Long-term infection rates associated with the pectoral versus abdominal approach to cardioverter- defibrillator implants.

Infection is an uncommon (0% to 6.7%) but serious complication after implantable cardioverter-defibrillator (ICD) implantation. All ICD primary implants, replacements, or revisions performed at the Massachusetts General Hospital between April 1983 and May 1999 were reviewed. A total of 21 ICD-related infections (1.2%) were identified among 1,700 procedures affecting 1.8% of the 1,170 patients who underwent a primary implant, a generator change, or a revision of their systems. The mean follow-up time was 35 +/- 33 months. Of the 959 patients with long-term follow-up, 19 of the 584 patients (3.2%) with abdominal and 2 of the 375 patients (0.5%) with pectoral systems developed ICD-related infections (p = 0.03). There was no significant difference between the infection rate among the 959 primary ICD implants and the 447 replacements or system revisions. Only 5 of the patients (24%) had systemic signs of infection, including fever (T>100.5) and elevated white blood count >12,000. Cultures from the wound revealed staphylococcal species in 16 patients (76%). Nineteen patients were treated with removal of the entire ICD system in addition to intravenous antibiotics for 2 to 4 weeks. A decrease in the incidence of ICD-related infection has occurred since the advent of transvenous pectoral systems. The main organism responsible for ICD infection is Staphylococcus. The mainstay of ICD infection management consists of complete removal of the entire implanted system.

Long-term clinical outcome of patients with prior myocardial infarction after palliative radiofrequency catheter ablation for frequent ventricular tachycardia.

Patients with coronary artery disease and hemodynamically tolerated, highly frequent, sustained monomorphic ventricular tachycardia (VT) may undergo radiofrequency catheter ablation (RFCA) for elimination of > or = 1 morphologically distinct VTs. The purpose of this study was to evaluate the long-term clinical benefit following RFCA as a palliative treatment of highly frequent or incessant ischemic VT. Fifty-five patients underwent RFCA of 62 VTs. The target VT was successfully ablated in 82% of patients. Complication and perioperative mortality rates were 7.2% and 1.8%, respectively. At 5 years, total mortality was 51% and probability of freedom from all ventricular tachyarrhythmias was 28%. All patients had highly frequent or incessant drug-refractory VT before RFCA. Clinical benefit was defined as either freedom from all ventricular tachyarrhythmias, or a reduction in frequency of recurrence from > 1 episode per month before RFCA to < or = 1 episode per year of any ventricular tachyarrhythmia, including all appropriate implantable cardioverter defibrillator (ICD) therapies. By this definition, 54% of the patients continued to benefit from RFCA at 5 years. Of 19 variables analyzed with a Cox univariate model, only the presence of a left ventricular aneurysm and a previously implanted ICD were predictive of any ventricular arrhythmia recurrence. However, at 5 years over half of the surviving patients still continued to benefit from RFCA of their clinical VT. Because the overall rate of any ventricular tachyarrhythmia occurrence during follow-up is high, additional protection, such as an ICD, is required.

Changes in health status and quality of life and the impact of uncertainty in patients who survive life-threatening arrhythmias.

OBJECTIVE: The purpose of this study was to describe the changes in perception of health status and quality of life from before treatment to 6 months after and the impact of uncertainty on these variables in survivors of life-threatening arrhythmia. DESIGN AND SETTING: A descriptive correlational design at a large urban teaching hospital. MEASURES: We measured health status, quality of life, and uncertainty before treatment and 6 months after a life-threatening arrhythmia. RESULTS: Survivors included 66 men and 15 women, 41 of whom received pharmacologic therapy and 36 of whom received an implantable cardioverter defibrillator (ICD), completed the Medical Outcomes Survey (SF-36), Ferrans and Powers Quality of Life Index (QLI), and the Mishel Uncertainty in Illness Scale (MUIS-C) before treatment and 6 months after. There were significant improvements in the mental and physical health composite summaries as measured by the SF36 (P <.01). Conversely, there were significant reductions in the overall score and specifically in socioeconomic and psychological/spiritual quality of life domains as measured by the QLI (P <.05). An increased perception of uncertainty was related to decreased perception of health status and quality of life at both measurement times, with higher correlations 6 months later. CONCLUSIONS: Survivors demonstrated improvements in perceived health status, although this did not appear to translate into improvements in the subjective domains of quality of life. The overall quality of life and the domains of psychological/spiritual state and socioeconomic status were lower 6 months after a life-threatening arrhythmia. Uncertainty had a significant impact on these perceptions, identifying an area for nursing interventions.

