Comparison of Right– and Left–Sided Pectoral Implantation Parameters with the Jewel Active Can Cardiodefibrillator

A total of 1,207 patients received a Medtronic jewel active, can ICD (models 721BC, 7219C), with a Transvene had in 97 centers in Europe and North America. Nineteen implants were from the right pectoral region. Patients with right–sided ICDs did not differ in terms of mean age. % male, left ventricular ejection fraction, New York Heart Association Functional Class, antiar–rhythmic drug therapy, indication for the implantable cardioverter defihrillator, and R wave values at implantation, but tended to have slightly higher pacing thresholds (1.2 ± 0.5 V vs 1.0 ± 0.6 V, P = 0.012) and higher defibrillation thresholds (14.7 ± 6.4 J vs 11.5 ± 6 J, P = 0.11) compared with patients with left sided implants. Patients with right–sided implants had a longer implantation time compared with patients with left–sided implants (118 ± 70 minutes vs 91 ± 46 minutes, P = 0.074). In follow–up, 5 patients with right–sided implantation received successful therapy for either ventricular fibrillation, (8 episodes) or ventricular tachycardia (5 episodes). No ineffective therapy from the device was delivered in any patients with right–sided implantation. Right–sided pectoral implants are feasible with the Medtronic Jewel active can ICD.     

The Effect of Polarity of the Initial Phase of a Biphasic Shock Waveform on the Defibrillation Threshold of Pectorally Implanted Defibrillators

The effect of initial phase polarity on the DFT of two pectorally implanted biphasic ICDs was tested in a randomized, prospective manner at the time of implantation. Twenty-two consecutive patients with VT or VF who received either the Medtronic PCD 7219C fewel device (10 patients) or PCD 7219D fewel device (12 patients) were studied. DFT testing was performed in a standard step-down manner. Both initial phase polarities—initial defibrillation current flowing from active can/SVC coil (± subcutaneous patch) to the RV coil (RV-) or from RV coil to active can/SVC coil (RV+)—were tested in random order. The mean DFT achieved with RV+ compared with RV- was lower for the 7219C patient group (6.6 ±3.1 vs 10.8 ± 5.5 J; P = 0.007). A similar trend was observed forthe 7219D group, though the difference did not reach statistical significance (12.0 ± 4.0 vs 16.3 ± 7.3 J; P = 0.07). Seven of the 10 patients in the 7219C group had a lower DFT with RV+, while the initial phase polarity made no difference in 3. In the 7219D group, 7 patients had a lower DFT using RV+, 2 patients had a lower DFT using RV-, and the initial phase polarity made no difference in 3. In conclusion, this study demonstrates that changing the polarity of the initial phase of a biphasic shock wave form can have a significant impact on the DFT achieved at the time of ICD implantation.     

Pectoral cardioverter defibrillators: comparison of prepectoral and submuscular implantation techniques

The purpose of this study was to compare the two techniques of pectoral ICD implantation, prepectoral and submuscular, performed by an electrophysiologist in the catheterization laboratory with use of general or local anesthesia in 45 consecutive patients. Over a period of 30 months, we implanted pectoral transvenous ICDs in 43 men and 2 women, aged 59 +/- 12 years, with use of general (n = 20) or local (n = 25) anesthesia in the catheterization laboratory. Patients had coronary (n = 30) or valvular (n = 4) disease, cardiomyopathy (n = 10) or no organic disease (n = 1), a mean left ventricular ejection fraction of 31%, and presented with ventricular tachycardia (n = 40) or fibrillation (n = 5). One-lead ICD systems (18 Endotak, 10 Transvene/8 Sprint, 2 EnGuard) were used in 38 patients, 2-lead (5 Transvene, 1 EnGuard) systems in 6 patients, and 1 atrioventricular lead ICD system in 1 patient. The prepectoral technique was employed in 29 patients with adequate subcutaneous tissue, while the submuscular technique was used in 16 patients who had a thin layer of subcutaneous tissue. The defibrillation threshold averaged 9-10 J in both groups and there were no differences in pace/sense thresholds. All implants were entirely transvenous with no subcutaneous patch. Biphasic ICD devices were employed in all patients. Active or hot can devices were used in 39 patients. There were no complications, operative deaths, or infections. Patients were discharged at a mean of 3 days. All devices functioned well at predis-charge testing. Over 14 +/- 8 months, 20 patients received appropriate device therapy (antitachycardia pacing or shocks). No late complications occurred. One patient died at 3 months of pump failure; there were no sudden deaths. In conclusion, for exclusive pectoral implantation of transvenous ICDs, electrophysiologists should master both prepectoral and submuscular techniques. One can thus avoid potential skin erosion or need for abdominal implantation in patients with a thin layer of subcutaneous tissue. Finally, there are no differences in pacing or defibrillation thresholds between the two techniques.     

