With the advent of implantable cardioverter defibrillators

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1 One-Incision Approach for Insertion of Implantable Cardioverter Defibrillators Andreas Markewitz, MD, Hans Kaulbach, MD, Soren Mattke, MD, Uwe Dorwarth, MD, Christian Weinhold, MD, Ellen Hoffmann, MD, Gerhard Steinbeck, MD, and Bruno Reichart, MD Departments of Cardiac Surgery and Cardiology, University of Munich, Grosshadern Hospital, Munich, Germany The placement of a transvenous implantable cardioverter defibrillator (lcd) system through a single infraclavicular skin incision has been a surgical goal for years. The development of a new investigational model of ICD with substantially reduced dimensions (volume, 83 cm 3 ; mass, 132 g) has made the one-incision approach a clinical reality. Between March and September 1993, 4 female and 19 male patients (mean age, 60 ± 9.6 years; range, 46 to 73 years) underwent implantation of this device for the treatment of ventricular fibrillation (n = 14) or ventricular tachycardia (n = 9). One transvenous lead was placed in the right ventricular apex and another in the left subclavian vein. A subpectoral pocket was formed in the infraclavicular area from the same incision to house the ICD generator and, if necessary, the subcutaneous patch. The mean operation time (81.5 ± 32.7 minutes; range, 54 to 195 minutes) was significantly shorter than that noted for a previous series made up of patients undergoing traditional transvenous ICD implantations. In 20 patients (87%), endovenous defibrillation without a subcutaneous patch successfully caused externally induced ventricular fibrillation to revert with a mean minimum energy output of 21.9 ± 3.5 J (range, 12 to 24 J). Endovenous defibrillation was more successful when biphasic (n = 16/17 [94%]) shocks rather than monophasic shocks (n = 4/6 [67%]) were used. No mortality, morbidity, or surgical complications were observed. These results indicate that the one-incision approach and the small size of the ICD generator can substantially facilitate ICD implantation and result in a reduction in the surgical trauma, the operation time, and the amount of material implanted. (Ann Thome Surg ) With the advent of implantable cardioverter defibrillators (ICDs), the therapeutic options have been expanded and the prognosis improved in patients with life-threatening ventricular arrhythmias [1,2]. Surgically, the ultimate goal has been to implant these devices through the same incision as that used for pacemaker implantation. Traditionally, a thoracotomy or a subxiphoid approach was the preferred technique for defibrillator implantation [1, 3-5]. However, these procedures were associated with substantial operative mortality and morbidity rates [6-8]. For editorial comment, see page In the late 1980s, the so-called nonthoracotomy lead (NTL) systems became available and these brought about a decrease in the pulmonary complication rate and a reduction in the mortality to 1% [7]. Three incisions were usually required for the implantation of these devices: one in the infraclavicular region for transvenous lead insertion, one in the lateral chest wall for the subcutaneous patch placement, and one in the paraumbilical area for implantation of the generator [6, 7, 9, 10]. Only occasionally were two incisions adequate for implanting Accepted for publication Feb 26, Address reprint requests to Dr Markewitz, Department of Cardiac Surgery, University of Munich, Grosshadern Hospital, PO Box , Munich, Germany by The Society of Thoracic Surgeons an NTL system, made possible either by using only transvenous leads [11] without the subcutaneous patch or by implanting the ICD generator in a subpectoral position [10, 12, 13]. With the availability of a new, substantially smaller ICD model, the one-incision approach has become a clinical reality. We summarize here our initial clinical experience with this new device, which may represent an essential step forward in the history of ICD implantation. Patients and Methods On March 6, 1993, we implanted a new investigational lcd device (Medtronic PCD 7219D Jewel; Medtronic Hall, Minneapolis, MN) in a patient at our institution. As of September 30, 1993, a total of 23 patients had received this ICD system. All patients had given written informed consent to implantation of this investigational device, and ethics committee approval was obtained before implantation of the first device. The criteria for selecting patients for the implantation of the new ICD model included (1) survival from at least one episode of cardiac arrest due to ventricular tachycardia or ventricular fibrillation that was not associated with acute myocardial infarction or (2) recurrent sustained ventricular tachycardia refractory to drug treatment. The mean age of the patients was 60 :': 9.6 years (range, 46 to 73 years); 4 patients were female and 19 were male. During preoperative invasive electrophysiologic testing, /94/$7.00