Mechanism of sustained monomorphic ventricular tachycardia in systemic sclerosis.

Three patients with advanced systemic sclerosis and recurrent or incessant monomorphic ventricular tachycardia underwent cardiac electrophysiologic studies. Biventricular transcatheter mapping showed findings most compatible with a reentrant mechanism, which was effectively treated with transcatheter ablation.

Runaway pacemaker in an implantable cardioverter defibrillator.

INTRODUCTION: Runaway pacemaker is a potentially catastrophic complication of any permanent pacing system. METHODS AND RESULTS: A 70-year-old man was found to have erratic behavior of his implantable cardioverter defibrillator (ICD) during a routine outpatient interrogation. His device was turned off, and he was hospitalized in preparation for a pulse generator replacement. During his hospitalization, his ICD unexpectedly began pacing rapidly. Despite prompt resuscitation attempts, the patient died. Postmortem examination of the device demonstrated a crystal oscillator failure. CONCLUSION: A previously unrecognized component malfunction is a potentially lethal complication of ICDs.

The treatment of patients with infected implantable cardioverter-defibrillator systems.

OBJECTIVE: The purpose of this study was to evaluate the treatment of patients with infected implantable cardioverter-defibrillator systems. METHODS: Retrospective analysis was done of the cases of 21 patients treated for implantable cardioverter-defibrillator infection during an 11-year period. RESULTS: Of 723 cardioverter-defibrillator implantations (550 primary implants, 173 replacements), nine (1.2%) were complicated by early postoperative device-related infections. Late infections developed in two patients 19 and 22 months, respectively, after implantation. Ten other patients were transferred to our institution for treatment of cardioverter-defibrillator infection. The time from implantation to overt infection was 2.2 +/- 1.3 months, excluding the two late infections. The responsible organisms were Staphylococcus aureus (9), Staphylococcus epidermidis (6), Streptococcus hemolyticus (1), gram-negative bacteria (3), Candida albicans (1), and Corynebacterium (1). All patients were treated with intravenous antibiotic drugs. Total system removal was done in 15 patients and partial removal in 2; in 4, the cardioverter-defibrillator system was not explanted. There were no perioperative deaths. A new implantable cardioverter-defibrillator system was reimplanted in 7 patients after 2 to 6 weeks of antibiotic therapy. Ten patients were treated without reimplantation (2 arrhythmia operation, 8 antiarrhythmic drugs). Four patients (3 patients without explantation and 1 with partial system removal) were treated with maintenance long-term antibiotic therapy. During a mean follow-up of 21 +/- 2.8 months, no patient had clinical recurrence of infection. One patient treated with antiarrhythmic drugs without system reimplantation died suddenly. CONCLUSIONS: Infections that involve implantable cardioverter-defibrillator systems can be safely managed by removing the entire system with reimplantation after intravenous antibiotic therapy. In selected patients in whom the risk for system explantation is high and anticipated life expectancy is short, long-term antibiotic therapy to suppress low-virulence infections may represent an acceptable alternative.

Transient right bundle branch block causing R wave attenuation postdefibrillation.

Transient and significant decrease in R wave amplitude, associated with transient right bundle branch block, was noted to occur after defibrillation in a defibrillator patient. The mechanism is probably stunning of the right bundle branch, causing right intraventricular conduction delay and decrease in signal amplitude reaching the endocardial sensing dipoles.

