title: Reduction of inappropriate anti-tachycardia pacing therapies and shocks by a novel suite of detection algorithms in heart failure patients with cardiac resynchronization therapy defibrillators: a historical comparison of a prospective database.
abstract: OBJECTIVE
  Implantable cardioverter defibrillators improve survival of patients at risk for ventricular arrhythmias, but inappropriate shocks occur in up to 30% of patients and have been associated with worse quality of life and prognosis. In heart failure patients with cardiac resynchronization therapy defibrillators (CRT-Ds), we evaluated whether a new generation of detection and discrimination algorithms reduces inappropriate shocks.
  
  
  RESULTS
  We analysed 1983 Medtronic CRT-D patients (80% male, 67 ± 10 years), 1368 with standard devices (Control CRT-D) and 615 with new generation devices (New CRT-D). Expert electrophysiologists reviewed and classified the electrograms of all device-detected ventricular tachycardia/fibrillation episodes. Total follow-up was 3751 patients-years. Incidence of inappropriate shocks at 1 year was 2.8% [95% confidence interval (CI) = 2.0-3.5] in Control CRT-D and 0.9% (CI = 0.4-2.2) in New CRT-D (hazard ratio = 0.37, CI = 0.21-0.66, P < 0.001). In New CRT-D, inappropriate shocks were reduced by 77% [incidence rate ratio (IRR) = 0.23, CI = 0.16-0.35, P < 0.001] and inappropriate anti-tachycardia pacing by 81% (IRR = 0.19, CI = 0.11-0.335, P < 0.001). Annual rate per 100 patient-years for appropriate VF detections was 3.0 (CI = 2.1-4.2) in New CRT-D and 3.2 (CI = 2.1-5.0) in Control CRT-D (P = 0.68), for syncope was 0.4 (CI = 0.2-0.9) in New CRT-D and 0.7 (CI = 0.5-1.0) in Control CRT-D (P = 0.266), and for death was 1.0 (CI = 0.6-1.6) in New CRT-D and 3.5 (CI = 3.0-4.1) in Control CRT-D (P < 0.001).
  
  
  CONCLUSIONS
  Detection and discrimination algorithms used in new generation CRT-D significantly reduced inappropriate shocks when compared with standard CRT-D. This result, with no compromise on VF sensitivity or risk of syncope, has important implications for patients' quality of life and prognosis.
authors.affiliation: 'A De Gasperis' Cardiac Department, Niguarda Ca' Granda Hospital, Piazza Ospedale Maggiore, 3, 20162 Milano, Italy maurizio.lunati@ospedaleniguarda.it.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Lunati
authors.affiliation: S. Maria della Misericordia Hospital, Udine, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Proclemer
authors.affiliation: University of Bologna and Azienda Ospedaliera S.Orsola-Malpighi, Bologna, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Boriani
authors.affiliation: Fondazione Policlinico S. Matteo IRCCS, Pavia, Italy Ospedale Maggiore, Crema (Cremona), Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Landolina
authors.affiliation: 'A De Gasperis' Cardiac Department, Niguarda Ca' Granda Hospital, Piazza Ospedale Maggiore, 3, 20162 Milano, Italy.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Locati
authors.affiliation: Fondazione Policlinico S. Matteo IRCCS, Pavia, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Rordorf
authors.affiliation: S. Maria della Misericordia Hospital, Udine, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Daleffe
authors.affiliation: San Filippo Neri Hospital, Rome, Italy.
authors.forename: Renato Pietro
authors.initials: RP
authors.lastname: Ricci
authors.affiliation: Santa Maria del Carmine Hospital, Rovereto, Italy.
authors.forename: Domenico
authors.initials: D
authors.lastname: Catanzariti
authors.affiliation: Azienda Ospedaliera Universitaria Integrata, Verona, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Tomasi
authors.affiliation: Ospedale Garibaldi Nesima, Catania, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Gulizia
authors.affiliation: Ospedale P. Cosma, Camposampiero, Italy.
authors.forename: Maria Stella
authors.initials: MS
authors.lastname: Baccillieri
authors.affiliation: Ospedale Sacro Cuore Don Calabria, Negrar, Italy.
authors.forename: Giulio
authors.initials: G
authors.lastname: Molon
authors.affiliation: IRCCS Istituto Clinico Humanitas, Rozzano, Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Gasparini
mesh_terms: D000368:Aged; D000465:Algorithms; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects; D058409:Cardiac Resynchronization Therapy Devices; D016208:Databases, Factual; D017147:Defibrillators, Implantable; D004554:Electric Countershock / Q000009:adverse effects / Q000295:instrumentation*; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D007558:Italy; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D057216:Propensity Score; D016016:Proportional Hazards Models; D011446:Prospective Studies; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012307:Risk Factors; D012815:Signal Processing, Computer-Assisted; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000503:physiopathology / Q000517:prevention & control*; D013997:Time Factors; D016896:Treatment Outcome; D014693:Ventricular Fibrillation / Q000175:diagnosis / Q000503:physiopathology / Q000517:prevention & control*
keywords: Anti-tachycardia pacing therapies; Cardiac resynchronization therapy; Implantable cardiac defibrillators; Shock