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Results of the international study of the implantable pacemaker cardioverter-defibrillator. A comparison of epicardial and endocardial lead systems. The Pacemaker-Cardioverter-Defibrillator Investigators.

BACKGROUND: The purpose of the present report was to document clinical experience derived from the implantation of 2834 epicardial and endocardial cardioverter-defibrillators (ICDs) in 2807 patients who were followed for almost 1 year and to compare the results obtained with the two systems. METHODS AND RESULTS: Patients in the two groups had similar clinical characteristics. More than half of the patients had a total of almost 50,000 spontaneous ventricular tachyarrhythmias that were terminated with equal success (approximately 98%) by epicardial and endocardial ICDs. Lead dislodgement and pocket infection occurred more often with the endocardial than with the epicardial ICD, whereas perioperative mortality was higher with the epicardial ICD than with the endocardial ICD. Mortality from sudden cardiac death was 1.4% in the epicardial ICD group and 0.6% in the endocardial ICD group at 1 year (P = .069). Overall mortality at 1 year was 12.2% and 6.9% for the epicardial and endocardial groups, respectively (P < .001), reflecting the higher surgical mortality for the epicardial system. CONCLUSIONS: The endocardial ICD is as effective as the epicardial ICD but incurs lower perioperative mortality.

Adult↗

[Massive myocardial hypertrophy in hypertrophic cardiomyopathy: a risk factor for sudden death and high defibrillation threshold during cardioverter-defibrillator implantation].

Two cases of hypertrophic cardiomyopathy with massive hypertrophy and high defibrillation threshold (DFT) are described. A 14-year-old boy, whose single risk factor for sudden death was extreme hypertrophy with maximum interventricular septum (IVS) thickness of 43 mm, survived an episode of ventricular fibrillation. During ICD implantation DFT testing showed energy requirements >30 J and the procedure was aborted. Amiodarone and verapamil treatment was discontinued and treatment with oral sotalol was instituted. After a period of amiodarone washout the procedure was repeated and DFT of 24 J was encountered. An 18-year-old female with massive hypertrophy (IVS thickness=35 mm) and other risk factors for sudden death underwent ICD implantation for primary prevention. During the procedure DFT=20 J and ICD with 30 J maximal output was implanted. An increase in DFT to more than 20 J was encountered during pre-discharge test. Lack of 10 J safety margin warranted ICD system revision and upgrade; during the second procedure DFT was 24 J and ICD with 35 J maximal output was implanted. In summary, in both cases ICDs with 35 J maximal output were successfully implanted.

Adolescent↗

["Circumscribed defibrillator erythema": a differential diagnostic and therapeutic problem in differential occult defibrillator infection diagnosis].

We report about three out of 452 patients (pts) (< 1 %) with circumscribed erythema (E) after implantation of an automatic cardioverter defibrillator (ICD). ICD-E occurred in two pts after pulse generator replacements and in one pt after initial ICD implantation. There were no clinical signs of inflammation and laboratory and technical finding were completely normal. Allergic reactions could be ruled out in all pts. Local or systemic drug treatment did not influence the ICD-E. During a follow-up of 28, 10 or 9 months, the ICD-E is still present in two patients and much improved in one pt without any treatment. We did not observe an infection in any of the pts. Our data show that the ICD-E occur rarely after ICD implantation and no special treatment is necessary if an infection or allergic reaction has been excluded. Nevertheless, it is sometimes difficult to exclude in those pts an atypical infection.

Adult↗

Student nurses can defibrillate within 90 seconds. An evaluation of a training programme for third year student nurses in the use of an automatic external defibrillator.

Automatic external defibrillators (AEDs) provide a means of reducing the response time in cardiac arrests but policies based on their use must take into account the costs of retraining. These depend on the level of retention of skills over time. This paper describes the retention of skills by student nurses following a training programme on the use of AEDs in cardiac resuscitation. Sixty-three student nurses were studied at intervals of 1 week, 1, 3 and 6 months following training. There was a slight deterioration in skills at 1 week and 1 month but the scores returned to the baseline level at 3 months and remained there. We conclude that there is now a case for a major study of the use of nurse-operated AEDs in the hospital setting.

Clinical Competence↗

Automatic external defibrillators for prevention of out-of-hospital sudden death: effectiveness of the automatic external defibrillator.

