Nonthoracotomy Implantable Cardioverter Defibrillators Research Articles

Complications of ICD Generator Change and Implantations

Although implantable cardioverter-defibrillator (ICD) therapy can be lifesaving, complications are a possibility with implantation and during longterm follow-up. Though early ICDs, placed via open thoracotomy, were associated with a significant risk, the modern era of transvenous ICD implantation has reduced the surgical risk substantially. The conclusion of several decades of randomized clinical trials supporting the use of ICDs and cardiac resynchronization therapy (CRT) in patients with moderate-to-advanced heart failure highlights an important paradox. Whereas nonthoracotomy ICD implantation can be performedwith fewercomplications thanearlydevices, the patients now considered for this therapy are generally more ill and often with advanced heart failure. The impact of significant cardiac disease and associated comorbid medical illness on complication rates must also be considered. This article reviews the available data reporting complications associated with ICD procedures. Adverse events associated with both the acute procedural risk as well as those events that occur later are examined.

Complications of Implantable Cardioverter Defibrillator Therapy in 440 Consecutive Patients

Although more than 150,000 implantable cardioverter defibrillators (ICDs) are implanted yearly worldwide, only few studies systematically examined complications of ICD therapy in large patient cohorts. We prospectively analyzed ICD-related complications in 440 consecutive patients who underwent first implantation of an ICD system for primary or secondary prevention of sudden cardiac death within the last 10 years at our institution. All study patients received pectoral nonthoracotomy ICD lead systems with the exception of one patient who had an artificial tricuspid valve. During 46 +/- 37 months follow-up, 136 of 440 patients (31%) experienced at least one complication including implant procedure-related complications in 43 patients (10%), ICD generator-related complications in 28 patients (6%), lead-related complications in 52 patients (12%), and inappropriate shocks in 54 patients (12%). The most serious complications included one perioperative death due to heart failure (0.2%), two ICD system infections necessitating device removal (0.5%) and two perioperative cerebrovascular strokes (0.5%). We conclude that more than one quarter of ICD patients experience complications during a mean follow-up of almost 4 years, although serious complications such as intraoperative death or ICD system infections are rare in patients with nonthoracotomy ICD systems. Recognition of these complications is the prerequisite for advances in ICD technology and management strategies to avoid their recurrence.

Lead system causing twiddler's syndrome in patients with an implantable cardioverter-defibrillator

Three male patients with an implantable cardioverterdefibrillator (ICD) were referred for lead extraction because of twiddler’s syndrome associated with lead malfunction detected during routine follow-up (Table 1). The ICDs were implanted in the left subpectoral region in a submuscular pocket. On chest radiograph, the position of the generator was the same as at implant in all 3 patients. All patients were satisfied with the device and denied manipulation of the generator or discomfort at the implant site. All had a history of recent strenuous physical exercise. None of the patients was obese or reported important weight loss since the time of implant. We could not rotate the generator within the generator pocket in any of the patients, even during surgery, because the pocket fitted snugly in all. The leads were twisted tightly outside the generator pocket, and atrial and defibrillation leads were twirled around each other in the patients with a dual-chamber ICD (Figure 1). The torque of the leads had deformed the insulation, and in 1 patient there were insulation defects at the site of the connector and the yoke. The leads were extracted in all 3 patients, in 2 with a laser sheath. New leads were inserted in 2 patients through an exchange procedure and by renewed catheterization of the subclavian vein in the first patient. Care was taken not to leave any redundant lead outside the generator pocket, which was closed separately. The original ICD was reimplanted in all patients. One patient had recurrence of the syndrome. Seven months after the revision, the chest radiograph showed an unchanged position of the leads and generator. He then took up swimming but presented 3 months later with recurrence of twiddler’s syndrome. The other patients showed no recurrence during a follow-up of 10 and 16 months. Discussion Twiddler’s syndrome of ICDs is typically attributed to either conscious or unconscious rotation of the generator. The patients are often obese women with large defibrillator pockets, sometimes attributed to weight loss facilitating manipulation and rotation of

Clinical significance of device-related complications in clinical trials and implications for future trials: insights from the Antiarrhytmics Versus Implantable Defibrillators (AVID) trial.