2 1610 MARKEWITZ ET AL!CD IMPLANTATION Ann Thorac Surg 14 patients were found to have inducible ventricular fibrillation and 9 patients, inducible ventricular tachycardia. Thirteen patients had coronary artery disease; 8 of these patients had suffered one (n = 5) to three (n = 1) myocardial infarctions. Seven patients had undergone coronary artery bypass grafting from 3 months to 7 years before implantation of the ICD device (mean, 2.3 ± 2.5 years). None of these patients was considered to be an appropriate candidate for initial or redo coronary artery bypass grafting. Of the remaining patients, 4 suffered from dilative cardiomyopathy, 2 had right ventricular dysplasia, and 1 had a hypertrophic nonobstructive cardiomyopathy. Two patients had preexisting myocarditis. In 1 patient who had undergone aortic valve replacement (Bjork-Shiley tilting disc valve, size 25) 21 years ago, ventricular arrhythmia most likely developed as the result of left ventricular hypertrophy. Cardiac catheterization before ICD implantation revealed a mean left ventricular ejection fraction of 0.42 ± 0.14, with 10 patients having an ejection fraction of less than 0.40, and 5 of these having an ejection fraction of less than The Device The PCD 7219D Jewel is a fourth-generation implantable arrhythmia control device possessing extensive programmable and diagnostic functions, and capable of delivering biphasic waveform shocks and storing electrograms. Upon the detection of ventricular tachycardias or episodes of ventricular fibrillation, the antitachycardia pacing, cardioversion, or defibrillation therapies programmed into the device are delivered. The maximum defibrillation energy output of the device is 34 J. In addition, the device provides bradycardia backup ventricular pacing. The PCD 7219D Jewel device has a projected longevity of 4.5 years and the capacity to deliver up to 300 shocks. The dimensions of the generator are 88 X 63 X 18 mm (height X length X thickness); it has a volume of 83 em" and a mass of 132 g. These physical characteristics show that there has been a favorable trend toward miniaturization of the device: the preceding ICD model (PCD 7217) had a height X length X thickness of 101 X 70 X 20 mm, a volume of 113 em", and a mass of 197 g. The PCD 7219D Jewel device is usually implanted with two transvenous endocardial leads and, if necessary, a subcutaneous patch. Implantation Procedure All implantations were performed with the patients under general anesthesia. A single transverse skin incision that was approximately 8 cm long was made in the left infraclavicular region, 3 to 5 cm below the clavicle. Venous access was obtained by cephalic vein cutdown or through a subclavian vein puncture. A tripolar endocardial screw-in lead (Medtronic 6936) was inserted and placed in the right ventricular apex for the purpose of bipolar pacing and sensing as well as endovenous defibrillation, mostly used as a defibrillation cathode. Another unipolar lead was introduced and positioned in the left subclavian vein for the purpose of providing endovenous defibrillation (Medtronic 6933), usually em- Fig 1. Chest roentgenogram ofa patient with an endovenous implantable cardioverter defibrilator. The defibrillation anode is placed in the left subclavian vein and the defibrillation cathode in the right ventricle. ploying the defibrillation anode (Fig 1). The amplitude and slew rate of the intraventricular signal as well as the pacing impedance and threshold were obtained using an external pacing system analyzer (Medtronic PSA 5311). After T-wave oversensing had been ruled out, a lowenergy test shock (0.6 J) was delivered to determine the impedance of the defibrillation pathway. Defibrillation efficacy was tested by inducing ventricular fibrillation externally, either by using AC stimulation or an external defibrillator implant support device (Medtronic DISD 5358). Proper detection of ventricular defibrillation was verified by the DISD 5358, and a defibrillation shock delivered. Before proceeding with ICD implantation, three shocks out of four attempts had to successfully revert ventricular fibrillation at energies of 24 J or less. In an initial group of 10 patients, 6 patients were randomized to receive a monophasic waveform shock and 4, a biphasic