Determinants of successful nonthoracotomy cardioverter-defibrillator implantation: experience in 101 patients using two different lead systems.
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.
Brooks
R
R
Cardiac Unit, Massachusetts General Hospital, Harvard Medical School, Boston 02114.
Garan
H
H
Torchiana
D
D
Vlahakes
G J
GJ
Jackson
G
G
Newell
J
J
McGovern
B A
BA
Ruskin
J N
JN
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*