Defibrillator therapy 1997. Prerequisites--results--prospects

BACKGROUND: The first human cardioverter defibrillator implant was performed in 1980. Since then, significant technological improvement has been performed and today, ICDs with multiple diagnostic and therapeutic features are available. We report on 541 patients who underwent ICD implantation between January 1984 and March 1997. Epicardial ICD implant was performed in 209 patients (39%) and 332 patients (61%) received transvenous ICDs. PATIENTS AND RESULTS: Perioperative mortality was 2% (13 patients), significantly more frequent after epicardial (12/209 patients, 6%) than after transvenous implantation (1/332 patients) (p < 0.01). During a mean follow-up of 28 +/- 23 months, 104 patients died (20%), 15 of them (3%) suddenly. 8407 arrhythmic episodes were observed and terminated by antitachycardia pacing in 6655 (79%). Infections occurred in 13 patients (2%), electrode complications in 43 patients (8%) and inappropriate shocks in 84 patients (16%). CONCLUSION: The ICD is an effective approach to treat patients with life-threatening ventricular tachyarrhythmias leading to a low incidence of sudden death. Today, there is a low operative risk and modern ICDs have multiple diagnostic and therapeutic features that allow individual ICD therapy.     

Characteristics related to STD/HIV in men working in Mexico City bars where female prostitution takes place

Today, we are facing an exponential increase in implantation of cardioverter defibrillators (ICD). The intraoperative and follow-up results are reported in 105 patients (pts) with ventricular tachyarrythmias who underwent ICD implantation in the catheterization laboratory. Fifty-seven pts (54%) hat their first ICD implant (G 1), whereas 46 pts (44%) underwent pulse generator replacement or electrode revision (2 pts, 2%) (G 2). In all pts, ICD implant or pulse generator replacement was performed under general anesthesia from the beginning. In 57/58 pts (98%) in G 1, ICD implantation was possible with a mean defibrillation threshold (DFT) of 13 +/- 8 joules. One patient hat a DFT of > 25 joules and ICD implantation was not achieved. This patient underwent epicardial lead implantation 1 day later. One patient in G 1 had a vessel rupture (v. subclavia) intraoperatively. During a mean follow-up of 5 +/- 2 (< 1-13) months, three pts (3%) died from congestive heart failure, 2, 4 and 6 months after device implantation. An infection occurred in 1 patient in G 2, 3 months after generator replacement. Our data show that in the majority of patients ICD implantation in the cath-lab is possible, safe, and the complication rate is low. Therefore, ICD implantation in the cath-lab can generally be recommended.     

Incidence of implantable defibrillator discharges after coronary revascularization in survivors of ischemic sudden cardiac death

Coronary revascularization has been suggested as sole therapy for secondary prevention of sudden cardiac arrest associated with ischemia. The use of implantable defibrillators (ICD) in combination with coronary revascularization for this patient population is unclear. Among 412 consecutive patients receiving an ICD, 23 (6%) were identified as sudden cardiac arrest survivors who were noninducible with programmed stimulation and had unstable angina or ischemia on a functional study; they underwent successful coronary revascularization. During a follow-up of 34 +/- 18 months, 10 (43%) of the 23 patients received ICD shocks (8 +/- 8 per patient, range 1 to 22 shocks), and nine of the 10 patients had syncope/presyncope associated with at least one ICD discharge. Patients with ICD discharges were compared with those without ICD discharges, and no clinical characteristics were statistically different between the two groups. In conclusion, revascularization alone may be inadequate therapy for survivors of sudden cardiac arrest associated with ischemia who are noninducible with programmed stimulation, and clinical variables cannot predict which patients are likely to have recurrent malignant ventricular arrhythmias.     

Can amiodarone pulmonary toxicity be predicted in patients undergoing implantable cardioverter defibrillator implantation?

