Automatic Internal Cardiac Defibrillator Research Articles

Left Mini Thoracotomy as a Method for Epicardial Implantable Cardioverter-Defibrillator Placement in a Child. An Effective Alternative to the Transvenous Approach

In infants and children, the small size of the systemic veins precludes safe and durable transvenous placement of automatic internal cardiac defibrillator (ICD). In such cases, an alternative method of implanting an automatic ICD is via thoracotomy. This report describes the technique used at Onassis Cardiac Surgery Center for the epicardial placement of an ICD system with a transvenous ICD coil placed in the posterior pericardium via a left thoracotomy, producing a stable location and excellent coil-to-can vector for successful defibrillation. To the best of our knowledge, this is the first case in Greece.

A Novel Method for Epicardial Defibrillator Lead Placement in Young Children: Coil Between the Great Arteries

The primary and secondary prevention of sudden cardiac death resulting from malignant arrhythmia, channelopathy, and hypertrophic cardiomyopathy often requires the implantation of automatic internal cardiac defibrillators (AICDs) in the pediatric population. In young patients, the small size of the systemic veins, complex anatomy of congenital heart disease, and body habitus often preclude safe and durable transvenous placement of the AICD coil, requiring innovative methods to circumvent this problem. This report describes the technique used at Rady Children's Hospital San Diego/UCSD for the epicardial placement of an ICD system with a transvenous ICD coil placed between the aorta and pulmonary artery, thereby producing a stable location and excellent coil-to-can vector for successful defibrillation.

CaMKII Inhibition

Electrical storm (ES), a medical emergency, is the frequent occurrence of ventricular tachycardia or fibrillation, defined as 3 or more episodes in a 24-hour period. Although ES can occur in a variety of settings, including ischemia, heart failure, and channelopathies, general incidence and awareness of this condition have dramatically risen since the advent of automatic internal cardiac defibrillators (ICDs). Approximately half of the patients who receive an ICD for secondary prevention of sudden cardiac death will receive an appropriate shock to abort a life-threatening ventricular arrhythmia within the first 2 years of device implantation, and 10% to 20% will experience ES.1 Although this number is lower (≈4%) in patients who receive an ICD for primary prevention, the absolute number is still very high given the large number of devices implanted for this indication (≈152 000 ICDs per year as of 2007). ES has serious prognostic implications, because patients who have had ES have a higher death rate than ICD patients who never experience ES, mostly because of worsening heart failure. The relentless progression of heart failure in many patients with structural heart disease highlights the fact that conventional ICD therapy does not favorably affect the pathways responsible for myocardial dysfunction. In addition to being a marker for early death, ES can be a terrifying experience in conscious patients. Clearly, improved ES therapies are necessary and desirable, but lack of understanding of the underlying mechanisms causing ES has led to limitations in successfully treating or preventing ES. Article see p 2192 Whereas multiple models have been described to study ventricular arrhythmias, there has been a paucity of animal models to study ES, which presents a unique set of challenges and complexities. In the current issue of Circulation , Tsuji et al2 developed a new rabbit model of ES by …

Amiodarone Is Poorly Effective for the Acute Termination of Ventricular Tachycardia

It is hypothesized that intravenous (IV) amiodarone is poorly effective for the acute termination of sustained monomorphic ventricular tachycardia because of the relatively slow onset of its Vaughn-Williams class III effect to prolong myocardial depolarization and the refractory period. This study is designed to determine the effectiveness and safety of IV amiodarone for the termination of sustained monomorphic ventricular tachycardia. A retrospective case series was collected at 4 urban university-affiliated hospitals from September 1996 to April 2005 after institutional review board approval with waiver of informed consent. Emergency department (ED) patients treated with IV amiodarone for ventricular tachycardia were identified by ED treatment and hospital pharmacy billing records, International Classification of Diseases, Ninth Revision discharge codes, and ECG characteristics. All consecutive patients who received at least 150 mg amiodarone in 15 minutes or less for spontaneous sustained monomorphic ventricular tachycardia were eligible for inclusion. Sustained monomorphic ventricular tachycardia was defined as a tachycardia with uninterrupted duration or rapid recurrence despite automatic internal cardiac defibrillator therapy for at least 5 minutes before amiodarone treatment, monomorphic morphology, rate greater than 120 beats/min, QRS duration greater than 120 ms, and subsequently determined to be ventricular tachycardia by ECG criteria (eg, atrioventricular dissociation), implanted device interrogation, or formal electrophysiology study. Measured outcomes included sustained termination of ventricular tachycardia within 20 minutes of initiation of amiodarone infusion and any documented adverse effects. Rates of successful termination and adverse effects and their 95% confidence intervals (CIs) were calculated. The presence or average values of potentially confounding predictors in patients with and without ventricular tachycardia termination after amiodarone were also calculated and compared. Thirty-three patients were identified and included. Five patients received electrical therapy within 20 minutes of initiation of amiodarone infusion, and the response to amiodarone was unknown. Twenty-seven of the remaining 28 patients received 150 mg amiodarone, and the rate of successful ventricular tachycardia termination was 8 of 28, 29% (95% CI 13 to 49). Two of 33 patients, 6% (95% CI 1 to 20), required direct current cardioversion for presyncope or hypotension temporally associated with amiodarone treatment. IV amiodarone, as currently administered, is relatively safe but ineffective for the acute termination of sustained ventricular tachycardia.