Drug therapy for atrial fibrillation--interactions with interventional therapy and implications for local drug delivery.

Multiple therapeutic alternatives, both pharmacological and non-pharmacological, are under active investigation for the treatment of atrial fibrillation. Although many promising approaches are being investigated, there is as yet no universally accepted therapy, nor is there likely to be in the foreseeable future. It is possible that, since no one therapeutic intervention is ideal, a combination of pharmacological and non-pharmacological approaches may succeed in patients in whom neither therapy alone would be effective. In this paper, we explore interactions between devices and antiarrhythmic drugs, as well as novel methods of delivering anti-arrhythmic drug therapy.

Evolving role of sotalol in the management of ventricular tachyarrhythmias.

Sotalol is a unique compound with several potential antiarrhythmic mechanisms, including beta blockade (class II activity), action potential duration prolongation (class III activity), and possibly reduction of QT dispersion. In recent years, trials such as the Cardiac Arrhythmia Suppression Trial (CAST) and the Electrophysiologic Study versus Electrocardiographic Monitoring (ESVEM) trial reported disappointing results with the use of class I agents in the management of ventricular arrhythmias in patients with coronary artery disease. These results have led to increased interest in class III antiarrhythmic agents, including sotalol. Sotalol is effective in suppressing ventricular premature complexes as well as nonsustained and sustained ventricular tachyarrhythmias. The interaction between sotalol and implantable cardioverter-defibrillators (ICDs) is generally favorable. As is the case with other antiarrhythmic drugs, there is no placebo-controlled trial assessing the effect of sotalol on mortality. It is not known if sotalol is more effective than placebo, conventional beta blockade, amiodarone, or ICDs in reducing mortality from life-threatening ventricular arrhythmias. In addition, the optimal method of selecting patients for sotalol therapy has yet to be determined. The safety profile of sotalol has been well established in > 3,000 patients worldwide. Proarrhythmia occurs in approximately 4% of patients, and torsades de pointes occurs in approximately 2.5%. The majority of episodes of torsades de pointes occurs within 3 days of commencing sotalol therapy, and the risk of torsades de pointes increases sharply at dosages > 320 mg daily. It is recommended that initiation of sotalol therapy or dosage increases be performed in a monitored setting. Overall, only 1% of patients enrolled in clinical trials of sotalol discontinued therapy as a result of drug-related congestive heart failure. However, these trials have excluded patients with poor left ventricular systolic function and/or overt heart failure. The optimal management of these patients, who are at greatest risk of sudden cardiac death, and of patients with substrates other than coronary artery disease remains to be elucidated.

Arrhythmias induced by exercise in athletes and others.

Athletes are subject to the same arrhythmias as the general population, but the frequency and significance of the arrhythmias may be different. Cardiovascular conditioning slows the heart rate and may make athletes more vulnerable to neurocardiogenic syncope and atrial fibrillation. Tachyarrhythmias may be precipitated by vigorous exercise and more severe rate-related symptoms may result because of the high sympathetic drive during sports activities. For those with pre-existing cardiovascular abnormalities, athletic activity may be beneficial in some cases, but dangerous and even life-threatening in others. A review of the subject and recommendations based on our personal experience and a recent consensus conference are provided.

Sex differences in cardiac arrest survivors.

