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[Implantable defibrillator and ventricular resynchronisation].

Ventricular resynchronisation by pacing, introduced at the end of the 1990s, has revolutionised the management of advanced chronic cardiac failure. Its value in the reduction of haemodynamic mortality has been demonstrated in the latest studies. However, despite these decisive advances, patients with cardiac failure continue to have a high incidence of sudden death which, classically, according to its stage of progression, represents 28 to 68% of deaths in this condition. The implantable automatic defibrillator (IAD) has been shown to be effective in preventing sudden death, mainly in patients with severe left ventricular dysfunction. Based on these data, and in a context of rapid technological progress, devices capable of both defibrillating and resylchronising the heart have been introduced. The problems experienced at the beginning of their utilisation, mainly related to "double-counting" of left and right ventricular electrical activation have been resolved and the method is now technically feasible. A complication rate >10%, mainly due to the implantation of the left heart catheter, continues to bear witness to the difficulties of this technique and to the severity of the condition of patients referred for the treatment. The COMPANION trial has shown a greater reduction in mortality of patients treated by resynchronisation associated with IAD compared with resynchronisation alone or medical therapy in > or = Stage III cardiac failure. The SCD-HeFT trial has recently demonstrated that the primary prevention of global mortality by the IAD is effective in cardiac failure irrespective of the underlying cardiac pathology, especially in functional Stage II. These results should lead to significant increase in the indications for implantation of devices capable of both resynchronisation and defibrillation. However, the obvious problems of cost associated with the difficulty of the technique mean that a systematic attitude cannot be recommended. A case-by-case discussion has its place but the causal cardiac disease, ischaemic or not, does not seem to be a determining factor.

Cardiac Pacing, Artificial↗

[Combined cardiac resynchronization and implantable cardioversion defibrillation].

OBJECTIVE: To examine the efficacy and safety of implantation of the device with combined cardiac resynchronization therapy (CRT) and implantable cardioversion defibrillation (ICD) capabilities. METHODS: Eleven patients aged 48 - 80 (71.6 +/- 9.5) years, 7 male and 4 female, were included in the study. All patients had either a history of aborted sudden cardiac death, ventricular tachyarrhythmia, or induced ventricular tachycardia during cardiac electrophysiological study, whose left ventricular ejection fractions were 35% or less and QRS durations were 120 or longer. The patients were implanted a Medtronic INSYNC II MARQUIS(TH) 7289. All left ventricular leads were implanted in left lateral or left posterior lateral side-branches of coronary sinus. The procedures were performed in general anesthesia status. The AV interval was optimized guided by ECHO in all the patients in the day after the procedure. RESULTS: All procedures were successfully completed without major complications. The fluoroscopy time was 19 - 73 (44.7 +/- 19.9) min. Atrial lead amplitude, resistance and threshold were 0.5 - 3.5 (2.47 +/- 0.77) mV, 410 - 749 (590 +/- 126) Omega and 0.9 - 3.0 (1.37 +/- 0.71) V respectively. Right ventricular septal lead amplitude, resistance and threshold were 6.8 - 15.8 (11.00 +/- 3.48) mV, 387 - 750 (586 +/- 116) Omega and 0.4 - 1.0 (0.69 +/- 0.21) V respectively. The amplitude, resistance and threshold of left ventricular leads were 1.2 - 25 (15.37 +/- 5.15) mV, 423 - 812 (602 +/- 125) Omega and 0.3 - 5.0 (1.62 +/- 1.59) V respectively. The defibrillation thresholds (DFT) of 20 J were obtained in 3 patients, 6 J in 3 patients, and 15 J, 12 J and 3 J in one patient respectively. One of the 11 patients with failed old device did not obtain successful DFT after lead and device replacement and was defibrillated externally during DFT test. The another one did not obtain successful DFT because of abnormal ST-T changes in ECG. All devices were programmed to maximum of 30 J and discharged from the hospital in 48 hours except the one who failed to obtain DFT. The patients with mitral regurgitation improved after the AV optimization. CONCLUSIONS: Implantation of device with CRT and ICD features is safe even in aging patients. The long time outcomes of the clinical efficacy of this combined device remain to be observed.

Aged↗

Automated external defibrillators for home use.