Subpectoral Implantation of ICD Generators: Long-Term Follow-Up

A nonthoracotomy surgical approach using an endocardial electrode and combined implantation of a subcutaneous patch and the implantable cardioverter defibrillator (ICD) generator in a Subpectoral pocket has been described. We report the long-term follow-up results in patients undergoing implantation using this approach. The patient population consisted of 28 patients (22 men and 6 women) with a mean age of 59 ± 12 years. The underlying heart disease consisted of coronary artery disease in 20 patients and dilated cardiomyopathy in 8 patients. Sustained ventricular tachycardia was the mode of presentation in 16 patients and sudden cardiac death in 12 patients. The mean left ventricular ejection fraction was 31%± 6%. The lead system consisted of an 8 French bipolar passive fixation rate sensing lead positioned at the right ventricular apex, an 11 French spring coil electrode positioned at the superior vena cava-right atrial junction (surface area 700 mm²), and submuscular placement of a large patch (surface area 28 cm²) on the anterolateral chest wall near the cardiac apex via a submammary incision. A defibrillation threshold of ≤ 15 joules (J) was required for implantation. This criterion was not satisfied in five patients; thus, a limited thoracotomy was performed via the submammary incision, and the large patch was placed epicardially. The mean R wave amplitude was 12 ± 3 mV, the mean pacing threshold was 1.0 ± 0.5 V at 0.5 msec, and the mean defibrillation threshold was 12.6 ± 3 J. ICD generators implanted were the Ventak-P in 17, PCD-7217 in 5, and the Cadence V-l00 in 6 patients. These patients have been followed for a mean of 14.6 ± 6 months. There was no perioperative mortality, and none of the patients developed an infection during follow-up. Generator migration or significant discomfort requiring ICD repositioning was not observed, although one patient developed an erosion requiring surgical repair.Conclusions: Subpectoral implantation of the ICD generator is feasible and was well tolerated by all patients with an acceptable complication rate (3.5%). As the size of future generation ICDs is reduced, subpectoral implantation may become the preferred approach.     

Incidence of ICD Lead Related Complications During Long-Term Follow-Up: Comparison of Epicardial and Endocardial Electrode Systems

The aim of this study was to evaluate the longterm stability of epicardial and endocardial lead systems for third-generation cardioverter defibrillators (ICDs) and to assess the usefulness of diagnostic tools. One hundred forty patients with 61 epicardial (43.6%) and 79 nonthoracotomy systems (56.4%) were followed for 2 5 ± 19 months. A total of 18 (12.9%) lead related complications were documented. Complications of epicardial systems were detected in 10 patients (16.4%) during a follow-up time of 36 ± 8 months: crinkling of patch electrodes in 6 patients (9.8%), insulation breakage of sensing electrodes in 2 patients (3.3%), and adapter defect in 2 patients (3.3%). Eight of the patients (10.1%) with transvenous-subcutaneous systems had lead related complications during a 13 ± 6 months follow-up: fracture of the subcutaneous patch lead in 2 patients (2.5%), dislodgment of the right ventricular lead in 2 patients (2.5%), dislodgment of the superior vena cava lead in 2 patients (2.5%), insulation breakage of sensing electrodes in 1 patient (1.3%), and connector defect in 1 patient (1.3%). There was no significant difference in the incidence of lead related complications between epicardial and endocardial systems (P > 0.05). Fractures, dislodgments, and crinklings were documented within the first 8 ± 5 months by regular chest X ray. Defects of insulation, adapter, or connector were detected 22 ± 10 months after implantation and were associated with delivery of multiple inappropriate ICD therapies. An operative lead revision was indicated for 4 epicardial (6.6%) and 6 endocardial (7.6%) lead systems. Conclusions: Endocardial lead systems offer a similar long-term stability as compared to epicardial had systems. Chest X ray is the most useful tool to detect lead fracture, dislodgment. and patch crinkling. Marker recordings or real-time electrograms have not been helpful in this series to identify patients with suspected lead defects prior to the experience of inappropriate ICD discharges.     

