Automatic Implantable Cardioverter Defibrillator Research Articles

Racial Disparities in Cardiovascular Care: A Review of Culprits and Potential Solutions

Cardiovascular disease is the leading cause of death for white and black Americans. Despite the presence of therapies that improve survival and quality of life in cardiac patients, African-Americans continue to have the worst heart disease survival rates of all racial groups. The literature has described racial disparities in cardiovascular care for at least 25 years. We review the current status of racial disparities in four areas of cardiovascular care: automatic implantable cardioverter-defibrillator (AICD) implantations in patients at risk for sudden cardiac death, cardiac resynchronization therapy with defibrillator (CRT-D) implantation in patients with severely depressed left ventricular function and refractory heart failure, reperfusion therapy in patients presenting with acute myocardial infarction, and revascularization in patients with critical limb ischemia. We will discuss potential culprits for these disparities with a particular focus on hospital quality, physician bias, and the relative lack of diversity among cardiovascular physicians in the USA. Finally, we will discuss strategies already in progress that hold promise to reduce or eliminate racial disparities in cardiovascular care.

Ventricular arrhythmias in patients with heart failure secondary to reduced ejection fraction

To review the management of ventricular arrhythmias in patients with heart failure secondary to reduced ejection fraction (HFrEF). Recurrent ventricular arrhythmias and automatic implantable cardioverter defibrillator (AICD) shocks are responsible for significant mortality and morbidity in patients with HFrEF. Antiarrhythmic drugs and catheter ablation are the main treatment options. Frequent premature ventricular contractions (PVCs; >10,000-20,000/24-h period) are being recognized as a cause of cardiomyopathy and suboptimal response to cardiac resynchronization therapy (CRT). Patients with ventricular assist devices (VADs) have frequent ventricular tachyarrhythmias resulting in increased morbidity and mortality. Such patients may need continuation of active ICD therapy and adjunctive catheter ablation. There is a pressing need to develop new antiarrhythmic drugs to treat patients with recurrent AICD shocks. The effectiveness of catheter ablation as first-line therapy for preventing ventricular arrhythmias and recurrent AICD shocks needs to be directly compared with amiodarone. Ventricular tachyarrhythmias are common in CRT patients and patients with VADs. Frequent PVCs may result in a reversible form of HFrEF.

Abstract W P128: Development and Validation of Clinical Prediction Model for Obstructive Sleep Apnea among Patients with Ischemic Stroke and TIA

Introduction: Obstructive sleep apnea (OSA) screening instruments that perform well in the general population have demonstrated poor correlation with OSA diagnosis in stroke and TIA populations. Given that OSA is common post-stroke/TIA, has been associated with recurrent vascular events, and is treatable, we sought to develop and validate a cerebrovascular disease specific prediction model for OSA. Methods: We developed and validated a clinical prediction model using data from two separate multi-site randomized, controlled strategy trials: the development population included chronic stroke/TIA patients; the validation population included acute stroke/TIA patients. Data on patient demographics, vital signs, anthropomorphic measurements, past medical history, medications, NIHSS, sleep questionnaires, and polysomnography (PSG) were obtained. OSA was defined as present if the apnea-hypopnea index (AHI) was ≥5 events/hour. Variables considered clinically important and required to remain in the multivariable logistic regression model were gender, weight, neck circumference (women >16”, men >17”), history of CHF, DM and NIHSS. Variables associated with OSA in bivariate analyses (p≤0.25) were also included: age, history of chronic obstructive COPD, automatic implantable cardioverter defibrillator (AICD), Charlson comorbidity, Epworth Sleepiness Scale (ESS), Berlin Questionnaire ≥10, and patient health questionnaire (PHQ8) depression scale. Backward elimination was used to identify factors that were independently associated with OSA (p<0.05). Results: Sleep apnea occurred commonly in the development (119/194; 61%) and validation (75/96; 76%) cohorts. The final model included: gender, CHF, DM, large neck, and the quadratics of weight, NIHSS, and ESS. The model showed reasonable discrimination in the development (c-statistic 0.73) and validation (c-statistic 0.70) cohorts. This model correctly classified 68% of patients in the validation sample as having OSA. Conclusions: A model based on readily available clinical information predicted the presence of OSA reasonably well. Future work is required to determine the utility of this model in clinical practice for the identification of patients who should receive OSA management.