Implantable cardioverter defibrillator (ICD) implantation is rapidly becoming accepted as primary therapy for malignant ventricular arrhythmias. Many patients undergoing ICD implantation are on concomitant antiarrhythmic drugs to decrease shock frequency, slow tachycardia rate, and suppress supraventricular arrhythmias. Amiodarone is a potent antiarrhythmic agent that is also frequently used in the treatment of patients with refractory ventricular arrhythmias. Ten to forty percent of patients undergoing ICD implantation will also be taking amiodarone. It has been reported to cause pulmonary toxicity in about 5% of patients per year. Acute amiodarone toxicity presenting as adult respiratory distress syndrome has been reported much less frequently. Although perioperative morbidity due to amiodarone has been described, the risk, predictability, and consequences of acute pulmonary toxicity from amiodarone in patients undergoing ICD implantation have not been previously described. We reviewed the records of 99 consecutive patients undergoing ICD implantation at our institution from October 1987 to April 1992. Thirty-nine patients were taking 480 +/- 230 mg of amiodarone (median 400 mg, lower 20th percentile 400 mg, upper 80th percentile 800 mg) for 291 +/- 554 days prior to ICD implantation. Ten patients taking amiodarone developed acute pulmonary toxicity clinically manifesting as diffuse pulmonary infiltrates on chest radiography and adult respiratory distress syndrome with hypoxia (arterial pO2 < 60 mmHg) without evidence of pneumonia or elevated pulmonary capillary wedge pressure (PCW < or = 15 mmHg). Of the 60 patients not taking amiodarone none developed adult respiratory distress syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)     

Potential benefit from implantable cardioverter-defibrillator therapy in patients with and without heart failure

BACKGROUND: Whether patients with heart failure derive a benefit from therapy with implantable cardioverter-defibrillators (ICDs) has been questioned. The purpose of this study was to investigate whether New York Heart Association (NYHA) functional class had an impact on the potential benefit from ICD therapy as assessed from data stored in the memory of ICDs. METHODS AND RESULTS: Between 1989 and 1996, 603 patients (77% men; 59% with coronary artery disease and 16% with dilated cardiomyopathy; age, 57+/-13 years; ejection fraction, 44+/-18%) were treated with an ICD with extended memory function (storage of electrograms and/or RR intervals from treated episodes) in combination with endocardial lead systems. The stages of heart failure (NYHA functional class I through III) at implantation were correlated with overall mortality and the recurrence of fast ventricular tachyarrhythmias (>240 bpm) during follow-up. The potential benefit of the device was estimated as the difference between overall mortality and the hypothetical death rate had the device not been implanted. The latter was based on the recurrence of fast and, without termination by the devices, presumably fatal ventricular tachyarrhythmias. In the overall group, a significant difference between hypothetical death rate and overall mortality was observed (13.9%, 23.5%, and 26.6% at 1, 3, and 5 years, respectively) that suggested a benefit from ICD implantation. In patients in NYHA class I, the estimated benefit, which increased over time, was 15.2%, 29.2%, and 35.6% after 1, 3, and 5 years, respectively. In patients in NYHA class II or III, the estimated benefit increased until the third year (21.8% and 21.9%, respectively) and then remained constant until the fifth year (22.9% and 23.8%, respectively). Even those patients in NYHA class III with a history of decompensated heart failure benefited from ICD implantation. CONCLUSIONS: Analysis of stored ECG data suggests that in patients with a history of ventricular tachycardia or ventricular fibrillation, ICD therapy may lead to a prolongation of life in NYHA classes I through III. The initial benefit is greatest in patients in NYHA class II and class III, but the estimated benefit might persist longest for patients in NYHA class I.     

Arterial embolism complicating implantable cardioverter defibrillator shocks with normal ventricular function

A 69-year-old man developed an embolus to his right femoral artery 24 h following the insertion of an implantable cardioverter defibrillator (ICD), with multiple shocks administered in the early postoperative period. He had nonobstructive hypertrophic cardiomyopathy with normal left ventricular function and no evidence of left atrial or ventricular thrombus seen on pre- or postoperative transthoracic echocardiography. There was no evidence of atrial fibrillation documented before or after implantation of the device. He had no other known risk factors for thromboembolic disease. Thromboembolic phenomena as a complication of ICD use have been described but arterial emboli believed related to ICD shocks have not been reported in patients without impaired systolic function.     

