title: Optimized pacing mode for hypertrophic cardiomyopathy: Impact of ECG fusion during pacing.
abstract: BACKGROUND
  Electrocardiographic (ECG) fusion with intrinsic QRS could reduce the benefit of atrial synchronous biventricular pacing (AS-BiVP) in patients with hypertrophic obstructive cardiomyopathy (HOCM).
  
  
  OBJECTIVE
  The purpose of this study was to assess the benefit of AS-BiVP and the influence of ECG fusion for reduction of left ventricular outflow tract gradient (LVOTG) in these patients.
  
  
  METHODS
  Twenty-one symptomatic HOCM patients with severe LVOTG were included. Twelve patients were evaluated retrospectively for the prevalence of fusion and its influence on outcomes after AS-BiVP. Eleven patients (2 of the first population were also evaluated retrospectively) were prospectively included to evaluate the benefit of performing atrioventricular node ablation (AVNA) to achieve full ventricular capture if fusion was present during AS-BiVP.
  
  
  RESULTS
  Seven of the first 12 patients (58%) had ECG fusion. After 54 ± 24 months of AS-BiVP, the presence of fusion was associated with lower values for reduction of resting, dynamic LVOTG and New York Heart Association (NYHA) class. In the prospectively evaluated patients, after 12 months of follow-up, resting LVOTG decreased from 98 ± 39 to 39 ± 24 mm Hg (P = .008); dynamic LVOTG decreased from 112 ± 38 to 60 ± 24 mm Hg (P = .013); NYHA class decreased from 2.8 ± 0.4 to 1.7 ± 0.6 (P = .014); endurance time during constant work rate cycling exercise (80% of peak oxygen consumption) increased from 399 ± 148 to 691 ± 249 seconds (P = .046); quality of life improved from 46 ± 22 to 22 ± 20 points (P = .02); and brain natriuretic peptide levels decreased from 318 ± 238 to 152 ± 118 pg/mL (P = .09). Eight of the 11 prospectively evaluated patients (73%) needed AVNA, which further decreased LVOTG from 108 ± 40 mm Hg at baseline to 89 ± 29 mm Hg after BiVP to 54 ± 22 mm Hg after AVNA (P = .003).
  
  
  CONCLUSIONS
  As-BiVP that ensures no ECG fusion, by means of AVNA when needed, appears to be the optimal pacing mode in HOCM patients.
authors.affiliation: Cardiology Department, Thorax Institute, Hospital Clinic, University of Barcelona, Catalonia, Spain. Electronic address: berruezo@clinic.ub.es.
authors.forename: Antonio
authors.initials: A
authors.lastname: Berruezo
authors.affiliation: Cardiology Department, Thorax Institute, Hospital Clinic, University of Barcelona, Catalonia, Spain.
authors.forename: Diego
authors.initials: D
authors.lastname: Penela
authors.affiliation: Pneumology Department, Thorax Institute, Hospital Clinic, University of Barcelona, Catalonia, Spain; Centro de Investigación en Red de Enfermedades Respiratorias (CibeRes), Palma de Mallorca, Spain.
authors.forename: Felip
authors.initials: F
authors.lastname: Burgos
authors.affiliation: Cardiology Department, Thorax Institute, Hospital Clinic, University of Barcelona, Catalonia, Spain.
authors.forename: Reinder
authors.initials: R
authors.lastname: Evertz
authors.affiliation: Cardiology Department, Thorax Institute, Hospital Clinic, University of Barcelona, Catalonia, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Fernández-Armenta
authors.affiliation: Pneumology Department, Thorax Institute, Hospital Clinic, University of Barcelona, Catalonia, Spain; Centro de Investigación en Red de Enfermedades Respiratorias (CibeRes), Palma de Mallorca, Spain.
authors.forename: Josep
authors.initials: J
authors.lastname: Roca
authors.affiliation: Cardiology Department, Thorax Institute, Hospital Clinic, University of Barcelona, Catalonia, Spain.
authors.forename: Ada
authors.initials: A
authors.lastname: Doltra
authors.affiliation: Cardiology Department, Thorax Institute, Hospital Clinic, University of Barcelona, Catalonia, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Acosta
authors.affiliation: Cardiology Department, Thorax Institute, Hospital Clinic, University of Barcelona, Catalonia, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Francino
authors.affiliation: Cardiology Department, Thorax Institute, Hospital Clinic, University of Barcelona, Catalonia, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Sitges
authors.affiliation: Pneumology Department, Thorax Institute, Hospital Clinic, University of Barcelona, Catalonia, Spain.
authors.forename: Xavi
authors.initials: X
authors.lastname: Alsina
authors.affiliation: Cardiology Department, Hospital Sant Pau I Santa Tecla, Tarragona, Catalonia, Spain.
authors.forename: Augusto
authors.initials: A
authors.lastname: Ordoñez
authors.affiliation: Arrhythmia Section, Cardiology Department, Hospital Germans Trias i Pujol de Badalona, Catalonia, Spain.
authors.forename: Roger
authors.initials: R
authors.lastname: Villuendas
authors.affiliation: Department of Medical Sciences, University of Girona, Catalonia, Spain and Cardiology Service, Hospital Josep Trueta, Girona, Catalonia, Spain.
authors.forename: Ramón
authors.initials: R
authors.lastname: Brugada
authors.affiliation: Cardiology Department, Thorax Institute, Hospital Clinic, University of Barcelona, Catalonia, Spain.
authors.forename: Lluis
authors.initials: L
authors.lastname: Mont
authors.affiliation: Cardiology Department, Thorax Institute, Hospital Clinic, University of Barcelona, Catalonia, Spain.
authors.forename: Josep
authors.initials: J
authors.lastname: Brugada
mesh_terms: D055011:Ablation Techniques / Q000009:adverse effects / Q000379:methods; D000328:Adult; D000368:Aged; D001283:Atrioventricular Node / Q000503:physiopathology / Q000601:surgery; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D024741:Cardiomyopathy, Hypertrophic, Familial / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery; D018618:Echocardiography, Doppler, Color / Q000379:methods; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013030:Spain; D016896:Treatment Outcome; D014694:Ventricular Outflow Obstruction / Q000175:diagnosis / Q000209:etiology / Q000601:surgery
keywords: Atrioventricular node ablation; Biventricular stimulation; Hypertrophic cardiomyopathy; Left ventricular outflow tract gradient; Pacing