Implantation of transvenous implantable cardioverter-defibrillators (ICDs) utilizing a non-thoracotomy approach has become routine therapy for survivors of life-threatening tachyarrhythmias. In the Antiarrhythmics versus Implantable Defibrillator (AVID) Trial, we sought to identify and prospectively characterize the frequency of lead and ICD-related complications. Between June 1, 1993, and April 7, 1997, 539 patients received non-thoracotomy ICDs. A total of 62 first complications occurred. The subclavian route of insertion resulted in more complications than the cephalic vein route, 46 of 339 (14%) versus 6 of 135 (4%), p =.005 as did the abdominal versus pectoral generator site; 31 of 238 (13%) versus 17 of 291 (6%), p <.02. Most dislodgements and system infections tended to occur in the 3 months following implantation, whereas lead fractures continued to occur throughout follow-up. Failure to use peri-operative antibiotics was a predictor of system infection (p =.001). These data suggest that cephalic vein access and pectoral generator site may result in fewer complications. Although implantation techniques and generator technology continue to evolve, the continued occurrence of lead fractures and the need for premature system revision supports the practice of close routine ICD system surveillance.

Lead- and device-related complications in the Antiarrhythmics Versus Implantable Defibrillators Trial

Background Implantation of transvenous implantable cardioverter defibrillators (ICDs) by use of a nonthoracotomy approach has become routine therapy for survivors of life-threatening tachyarrhythmias. The purpose of this study was to identify and prospectively characterize the frequency of lead- and ICD-related complications from the Antiarrhythmics versus Implantable Defibrillators (AVID) Trial. Methods and Results Between June 1, 1993, and April 7, 1997, 539 patients received nonthoracotomy ICDs either as initial treatment assignment (477) or as crossover from medical management (62). A total of 62 first complications occurred. The subclavian route of insertion resulted in more complications than the cephalic vein route, 46 of 339 (14%) versus 6 of 135 (4%), P =.005, as did the abdominal versus pectoral generator site, 31 of 238 (13%) versus 17 of 291 (6%), P <.02. Most dislodgements and system infections tended to occur in the 3 months after implantation, whereas lead fractures continued to occur throughout follow-up. Failure to use perioperative antibiotics was a predictor of system infection (P =.001). Conclusions These data suggest that cephalic vein access and pectoral generator site may result in fewer complications. The continued occurrence of lead fractures and the need for premature system revision supports the practice of close routine ICD system surveillance. (Am Heart J 2001;141:92-8.)

Meta-analysis of the implantable cardioverter defibrillator secondary prevention trials. AVID, CASH and CIDS studies. Antiarrhythmics vs Implantable Defibrillator study. Cardiac Arrest Study Hamburg . Canadian Implantable Defibrillator Study.

Three randomized trials of implantable cardioverter defibrillator (ICD) therapy vs medical treatment for the prevention of death in survivors of ventricular fibrillation or sustained ventricular tachycardia have been reported with what might appear to be different results. The present analysis was performed to obtain the most precise estimate of the efficacy of the ICD, compared to amiodarone, for prolonging survival in patients with malignant ventricular arrhythmia. Individual patient data from the Antiarrhythmics vs Implantable Defibrillator (AVID) study, the Cardiac Arrest Study Hamburg (CASH) and the Canadian Implantable Defibrillator Study (CIDS) were merged into a master database according to a pre-specified protocol. Proportional hazard modelling of individual patient data was used to estimate hazard ratios and to investigate subgroup interactions. Fixed effect meta-analysis techniques were also used to evaluate treatment effects and to assess heterogeneity across studies. The classic fixed effects meta-analysis showed that the estimates of ICD benefit from the three studies were consistent with each other (P heterogeneity=0.306). It also showed a significant reduction in death from any cause with the ICD; with a summary hazard ratio (ICD:amiodarone) of 0.72 (95% confidence interval 0.60, 0.87;P=0.0006). For the outcome of arrhythmic death, the hazard ratio was 0.50 (95% confidence interval 0.37, 0.67;P<0.0001). Survival was extended by a mean of 4.4 months by the ICD over a follow-up period of 6 years. Patients with left ventricular ejection fraction < or = 35% derived significantly more benefit from ICD therapy than those with better preserved left ventricular function. Patients treated before the availability of non-thoracotomy ICD implants derived significantly less benefit from ICD therapy than those treated in the non-thoracotomy era. Results from the three trials of the ICD vs amiodarone are consistent with each other. There is a 28% reduction in the relative risk of death with the ICD that is due almost entirely to a 50% reduction in arrhythmic death.