The Philips HeartStart Home Defibrillator is an automated external defibrillator (AED) that is approved for home use by untrained users. Most cardiac arrests occur in the home, so a rapid response with cardiopulmonary resuscitation (CPR) and defibrillation is critical for survival. No prospective studies demonstrate that the use of AEDs in the home by untrained persons improves health outcomes. Further investigation is needed to determine the benefit and harm of AEDs in the home.

Adult↗

[Evaluation and surveillance of patients with an implantable defibrillator].

The implantable cardioverter-defibrillator became in some years the reference treatment of ventricular arrhythmias in association with heart disease. Recently, this technique showed its efficiency in primary prevention for patients at high risk of sudden death. The follow-up of patients with automatic defibrillator requires a detailed knowledge of both electrophysiology and stimulation. This training is based on a practical and theoretical formation. In France, a specific diploma validation is necessary and centres organisation is required. The purpose of this general review is to supply a set of updated data necessary for the coverage and the follow-up of patients with an implantable cardioverter-defibrillator.

Atrial Fibrillation↗

[The design of the external defibrillator using the truncated exponential biphasic waveform].

The external defibrillator is an emergency instrument used very widely in clinics. It plays an important role in rescuing ventricle fibrillation (VF) patients. We have designed an external defibrillator using the truncated exponential biphasic waveform. The system consists of three parts: the ECG collection module, the control module and the defibrillator module. They are introduced respectively, listing the main problems and the methods to solve them. Some experiments have been done and the corresponding results are given.

Animals↗

[Radiofrequency ablation in ventricular tachycardia: an alternative to implanted cardioverter defibrillator?].

Patients with ventricular tachycardia (VT) are subject to frequent recurrences despite antiarrhythmic drug therapy. Radiofrequency ablation is a useful alternative. Implantable defibrillators terminate episodes of VT but do not prevent them. The efficacy of catheter ablation depends on the cause and location of VT. There are two situations: VT in patients without identifiable structural heart disease or idiopathic VT and VT related to structural heart disease. After catheter ablation, idiopathic VT has a good prognosis and implantable defibrillators are usually not indicated. Scar-related VT are more difficult to treat with catheter ablation, but this technique is particularly useful for controlling frequent defibrillator shocks and incessant VT.

Catheter Ablation↗

The role of automated external defibrillators in dental practice.

Dental practices are seeing an increasing number of elderly and medically compromised patients, making it likely that staff will be called upon to respond to medical emergencies in the office, including cardiac arrest. Out-of-hospital cardiac arrests account for nearly half of all cardiovascular deaths in the United States. In adult cardiac arrest victims, the most frequent cause of sudden cardiac arrest is ventricular dysrhythmia, either ventricular tachycardia or ventricular fibrillation. The survival rate for sufferers of out-of-hospital cardiac arrests is a dismal 1% to 5% to hospital discharge. A majority of people who survive to discharge sustain significant morbidity. Untreated ventricular fibrillation degenerates into asystole, which is often refractory to resuscitative efforts and represents a terminal event. The development and availability of the automated external defibrillator (AED) represents a promising advance in the pre-hospital early defibrillation of victims of sudden cardiac arrest in a variety of settings, often remote from hospitals or EMS personnel. Given the medically compromised segment of the population treated in many dental practices today, it is imperative that dental practitioners and allied health providers become trained in the recognition and prompt initiation of emergency care, including basic life support with early defibrillation. The AED is becoming more accessible, with increasingly widespread availability, training in its use and relative ease of operation, making the goal of increased survival one in which dental health professionals can play a part.

Adult↗

Update on implantable cardioverter defibrillators: knowing the differences in devices and their impact on patient care.

Sudden cardiac death, a common cause of cardiac mortality, can be treated with either pharmacologic therapy or implantation of an implantable cardioverter defibrillator. Tremendous technologic advances have changed implantable cardioverter defibrillator therapy from shock-only therapy to multiprogrammable, tiered-therapy devices with backup pacing. Methods of implantation have changed from open chest to non-thoracotomy procedures. To provide optimal patient care, the critical care nurse is challenged to be knowledgeable about the different devices. In this article, the authors examine the commonalities and differences in device function in the seven currently available implantable cardioverter defibrillators and their impact on patient care.