Total Pectoral Implantation: A New Technique for Implantation of Transvenous Defibrillator Lead Systems and Implantable Cardioverter Defibrillator

We describe a new approach to tolal pectoral implantation of cardioverter defibrillators with an endocardial defibrillation lead system. Endocardial lead configuration used was an FDA approved right atrial-superior vena cavo defibriliation spring electrode, right ventricular bipolar sensing electrode, and a pectoral patch. Endocardial leads were implanted via a cephalic or an axillary venesection. Pectoral patch was placed in a sabmuscular position. In case of failure to obtain satisfactory thresholds, a small intercostal thoracofomy was performed via fhe same skin incision and patch placed over the epicardium instead of submuscular position and used with Ihe right atrial spring electrode. The device was implanted in the pectoral region, submuscularly, over the patch. Sixteen consecutive patients underwent this approach. With a submascular patch, adequate defibrillation thresholds (< 15 joules [J]) were obtained in 14 (87.5%) patients. In the other two, defibrillation thresholds of ≤ 15) were obtained with a epicardial patch. Pectoral implantation of the device was feasible in all 16 patients and none needed repositioning. Average postimplant hospital stay was 5 days. During follow-up period (average 5 months), none of the patients reported any major local symptoms and no problems have been encountered in device interrogation. Thus, total pectoral implantation of the cardioverter defibrillator including the patch, leads, and the device is feasible. Furthermore, in case of foilure to obtain adequate defibrillotjon thresholds with submuscular patch, an epicardial patch can easily be implanted and allows 100% successful defibrillation at energy levels of ≤ 15 J with right atrial patch configuration.     

Late Complications in Patients with Pectoral Defibrillator Implants with Transvenous Defibrillator Lead Systems: High Incidence of Insulation Breakdown

As the majority of ICDs with transvenous leads are now implanted in tbe pectoral region, complications associated with the technique are being identified. To determine the incidence of lead complications in patients with transvenous defibrillator leads and ICDs implanted in the pectoral region, 132 unselected consecutive patients with transvenous defibrillator leads had ICDs implanted in the pectoral region. Three lead systems were used:(1) lead system 1(45 patients) consisted of a transvenous pacing sensing lead and a superior vena cava coil with a submuscular patch used for defibrillation;(2) lead system 2(36 patients) utilized a CPI Endotak lead system: and(3) lead system 3(51 patients) utilized a Medtronic Transvene lead system. Patients were followed for 3–54 months(cumulative 2,269, mean 18 months). The average duration of follow-up with the three systems was 32, 12, and 11 months, respectively. At 30 months follow-up, all three lead systems had a low incidence of complications. However, there was a 13% overall incidence(45% actuarial incidence) of erosion of the insulation of the pacing sensing lead of system 1 at 50 months of follow-up. All lead complications were seen in patients with ICDs whose weights were > 195 g and volumes > 115 cc. The erosion was probably a consequence of the pressure by the large ICD against the lead in the pectoral pocket. Follow-up with lead systems 2 and 3 is relatively short(average 12 months) but no lead erosions were seen. Pectoral implantation of ICDs with long transvenous leads and large generators is associated with a moderate risk of late complications in the form of insulation breaks caused by pressure of the generator against the leads. The use of less redundant leads coupled with smaller ICDs will probably eliminate this complication.     

Electrophysiologist-implanted transvenous cardioverter defibrillators using local versus general anesthesia

With the advent of smaller biphasic transvenous implantable cardioverter defibrillators (ICDs) and the experience gained over the years, it is now feasible for electrophysiologists to implant them safely in the abdominal or pectoral area without surgical assistance. Throughout the years, general anesthesia has been used as the standard technique of anesthesia for these procedures. However, use of local anesthesia combined with deep sedation only for defibrillation threshold (DFT) testing might further facilitate and simplify these procedures. The purpose of this study was to test the feasibility of using local anesthesia and compare it with the standard technique of general anesthesia, during implantation of transvenous ICDs performed by an electrophysiologist in the electrophysiology laboratory. For over 4 years in the electrophysiology laboratory, we have implanted transvenous ICDs in 90 consecutive patients (84 men and 6 women, aged 58 +/- 15 years). Early on, general anesthesia was used (n = 40, group I), but in recent series (n = 50, group II) local anesthesia was combined with deep sedation for DFT testing. Patients had coronary (n = 58) or valvular (n = 4) disease, cardiomyopathy (n = 25) or no organic disease (n = 3), a mean left ventricular ejection fraction of 35%, and presented with ventricular tachycardia (n = 72) or fibrillation (n = 16), or syncope (n = 2). One-lead ICD systems were used in 74 patients, two-lead systems in 10 patients, and an AVICD in 6 patients. ICDs were implanted in abdominal (n = 17, all in group I) or more recently in pectoral (n = 73) pockets. The DFT averaged 9.7 +/- 3.6 J and 10.2 +/- 3.6 J in the two groups, respectively (P = NS) and there were no differences in pace-sense thresholds. The total procedural duration was shorter (2.1 +/- 0.5 hours) in group II (all pectoral implants) compared with 23 pectoral implants of group I (2.9 +/- 0.5 hours) (P < 0.0001). Biphasic devices were used in all patients and active shell devices in 67 patients; no patient needed a subcutaneous patch. There were six complications (7%), four in group I and two in group II: one pulmonary edema and one respiratory insufficiency that delayed extubation for 3 hours in a patient with prior lung resection, both probably related to general anesthesia, one lead insulation break that required reoperation on day 3, two pocket hematomas, and one pneumothorax. There was one postoperative arrhythmic death at 48 hours in group I. No infections occurred. Patients were discharged at a mean time of 3 days. All devices functioned well at predischarge testing. Thus, it is feasible to use local anesthesia for current ICD implants to expedite the procedure and avoid general anesthesia related cost and possible complications.     