Effect of sensing system on the incidence of myopotential oversensing during bradycardia pacing in implantable cardioverter-defibrillators

Oversensing during bradycardia pacing, sometimes leading to spurious tachyarrhythmia detection and inappropriately delivered shocks, has been reported with Ventritex (St. Jude Corporation, Sunnyvale, California) Cadence (models V-100 and V-110) implantable cardioverter-defibrillators (ICDs). 1 Kelly P.A. Mann D.E. Damle R.S. Reiter M.J. Oversensing during ventricular pacing in patients with a third-generation implantable cardioverter-defibrillator. J Am Coll Cardiol. 1994; 23: 1531-1534 Abstract Full Text PDF PubMed Scopus (47) Google Scholar , 2 Rosenthal M.E. Paskman C. Noise detection during bradycardia pacing with a hybrid nonthoracotomy implantable cardioverter defibrillator system. PACE. 1998; 21: 1380-1386 Crossref Scopus (9) Google Scholar , 3 Peters W. Kowallik P. Wittenberg G. Scholl C. Meesmann M. Inappropriate discharge of an implantable cardioverter defibrillator during atrial flutter and intermittent ventricular antibradycardia pacing. J Cardiovasc Electrophysiol. 1997; 8: 1167-1174 Crossref PubMed Scopus (15) Google Scholar One cause of this problem is sensing of diaphragmatic or abdominal myopotentials in the setting of the high sensitivity that automatically occurs during bradycardia pacing. 2 Rosenthal M.E. Paskman C. Noise detection during bradycardia pacing with a hybrid nonthoracotomy implantable cardioverter defibrillator system. PACE. 1998; 21: 1380-1386 Crossref Scopus (9) Google Scholar Ventritex ICDs use a stepwise automatic amplifier gain control, and amplifier gain is continuously maximal during bradycardia pacing, with a minimal sensed signal of approximately 0.2 mV. 4 Reiter M.J. Mann D.E. Sensing and tachyarrhythmia detection problems in implantable cardioverter-defibrillators. J Cardiovasc Electrophysiol. 1996; 7: 542-558 Crossref PubMed Scopus (60) Google Scholar Newer Ventritex devices, Cadet, Contour, and Angstrom (models V-115, V-145, V-180, and V-190) use a similar automatic gain control, although gain changes occur more rapidly than in the Cadence models. 5 Mann D.E. Damle R.S. Kelly P.A. Landers M. Otto L. Reiter M.J. Comparison of oversensing during bradycardia pacing in two types of implantable cardioverter-defibrillator systems. Am Heart J. 1998; 136: 658-663 Abstract Full Text Full Text PDF PubMed Scopus (20) Google Scholar Other ICDs use different sensing algorithms. Medtronic (Minneapolis, Minnesota) and CPI Guidant (St. Paul, Minnesota) devices automatically adjust sensitivity or gain on a beat-by-beat basis. Sensitivity or gain is adjusted according to the amplitude of each sensed complex. Between complexes, sensitivity or gain exponentially increases, eventually reaching a maximum level that in some devices is programmable. In Medtronic and CPI devices, sensitivity or gain during bradycardia pacing is maximal for less of the cardiac cycle than in Ventritex devices, and thus the propensity to oversense could be less in these devices. 4 Reiter M.J. Mann D.E. Sensing and tachyarrhythmia detection problems in implantable cardioverter-defibrillators. J Cardiovasc Electrophysiol. 1996; 7: 542-558 Crossref PubMed Scopus (60) Google Scholar To assess the effect these differences in sensing function may have on oversensing of myopotentials, we performed the following prospective study.