Critical Care↗

[Implantable pacemaker-cardioconverter-defibrillator].

The aim of this article is to introduce the automatic, implantable cardioverter-defibrillator (AICD) device in connection with the first two cases in Hungary. At present time, the indications of the AICD implantation in the European Community are as follows: recurrent sustained episodes of ventricular tachycardia ventricular fibrillation or aborted sudden cardiac (arrhythmic) death, when the treatment of the underlying heart disease and/or the application of antiarrhythmic drugs, antitachycardia surgery (or catheter ablation procedures) proved to be unsuccessful in the prevention of the ventricular tachyarrhythmias (guided by serial intracardiac electrophysiologic testing and exercise testing), Holter monitoring. On the one hand the implantation of an AICD is not a causative treatment, on the other hand the cost of an AICD is extremely expensive. On the 8th of January, 1992, the first AICD (PCD Medtronic 7217B) implantation was performed in the Hungarian Institute of Cardiology. At the first patient with dilatative cardiomyopathy, the cardioverter defibrillator discharged successfully at 16 times. Unfortunately, the implantation of this patient with AICD could prolong his life only with months due to the rapid progression of the underlying cardiomyopathy. The second patient with AICD implantation went home after the uneventful surgery. The implanted cardioverter defibrillator unit worked properly, spontaneous ventricular tachycardia was terminated successfully. The AICD treatment considerably decreases the risk of sudden cardiac (arrhythmic) deaths.

Adult↗

[New approach for implantation of automatic defibrillators using videothoracoscopy].

Nonthoracotomy lead systems are increasingly used in patients (pts) with implantable cardioverter defibrillator (ICD). In this setting, due to high energy requirements, a subcutaneous patch may be necessary in addition to endocardial leads. However in some patients, high defibrillation threshold (DT) may persist leading to thoracotomy for epicardial patch placement. In a preliminary experience, 3 patients with high DT (> 20 J) following endocardial lead system, underwent the insertion of a extrapericardial patch under video-thoracoscopic control. A left subcostal incision extended to the left pleural cavity was performed. Using thoracoscopy the patch was positioned on the pericardium, sutured and connected to the defibrillator. DTs were 10, 10 and 20 J respectively in our 3 patients. Postoperative course was uneventful. Thoracoscopy allows other techniques such as a stellectomy, which we performed in a 33 year old woman with long QT syndrome. Patients were reassessed after 8 days and 2 months. Termination of induced ventricular fibrillation was achieved with the same minimal energy levels used peroperatively. In conclusion, extrapericardial patch insertion using thoracoscopy may help reduce DT in ICD patients with a non thoracotomy lead system. Comparison with other lead configurations requires further investigation.

Adult↗

[Psychosocial needs of patients carrying an implantable defibrillator].

Implantable defibrillators have created a new cardiac population. But with that population come particular needs. Eighty-five per cent of patients with implantable defibrillators experience significant fears and worries. Many of them fear the first shock or worry about the device's reliability. Others wonder if they will be able to remain in their current occupation. Despite these worries and others, 60 per cent of patients state being satisfied with the device. On the other hand, 53 per cent of these patients' spouses still fear the defibrillators. The authors of this article underline that nurses must learn to intervene appropriately to meet their patients' physical, learning and psychosocial needs. The nurse's responsibilities are to help patients identify their social support system and mobilize their resources, and to help family members in meeting patients' needs.

Defibrillators, Implantable↗

[New approach to implantation of automatic defibrillators using video-thoracoscopy].

Nonthoracotomy lead systems are increasingly used in patients (pts) with implantable cardioverter defibrillator (ICD). In this setting, due to high energy requirements, a subcutaneous patch may be necessary in addition to endocardial leads. However in some patients, high defibrillation threshold (DT) may persist leading to thoracotomy for epicardial patch placement. In a preliminary experience, 3 patients with high DT (> 20J) following endocardial lead system, underwent the insertion of a extrapericardial patch under video-thoracoscopic control. A left subcostal incision extended to the left pleural cavity was performed. Using thoracoscopy the patch was positioned on the pericardium, sutured and connected to the defibrillator. DTs were 10, 10 and 20 J respectively in our 3 patients. Postoperative course was uneventful. Thoracoscopy allows other techniques such as a stellectomy, which we performed in a 33 year old woman with long QT syndrome. Patients were reassessed after 8 days and 2 months. Termination of induced ventricular fibrillation was achieved with the same minimal energy levels used peroperatively. In conclusion, extrapericardial patch insertion using thoracoscopy may help reduce DT in ICD patients with a non thoracotomy lead system. Comparison with other lead configurations requires further investigation.