Italian Multicenter Clinical Experience with Endocardial Defibrillation: Acute and Long-Term Results in 307 Patients

This study presents the acute and long-term results of 307 patients (267 men, mean age 57.5 years, 205 suffering from coronary artery disease, mean left ventricular ejection fraction 33.3%) with malignant ventricular tachyarrhythmias who underwent attempted transvenous ICD implantation with the CPI Endotak lead system in 37 Italian centers. Transvenous ICD implantation was ultimately accomplished in 306 (99.7%) patients. These included 19 subjects with high (< 10 J below output energy of implanted device) defibrillation threshold (DFT) at implant. One hundred sixty-four patients (53%) were implanted with the endocardial lead alone, while 142 also received an SQ patch or SQ array. The mean DFT (not always step-down DFT) at implant was 16.9 ± 5.7 joules; 15.3 ± 5.2 joules with biphasic shock and 19.6 ± 5.4 joules with monophasic shock; P < 0.0001. A significantly higher percentage of patients tested with a biphasic shock could be implanted with adequate safety margin and without an additional SQ patch or SQ array (98% and 81 %, respectively). No perioperative deaths occurred. During the mean follow-up of 14.5 ± 10.2 months, 140 patients (52%) received at least one appropriate shock. An inappropriate shock was observed in 26% of episodes. The 1- and 3-year actuarial incidence of sudden death was 2% and 4%, respectively, and that of total death was 10% and 20%, respectively. A pocket infection requiring ICD explantation occurred in 4 patients (1.4%) and an endocardial lead dislodgment in 11 patients (3.6%). Two patients (0.3%) showed a sensing pin disconnection and six patients (2.3%) had a lead insulation break. The results of this Italian multicenter trial indicate that the GPl Endotak lead system is a simple, safe, and reliable system for endocardial defibrillation. When compared to epicardial leads, it clearly reduces the perioperative mortality and morbidity, while maintaining a similar efficacy in preventing sudden death and terminating ventricular arrhythmias.     

Initial Clinical Experience with a New Small Sized Third-Generation Implantable Cardioverter Defibrillator: Results of a Multicenter Study

This study reports the acute clinical experience with the new CPI VENTAK MINI: a small sized (68 cc), implantable cardioverter defibrillator (ICD) with 33 J stored energy. Implantation of the device was attempted in 113 patients (90 men, mean age 57 ± 16 years, 64 with coronary artery disease, mean left ventricular ejection fraction 41%) with ventricular tachycardia or ventricular fibrillation (VF). All 113 patients (100%) were ultimately implanted, 12% of them for ICD replacement. Transvenous lead implantation was accomplished in all 104 patients (100%) receiving new leads, 95% of them with a single lead configuration. The safety criteria for implantation (2 consecutive VF conversions at 15 J or 3 at 20 J. in both cases without failures to convert) were demonstrated in all but 7 patients (6%). In 6 of these, safety criteria were not fully assessed while in the last patient defibriliation efficacy was not determined. Of the 104 patients with new leads, 90% underwent pectoral implantation. Of the 9 patients (9%) abdominally implanted, only 4 (4%) (3 children) were judged small sized for pectoral implant. At predischarge testing, reliable VF detection and conversion were noted in 96 of 97 patients tested. There was no perioperative mortality. At a 3.6 ± 1.3 months follow-up, 34% of the patients had a spontaneous arrhythmic event, and 24% of the patients received shocks. Clinically inappropriate therapies occurred in 8% of the episodes in which any kind of therapy was delivered. This study demonstrates the short-term clinical efficacy and safety of the new device, and that pectoral implantation can be performed in the large majority of patients.     