Sudden cardiac death and the use of implantable cardioverter-defibrillators in pediatric patients. The Pediatric Electrophysiology Society

BACKGROUND: During the past decade, the implantable cardioverter-defibrillator (ICD) has emerged as the primary therapeutic option for survivors of sudden cardiac death (SCD). Investigation of the clinical efficacy of these devices has primarily assessed outcome in adults with coronary artery disease. The purpose of this cooperative, international study was to evaluate the impact of ICDs on the pediatric population of SCD survivors, based on an analysis of the clinical characteristics and outcomes of young patients who underwent ICD implantation following an episode of life-threatening ventricular tachycardia or resuscitation from SCD. METHODS AND RESULTS: An initial data base, established by contacting the manufacturers of the various commercially and investigationally available devices, identified 177 patients who were less than 20 years of age at the time of initial implantation of an ICD. With this data base as a reference, detailed responses were subsequently obtained from physicians involved in the care of 125 (71%) of these patients. The patients ranged in age from 1.9 to 19.9 years (mean, 14.5 +/- 4 years) and weighted 9.7-117 kg (mean, 44.6 +/- 14 kg). Of the 125 patients, 76% were survivors of SCD, 10% had drug refractory ventricular tachycardia, and 10% had syncope with heart disease and inducible sustained ventricular tachyarrhythmias. The most common types of associated cardiovascular disease were hypertrophic and dilated cardiomyopathies (54%), primary electrical diseases (26%), and congenital heart defects (18%). Ventricular function was abnormal in 46% of the patients. During a mean follow-up of 31 +/- 23 months, at least one ICD discharge occurred in 85 of the 125 (68%) patients. Seventy-three patients (59%) received at least one appropriate ICD discharge, and 25 patients (20%) had one or more spurious or indeterminate discharges. Duration of follow-up > 24 months (p = 0.001) and inducibility of a sustained ventricular arrhythmia (p = 0.05) were correlated with appropriate ICD discharges. There were nine deaths during the study period: five sudden, two due to recurrent ventricular arrhythmias, and two related to congestive heart failure. Abnormal ventricular function (p = 0.002) and prior ICD discharge (p = 0.01) were univariate correlates of patient mortality; by multivariate logistic regression, abnormal ventricular function was the only significant correlate of death (p = 0.005). By actuarial analysis, the estimated overall post-ICD implant survival rates at 1, 2, and 5 years were 95%, 93%, and 85%, respectively. The corresponding sudden death-free survival rates were 97%, 95%, and 90%. CONCLUSIONS: Pediatric patients resuscitated from SCD appear to remain at risk for recurrence of life-threatening tachyarrhythmias. During a mean follow-up of 31 months, the ICD provided an effective therapy for such arrhythmias in the majority of patients in this study. Following ICD implant, impaired ventricular function was the primary factor correlated with mortality. The patterns of ICD discharge observed in young patients and, thus, inferred risk of recurrent life threatening arrhythmias are similar to those of adult survivors of SCD. Thus, the use of ICDs in pediatric patients, with implant selection criteria similar to adults, appears valid.     

Predictors of arrhythmic death and cardiac arrest in the ESVEM trial. Electrophysiologic Study Versus Electromagnetic Monitoring

BACKGROUND: The purpose of this study was to determine if the presenting ventricular arrhythmia (ventricular tachycardia or ventricular fibrillation/cardiac arrest) predicted the type of arrhythmia recurrence in patients treated with antiarrhythmic drugs. METHODS AND RESULTS: In the previously reported Electrophysiologic Study Versus Electrocardiographic Monitoring (ESVEM) trial, there were 486 patients who were randomized to antiarrhythmic drug testing guided by electrophysiological study or by ambulatory ECG monitoring. Use of a defibrillator (implantable cardioverter-defibrillator, ICD) without stored electrograms among 81 patients precluded determination of the type of arrhythmia recurrence; thus these patients were censored at the time of ICD implantation. Of the 486 patients, 381 presented with ventricular tachycardia and 105 with cardiac arrest. Over a 6-year follow-up period, 285 of the 486 patients had an arrhythmia recurrence; of these, 97 had an arrhythmic death or cardiac arrest as a first recurrence. In the current analysis, all 129 arrhythmic deaths/cardiac arrests that occurred any time during follow-up were evaluated as end points. CONCLUSIONS: Although univariate analysis suggested that there was an association between the presenting arrhythmia and outcome, multivariate analysis failed to substantiate the predictive value of the presenting arrhythmia. Left ventricular ejection fraction was the single most important predictor of arrhythmic death or cardiac arrest. This information may be an important factor in deciding whether to advise ICD therapy.     