BACKGROUND: Important sex differences in the epidemiology of sudden death and in the results of electrophysiological testing in survivors of cardiac arrest have been identified. These differences are currently poorly understood. METHODS AND RESULTS: Three hundred fifty-five consecutive survivors of out-of-hospital cardiac arrest (84 women and 271 men) referred for electrophysiologically guided therapy were analyzed retrospectively for sex differences in underlying pathology and predictors of outcome. Women were significantly less likely to have underlying coronary artery disease than men (45% versus 80%) and more likely to have other forms of heart disease or structurally normal hearts (P<.0001). The mean left ventricular ejection fraction was higher in women (0.46+/-0.18 versus 0.41+/-0.18, P<.05), and women were more likely to have no inducible arrhythmia at baseline electrophysiological testing (46% versus 27%, P=.002), although when the patients were stratified by coronary artery disease status, these sex differences were no longer present. The independent predictors of outcome differed between men and women. In men, a left ventricular ejection fraction of <0.40 was the most powerful independent predictor of total (relative risk, 2.8; 95% CI, 1.6 to 5.0; P<.0001) and cardiac (relative risk, 6.3; 95% CI, 2.9 to 13.5; P<.0001) mortality. In contrast, the presence of coronary artery disease was the only independent predictor of total (relative risk, 4.5; 95% CI, 1.5 to 13.4; P=.003) and cardiac (relative risk, 4.4; 95% CI, 1.2 to 15.6; P=.012) mortality in women. CONCLUSIONS: Females survivors of cardiac arrest are less likely to have underlying coronary artery disease. The predictors of total and cardiac mortality differ between male and female survivors. Coronary artery disease status is the most important predictor in women, and impaired left ventricular function is the most important predictor in men.

Comparison of cycle lengths between induced and spontaneous sustained ventricular tachycardia during concordant antiarrhythmic therapy associated with healed myocardial infarction.

We propose that in clinical practice, whenever possible, the VT detection interval should be selected by adding >60 ms to the induced maximal VT cycle length in order to ensure a high sensitivity for the detection of future spontaneous VT episodes.

Influence of the implantable cardioverter/defibrillator on sudden death and total mortality in patients evaluated for cardiac transplantation.

BACKGROUND: Implantable cardioverter/defibrillators (ICDs) may reduce sudden tachyarrhythmic death in patients with severe left ventricular dysfunction. It is uncertain whether this improves survival, particularly in patients awaiting cardiac transplantation. METHODS AND RESULTS: The effect of treatment for spontaneous ventricular arrhythmias (ICD [n = 59], antiarrhythmic drugs [n = 53], or no antiarrhythmic treatment [n = 179]) on total mortality and mode of cardiac death was analyzed in 291 consecutive patients evaluated for cardiac transplantation between January 1986 and January 1995. There were 109 deaths (37.4%) (63 [21.6%] sudden, 40 [13.7%] nonsudden, and 6 [2.1%] noncardiac) during mean follow-up of 15 months (range, 1 to 118 months). Baseline clinical variables, medical therapies for heart failure, and actuarial rates of transplantation were similar between treatment groups. Kaplan-Meier sudden death rates were lowest in the ICD group, intermediate in the no antiarrhythmic treatment group, and highest in the drug treatment group throughout follow-up (12-month sudden death rates, 9.2%, 16.0%, and 34.7%, respectively; P = .004). Total mortality and nonsudden death rates did not differ. Cox proportional-hazards model revealed that antiarrhythmic drug treatment was associated with sudden death (relative risk, 2.1; 95% CI, 1.04 to 3.39; P = .04) and ICD was associated with nonsudden death (relative risk, 2.26; 95% CI, 1.12 to 4.62; P = .02). CONCLUSIONS: Sudden death rates were lowest in patients treated with ICDs compared with drug treatment or no antiarrhythmic treatment. However, although ICDs reduced sudden death in selected high-risk patients with severe left ventricular dysfunction, the effect on long-term survival was limited, principally by high nonsudden death rates.

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

OBJECTIVE: 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. MATERIALS AND METHODS: 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. RESULTS: 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). CONCLUSION: Malfunction of nonthoracotomy implantable cardioverter-defibrillator systems develops infrequently after device implantation. In most cases, the cause can be identified on chest radiographs.

Electrocardiographic pseudo-infarct patterns after implantation of cardioverter-defibrillators.