Defibrillation Threshold Testing in Patients with Hypertrophic Cardiomyopathy

Introduction: Implantable cardioverter‐defibrillators (ICDs) decrease sudden cardiac death in patients with hypertrophic cardiomyopathy (HCM). One of the vital aspects of ICD implantation is the demonstration that the myocardium can be reliably defibrillated, which is defined by the defibrillation threshold (DFT). We hypothesized that patients with HCM have higher DFTs than patients implanted for other standard indications. Methods: We retrospectively reviewed the medical records of patients implanted with an ICD at the University of Maryland from 1996 to 2008. All patients with HCM who had DFTs determined were included. Data were compared to selected patients implanted for other standard indications over the same time period. All patients had a dual‐coil lead with an active pectoral can system and had full DFT testing using either a step‐down or binary search protocol. Results: The study group consisted of 23 HCM patients. The comparison group consisted of 294 patients. As expected, the HCM patients were younger (49 ± 18 years vs 63 ± 12 years; P < 0.00001) and had higher left ventricular ejection fractions (66% vs 32%; P < 0.000001). The average DFT in the HCM group was 13.9 ± 7.0 Joules (J) versus 9.8 ± 5.1 J in the comparison group (P = 0.0004). In the HCM group, five of the 23 patients (22%) had a DFT ≥ 20 J compared to 19 of 294 comparison patients (6%). There was a significant correlation between DFT and left ventricle wall thickness in the HCM group as measured by echocardiography (r = 0.44; P = 0.03); however, there was no correlation between DFT and QRS width in the HCM group (r = 0.1; P = NS). Conclusions: Our results suggest that patients with HCM have higher DFTs than patients implanted with ICDs for other indications. More importantly, a higher percentage of HCM patients have DFTs ≥ 20 J and the DFT increases with increasing left ventricle wall thickness. These data suggest that DFT testing should always be considered after implanting ICDs in HCM patients. (PACE 2010; 1342–1346)     

Acute Efficacy and Chronic Follow-Up of Patients with Non-Thoracotomy Third Generation Implantahle Defibrillators

Non-thoracotomy implantation of implantable cardioverter defibrillators (ICDs) has simplified the process of device inserfion, promising to decrease associated procedural coniplications while providing sudden death protection at least equal to epicardial systems. This study presents the acute and chronic results of 110 patients who underwent attempted non-thoracotomy ICD impiuntation wiih the Medtronic Transvene lead system and PCD model 7217 or 7219. Of the 110 patients attempted, 100 (91%) had the system successfully implanted without the need for an epicar-dial patch. One patient died 1 week postoperatively of septic shock related to the implantation (0.9% perioperative mortality). During folloiv-up of 16 ± 11 months, 45% of the patients had an event detected as ventricular tachycardia; 26% of these detections were felt clinically to be due to supraventricular rhythms. Of the remainder, 87% were successfully treated with the first VT therapy, and 98% were terminated by the final therapy; 66% of the patients had at least one episode of ventricular fibrillation, of which 5% were felt to be inappropriate detections; 65% of the appropriate episodes were successfully treated with the first VF therapy, and all were converted by the final therapy. Total mortality at 6, 12, and 24 months was 3%, 11%, and 19% respectively. Only one patient had sudden cardiac death, occurring at 13 months postimplant. Overall, the non-thoracotomy lead system for this ICD displayed infrequent implant complications and proved to be reliable ai terminating arrhythmias and maintaining a low rate of sudden cardiac death in this high risk popuiation.     

Upgrade of permanent pacemakers and single chamber implantable cardioverter defibrillators to pectoral dual chamber implantable cardioverter defibrillators: indications,surgical approach,and long-term clinical results

The aim of this study was to describe the indications for upgrade of pacemakers (PMs) or single chamber (VVIR) ICDs to dual chamber (DDDR) ICDs, surgical approach, hardware hybridization, and clinical outcome. Patients with preexisting PMs or VVIR ICDs may develop indications for ICD therapy or dual chamber pacing, respectively, that can be served by DDDR ICDs that incorporate preexisting transvenous leads. Fifty-seven patients underwent upgrade from PMs (29/57) or VVIR ICDs (28/57) to pectoral DDDR ICDs. Preexisting transvenous atrial and/or ventricular leads suitable for continued use were incorporated into new DDDR ICDs in 88.5% and 100% of PM and VVIR ICD upgrades, respectively. Acceptable DFTs were achieved in 56 (98.2%) of 57 patients. Appropriate VT/VF therapies were registered among 33.3% of patients during follow-up. No shocks due to lead noise were observed in any patient with hybridized transvenous leads. Atrial far-field R wave (FFRW) oversensing occurred in 24% of DDDR ICD systems incorporating a preexisting atrial lead. FFRW was overcome by programming reduced atrial sensitivity without interfering with the normal ICD system performance in all instances. Upgrade of PMs and VVIR ICDs to pectoral DDDR ICDs is safe and technically feasible in most patients. Preexisting transvenous leads can be successfully incorporated into new DDDR ICDs, simplifying the surgical procedure, minimizing transvenous hardware, and eliminating the possibility of hazardous pacemaker-ICD interactions.     