Adverse events with transvenous implantable cardioverter-defibrillators: a prospective multicenter study. European 7219 Jewel ICD investigators

BACKGROUND: A newly developed classification system relates adverse events to the surgical procedure or the function of the implantable defibrillator. METHODS AND RESULTS: Adverse events were monitored during prospective clinical evaluation of the Medtronic model 7219 Jewel ICD and were classified according to the definitions of the ISO 14155 standard for device clinical trials into 3 groups: severe and mild device-related and severe non-device-related adverse events. In addition, events were related to the surgical procedure, treatment with the device, or cardiac function. Seven hundred seventy-eight patients were followed up for an average of 4.0 months after ICD implantation. In total, 356 adverse events were observed in 259 patients. At 1, 3, and 12 months after ICD implantation, 99%, 98%, and 97% of the patients, respectively, survived; 95%, 93%, and 92%, respectively, were free of surgical reintervention; and 79%, 68%, and 51%, respectively, were free of any adverse event. Twenty patients died: 6 deaths were related to the surgical procedure, 12 deaths were considered unrelated to ICD treatment, and 2 patients died of an unknown cause. Of 111 nonlethal severe adverse device effects, 47 required surgical intervention, 19 times for correction of a dislodged lead. Inappropriate delivery of therapy was observed 128 times in 111 patients, and the events were typically resolved by reprogramming or drug adjustment. Nine of these required rehospitalization. CONCLUSIONS: Approximately 50% of patients experience an adverse event within the first year after ICD implantation. The observed adverse event rate depends on the definitions and the prospective monitoring. The incidence of inappropriate therapy emphasizes the need for improved detection algorithms and for quality-of-life evaluations, especially when considering ICD treatment in high-risk but arrhythmia-free patients.     

Comparison of three cardioverter defibrillator implantation techniques: initial results with transvenous pectoral implantation

A total of 121 patients underwent epicardial (n = 32), transvenous abdominal (n = 30), and transvenous pectoral (n = 59) ICD implants. Perioperative complications were defined as those occurring within 30 days after surgery. Hospital costs were calculated with $750 per day as a fixed charge. Duration of surgery was the time between the first skin incision and the last skin suture. Severe perioperative complications that were life-threatening or required surgical intervention occurred in the epicardial (6%) and transvenous (10%) abdominal groups, but not in the pectoral group. Perioperative mortality occurred only in the epicardial abdominal group, predominantly in patients with concomitant surgery (18%), and in 5% of patients without concomitant surgery. The duration of surgery was significantly shorter for transvenous pectoral implantation (58 +/- 15 min, P < 0.05) compared to transvenous abdominal implantation (115 +/- 38 min). Epicardial abdominal ICD implantation had the longest procedure time (154 +/- 31 min). The postimplant hospital length of stay was significantly shorter for pectoral implantation (5 +/- 3 days, P < 0.05) compared to transvenous (13 +/- 5) and epicardial (19 +/- 5) abdominal implantation. Total hospitalization costs significantly decreased in the pectoral implantation group ($4,068 +/- $2,099 for the pectoral group vs $14,887 +/- $4,415 and $9,975 +/- $3,657 for the epicardial and the transvenous abdominal group, respectively, P < 0.05). These initial results demonstrate the advantage of transvenous pectoral ICD implantation in terms of perioperative complications, procedure time, hospital length of stay, and hospitalization costs.     