Approaches to the prevention of sudden cardiac death (SCD) include strategies designed to attack the problem from the multiple perspectives of primary prevention of the underlying diseases, prophylactic treatment of high-risk individuals with identified diseases, and responses to cardiac arrest victims in the community. The latter strategy began with conventional fire department-based emergency rescue systems (emergency medical services [EMS]) that originated in the early 1970s. Although such systems were innovative and impressive at the time, they are limited by less-than-optimal response times that translate to low survival rates. Newer strategies, designed to respond faster, include a variety of methods, including ambulance- and police-based automatic external defibrillators (AEDs), deployment of AEDs in settings in which crowds accumulate and designated rescuers are available, and more general public access sites. The value of conventional EMS systems remains because of their ability to provide advanced life support as part of a dual-response system. These approaches, in conjunction with better primary and secondary prevention strategies, offer the hope of reducing the SCD burden.

Arrhythmias, Cardiac↗

High-dose lidocaine does not affect defibrillation efficacy: implications for defibrillation mechanisms.

This study assessed the effect of low (10 mg.kg-1.h-1) and very high (18 mg.kg-1.h-1) doses of lidocaine on defibrillation energy requirements (DER) to relate changes in indexes of sodium-channel blockade with changes in DER values using a dose-response study design. In group 1 (control; n = 6 pigs), DER values were determined at baseline and during treatment with 5% dextrose in water (D5W) and with D5W added to D5W. In group 2 (n = 7), DER values were determined at baseline and during treatment with low-dose lidocaine followed by high-dose lidocaine. In group 3 (n = 3), DER values were determined at baseline and high-dose lidocaine. Group 3 controlled for the order of lidocaine treatment with the addition of high-dose lidocaine after baseline. DER values in group 1 did not change during D5W. In group 2, low-dose lidocaine increased DER values by 51% (P = 0.01), whereas high-dose lidocaine added to low-dose lidocaine reduced DER values back to within 6% of baseline values (P = 0.02, low dose vs. high dose). DER values during high-dose lidocaine in group 3 also remained near baseline values (16.2 +/- 2.7 to 12.9 +/- 2.7 J), demonstrating that treatment order had no impact on group 2. Progressive sodium-channel blockade was evident as incremental reduction in ventricular conduction velocity as the lidocaine dose increased. Lidocaine also significantly increased ventricular fibrillation cycle length as the lidocaine dose increased. However, the greatest increase in DER occurred when ventricular fibrillation cycle length was minimally affected, demonstrating a negative correlation (P = 0.04). In summary, lidocaine has an inverted U-shaped DER dose-response curve. At very high lidocaine doses, DER values are similar to baseline and tend to decrease rather than increase. Increased refractoriness during ventricular fibrillation may be the electrophysiological mechanism by which high-dose lidocaine limits the adverse effects that low-dose lidocaine has on DER values. However, there is a possibility that an unidentified action of lidocaine is responsible for these effects.

Animals↗

Is arrhythmia detection by automatic external defibrillator accurate for children?: sensitivity and specificity of an automatic external defibrillator algorithm in 696 pediatric arrhythmias.

BACKGROUND: Use of automatic external defibrillators (AEDs) in children aged <8 years is not recommended. The purpose of this study was to develop an ECG database of shockable and nonshockable rhythms from a broad age range of pediatric patients and to test the accuracy of the Agilent Heartstream FR2 Patient Analysis System for sensitivity and specificity. METHODS AND RESULTS: Children aged </=12 years who either developed arrhythmias or were at risk for developing arrhythmias were studied. Two sources were used for the database: children whose rhythms were recorded prospectively via a modified AED and children who had arrhythmias captured on paper and digitized for subsequent analysis. The rhythms were divided into 5-second strips, classified by 3 reviewers, and then assessed by the AED analysis algorithm. A total of 696 five-second rhythm strips from 191 children (81 female and 110 male) aged 1 day to 12 years (median 3.0 years) were analyzed. There was 100% specificity for nonshockable rhythms. Sensitivity for ventricular fibrillation was 96%. CONCLUSIONS: There was excellent AED rhythm analysis sensitivity and specificity in all age groups for ventricular fibrillation and nonshockable rhythms. The high specificity and sensitivity indicate that there is a very low risk of an inappropriate shock and that the AED correctly identifies shockable rhythms, making the algorithm both safe and effective for children.

Adult↗

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

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

Aged↗