斑点追踪技术评价右心室流出道起搏对左心室收缩同步性的影响

目的 应用超声二维斑点追踪技术比较右心室流出道(RVOT)及右心室心尖部(RVA)起搏对左心室收缩同步性的影响。 方法 将60例符合ACC/AHA起搏器植入适应证患者随机分为RVA组和RVOT组,常规将右心房电极置入右心耳处,将右心室电极分别植入RVOT间隔部及RVA。术后1周在保证心室100%起搏下进行二维斑点超声成像分析,记录左心室收缩的纵向、环向及径向应变指标。 结果 RVA组左心室收缩时纵向应变(LS)及环向应变(CS)达峰时间的最大差(TD)分别为(191.07±39.24)ms、(135.92±33.40)ms;RVOT组分别为(129.18±26.20)ms、(69.78±19.10)ms。RVA组LS及CS达峰时间标准差(SD)分别为(62.90±12.63)ms、(52.62±13.58)ms;RVOT组为(41.62±5.71)ms、(28.54±7.96)ms。两组比较,LS及CS达峰时间的TD及SD的差异均有统计学意义(P均<0.001)。RVA组与RVOT组左心室收缩时径向应变(RS)达峰时间的TD分别为(105.43±58.08)ms、(42.00±21.39)ms;SD分别为(41.98±29.48)ms、(17.08±10.46)ms。两组比较,RS的TD及SD的差异均有统计学意义(P均<0.005)。 结论 RVOT起搏时,左心室收缩同步性优于RVA起搏。     

Nontraditional Implantable Cardioverter Defibrillator Placement in Adult Patients with Limited Venous Access: A Case Series

Background: Conventional transvenous approaches for implantable cardioverter defibrillator (ICD) lead placement are not possible in some patients with limited venous access or severe tricuspid valve dysfunction. Methods: We retrospectively identified six patients who underwent ICD placement or revision requiring nontraditional alternative surgical lead placement at our institution between November 2006 and August 2008. The baseline and operative patient characteristic data were accumulated and reviewed. Results: All the patients (mean age 71 ± 3.4 years) underwent nontraditional surgical placement of epicardial ICD leads and traditional placement of ventricular epicardial bipolar pacing/sensing leads. Five patients had the distal lead tip fixed to the anterior epicardium of the right ventricular outflow tract, which was then looped under and around the ventricles, forming a “sling,” and tunneled to a left subclavicular pocket. One patient had a single unipolar subcutaneous array lead fashioned into a “loop” and placed under the inferior aspect of the ventricles. The average procedure time was 311 ± 115 minutes with a mean defibrillatory threshold (DFT) of ≤ 22 + 3 J. Post‐procedure hospitalization was 9.3 ± 4.4 days and no device‐related complications were encountered. Mean device follow‐up of 451 + 330 days showed normal function and two appropriate successful ICD discharges. Conclusion: Nontraditional alternative surgical methods for the placement of ICD systems in adult patients with limited venous access or TV dysfunction can achieve results similar to those of conventionally placed endovascular leads with limited complications and comparable DFTs in short‐term follow‐up. (PACE 2010; 33:217–225)     

Transtelephonic Monitoring and Transmission of Stored Arrhythmia Detection and Therapy Data From an Implantable Cardioverter Defibrillator