Comparison of results in two implantable defibrillators

The Jewel 7219D was the first non-thoracotomy implantable cardioverter-defibrillator (ICD) with biphasic shock capability small enough to be placed in the prepectoral subcutaneous position. Size reduction of ICDs is desirable, but safety and efficacy of smaller devices must be demonstrated. Outcomes of patients treated with the Jewel 7219D defibrillator (n = 1,781) and with its precursor model PCD 7217B (n = 2,637) were compared. To use PCD patients (n = 2,637) as historical (n = 2,574) and concurrent controls (n = 63), statistical adjustments using the Cox proportional-hazards regression model were made. Jewel recipients (n = 1,781) treated in 106 US and 32 non-US centers exhibited similar characteristics including a mean age of 59 years, 78% men, ejection fraction of 34%, history of aborted sudden cardiac death in 41%, and coronary artery disease in 70%. Implantation was completed in 1,777 of 1,781 (99.9%) attempts and success with the first electrode configuration and polarity was 89.5%. Kaplan-Meier cumulative first-year survivals for cardiac and all-cause mortality were 98.5% and 93.3%. Complication-free first-year survival for Jewel implants in prepectoral subcutaneous (n = 582), subpectoral submuscular (n = 366), and abdominal (n = 449) positions did not differ (p >0.05). First-year survival free of pocket-related complications exceeded 98% in all locations. Adjusted cardiac and all-cause first-year mortality, and efficacy in terminating spontaneous tachyarrhythmias did not differ between the 2 device groups. In conclusion, the safety and efficacy of Jewel model 7219D in the prepectoral subcutaneous position are at least equal to either those of Jewel models implanted in different positions or to those of the previously extensively characterized PCD 7217B.

Long-term follow up of patients with implantable cardioverter-defibrillators and mild, moderate, or severe impairment of left ventricular function.

OBJECTIVE: To determine whether patients with life threatening ventricular tachyarrhythmias, impaired left ventricular function, and severe heart failure will benefit from implantable cardioverter-defibrillator (ICD) treatment. DESIGN: 410 patients were followed...

Combined use of non-thoracotomy cardioverter defibrillators and endocardial pacemakers.

OBJECTIVE: To study the potential interactions in patients with endocardial permanent pacemakers and non-thoracotomy implantable cardioverter defibrillator (ICD) systems. DESIGN: Case series and cohort study. SETTING: Tertiary referral centre. PATIENTS:...

The “Modern” Implantable Cardioverter-Defribrillator: Comparing It to Those of the Late 1980s

To determine whether implantable cardioverter-defibrillator (ICD) therapy is influenced by new technological advances, we studied the follow-up of 480 patients who underwent ICD implantation between January 1984 and March 1996. In these patients surgical risk, complications, and mean survival was evaluated in relation to the time of ICD implant: 124 patients (26%) underwent ICD implantation during 1984–1989 (group 1) and 356 patients (74%) during 1990–1996 (group 2). Epicardial lead systems were implanted in 209 patients (44%), whereas transvenous lead systems were implanted in 271 patients (56%). Perioperatively, 13 patients (3%) died, significantly more frequently after epicardial (12 of 209 patients, 5%) than after transvenous (1 of 271 patients, <1%) ICD implantation (p < 0.05). During a mean follow-up of 28 ± 26 months (range < 1 to 129 months), 97 patients (20%) died. Of these, 9 patients (2%) died from sudden arrhythmic death; 7 patients (1%) died suddenly, probably as a result of nonarrhythmic causes; 60 (13%) died from other cardiac causes (congestive heart failure, myocardial infarction); and 21 (4%) died from noncardiac causes. The 3-, 5-, and 6-year survival for arrhythmic mortality was 90% and 89% in patients who underwent ICD implantation during 1984–1989 as compared with a 3-, 5-, and 6-year survival rate of 97% in patients with ICD implant since 1990 (p <0.05). In addition, the 3-, 5-, and 6-year total mortality was significantly better in group 2 (81%, 67%, 67%) than in group 1 (70%, 61%, 54%) (p <0.05). A total of 362 (75%) received ICD discharges (mean incidence 21 ± 43 shocks per patient), with a similar incidence among both patient groups (group 1: 78%; group 2: 74%; p = nonsignificant). The mean interval between ICD implant and the first ICD therapy was similar between both groups with a mean interval of 11 ± 13 months (group 1: 11 ± 13 months, group 2: 9 ± 6 months; p = nonsignificant). Our data demonstrate that patients who underwent ICD implantation since 1990 clearly benefit from technical advances (nonthoracotomy ICDs, biphasic shocks, antitachycardia pacing). (Am J Cardiol 1996;78(suppl 5A):3–8)

