitario de Granada, Granada, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Álvarez
authors.affiliation: Arrhythmia Unit, Cardiology Department, Ramón y Cajal Hospital, Madrid, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Moreno
mesh_terms: D000465:Algorithms; D002304:Cardiac Pacing, Artificial; D017147:Defibrillators, Implantable; D003936:Diagnosis, Computer-Assisted / Q000379:methods; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000379:methods; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013030:Spain; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000517:prevention & control*; D013813:Therapy, Computer-Assisted / Q000379:methods; D016896:Treatment Outcome; D014693:Ventricular Fibrillation / Q000175:diagnosis* / Q000517:prevention & control*
keywords: ICD; antitachycardia pacing; morphology algorithm; ventricular tachycardia