High dose radiotherapy to automated implantable cardioverter-defibrillator: a case report and review of the literature.

We report a case of successful full-dose chemoradiotherapy to stage IIIB nonsmall cell lung cancer (NSCLC) in a 59-year-old man with extensive cardiac history and an automated implantable cardioverter-defibrillator (AICD) located within the radiotherapeutic field. In this case, the AICD was a St. Jude Medical Fortify Assura VR 1257-40Q ICD, and it was implanted prophylactically during bypass grafting. Although we do not recommend routine radiotherapy dose to exceed recommended current guidelines due to the potential risks to the patient, this is a situation where relocation of the device was not possible. Fortunately, our patient was not AICD-dependent; so following much discussion and deliberation, the decision was made to treat the patient with AICD in place. The patient completed definitive chemoradiotherapy with concurrent cisplatin and etoposide and thoracic irradiation to 69.6 Gy. The minimum, maximum, and mean doses to the AICD directly were 13.5 Gy, 52.4 Gy, and 29.3 Gy, respectively. The device withstood full thoracic radiation dose, and the patient denied cardiac symptoms during the time before, during, and after completion of therapy. We sought to offer this case for both teaching and guidance in practice and to contribute to the published literature currently available in this area.

Radiology of ventilatory, feeding, and circulatory lines and tubes in the critically sick

A variety of supportive ventilatory, feeding and circulatory devices are employed in the management of critically sick patients. The hardware ranges from endotracheal, tracheostomy and chest tubes, nasogastric and nasoenteric feeding tubes, to central venous lines, umbilical venous and arterial catheters, pacers and automatic implantable cardioverter defibrillators, intraaortic balloon pumps and ventricular assist devices. The accurate positioning of this hardware is critical to the well being of a patient. However, these devices may not be positioned appropriately. Faults may occur at the time of their insertion, or the hardware may get dislodged while in use. A portable chest radiograph can be extremely useful in identifying such mishaps. This pictorial review captures some of the critical scenarios which must be known to radiologists and the treating intensivists.

Granulomatous myocarditis in severe heart failure patients undergoing implantation of a left ventricular assist device

Granulomatous myocarditis may develop into cardiomyopathy and severe congestive heart failure that requires implantation of a left ventricular assist device (LVAD). Left ventricular (LV) core samples were collected from 177 patients with severe heart failure at the time of LVAD implantation, and samples were histologically examined and graded for severity of hypertrophy and fibrosis. Granulomatous myocarditis incidentally seen in a subset of samples was characterized by staining and culturing for mycobacteria and fungi. Various clinical parameters in these patients were analyzed. Of the 177 LV core samples examined, 6 (3.4%) showed nonnecrotizing granulomatous inflammation in the myocardial wall. Stains and cultures for mycobacteria and fungi were negative. All six patients [three women, three men; five African American, one Asian; mean age, 52±9 years (range, 41-61 years)] had arrhythmias and required an automatic implantable cardioverter defibrillator. Before LVAD implantation, the patients' mean cardiac index was 1.8±0.4 l/min/m(2); cardiac output, 2.9±0.6 l/min; and ejection fraction, 20±2%. One year after LVAD implantation, one patient had undergone heart transplantation. At 2 years, a second patient was transplanted, and one died. At 3 years, a third patient was transplanted and died postoperatively; two patients remained on support. No clinical evidence indicated involvement of other organs or recurrence in the transplanted patients. The incidental diagnosis of granulomatous myocarditis in our patients indicates that histological study of LV core samples in patients who undergo LVAD implantation may contribute to the diagnosis and be a consideration in the management of the underlying cause of heart failure.

Arrhythmogenic right ventricular cardiomyopathy: use of a left ventricular assist device as a bridge to transplantation?

The principal characteristic of arrhythmogenic right ventricular cardiomyopathy (ARVC) is the tendency for ventricular arrhythmia and sudden death to occur without overt ventricular dysfunction. Current recommendations for management of patients with ARVC include insertion of an automated implantable cardioverter-defibrillator (AICD) to prevent sudden cardiac death. However, despite the use of AICD and/or anti-arrhythmic drugs some patients suffer recurrent ventricular arrhythmias unresponsive to optimum medical management. We present two cases of ARVC with refractory recurrent ventricular arrhythmias that were successfully managed by left ventricular assist device (LVAD) implantation, as a bridge to transplant (BTT). These two cases are unconventional examples of use of LVAD, given the predominant right ventricular pathology of ARVC and the arrhythmogenic nature of their presentation. The novelty of these cases should be taken in the context of increasing pressure to standardize indications for use of mechanical circulatory support.