Non-pharmacologic prevention of sudden cardiac death

Non-pharmacologic therapy has revolutionized the management of arrhythmias and prevention of sudden cardiac death (SCD). Of particular importance is the introduction of radiofrequent catheter ablation (RFCA) and implantable cardioverter-defibrillator (ICD). RFCA is effective and useful in the treatment and prevention of SCD, especially in supraventricular tachyarrhythmias related to dual or accessory atrioventricular pathways. There are some limitations in using this method in the prevention of SCD in ventricular tachyarrhythmias. RFCA is very successful, particularly in the treatment of bundle branch reentrant ventricular tachycardia and ventricular tachycardia in patients without structural heart disease. RFCA can be used as a palliative treatment of incessant or frequent VT before and after ICD implantation. Antibradycardia pacing decreases SCD not only by the removal of serious bradyarrhythmias but also by prevention of the occurrence of malignant ventricular tachyarrhythmias induced by bradyarrhythmia. Antitachycardia pacing is used in the prevention of SCD only as a part of ICD device. Implantation of an antitachycardia pacemaker as an isolated permanent treatment of tachycardias is currently almost not used. This method was replaced by RFCA in supraventricular tachyarrhythmias and by ICD in ventricular tachyarrhythmias. ICD is a very perspective non-pharmacologic approach to SCD prevention, particularly as transvenous leads were introduced and device construction was simplified. ICD is indicated especially in patients with spontaneous sustained hemodynamically significant ventricular tachycardia/ventricular fibrillation and when antiarrhythmic drug treatment, RFCA or antitachycardia surgery are ineffective, intolerated, contraindicated or cannot be performed. ICD as the treatment of first choice instead of antiarrhythmic drugs as well as prophylactic ICD implantation in asymptomatic patients at high risk is a subject of discussion. ICD decreases the incidence of SCD significantly. However, the decrease in overall mortality was not verified. Antitachycardia surgery is less frequently used after RFCA, and ICD have been introduced. At present, this therapy is reserved only for the cases of failure of RFCA or the impossibility to use RFCA and ICD. Surgical therapy can be combined also with concommitant surgical correction of associated structural heart disease. Sympathectomy is used in prevention of malignant ventricular tachyarrhythmias and SCD in patients with congenital long Q-T syndrome. Selective left cardiac sympathetic denervation significantly reduces the risk of SCD in these patients but does not remove it completely. Heart transplantation is the last alternative of non-pharmacologic prevention of SCD. It is indicated in cases when all pharmacologic and non-pharmacologic approaches have been exhausted. Heart transplantation is the only effective modality for the improvement of long-term prognosis in patients with malignant ventricular tachyarrhythmias and advanced chronic heart failure.     

Short-term and long-term outcome of left heart function after cardioverter defibrillator implantation

The usefulness and problems of implantable cardioverter defibrillators (ICD) were examined in patients with reduced heart function. Of 36 patients who received ICD for refractory ventricular tachycardia (VT) or ventricular fibrillation (VF), VT and/or VF was associated with underlying heart disease in 26 patients, and VF without underlying heart disease in 10. Of the former 26 patients, 13 with left ventricular ejection fraction (LVEF) of less than 30% were assigned to group A, 13 with LVEF of greater than 30% to group B, and the other 10 with idiopathic VF to group C. Intraoperative death, cardiac death due to heart failure, sudden death, functional status of the ICD, exacerbation of heart failure symptoms and complications were compared between the three groups. There were no intraoperative deaths in any of the groups. During the median follow-up period of 36 +/- 22 months, there was only one sudden death in group A. There were no significant differences between the three groups. There were five cardiac deaths in group A, but none in groups B or C. The cardiac death-free rates 12, 24, and 36 months after implantation in group A were 83%, 60% and 50%, respectively. These values significantly differed from those in groups B and C (p < 0.05). The number of patients who received defibrillation therapy was higher in group A (p < 0.05). Defibrillation therapy was administered earlier in group A than in groups B and C (p < 0.05). The incidence of exacerbation of heart failure after implantation was 69%, 23% and 0% in groups A, B, and C, respectively. In group A, defibrillation therapy was administered in all patients with exacerbation of heart failure. The administration of defibrillation therapy significantly differed from that in patients without exacerbation of heart failure (p < 0.05). Exacerbation of heart failure during the postoperative acute stage occurred in both patients in group A in whom an epicardial lead system was used, but not in the four patients in group B or five in group C (p < 0.05). There were no differences in the incidence of other complications between the three groups. In group A, patients with reduced heart function, ICD greatly decreased the risk of sudden death. However, heart failure mortality remained high. Therefore, ICD may have limitations for improved prognosis. In group A patients, defibrillation therapy was administered in all patients with exacerbation of heart failure or death due to heart failure. In patients with reduced heart function, treatment for heart failure and prophylaxis of VT and/or VF should be administered.     