Adult↗

[Treatment of ventricular tachyarrhythmias with an implantable pacemaker-cardioverter-defibrillator].

During the period from November 1989 to January 1992, 17 patients with ventricular tachyarrhythmias received an implantable pacemaker-cardioverter-defibrillator. The material consists of three female and 14 male patients with an age range of 13-66 years, mean 50.8 +/- 16.6 years. 13 patients had coronary artery disease, one cardiomyopathy, one a myocarditis sequela and two primary rhythm disorder. Four patients received epicardial and 13 endocardial electrode systems. The observation period varied from 4-30 months (april 1992), mean 15.2 +/- 8.8 months. 11 out of 17 patients (65%) experienced one or more episodes of tachyarrhythmias which was treated successfully with overdrive pacing (ramp or burst), cardioversion or defibrillation. One patient died of heart failure after an observation period of 13 months. His pacemaker-cardioverter-defibrillator had been activated more than 100 times. Two children, 13 and 15 years, were treated successfully for ventricular fibrillation four and five months after implantation of the device. The actual one year survival is 100%. Assuming that therapy with a device had not taken place, and that the six patients who experienced episodes of ventricular fibrillation died, the hypothetical probability of survival would have been 62.1 +/- 12.3%.

Adolescent↗

[Automatic implantable defibrillators. Clinical experience apropos of 45 patients].

The aim of this study was to analyse the efficacy and survival after implantation of an automatic cardioverter-defibrillator.. Forty-five patients including 37 men were followed up for 0 to 51 months. The indications were ventricular fibrillation with no curable cause (n = 27) and sustained resistant or poorly tolerated ventricular tachycardia (n = 17) when programmed ventricular pacing with antiarrhythmic therapy was not applicable or gave poor results. One patient was implanted with this device for torsades de pointes. The underlying cardiac disease was ischaemic in 34 cases, non-ischaemic in 8 cases, and 3 patients had no apparent cardiac disease. Twenty patients were implanted with an epicardial system (group I) and 25 patients with endocardial system (group II). In group II, there was one complete failure of implantation requiring the use of an epicardial system and 2 partial failures requiring an additional epicardial patch electrode. The perioperative mortality was 2/45 (4.4%), both cases being due to permanent arrhythmias. In 5 patients, the minimal effective energy of defibrillation was over 25 Joules at implantation, without any untoward consequences on the clinical outcome. Ten non-fatal complications were observed including two major problems (haemopericardium); there were two cases of late increase of the minimal effective energy of defibrillation requiring the addition of a subcutaneous patch. Twenty-four patient (53%) received at least one appropriate therapy; 14 patients (36%) had at least one inappropriate shock during follow-up. During follow-up, 7 patients died, 6 of a cardiac cause and 3 of an arrhythmic problem.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

[Clinical value of intracavitary electrograms stored by implantable automatic defibrillator in patients resuscitated after cardiac arrest].

A major limitation of implantable defibrillators in the past has been the inability to document the arrhythmia precipitating discharge of the device. Although symptoms can be of some help in identifying the arrhythmia, symptomatic supraventricular arrhythmias and asymptomatic ventricular tachycardia (VT) have been documented in some cases before device discharge. The aim of this study was to systematically assess the value of stored intracardiac electrograms by implantable cardioverter-defibrillator in survivors of cardiac arrest during an antiarrhythmic drug free-period, in order to better define the arrhythmic profile determining device activation. The stored intracardiac electrograms of a fourth-generation cardioverter-defibrillator, implanted in 18 survivors of cardiac arrest were retrieved. The number of device activations, and the characteristics of any stored arrhythmic events were analyzed. A total number of 249 arrhythmic events were detected and stored over a mean follow-up of 378 +/- 107 days. These resulted in 78 delivered shocks, 84% of which were appropriate. Most of the detected events were episodes of unsustained VTs (33%), and atrial fibrillation or flutter (31%), which led to inappropriate shocks in 16% of the cases. The remaining recorded events were: sustained VT or fibrillation (66 episodes, 26%), sinus rhythm (11 events, 4%), not classified episode (6%). Of the 171 (69%) arrhythmic episodes not resulting in shocks, 73 events aborted before shock delivery by the device's reconfirmation algorithm, and the remaining 98 (39%) were detected but unsustained in duration, thus terminating before charging. In some cases, sustained and unsustained episodes of both supraventricular and ventricular arrhythmias gave symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Reimplantation of an infected, abdominally implanted defibrillator in the subpectoral region.

