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Determinants of successful nonthoracotomy cardioverter-defibrillator implantation: experience in 101 patients using
R Brooks1, H Garan, D Torchiana
1Cardiac Unit, Massachusetts General Hospital, Harvard Medical School, Boston 02114.
Insights
Successful nonthoracotomy cardioverter-defibrillator implantation is achievable in most patients. Smaller cardiac size and female gender are key predictors for successful implantation of these life-saving devices.
Area of Science:
- Cardiology
- Medical Devices
- Surgical Innovation
Background:
- Traditional cardioverter-defibrillator implantation required invasive thoracotomy or sternotomy.
- Advancements include nonthoracotomy lead systems with transvenous coil and subcutaneous patch electrodes.
- Factors influencing the success of this minimally invasive approach were previously undefined.
Purpose of the Study:
- To identify predictors of successful nonthoracotomy cardioverter-defibrillator implantation.
- To evaluate the feasibility of a less invasive implantation strategy.
Main Methods:
- Prospective analysis of 101 consecutive patients undergoing initial nonthoracotomy cardioverter-defibrillator implantation.
- Identification of factors associated with successful implantation versus those requiring thoracotomy.
Main Results:
- Nonthoracotomy implantation succeeded in 71% of patients; 29% required thoracotomy.
- Predictors of success included smaller cardiac size, smaller cardiothoracic ratio, shorter QRS duration, female gender, ventricular fibrillation, and smaller left ventricular size.
- Multivariate analysis identified smaller cardiac size and female gender as significant predictors.
Conclusions:
- A majority of patients can receive a cardioverter-defibrillator via a nonthoracotomy approach.
- Smaller cardiac size and female gender are strongly associated with successful nonthoracotomy implantation.
Objectives:
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.