title: Determinants of successful nonthoracotomy cardioverter-defibrillator implantation: experience in 101 patients using two different lead systems.
abstract: OBJECTIVE
  This study was conducted to identify the determinants of successful nonthoracotomy cardioverter-defibrillator implantation.
  
  
  BACKGROUND
  Until recently, either median sternotomy or thoracotomy was necessary to implant the electrodes used for internal cardioverter-defibrillator systems. A number of manufacturers have developed nonthoracotomy lead systems comprising two transvenous coil electrodes and a subcutaneous patch electrode. At present, the factors associated with the success or failure of a nonthoracotomy approach are unknown.
  
  
  METHODS
  A total of 101 consecutive patients requiring a cardioverter-defibrillator underwent an initial nonthoracotomy approach. Factors associated with successful nonthoracotomy implantation were prospectively determined.
  
  
  RESULTS
  A nonthoracotomy system was implanted in 72 (71%) of 101 patients. Twenty-nine patients (29%) required thoracotomy. Univariate predictors of successful nonthoracotomy implantation included smaller cardiac size (p < 0.0001), smaller cardiothoracic ratio (p < 0.0002), QRS duration < 120 ms (p = 0.003), female gender (p = 0.006), ventricular fibrillation as the presenting arrhythmia (p = 0.03) and smaller echocardiographic left ventricular size (p = 0.04). Multivariate predictors included smaller cardiac size (p < 0.002) and female gender (p < 0.007). Total actuarial survival over a mean (+/- SD) follow-up interval of 12 +/- 7 months was 91 +/- 0.03% and was not different in the thoracotomy and nonthoracotomy groups.
  
  
  CONCLUSIONS
  A nonthoracotomy cardioverter-defibrillator system can be implanted in a majority of patients. Smaller cardiac size and female gender are associated with a high probability of successful implantation.
authors.affiliation: Cardiac Unit, Massachusetts General Hospital, Harvard Medical School, Boston 02114.
authors.forename: R
authors.initials: R
authors.lastname: Brooks
authors.forename: H
authors.initials: H
authors.lastname: Garan
authors.forename: D
authors.initials: D
authors.lastname: Torchiana
authors.forename: G J
authors.initials: GJ
authors.lastname: Vlahakes
authors.forename: G
authors.initials: G
authors.lastname: Jackson
authors.forename: J
authors.initials: J
authors.lastname: Newell
authors.forename: B A
authors.initials: BA
authors.lastname: McGovern
authors.forename: J N
authors.initials: JN
authors.lastname: Ruskin
mesh_terms: D000206:Actuarial Analysis; D000465:Algorithms; D017147:Defibrillators, Implantable / Q000706:statistics & numerical data; D004567:Electrodes, Implanted; D004867:Equipment Design; D005260:Female; D006321:Heart / Q000033:anatomy & histology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011446:Prospective Studies; D012737:Sex Factors; D013249:Sternum / Q000601:surgery; D017180:Tachycardia, Ventricular / Q000453:epidemiology / Q000628:therapy*; D013908:Thoracotomy; D014693:Ventricular Fibrillation / Q000453:epidemiology / Q000628:therapy*