Favorable results of implantable cardioverter-defibrillator implantation in patients older than 70 years

BACKGROUND: The clinical results of implantable cardioverter-defibrillator (ICD) implantation in the elderly have received limited documentation. As the longevity of the U.S. population has increased, so has the need for ICD implantation in the elderly. We evaluated the efficacy and outcome of ICD implantation in elderly patients (>70 years) compared with younger patients. METHODS: The case records of all consecutive patients who underwent ICD implantation at our institution between 1986 and 1994 were reviewed. Of a total of 238 patients, 78 patients were 70 years of age or older and 160 patients were younger than 70 years of age. RESULTS: The mean age of the younger group was 58 years and that of the elderly group was 74 years. There were no statistical differences in the presence of coronary artery disease, left ventricular systolic function, the inducibility of arrhythmias, or the history of sudden cardiac death. The hospital morbidity rate was similar in both groups (6.9% in the younger group and 7.7% in the elderly group; p = not significant). The operative mortality rate was 1.9% for the younger group and 1.3% for the elderly group (p = not significant). At a mean follow-up of 33 +/- 26 months, Kaplan-Meier survival curves demonstrated similar survival rates, with 93%, 82%, and 65% of the patients alive at 1, 3, and 6 years, respectively. CONCLUSIONS: Implantable cardioverter-defibrillator implantation was equally effective in the treatment of patients older than 70 years as in younger patients. No differences in theoretic survival or morbidity were observed.     

Complications associated with pectoral cardioverter-defibrillator implantation: comparison of subcutaneous and submuscular approaches. Worldwide Jewel Investigators

OBJECTIVES: The aim of this study was to compare complications in a large cohort of patients undergoing pectoral cardioverter-defibrillator implantation with a subcutaneous or submuscular approach. BACKGROUND: Pectoral placement of implantable cardioverter-defibrillator (ICD) pulse generators is now routine because of downsizing of these devices. subcutaneous implantation has been advocated by some because it is a simple surgical procedure comparable to pacemaker insertion. Others have favored submuscular insertion to avoid wound complications. These surgical approaches have not been compared previously. METHODS: The subjects for this study were 1,000 consecutive patients receiving a Medtronic Jewel ICD at 93 centers worldwide. Cumulative follow-up for all patients was 633.7 patient-years, with 64.9% of patients followed up for > or = 6 months. The complications evaluated were erosion, pocket hematoma, seroma, wound infection, dehiscence, device migration, lead fracture and dislodgment. RESULTS: Subcutaneous implantation was performed in 604 patients and submuscular implantation in the remaining 396. The median procedural times were shorter for subcutaneous implantation (p = 0.014). In addition, the cumulative percentage of patients free from erosion was greater for subcutaneous implantations (p = 0.03, 100% vs. 99.1% at 6 months). However, lead dislodgment was more common with subcutaneous implantations (p = 0.019, 2.3% vs. 0.5% at 6 months) and occurred primarily during the first month postoperatively. Overall, there were no significant differences in cumulative freedom from complications between groups (4.1% vs. 2.5%, p = 0.1836). CONCLUSIONS: Subcutaneous pectoral implantation of this ICD can be performed safely and has a low complication rate. This approach requires a simple surgical procedure and, compared with the submuscular approach, is associated with shorter procedure times and comparable overall complication rates. However, early follow-up is important in view of the increased lead dislodgment rate.     

Mechanisms of syncope in implantable cardioverter-defibrillator recipients who receive device therapies

A significant proportion of implantable cardioverter defibrillator (ICD) recipients ultimately receive device therapies. Determinants and mechanisms of syncopal events in these patients are not established. To address this issue, we reviewed prospectively collected data on 114 ICD recipients who received device therapies. There were 99 men and 15 women with a mean age of 63+/-10 years. Ejection fraction was 29+/-13%. At initial presentation, 74 patients (65%) had syncope during arrhythmia. Of 114 patients, 18 patients (16%) subsequently experienced syncope during device therapies over a period of 35+/-24 months of follow-up. Arrhythmias during syncopal events documented by telemetry, event recorders, RR intervals, or ICD stored electrograms were obtainable in 13 patients, and included sustained monomorphic ventricular tachycardia (VT) in 10 patients, ventricular fibrillation (VF) in 2 patients, and atrial fibrillation in 1 patient. The explanations for arrhythmia-related syncope included ICD proarrhythmia in 8 patients (62%), rapid monomorphic VT in 3 (23%), and VF in 2 patients (15%). Patients with syncope could not be differentiated from those without syncope by demographic, clinical, or electrophysiologic variables. There was no significant difference in mortality between patients with or without syncope (39% vs 25%, p = 0.25). Syncope is not uncommon in ICD recipients who receive device therapies. When it occurs, syncope is often due to ICD proarrhythmia; hence, it is potentially preventable by meticulous device programming.     