Saving lives and reducing inappropriate device therapy: The MADIT family of implantable cardioverter-defibrillator and cardiac resynchronization therapy trials

In 1980, Mirowski et al. [1] reported the first 3 patients treated with an automatic implantable defibrillator (AID). At that time, the AID was implanted with electrodes attached to the epicardium through a surgical thoracotomy with the battery portion of the unit placed undeer the skin in the abdominal wall. The AID detected the onset of ventricular fibrillation through a unique algorithm and the device was considered a “shock box” since shock was the only therapy delivered. The U.S. Food and Drug Administration (FDA) initially provided approval for use of the AID device in high-risk cardiac patients who had been resuscitated from a prior aborted cardiac arrest. Around the same time frame, Medtronic developed a pacing approach (antitachycardia pacing [ATP]) to terminate rapid ventricular tachycardia (VT) by delivering a series of appropriately timed pacing stimuli in the interval between the QRS and T-wave complexes of the tachycardia (review article [2]). This pacing technique was effective in terminating VT in a majority of patients with ventricular tachyarrhythmias. However, this ATP approach produced acceleration of VT and even ventricular fibrillation and sudden death in a small percentage of patients, and ATP therapy was not approved by the FDA as a stand-alone therapy. The AID was initially developed by Drs. Mirowski and Mower in association with Dr. M. Stephen Heilman at the Medrad/Intec Company in Pittsburgh, Pennsylvania, and the implantable defibrillator was subsequently sold to CPI/Guidant Corporation in 1985. Although CPI/Guidant and Medtronic were competitors in the pacemaker field, both companies recognized the need for a device with tiered therapy that would include ATP and defibrillation. Through a cooperative agreement, CPI/Guidant and Medtronic jointly agreed on a device involving ATP and shock therapy, called the automatic implantable cardioverter defibrillator (AICD) for treating patients at risk for life-threatening VT and/or ventricular fibrillation.

Consideraciones sobre el parto en una paciente con miocardiopatía hipertrófica y desfibrilador automático implantable

Hypertrophic cardiomyopathy is inherited as an autosomal dominant trait and can be diagnosed during pregnancy. Cardiomyopathy is the leading cause of nonobstetric maternal morbidity and mortality. We present the case of a 26-year-old pregnant woman with hypertrophic cardiomyopathy and an automatic implantable cardioverter defibrillator and we discuss the most important therapeutic considerations in the management of these patients before and during delivery and in the immediate postpartum period.

Anesthetic management of patient with hypertrophic cardiomyopathy and automatic implantable cardioverter defibrillator with a hand fracture

Anesthetic management of patient with hypertrophic cardiomyopathy and automatic implantable cardioverter defibrillator with a hand fracture

Rechargeable Automated Implantable Cardioverter Defibrillator

An automated Implantable Cardioverter Defibrillator (AICD) is a small battery powered electrical impulse generator, implanted in patients who are in the risk of sudden cardiac death or ventricular tachycardia, and is programmed to detect the cardiac arrhythmia. Components of AICD are Leads, Electrode and Generator (1) . The electric shock is created by the generator carried by leads and delivered with the electrodes. The generator is of the size of 2 inches approximately, and 3 ounces weight. Working of AICD includes rectification of arrhythmia by means of pacing Cardioversion defibrillation. Current devices have appreciable functions including diagnosis, stored electro-grams and verification of shock appropriations and battery longevity upto 6 yrs. Here using mutual inductance (2) functions carried out with the help of a transcutaneous transformer and storing electric charge through magnetic field absolute longevity of the battery could be reached. Since, battery longevity has been tremendously increased the recurrence of surgery can be prevented. Thus, our device will bring remarkable revolution in cardiology by saving human lives from arrhythmia and periodical replacement of the device. Keywords:-ADC, Faraday's Law, Micro-controller (MC), Mutual inductance, Transcutaneous transformer.