A new transtelephonic monitoring device designed for use with implantable Cardioverter defibrillators (ICDs) was evaluated. It is capable of interrogating ICDs and transmitting the following data via telephone: programmed parameters (e.g., ventricular tachycardia [VT] and ventricular fibrillation [VF] detection, therapies), number of VT and VF episodes, identification of successful therapies, the 20 cycle lengths preceding the last episode detected, the 10 cycle lengths after the last delivered therapy, battery voltage, and real-time transmission of the patient's rhythm. Eighteen patients (mean age 64 ± 17years; 15 males) were implanted with an ICD and epicardial lead system. The patients who did not live near the primary hospital were provided with this transmitter and instructed to transmit monthly and whenever presyncope, syncope, or a shock were experienced. Five hundred ten episodes of spontaneous arrhythmia (495 VT, 15 VF) were detected in 14 of 18 patients in a 24-month period and the success of each therapy (antitachycardia pacing, cardioversion 0.4-34 J, defibrillation 34 J) was analyzed. The number of therapies delivered and their success (%) in terminating the arrhythmia were: 380 ramp/86%, 116 burst/84%, 119 cardioversion/57%, and 15 defibrillations/ 100%. Sixty-three (42%) of the 152 transmissions indicated an arrhythmia. Twenty-five (16%) of the 152 were transmitted because of symptoms. Sixteen (9.7%) of 165 VT episodes could not be terminated by the full set of programmed VT therapies. Analysis of the pre- and post-episode intervals along with the patient's transmitted rhythm indicated that sinus tachycardia or atrial fibrillation were likely responsible for these episodes. The transmitted data included the real-time ECG, which provided acute rhythm status plus stored data from the ICDs memory identifying the chronic arrhythmias detected, the therapies delivered, and the number and type of successful and ineffective therapies. This information provided the clinical data to the primary physician in order to determine the effectiveness of the programmed detection and therapy parameters and in some cases recommend to the home physician modifications to the device parameters or medication adjustments for enhanced arrhythmia control. We conclude that telephone transmission of stored ICD data is feasible and useful for patient management. It may obviate the need for patients experiencing symptoms to return to a site capable of device interrogation.     

Defibrillation Energy Requirements with Single Endocardial (Endotak™) Lead

The need for thoracotomy in usually high risk patients has limited the use of the implantable cardioverter defibrillator. Initial clinical results with endocardial and subcutanous patch electrodes (SQPs) are en couraging. Using a single endocardial lead in the absence of a SQP for chronic implantation of the cardioverter defibrillator, the goal of the study was to obtain defibrillation thresholds (DFTs) of 15 Joules (J) or less and to investigate changes in DFT over time. We tested 19 consecutive patients (15 men, 4 women] age 62 ± 8.5 years with malignant ventricular arrhythmias (14 VT/5 VF). The underlying heart disease was coronary artery disease in 15 pafients, dilative cardiomyopathy in two patients, and primary electricaJ disease in two patients. Four patients had undergone previous cardiac surgery. Left ventricular ejection fraction ranged between 14% and 66% (39%± 12.6%). Pacing thresholds (0.54 ± 0.17 Vat 0.5 msec), R wave amplitude for pacemaker sensing (14.2 ± 7.0 mV), slew rate (2.12 ± 1.4 V/sec), and resistance (500.3 ± 73.9 W) were sufficient in all patients. Eighteen patients met our endocardial impiant criteria with a DFT ≤ 15 J (10.05 ± 4.03 J) using monophasic (14 patients) or biphasic (four patients) pulse wave forms. In the one remaining patient, with a DFT of 20 J, we implanted a SQP but there was no reduction of the DFT. All patients tested showed successful defibrillation prior to discharge. During follow-up of 88 patient-months (1–9 months), 114 spontaneous VT/VF episodes occurred in five patients and were all successfully terminated. Eleven patients with a minimum follow-up of 2 months were reassessed. In seven out of 11 patients, termination of VF was achieved with the same minimal energy requirements obtained intraoperatively. In three patients, DFT increased by 5 J (one patient) and 10 J (two patients). In a further patient, X ray revealed dislocation of the endocardial lead. Our data suggest that effective defibrillation is feasible with a single endocardial lead for implantation of cardioverter defibrillator. In addition, we strongly recommend repetitive x-ray control to detect asymptomatic lead dislocation. Despite stable DFTs in most of our patients, an energy difference of ≤ 15 J between acute DFT and cardioverter defibrillator energy rating seems to be currently desirable to ensure successful postoperative defibrillation.     

A Prospective, Randomized, Comparison in Patients Between a Pectoral Unipolar Defibrillation System and That Using an Additional Inferior Vena Cava Electrode