Malfunction of implantable cardioverter defibrillators placed by a nonthoracotomy approach: frequency of malfunction and value of chest radiography in determining cause.

The purpose of this study was to determine the frequency of system malfunction in patients with nonthoracotomy implantable cardioverter defibrillators and to assess the role of chest radiography in detecting and determining the cause of malfunction. The study population consisted of 300 consecutive patients in whom implantable cardioverter defibrillators were implanted using an initial nonthoracotomy approach between September 1990 and October 1994. Transvenous electrodes were placed via the subclavian or cephalic vein under local anesthetic. Intraoperative testing, pulse generator implantation, and, if necessary, subcutaneous patch or extrapericardial patch placement via thoracotomy were done in the operating room under general anesthetic. Follow-up consisted of routine device interrogation every 2-3 months and annual chest radiography. Chest radiographs were obtained more often if patients were symptomatic or if results of device interrogation were abnormal. Patients were followed up for a mean +/- SD of 19 +/- 14 months following implantation. Implantable cardioverter-defibrillator malfunction occurred in 17 patients (6%) during the follow-up period. Of these, 12 (71%) had component abnormalities on chest radiographs. Patients with radiographically apparent implantable cardioverter-defibrillator abnormalities presented in two discrete time periods after device implantation, early (mean, 35 +/- 14 days) and late (mean, 18 +/- 5 months). Malfunction of nonthoracotomy implantable cardioverter-defibrillator systems develops infrequently after device implantation. In most cases, the cause can be identified on chest radiographs.

Increase in defibrillation threshold in non-thoracotorny implantable defibrillators using a biphasic waveform

We have previously reported a chronic increase in defibrillation threshold in a non-thoracotomy implantable cardioverter-defibrillator (ICD) system using monophasic waveforms. To determine if this phenomenon is related to the lead system or the waveform used, we studied the chronic defibrillation threshold in consecutive patients receiving an ICD capable of delivering biphasic waveforms with the same lead system previously evaluated. Twenty-five patients received an ICD with biphasic shock waveform and have been followed for 4 to 15 months. All have undergone defibrillation threshold measurements using the identical testing protocol with biphasic waveforms at implant and at 2 months. Coronary artery disease was present in 15, idiopathic dilated cardiomyopathy in 9, and valvular heart disease in 1. The presenting arrhythmia was ventricular fibrillation in 11, ventricular tachycardia in 10, and syncope with inducible ventricular tachycardia in 4. The configuration of the shocking electrodes was randomized; the lead-only configuration was used in 14 patients (56%), and a subcutaneous patch was used in the remaining patients. Mean defibrillation threshold using a step-down technique was 9.8 ± 1.0 J at implant, 13.2 ± 1.6 J at 2 months, and 12.4 ± 1.5 J at 6 months (p = 0.01 by analysis of variance). There was no change in clinical status, cardiac size, radiographic lead position, or impedance between implant and 2 months. These findings suggest the increase in defibrillation threshold in this ICD system is not related to the type of waveform used, but rather is a feature of non-thoracotomy as opposed to epicardial electrodes.