Technology at the Crossroads with Care and Costs: The Implantation of the Automatic Internal Cardiac Defibrillator

Technology at the Crossroads with Care and Costs: The Implantation of the Automatic Internal Cardiac Defibrillator

Ventricular Tachycardia in an Adolescent With Arrhythmogenic Right Ventricular Dysplasia

We report the case of an adolescent boy with exertional syncope and ventricular tachycardia caused by arrhythmogenic right ventricular dysplasia. Diagnosis was determined by transthoracic echocardiography and definitive management with an automatic internal cardiac defibrillator. Emergency physicians must be aware of this serious but treatable cause of adolescent exertional syncope. [Berlin D, Pollack M: Ventricular tachycardia in an adolescent with arrythmogenic right ventricular dysplasia. Ann Emerg Med December 1999;34:796-798.]

Introduction to Anesthesia, Ninth Edition

Introduction to Anesthesia, Ninth Edition

Cerebral monitoring during implantation of automatic internal cardiac defibrillators.

Implantation of automatic internal cardiac defibrillators (AICD) for management of arrhythmias necessitates the induction of ventricular fibrillation (VF) to test the device adequately. The profound hypotension associated with induced arrhythmia and subsequent circulatory arrest may result in cerebral ischemia. To characterize cerebral ischemia, we used a five-lead Lifescan brain activity monitor to examine changes in cerebral activity in 10 patients having AICD placement. The duration of hypotension, as defined by a mean arterial pressure (MAP) < 50 mm Hg, was recorded, and the corresponding changes in brain activity were evaluated during 51 episodes of circulatory arrest. The number of episodes for each patient ranged from 2 to 14. The average duration of hypotension per episode was 26.2 seconds, with a range of 8 to 67 seconds. Brain activity changes characteristic of cerebral ischemia occurred in 46 of the 51 events (90%). Cerebral ischemia did not occur when the duration of hypotension was less than 16 seconds (5 episodes). The duration of cerebral ischemia ranged from 50 to 279 seconds (average 84.9 seconds) and did not correlate with the duration of hypotension or the order of the episodes in the testing sequence. These findings suggest that reevaluation of standard monitoring practice for AICD implantation may be warranted.

Implantable Cardioverter Defibrillator Infection Causing Constrictive Pericarditis

A case of severe constrictive pericarditis resulting from an indolent Pseudomonas aeruginosa infection of the automatic internal cardiac defibrillator is described. Total explanation of the device was attempted after nine months but was unsuccessful because of dense adhesions under the patch electrodes. The patient subsequently developed clinical and hemodynamic findings of constrictive pericarditis and a second desperate attempt to remove the patches resulted in operative death. Diagnostic modalities for detecting infection of the AICD are reviewed. As soon as there is infection involving any component, the entire lead system and pulse generator should be removed.