RB protein status and chemosensitivity in non-small cell lung cancers

A total of 1,207 patients received a Medtronic Jewel active can ICD (models 7218C, 7219C), with a Transvene lead 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, antiarrhythmic drug therapy, indication for the implantable cardioverter defibrillator, 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.     

Bronchodilator response to salbutamol after chronic dosing with salmeterol or placebo

OBJECTIVES: We report the occurrence of cardiac events during long-term follow-up in patients with hypertrophic cardiomyopathy (HCM) after cardioverter-defibrillator implantation. BACKGROUND: The identification of patients at high risk for sudden death and the prevention of recurrence of sudden death in HCM represents a difficult problem. METHODS: We retrospectively analyzed the occurrence of cardiac events during follow-up of 13 patients with HCM who received an implantable cardioverter-defibrillator (ICD) because of aborted sudden death (n = 10) or sustained ventricular tachycardia (n = 3) (group I). Findings were compared with those in 215 patients with an ICD and other structural heart disease or idiopathic ventricular fibrillation (group II). RESULTS: After a mean (+/-SD) follow-up period of 26+/-18 months, 2 of 13 patients in group I received appropriate shocks. The calculated cumulative incidence of shocks was 21% in group I and 66% in group II after 40 months (p < 0.05). We observed a low incidence of recurrence of ventricular tachycardia/fibrillation during follow-up in patients with HCM. No deaths occurred. CONCLUSIONS: Our data suggest that ventricular tachyarrhythmias may not always be the primary mechanism of syncope and sudden death in patients with HCM. The ICD seems to have a less important impact on prognosis in patients with HCM than in patients with other etiologies of aborted sudden death.     

Syncope in patients with an implantable cardioverter-defibrillator: incidence, prediction and implications for driving restrictions

OBJECTIVES: This retrospective study was undertaken to provide information on occurrence, risk prediction and prevention of syncope in patients with an implantable cardioverter-defibrillator (ICD). BACKGROUND: ICDs effectively terminate ventricular tachycardia and fibrillation (VT/VF). Incapacitating symptoms, such as syncope, may still occur. METHODS: We performed a retrospective analysis of data from 421 patients (clinical history, outpatient chart reviews and episode data) with mean (+/-SD) follow-up of 26 +/- 18 months. RESULTS: Of 421 patients, 229 (54.4%) had recurrent VT/VF, and 62 (14.7%) had syncope. The actuarial survival rate free of VT/VF was 58%, 45% and 37% and that for survival free of syncope was 90%, 85% and 81% at 12, 24 and 36 months after implantation, respectively. Once VT/VF had occurred, 76%, 68% and 62% of patients remained free of syncope during the following 12, 24 and 36 months, and 68%, 64% and 56% remained free of second syncope 12, 24 and 36 months after first syncope, respectively. In cases of syncope, the mean cycle length (CL) of VT was 251 +/- 56 ms. A low baseline left ventricular ejection fraction (LVEF), induction of fast VT (CL <300 ms) during programmed ventricular stimulation and chronic atrial fibrillation (AF) were associated with an increased risk of syncope. If the LVEF was >40%, fast VT had not been induced, and patients had no chronic AF; 96%, 92% and 92% of patients remained free of syncope after 12, 24 and 36 months, respectively. Once patients had a VT recurrence, syncope during the first VT and a high VT rate were the strongest risk predictors of future syncope. CONCLUSIONS: Identification of patients with an ICD with a low and high risk of syncope seems to be feasible and might help as a guide to driving restrictions in such patients.