Long-Term outcomes and modes of death of patients treated with nonthoracotomy implantable defibrillators

Long-term outcomes of all patients who underwent nonthoracotomy implantable cardioverter-defibrillator (ICD) implantation at our institution from April 1991 to October 1994 were studied using the intention-to-treat analysis. Of 94 consecutive patients, 81 underwent nonthoracotomy ICD implantation and 13 underwent thoracotomy (for concomitant surgery in 11 and unavailability of nonthoracolomy leads in 2). Six of 81 patients had a high defibrillation threshold, 4 subsequently underwent thoracotomy, and 2 were treated with amiodarone. Surgical mortality was 0%. The duration of follow-up was 20 ± 13 months, and was >12 months in 74% of 67 living patients. Actuarial survival rates at 1 and 2 years were, respectively, 98% and 94% for sudden death and 91% and 83% for total mortality. Deaths during long-term follow-up were mostly due to nonsudden cardiac or noncardiac deaths. Two-year mortality rates were 12% and 25% in patients with ejection fraction ≥30% and <30%, respectively. Thus, instances of sudden death and surgical mortality are very few in patients with nonthoracotomy ICDs. Deaths during long-term follow-up are mostly due to nonsudden cardiac and noncardiac deaths. Therefore, ICD therapy may have greater impact on survival in patients with lower risks of nonsudden cardiac and cardiac death (e.g., younger patients with minimal heart disease) than in patients with severe cardiac or noncardiac disease. Prospective studies are needed to address this question.

Comparison of implantation of nonthoracotomy defibrillators in the operating room versus the electrophysiology laboratory

Implantable cardioverter-defibrillators (ICDs) with nonthoracotomy lead systems are widely available, and are implanted either in the electrophysiology laboratory or the operating room. The purpose of this study was to prospectively evaluate the safety and efficacy of nonthoracotomy ICD implantation in an electrophysiology laboratory versus an operating room. During a 7-month period, 62 consecutive ICDs with nonthoracotomy lead systems were implanted in patients in an electrophysiology laboratory. During the next 10 months, 110 consecutive ICDs were implanted in patients in a surgical operating room. All ICD implantations were performed under general anesthesia by electrophysiologists. There were no differences in age (58 ± 14 vs 62 ± 12 years, p = 0.06), gender distribution ( p = 0.3), frequency of structural heart disease (97% vs 97%, p = 0.9), ejection fraction (0.31 ± 0.15 vs 0.29 ± 0.13, p = 0.3), or presentation with cardiac arrest (65% vs 53%, p = 0.2) between patients undergoing ICD implantation in the electrophysiology laboratory and operating room, respectively. The rate of successful implantation and of complications for systems implanted in the electrophysiology laboratory (95% and 13%, respectively) and in the operating room (98% and 14%, respectively) were similar ( p = 0.4 and p = 0.8, respectively). Specifically, the rate of infection (0% vs 4%, p = 0.3) and hematoma formation (2% vs 4%, p = 0.8) were not statistically significantly different. Three patients who had undergone ICD implantation in an operating room died within 30 days. ICDs with nonthoracotomy lead systems can be implanted with a similarly high rate of success and acceptable complication rate in the electrophysiology laboratory and in the operating room.

Cost and Length of Hospital Stay: Comparisons Between Nonthoracotomy and Epicardial Techniques in Patients Receiving Implantable Cardioverter Defibrillators