The decrease of defibrillation energy requirement would render the currently available transvenous defibrillator more effective and favor the device miniaturization process and the increase of longevity. The unipolar defibrillation systems using a single RV electrode and the pectoral pulse generator titanium shell (CAN) proved to be very efficient. The addition of a third defibrillating electrode in the coronary sinus did not prove to offer advantages and in the superior vena cava showed only a slight reduction of the defibrillation threshold (DFT). The purpose of this study was to determine whether the defibrillation efficacy of the single lead unipolar transvenous system could be improved by adding an electrode in the inferior vena cava (IVC). In 17 patients, we prospectively and randomly compared the DFT obtained with a single lead unipolar system with the DFT obtained using an additional of an IVC lead. The RV electrode, Medtronic 6936, was used as anode (first phase of biphasic) in both configurations. A 108 cm2 surface CAN, Medtronic 7219/7220 C, was inserted in a left submuscular infraclavicular pocket and used as cathode, alone or in combination with IVC, Medtronic 6933. The superior edge of the IVC coil was positioned 2-3 cm below the right atrium-IVC junction. Thus, using biphasic 65% tilt pulses generated by a 120 microF external defibrillator, Medtronic D.I.S.D. 5358 CL, the RV-CAN DFT was compared with that obtained with the RV-CAN plus IVC configuration. Mean energy DFTs were 7.8 +/- 3.6 and 4.8 +/- 1.7 J (P < 0.0001) and mean impedance 65.8 +/- 13 O and 43.1 +/- 5.5 O (P < 0.0001) with the RV-CAN and the IVC configuration, respectively. The addition of IVC significantly reduces the DFT of a single lead active CAN pectoral pulse generator. The clinical use of this biphasic and dual pathway configuration may be considered in patients not meeting implant criteria with the single lead or the dual lead RV-superior vena cava systems. This configuration may also prove helpful in the use of very small, low output ICDs, where the clinical impact of ICD generator size, longevity, and related cost may offset the problems of dual lead systems.     

A randomized prospective study of single coil versus dual coil defibrillation in patients with ventricular arrhythmias undergoing implantable cardioverter defibrillator therapy

ICD implantation is standard therapy for malignant ventricular arrhythmias. The advantage of dual and single coil defibrillator leads in the successful conversion of arrhythmias is unclear. This study compared the effectiveness of dual versus single coil defibrillation leads. The study was a prospective, multicenter, randomized study comparing a dual with a single coil defibrillation system as part of an ICD using an active pectoral electrode. Seventy-six patients (64 men, 12 women; age 61 +/- 11 years) were implanted with a dual (group 1, n = 38) or single coil lead system (group 2,n = 38). The patients represented a typical ICD cohort: 60% presented with ischemic cardiomyopathy as their primary cardiac disease, the mean left ventricular ejection fraction was 0.406 +/- 0.158. The primary tachyarrhythmia was monomorphic ventricular tachyarrhythmia in 52.6% patients and ventricular fibrillation in 38.4%. There was no significant difference in terms of P and R wave amplitudes, pacing thresholds, and lead impedance at implantation and follow-up in the two groups. There was similarly no difference in terms of defibrillation thresholds (DFT) at implantation. Patients in group 1 had an average DFT of 10.2 +/- 5.2 J compared to 10.3 +/- 4.1 J in Group 2, P = NS. This study demonstrates no significant advantage of a dual coil lead system over a single coil system in terms of lead values and defibrillation thresholds. This may have important bearing on the choice of lead systems when implanting ICDs.     

Do Traditional VT Zones Improve Outcome in Primary Prevention ICD Patients?

Aims: We reviewed outcomes in our primary prevention implantable cardioverter defibrillator (ICD) population according to whether the device was programmed with a single ventricular fibrillation (VF) zone or with two zones including a ventricular tachycardia (VT) zone in addition to a VF zone. Methods: This retrospective study examined 137 patients with primary prevention ICDs implanted at our institution between 2004 and 2006. Device programming and events during follow‐up were reviewed. Outcomes included all‐cause mortality, time to first shock, and incidence of shocks. Results: Eighty‐seven ICDs were programmed with a single VF zone (mean >193 ± 1 beats per minute [bpm]) comprising shocks only. Fifty ICDs had two zones (mean VT zone >171 ± 2 bpm; VF zone >205 ± 2 bpm), comprising antitachycardia pacing (100%), shocks (96%), and supraventricular (SVT) discriminators (98%) . Discriminator “time out” functions were disabled. Mean follow‐up was 30 ± 0.5 months and similar in both groups. All‐cause mortality (12.6% and 12.0%) and time to first shock were similar. However, the two‐zone group received more shocks (32.0% vs 13.8% P = 0.01). Five of 16 shocks in these patients were inappropriate for SVT rhythms. The single‐zone group had no inappropriate shocks for SVTs. Eighteen of 21 appropriate shocks were for ventricular arrhythmias at rates >200 bpm (three VF, 15 VT). This suggests that primary prevention ICD patients infrequently suffer ventricular arrhythmias at rates <200 bpm and that ATP may play a role in terminating rapid VTs. Conclusions: Patients with two‐zone devices received more shocks without any mortality benefit. (PACE 2010; 1353–1358)