Postoperative electrocardiographic (ECG) changes are frequently present after insertion of implantable cardioverter-defibrillators (ICD) and may mimic perioperative myocardial infarction (MI). The purpose of this study was to assess the incidence and clinical significance of postoperative ECG changes in relation to clinical, laboratory, and implantation data. In 25 (16%) of 156 patients undergoing ICD implantation, significant ECG changes (> or = 50% reduction in R-wave amplitude in > or = 3 leads or new Q waves in > or = 2 leads) were present 1 to 3 days after the operation and persisted at hospital discharge in 12 (8%). Presence of thoracotomy, the total number of induced ventricular fibrillation episodes, and the number of defibrillation shocks required during defibrillation threshold (DFT) testing correlated with postoperative ECG changes. Other factors associated with a significant R-wave loss in the lateral precordial leads included left-sided pleural effusion, lung infiltrates or atelectasis, and large defibrillator patch electrodes over the left ventricle or the lateral chest wall. Myocardial necrosis documented by elevated cardiac enzymes occurred in 6 (5%) of 151 patients without significant ECG changes and in 3 (12%) with (p value not significant). However, postoperative ECG changes associated with elevated enzymes were indistinguishable from changes unrelated to necrosis. Therefore the sensitivity and specificity of the surface ECG for detection of MI after ICD placement is poor. Multiple factors such as thoracotomy, myocardial injury from DFT testing, electric insulation, or shielding of the heart may contribute to the development of electrocardiographic pseudo-infarct patterns.

Implantation of transvenous nonthoracotomy cardioverter-defibrillator systems in patients with permanent endocardial pacemakers.

Among 177 patients in whom a nonthoracotomy approach was initially used to implant a cardioverter-defibrillator system, 11 (6%) patients also received a separately implanted permanent pacemaker. The main problem encountered in these patients were previously implanted unipolar pacemakers (n = 3) and ventricular pacing leads positioned at the right ventricular apex, the latter interfering with optimal placement of the tripolar implantable cardioverter-defibrillator (ICD) lead (n = 9). The approaches used to solve these problems were individualized and included placement of the ICD sensing lead at the right ventricular outflow tract (n = 3), initial placement (n = 1) or subsequent repositioning (n = 2) of the right ventricular pacing lead at the outflow tract, upgrade from unipolar to bipolar systems (n = 2), reprogramming from the DDD to AAI mode (n = 2), inactivation of the pacemaker (n = 1), and simultaneous placement of a single-chamber atrial pacemaker with the ICD lead (n = 2). These revisions fulfilled the pacing needs in each patient and prevented unfavorable sensing interaction between the two systems.

Three-year outcome of a nonthoracotomy approach to cardioverter-defibrillator implantation in 189 consecutive patients.

To date, no long-term clinical data have been published in patients undergoing a nonthoracotomy approach to cardioverter-defibrillator system implantation. In the present report, 189 consecutive patients prospectively underwent a standardized approach to cardioverter-defibrillator system implantation in which the nonthoracotomy configurations were tested first. If satisfactory defibrillation thresholds were not obtained, thoracotomy was performed during the same intraoperative session. A nonthoracotomy system was successfully implanted in 149 of 189 patients (79%), with a higher success rate (90%) observed in patients who had more recent implantations. The overall rate of complications associated with these systems was low (11%). Over a mean follow-up of 12.5 +/- 9.3 months, 17 patients (9%) died. Three-year total, cardiac, and sudden death-free actuarial survival for all patients was 83 +/- 11%, 88 +/- 7%, and 94 +/- 2%, respectively. Three-year sudden death-free actuarial survival was higher in the nonthoracotomy than in the thoracotomy patients (97 +/- 2% vs 87 +/- 6%, p = 0.047), although total survival was similar (77 +/- 11% vs 83 +/- 7%, p = 0.77). These data suggest that a majority of patients (> 80%) requiring a cardioverter-defibrillator system can undergo implantation using a nonthoracotomy approach. Patients receiving nonthoracotomy systems have 3-year outcomes comparable to those implanted via thoracotomy. If these results are maintained, a nonthoracotomy approach will supplant thoracotomy-implanted systems as the preferred method because of the simpler implant procedure and lower overall cost involved.