Twenty-five patients with implantable cardioverter defibrillators (ICDs) implanted intrathoracically (group I) were compared with 25 patients who underwent implant using the nonthoracotomy approach (group II). All systems were implanted by the same medical team, in the same high volume implanting center. Indications for implantation were comparable in both groups. Patient characteristics were not statistically different with the exception of age (66-group I vs 71-group II; P < 0.05). Although left ventricular ejection fractions appeared to differ (32% vs 37%, respectively), this difference was not statistically significant (P = 0.06). ICD models used in group I were: Ventritex Cadence (16), Telectronics Guardian 4211 (2), Medtronic PCD (7); in group II they were: Ventritex Cadence (15), Guardian 4211 (2), and CPI 1600 (1). Total length of hospital stay was 16 +/- 6 days for group I versus 12 +/- 5 for group II (P < 0.05). Number of postoperative days in an intensive care unit was 3.2 +/- 2.8 for group I versus 0.5 +/- 0.6 for group II (P < 0.0001). Postoperative length of stay was 8.2 +/- 3.1 for group I versus 5.7 +/- 4.4 for group II (P < 0.001). Mean total hospital charges for the entire length of stay were $72,918 +/- $26,770 in group I versus $55,031 +/- $42,870 in group II, representing a mean reduction of 21% in global costs for group II patients. These data confirm that nonthoracotomy ICD implantation in an experienced center is associated with significantly shorter hospital stays, a virtual elimination of the need for postoperative intensive care, and globally lower total hospital costs. In addition, the presence of a statistically older population in group II does not negate these beneficial effects.

Comparison and frequency of ventricular arrhythmias after defibrillator implantation by thoracotomy versus nonthoracotomy approaches

Postoperative exacerbation of ventricular arrhythmias has been reported in some patients treated with thoracotomy implantable cardioverter-defibrillators (ICDs). This phenomenon, which may be related to epicardial patch electrodes, may be less frequent after nonthoracotomy ICD implantation. In this nonrandomized study, postoperative arrhythmias in thoracotomy approaches (n = 52) were compared with those in nonthoracotomy approaches (n = 59). Preoperatively, all patients were clinically stable receiving an antiarrhythmic regimen chosen by serial drug testing. Nine of 52 patients in the thoracotomy group developed sustained ventricular tachycardia postoperatively while receiving the same antiarrhythmic regimen chosen preoperatively, and 1 patient eventually died. Two additional patients developed frequent and prolonged episodes of nonsustained ventricular tachycardia requiring changes in the antiarrhythmic regimen. In the nonthoracotomy group, only 3 of 59 patients developed sustained ventricular tachycardia and 1 developed frequent nonsustained ventricular tachycardia. Thus, only 4 of 59 patients in the nonthoracotomy group developed clinically significant ventricular arrhythmia during the postoperative period compared with 11 of 52 patients in the thoracotomy group (p < 0.05). Surgical mortality was 6% in the thoracotomy group, and 0% in the nonthoracotomy group. In the remaining clinically stable patients, a marked (sevenfold) increase in asymptomatic ventricular arrhythmias was noted in 15 of 39 patients in the thoracotomy group, and in 3 of 55 patients in the nonthoracotomy group (p < 0.05). Thus, postoperative exacerbation of ventricular arrhythmia, sometimes noted with thoracotomy approaches, is very rare with nonthoracotomy approaches.

Acute efficacy and chronic follow-up of patients with non-thoracotomy third generation implantable defibrillators.

Non-thoracotomy implantation of implantable cardioverter defibrillators (ICDs) has simplified the process of device insertion, promising to decrease associated procedural complications 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 implantation with 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 epicardial patch. One patient died 1 week postoperatively of septic shock related to the implantation (0.9% perioperative mortality). During follow-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; 85% 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 at terminating arrhythmias and maintaining a low rate of sudden cardiac death in this high risk population.

Intracardiac emergency defibrillation for refractory ventricular fibrillation during implantation of cardioverter defibrillators with nonthoracotomy lead systems.

Implantable cardioverter defibrillators (ICDs) are being implanted in increasing numbers. At intraoperative defibrillation threshold tests refractory ventricular fibrillation (VF) requiring emergency open chest resuscitation is a major concern during implantation of nonthoracotomy ICD lead systems. A new method of high energy endocardial/extrathoracic defibrillation via the implanted ICD transvenous defibrillation electrode (TDE) was used to terminate refractory VF. During implantation of ICD with TDE in 20 patients refractory VF occurred in two patients. The arrhythmia was terminated with endocardial/extrathoracic defibrillation in both cases, and no complications were observed.