This report regards a 55-year-old patient with an abdominally implanted, nonthoracotomy, cardioverter defibrillator system (Medtronic PCD 7217B) due to recurrent ventricular tachycardia and survived sudden cardiac death. Fifteen months after defibrillator implantation clinical signs of system infection occurred. The defibrillator and the two leads (Medtronic 6963 and 6966) were removed and treatment with intravenous antibiotic therapy was started. Thereafter the original resterilized ICD was re-implanted in a right subpectoral position with new right ventricular-and superior vena cava leads. This report shows that reuse of the relatively large Medtronic PCD 7217B with a new transvenous lead system in a retropectoral location is feasible and economically beneficial with regard to the high device cost.

Anti-Bacterial Agents↗

[Transvenous cardioverter-defibrillators: clinical experience at implantation and follow-up].

Thirty-seven patients with ventricular tachyarrhythmias refractory to antiarrhythmic drug treatment, guided by electrophysiological testing, were submitted to implantation of a cardioverter-defibrillator by the transvenous technique. Mean age was 55 +/- 14 years and the underlying heart disease was coronary heart disease in 24 patients, cardiomyopathy or other etiologies in 11 patients. In 2 patients ventricular arrhythmias were idiopathic. Left ventricular ejection fraction was < or equal to 40% in 65% of the patients. The following devices were implanted: CPI Ventak P in 2 patients, Ventak P2 in 9 patients, Ventak PRx in 9 patients, Ventak PRxII in 2 patients, Telectronics Guardian ATP III 4215 in 9 patients, Siemens Siecure in 5 patients, Medtronic Jewel PCD in 1 patient. At implantation defibrillation threshold was lower with biphasic shocks than with monophasic shocks (17.0 +/- 3.2 vs 20.9 +/- 3.8 J, p < 0.003) and the need for subcutaneous patches was lower when biphasic shocks were employed. Operative and perioperative mortality were 0% and no significant complications were observed. During the follow-up (16 +/- 11 months) 35% of the patients had appropriate shocks and 93% of the patients with antitachycardia pacing availability (n = 15) had effective antitachycardia pacing interventions. The following complications were observed: lead failure in 4 patients (3 insulation breaks and 1 elongation for stretching), late lead dislodgement in 2 patients, lead recall in 1 patient, all of which required reintervention. Inappropriate shocks occurred in 30% of the patients and were related to lead failure, supraventricular arrhythmias or alternating current interference. During the follow-up one patient died of sudden death and one was submitted to heart transplantation. In conclusion, implantation of a cardioverter-defibrillator by the transvenous technique is a procedure relatively free from complications. During the follow-up lead failure appears to be one of the most relevant complications. Antitachycardia pacing allows effective termination of ventricular tachycardias without cardioversion, with a better compliance.

Adult↗

Migration of an automatic implantable cardioverter-defibrillator patch causing massive hemothorax.

The automatic implantable cardioverter-defibrillator is composed of shocking electrodes (patches or coils), sensing electrodes, and a generator implanted in the abdominal wall. A number of complications with defibrillators have been reported, including migration of the various components. We describe a patient in whom one of the patches, originally sutured extrapericardially, migrated in the right hemithorax and eroded into the ipsilateral lung. The resultant massive hemothorax necessitated urgent thoracotomy, patch removal, and hematoma evacuation. A hybrid implantable cardioverter-defibrillator system was created as a replacement to minimize surgery while protecting the patient from sudden death.

Defibrillators, Implantable↗