Surgical Outcome for "Normal" Coronary Ventricular Tachyarrhythmias

Analyses of 75 surgically treated patients for potential life-threatening ven tricular tachyarrhythmias demonstrate a distinct subset of patients with "nor mal" coronary ventricular tachyarrhythmias. This subset of 10 patients (Group A) was compared with the remaining 65 patients (Group B), who had intra luminally obstructed and ischemic lesions. The etiologies for Group A patients included 4 hypertrophic cardiomyopathies, 4 dynamic intramyocardial muscle bridges, and 2 congenital aneurysms or diverticula. The localized arrhythmic foci for Group A were all preoperatively or intraoperatively determined as com pared with only 33 of 65 (51 %, p &lt; 0.05) in Group B. While the specific types of surgical intervention for the two groups were seemingly identical (ie, revascu larization, endocardial resection, aneurysmectomy and reconstruction, and/or insertion of automatic internal cardiac defibrillators), the mortality rates were significantly different (mortality A vs B: early 0/10 vs 5/65, p &lt; 0.05 and late 0/ 10 vs 4/60, p &lt; 0.05). All Group A patients underwent repeated studies demon strating maintained ventricular function, in contrast to Group B patients, who exhibited severe ventricular impairment (7/60, p &lt; 0.05). In summary, "normal" coronary ventricular tachyarrhythmias are found in a distinctive subset of patients. Their different etiologies result in better out comes from direct operation, and hence, these patients should be managed with this important premise. Indirect or non-operative approaches should not be used in place of these potential cures.

Operative Management of Symptomatic MB

The relationships between coronary myocardial bridging (MB) and clinical symptoms have been controversial. Five young male patients underwent testing for symptomatic MB, manifested as angina with evidence of ischemia or sudden death. Preoperative testing included atrial stimulation studies for evidence of lactate extraction and serial cardiac catheterization. Positive lactate production and/or extensive milking (&gt;90%) of the proximal left anerior descending artery (LAD) were documented in 4 patients, who were, therefore, treated surgically by supra-arterial myotomy. Associated intraoperative mapping and endocardial resection were required for significant anterior aneurysm and scars. Postopera tive studies demonstrated resolution of the milking and/or intracoronary gradi ents. The remaining patient had recurrent sudden death, but negative lactate study, and was treated by automatic internal cardiac defibrillator (AICD). Symptomatic young patients can present with pathologic compression of the proximal LAD from extensive MB. Complete supra-arterial myotomies were successful treatments. Other adjunctive surgical procedures: (1) mapping, (2) endocardial resection, and/or (3) AICD, were based on their preoperative stress testing and intraoperative findings.

Surgical options for treating ventricular tachyarrhythmia and sudden death

From 1981 to 1987, 62 patients with ventricular tachyarrhythmias and associated sudden death required treatment after unsuccessful initial medical therapy (51 patients) and previous surgical therapy (11 patients). Surgical options included direct revascularization (group I, 11 patients), endocardial resection (group II, 7 patients), automatic internal cardiac defibrillators (group III, 18 patients), and these combinations of operations: revascularization and endocardial resection (group IV, 18 patients), revascularization and insertion of automatic internal cardiac defibrillators (group V, 5 patients), and endocardial resection and insertion of cardiac defibrillator (group VI, 3 patients). Five underwent repeat revascularization (4) or endocardial resection (4) with mitral valve replacement (1) or papillary muscle reconstruction (2). The overall operative mortality of 8.1% (5/62) has been acceptable (2.8% or 1/36 for the simple procedures [groups I, II, and III] and 15.4% or 4/26 for the combined procedures [IV, V, and VI]; p less than 0.074). Operative risk factors included recent myocardial infarction (4/5 deaths) and depressed ejection fraction of 23% or less (5/5 deaths). These operative risks were highest in group IV and, thus, the highest mortality was in group IV (4/18 patients or 22%, p less than 0.022). Six late deaths (4 patients in group III) brought the overall survival rate to 82% or 51/62 patients at a mean follow-up of 30 months. Surgical treatment of sudden death ventricular tachyarrhythmias requires a planned, combined operative approach, since initial medical or surgical failures can occur. The optimal surgical approach requires complete revascularization, resection of the localized subendocardial arrhythmogenic focus, and ventricular reconstruction. An automatic defibrillator is a palliative alternative for less favorable surgical anatomy and for patients who are poor operative candidates for these combined or reoperative procedures.

Nonpharmacologic treatment of life-threatening cardiac arrhythmias

Numerous nonpharmacologic modalities have been introduced for the management of patients with life-threatening arrhythmias. These include cardiac pacing, insertion of an automatic internal cardiac defibrillator (AICD), cardiac electrosurgery, and catheter ablative techniques. Each modality is effective; AICD shows particular promise because it has demonstrated remarkable efficacy in decreasing the incidence of sudden cardiac death in patients with malignant ventricular arrhythmias. Each modality also has its limitations or contraindications. Nonpharmacologic antiarrhythmic therapy represents an important advance against the serious public health problem of sudden cardiac death.