Unique presentation of Twiddler’s syndrome

We present a rare case of Twiddler's syndrome diagnosed in an asymptomatic patient on a routine follow up. This case reiterates the need for frequent monitoring of the implanted device. In addition, it was detected 4 years after implantation of an automatic implantable cardioverter defibrillator. This late representation is extremely uncommon.

Surgical ventricular reconstruction with endocardectomy along radiofrequency ablation-induced markings

The objective of this study was to evaluate the efficacy of a novel approach for endocardectomy during coronary artery bypass graft with surgical ventricular restoration in patients with postinfarction left ventricular aneurysm. One hundred sixty-eight patients underwent coronary artery bypass graft with surgical ventricular restoration from 2005 to 2011. Endocardectomy was performed as an integral part of surgical ventricular restoration for the prevention of ventricular tachycardia. The experimental group (surgical ventricular restoration-endocardectomy group; n=74) underwent preoperative electrophysiologic study with electroanatomic left ventricular mapping. Radiofrequency ablation-induced markings were placed and were used later as guides for performing endocardectomy during coronary artery bypass graft with surgical ventricular restoration. The control group (surgical ventricular restoration group; n=94) underwent surgical ventricular restoration without endocardectomy. The 1-year mortality rates in the surgical ventricular restoration-endocardectomy and surgical ventricular restoration (control) groups were 5% and 13%, respectively. During the postoperative period, 3% of patients in the surgical ventricular restoration-endocardectomy group and 38% of patients in the surgical ventricular restoration group experienced ventricular tachycardia events (P<.05). Automatic implantable cardioverter-defibrillators were implanted in 11 patients in the surgical ventricular restoration group and in 1 patient of the surgical ventricular restoration-endocardectomy group for secondary prevention of sudden cardiac death. When performed as an integral part of surgical ventricular restoration, endocardectomy was crucial in preventing postoperative ventricular tachycardia. Use of radiofrequency ablation-induced markings allowed clear visualization of the reentry zones for efficient endocardectomy during coronary artery bypass graft with surgical ventricular restoration, resulting in better patient outcomes.

The Treatment of Medically Intractable Trigeminal Autonomic Cephalalgia With Supraorbital/Supratrochlear Stimulation: A Retrospective Case Series

This is a retrospective case series of five patients with intractable trigeminal autonomic cephalalgia (TAC) who were implanted with a supraorbital/supratrochlear neuromodulation system. The aim of this Institutional Review Board-approved study was to investigate the percentage of pain relief, treatment response, pain level, work status, medication intake, implantation technique, lead placement, programming information, and device use. Trial stimulation led to implantation of all five patients. All patients reported improvement in their functional status in regard to activities of daily living. The device was revised in two patients due to skin erosion. It was later reimplanted in both patients due to worsening of symptoms, again with good pain relief. The device was explanted in two other patients because of the need to perform a magnetic resonance imaging or implant an automatic implantable cardioverter defibrillator. The follow-up of the patients ranged between 18 months and 36 months, with a mean of 25.2 months. There was no change in work status. Following the implant, the Visual Analog Scale score was reduced to a mean of 1.6 from an initial mean score of 8.9. Three patients were completely weaned off opioid medications, while two patients continued to take opioid at a lower dosage. All patients experienced a decrease of the adjuvant neuropathic drugs. Supraorbital/supratrochlear nerve stimulation appears to be a promising modality for the treatment of patients with intractable TAC.

Quality of life of pediatric cardiac patients who previously required extracorporeal membrane oxygenation*