waveform shock, in accordance with the study randomization protocol. Only biphasic shocks were used in the remaining 13 patients. If transvenous defibrillation between the right ventricular and the subclavian lead failed to cause the ventricular fibrillation to revert, an external transthoracic defibrillator was used to terminate ventricular fibrillation and a subcutaneous patch implanted. The pocket for housing the subcutaneous patch and the ICD generator was formed below the major pectoral muscle. The patch was inserted into the generator pocket (Fig 2) and defibrillation efficacy testing repeated. The defibrillation threshold is defined as the lowest possible energy that successfully terminates ventricular fibrillation. An average of 4.6 ± 1.8 testing episodes (range, 3 to 9) were necessary to determine the

3 Ann Thorae Surg MARKEWITZ ET AL 1611 ICD IMPLANTATION of a combination of vancomycin and imipenem-cilastatin, and was maintained for 48 hours. Patients were extubated immediately after the operation. Results Clinical Results In the 23 patients who underwent implantation of the ICD device, there was no operative mortality or morbidity. Perioperative surgical complications such as early infection and lead dislodgement were not encountered. Fig 2. Chest roentgenogram of a patient with a transvenous implantable cardioverter defibrillator that required insertion of a subcutaneous patch. The patch is positioned in a subpectoral pocket underneath the generator of the device. defibrillation threshold. Once all defibrillation thresholds were found to be in the same range, testing was limited to a minimum in the remaining 13 patients and no defibrillation thresholds were determined. For these patients, the lowest energy tested is reported, which is usually higher than the defibrillation threshold. After completion of the testing, several sutures were used to fix the leads at the venous entry site and the leads connected to the ICD generator. The device was inserted into the preformed subpectoral pocket and the wound closed (Fig 3). A drainage tube was placed in the pocket and removed 24 to 48 hours postoperatively. Drainage was implemented to prevent hematomas from forming in the pocket, which might cause infection to develop. The perioperative prophylactic antibiotic regimen consisted Fig 3. Patient who underwent coronary artery bypass grafting 2 years before subpectoral implantation of a cardioverter defibrillator. The generator causes nearly no bulging of the prepectoral tissue. Venous Access Cephalic cutdown was suitable for the insertion of two leads in 4 patients, and for one lead in 2 patients. Subclavian puncture was required in 19 patients. No complications related to the venous access were observed. Ventricular Signals The mean R-wave amplitude was 14.6 ± 6.1 mv (range, 3 to 25 my) with a mean slew rate of 1.58 ± 0.97 VIs (range, 0.2 to 4.1 VIs). Pacing Impedance and Threshold The mean pacing impedance was 719 ± 122 ohms (range, 480 to 1,031 ohms) and the mean pacing threshold was 0.9 ± 004 V (range, 0.3 to 1.5 V) at a 0.5-ms pulse width. Defibrillation Efficacy A monophasic shock was used for defibrillation in 6 patients and a biphasic shock, in 17 patients. Endovenous defibrillation without a subcutaneous patch was successful in 4 of the 6 patients (67%) in whom the monophasic shock was used and in 16 of the 17 patients (94%) in whom the biphasic shock was used. The mean monophasic defibrillation threshold in 4 patients was 22.5 ± 3 J (range, 18 to 24 J) and the mean biphasic defibrillation threshold in 4 patients was 19.5 ± 5.7 J (range, 12 to 24 J). In 12 patients, the lowest energy tested was 22.5 ::':: 2.7 J (18 to 24 J) when the biphasic waveform shock was used exclusively. Three patients required insertion of a subcutaneous patch. Defibrillation was successfully achieved with an energy of 24 J in 2 patients, representing the defibrillation threshold in 1 patient and the lowest energy tested in the other patient. In the third patient, a defibrillation threshold of 34 J was accepted because the patient had refused epicardial patch placement after having undergone coronary artery bypass grafting 2 years before. The high defibrillation threshold was attributed to the ongoing amiodarone therapy in this patient. Operation Time The mean operation time was 81.5 ± 32.7 minutes (range, 54 to 195 minutes), which was significantly shorter than that reported for a previous series of 73 patients who underwent implantation of a traditional NTL system involving the creation of an abdominal generator pocket (9504 ± 31.9 minutes; range, 45 to 205 minutes).