We sought to assess quality of life of pediatric cardiac extracorporeal membrane oxygenation survivors. We hypothesized that these patients would have decreased quality of life when compared to that of a general U.S. population sample. Cross-sectional study. Patient homes and Children's Hospital Boston. Cardiac extracorporeal membrane oxygenation survivors currently 5-18 yrs old. None. Quality of life was assessed by parent proxy report using the Child Health Questionnaire Parent Form 50 and was compared to that of a general U.S. population sample and other cardiac populations. Factors associated with lower quality of life were sought. Physical summary scores for 41 cardiac extracorporeal membrane oxygenation survivors were lower than the mean of the general population sample (42.4 ± 16.4 vs. 53.0 ± 8.8; p < .001) but similar to those of children with Fontan physiology or an automatic implantable cardioverter defibrillator. Psychosocial summary scores in extracorporeal membrane oxygenation patients were not different from those of the general population (48.2 ± 11.8 vs. 51.2 ± 9.1; p = .11) or of other cardiac samples. Postcardiotomy extracorporeal membrane oxygenation, more noncardiac operations, total intensive care and hospital days, noncardiac medical conditions, medications, and the need for physical, occupational, or speech therapy were associated with low physical summary scores. More noncardiac operations, noncardiac medical conditions, and the need for special education, physical, occupational, or speech therapy were associated with low psychosocial summary scores. In pediatric cardiac extracorporeal membrane oxygenation survivors, the physical component of health-related quality of life is lower than that of the general population but similar to that of patients with complex cardiac disease, whereas psychosocial quality of life is similar to that of the general population and of other pediatric cardiac populations.

Perioperative management of a patient with Automated Implantable Cardioverter Defibrillator (AICD)

The Sri Lankan Journal of Anaesthesiology is the official journal of the College of Anaesthesiologists of Sri Lanka. It publishes clinical investigations, research articles, audits, case reports, review articles and CME articles relating to anaesthesiology, critical care and pain. It is published bi annually in January and June. Sri Lankan Journal of Anaesthesiology is included on DOAJ and Scopus.

Chest Radiography in the ICU: Part 2, Evaluation of Cardiovascular Lines and Other Devices

In this pictorial essay, we discuss and illustrate normal and aberrant positioning of the cardiovascular support and monitoring devices frequently used in critically ill patients, including central venous catheters, pulmonary artery catheters, left atrial catheters, transvenous pacemakers, automatic implantable cardioverter defibrillators, intraaortic counterpulsation balloon pump, and ventricular assist devices, as well as their inherent complications. The radiographic evaluation of the support and monitoring devices used in patients in the ICU is important, because the potentially serious complications arising from their introduction and use are often not clinically apparent. Familiarity with normal and abnormal radiographic findings is critical for the detection of these complications.

Shockable Rhythm Detection Algorithms for Electrocardiograph Rhythm in Automated Defibrillators

The quick and accurate detection of shockable rhythms is important in real application of automatic external defibrillator or implantable cardioverter defibrillator to save lives. The crucial component in automatic defibrillator is the detection algorithm for shockable rhythms, including ventricular fibrillation and pulseless ventricular tachycardia. We summarized the main development of the algorithms, including the time-field detection method, frequency-field detection method, time-frequency analysis detection method and dynamics analysis method. Furthermore, the key issues for further study are also presented.

Asymptomatic Coronary Artery Spasm and Severe Ventricular Arrhythmias

SUMMARY 2010;78:445-448 Coronary artery spasm generally evolves with episodes of chest pain and ST elevation. However, there are cases of coronary artery spasm without chest pain with documented ventricular tachyarrhythmias. Its incidence is unknown and it should be included in the differential diagnosis of idiopathic ventricular tachycardia or fibrillation. The case of a patient with history of two syncopal episodes with no apparent structural heart disease is described in this work. Continuous ECG monitoring revealed episodes of ST elevation that led to polymorphic ventricular tachycardia. With the diagnosis of asymptomatic coronary artery spasm, a treatment with calcium channel blockers was begun and an automatic implantable cardioverter defibrillator was implanted. R EV A RGENT C ARDIOL

Transoesophageal echocardiographic Doppler colour flow patterns of a normally functioning third-generation centrifugal left ventricular assist device

A 75-year-old man with history of atrial fibrillation, ischaemic cardiomyopathy, and biventricular pacemaker implantable cardioverter-defibrillator presented with automated implantable cardioverter-defibrillator (AICD) discharge and worsened exertional dyspnoea and lower extremity oedema. Six months previously, he received a left ventricular assist device (LVAD) (HeartWare International Inc., Framingham, MA, USA), a third-generation, continuous flow centrifugal pump, for destination therapy. AICD interrogation revealed development of atrial flutter coincident with worsening heart failure symptoms. Power consumption and pump diagnostics showed no LVAD malfunction. Cardioversion of atrial flutter followed transoesophageal echocardiography (TEE) showing no intracardiac thrombus. Real-time three-dimensional TEE ( Panel A ; Supplementary data online, …