4 1612 MARKEWITZ ET AL!CD IMPLANTATION Ann Thorae Surg Comment Our preliminary clinical experience with the smallest ICD device available today has demonstrated that the surgical goal of one-incision ICD implantation has been achieved, with a considerable reduction in the operation time an ultimate benefit. There are three other reports in the literature of the successful subpectoral implantation of an ICD device in obese patients in which two incisions were employed [10, 12, 13]. With the advent of the PCD 7219D Jewel device, single-incision subpectoral ICD implantation is now possible in all patients In addition, we found that transvenous defibrillation without the need for a subcutaneous patch is possible in most patients. Endovenous defibrillation without the need for a subcutaneous patch was successful in 87% of our patients, and this is within the range reported by Winter and associates [11], who found endovenous defibrillation to be successful in 18 of 19 patients (95%) in whom the Endotak lead system (Cardiac Pacemaker, St. Paul, MN) was installed. In light of the rapid technologic progress that has taken place within the recent few years, it may even prove possible in the near future to perform ICD implantation with the patient under local anesthesia, with general anesthesia used only for the testing episodes and the preparation of the submuscular pocket. This will certainly be achieved if further improvements in lead and generator technology permit the number of testing episodes to be reduced to one or two and if an additional decrease in the size of the devices allows subcutaneous implantation of the generator. Our placement of the second defibrillation lead in the left subclavian vein and the subcutaneous patch in the anterior chest wall is unusual as compared with the methods described in other reports [6, 7, 9-11]. However, with the second defibrillation lead in the left subclavian vein, the success rate of transvenous defibrillation without the patch was significantly better than those cited in these other reports. In addition, we found the defibrillation efficacy associated with the placement of the subcutaneous patch in the anterior chest wall did not differ from that observed for placement in the common position in the lateral chest wall [14]. This observation was recently confirmed by Adler and associates [15]. In our experience, the anterior chest wall patch position is less prone to complications such as patch crinkling than is the lateral chest wall position [14]. With this advantage, together with the lack of difference in defibrillation efficacy, the anterior chest wall may represent an attractive alternative site for subcutaneous patch placement. We did not observe any surgical complications related to implantation of the new ICD device. This may be attributed to the small numbers of patients involved and the short follow-up period. However, this device involves the implantation of substantially less foreign material than that involved in the placement of the former ICD systems. Both the surgical trauma and the operation time are lessened with the one-incision approach versus those seen for the common surgical technique employed for the NTL systems [6]. These factors may reduce the susceptibility to infections, as has been demonstrated for patients who undergo transvenous ICD implantation versus those who undergo epicardial ICD implantation [16]. The defibrillation thresholds reported in this study are higher than those reported for other studies in which the same [7] or another NTL device using the Endotak lead system [9, 11] was used. We cannot explain this difference. It may stem from the fact that implanting an endovenous NTL system without a subcutaneous patch is a more important goal for us than achieving defibrillation thresholds below a certain value. In general it is not our policy to determine certain defibrillation thresholds but to successfully terminate externally induced ventricular fibrillation with an energy of 18 or 24 J. The advantage of this relatively high limit is that only a limited number of testing episodes are necessary; this was usually three but never exceeded nine in our patients. This implies that the induction of ventricular fibrillation in patients undergoing ICD implantation who frequently show an impairment in left ventricular function [17] can be kept to a minimum, which may have contributed to the absence of mortality and morbidity in our patients. In addition, the operation time is shortened. Because of the small number of patients investigated, we did not find a significant difference in the effect of monophasic and biphasic shocks. However, endovenous defibrillation without a subcutaneous patch was substantially more successful when a biphasic shock was used as opposed to a monophasic shock (94% versus 67%), indicating that biphasic shocks usually have a higher defibrillation efficacy. In summary, our preliminary clinical experience has shown that the new smaller ICD device can be implanted through a single infraclavicular incision in all patients. In addition, a subcutaneous patch is needed in only a minority of patients, resulting in a significant reduction in the surgical trauma, the operation time, and the amount of foreign material implanted. This may help simplify ICD implantation. Patient comfort is also improved as the result of the small size of the device, and the cosmetic results obtained with the one-incision approach are favorable. The careful preparation of the manuscript by Mrs Chirata Rinea, Miss Michaela Schraml, and Mrs Carole Hamilton, as well as the expert technical assistance provided by Hans-jurgen Geywitz, PhD, are gratefully acknowledged. References 1. Mirowski M, Reid PR, Mower MM, et al. Termination of malignant ventricular arrhythmias with an implanted automatic defibrillator in human beings. N Engl J Med 1980;303: Nisam S, Mower MM, Thomas A, Hauser R. Patient survival comparison in three generations of automatic implantable cardioverter defibrillators: review of 12 years, patients. 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5 Ann Thorac Surg MARKEWITZ ET AL 1613 ICD IMPLANTATION 3. Watkins L, Mirowski M, Mower MM, et al. Automatic defibrillation in man: the initial surgical experience. J Thorac Cardiovasc Surg 1981;82: Lawrie GM, Griffin JC, Wyndham CRC, et al. Epicardial implantation of the automatic implantable defibrillator by left subcostal thoracotomy. PACE 1984;7: Watkins L, Mirowski M, Mower MM, et al. Implantation of the automatic defibrillator: the subxiphoid approach. Ann Thorac Surg 1982;34: Frame R, Brodman R, Gross J, et al. Initial experience with transvenous implantable cardioverter defibrillator lead systems: operative morbidity and mortality. PACE 1993;16: Saksena S, The PCD Investigators, Participating Institutions. Defibrillation thresholds and perioperative mortality associated with endocardial and epicardial defibrillation lead systems. PACE 1993;16: Grimm W, Flores BF, Marchlinski FE. Complications of implantable cardioverter defibrillator therapy: follow-up of 241 patients. PACE 1993;16: Trappe HJ, Klein H, Fieguth HG, Kielblock B, Wenzlaff P, Lichtlen PRo Initial experience with a new transvenous defibrillation system. PACE 1993;16: Block M, Hammel D, Isbruch F, et al. Results and realistic expectations with transvenous lead systems. PACE 1992;15: U Winter J, Vester EG, Kuhls S, et al. Defibrillation energy requirements with single endocardial (EndotakTM) lead. PACE 1993;16: Hammel D, Block M, Borggrefe M, Konertz W, Breithard G, Scheld HH. Implantation of a cardioverter/defibrillator in the subpectoral region combined with a nonthoracotomy lead system. PACE 1992;15: Camunas J, Mehta D, Ip J, Pe E, Gomes JA. Total pectoral implantation: a new technique for implantation of transvenous defibrillator lead systems and implantable cardioverter defibrillator. PACE 1993;16: Markewitz A, Kaulbach H, Schmoeckel M, et al. Alternative superior vena cava lead and subcutaneous patch positions for successful implantable cardioverter-defibrillator therapy [Abstract]. PACE 1993;16: Adler SW, Remole SC, Lurie KG, et al. Prepectoral anode electrode position optimizes defibrillation efficacy for a "unipolar" transvenous implantable defibrillator [Abstract]. PACE 1993;16: Kleman JM, Pinski SL, Helguera ML, et al. An intention to treat analysis of transvenous and epicardial ICD system implantation [Abstract]. PACE 1993;16: Mehta D, Saksena S, Krol RB, et al. Device use patterns and clinical outcome of implantable cardioverter defibrillator patients with moderate and severe impairment of left ventricular function. PACE 1993;16: Bound volumes available to subscribers Bound volumes of the 1994 issues of The Annals of Thoracic Surgery are available only to subscribers from the Publisher. The cost is $96.00 (outside US add $25.00 for postage) for volumes 57 and 58. Each bound volume contains a subject and author index, and all advertising is removed. The binding is durable buckram with the name of the journal, volume number, and year stamped on the spine. Payment must accompany all orders. Contact Elsevier Science Inc, 655 Avenue of the Americas, New York, NY 10010; or telephone (212) (facsimile: (212) ).