Outcomes and in-hospital treatment of out-of-hospital cardiac arrest patients resuscitated from ventricular fibrillation by early defibrillation

OBJECTIVE: To describe and evaluate the in-hospital treatment of ventricular arrhythmias and underlying structural heart disease in patients who survive ventricular fibrillation (VF) out-of-hospital cardiac arrest (OHCA) in a region with a high survival rate after hospital discharge. PATIENTS AND METHODS: The study included all patients presenting in Olmsted County, Minnesota, who had experienced OHCA between November 1990 and December 2000 and who underwent defibrillation of VF by an emergency medical service system. RESULTS: Of 200 patients who experienced VF arrest, 138 (69%) survived to hospital admission (7 died in the emergency department before admission), and 79 (40%) were discharged. Of patients who were discharged, 37 (47%) had a reversible cause of the arrest (perimyocardial infarction) and received treatment of the primary process. The other 42 patients who were discharged had ischemic coronary heart disease (CHD) (n=25), nonischemic CHD (n=10), or idiopathic VF (n=7). Four of the patients with CHD but no left ventricular dysfunction were treated with coronary artery bypass grafting or percutaneous coronary intervention alone. A total of 52 patients (66%) were candidates for electrophysiologic testing. Of these patients, 48 (92%) underwent electrophysiologic testing; of these patients, 10 received amiodarone alone, and 35 received an implantable cardioverter-defibrillator (ICD) (of whom 3 also received amiodarone). Patients who did not receive ICD therapy typically presented before 1998 with CHD and underwent coronary artery bypass grafting or percutaneous coronary intervention only. Of 79 patients who were discharged, 14 (18%) with an ICD have received subsequent shocks. Nineteen (24%) of 79 patients have died, 5 of a primary cardiac etiology (including 2 with repeated OHCA). CONCLUSIONS: The VF OHCA survival rate is high in the setting of rapid defibrillation, with 40% of patients being discharged from the hospital. By the end of the 10-year study, more patients were receiving antiarrhythmic therapy, in particular ICD implantation, after hospital admission. Overall, the long-term survival in patients with VF OHCA is favorable.     

Implantable cardioverter-defibrillator in patients with chronic heart failure

Sudden cardiac death (SCD) is a major cause of death in patients with chronic heart failure. The implantable cardioverter-defibrillator (ICD) effectively treats malignant ventricular tachyarrhythmias and reduces significantly the total mortality as well as the incidence of SCD in heart failure patients. It is evident that ICD is indicated for the secondary prevention of SCD. There is growing evidence for the use of the ICD for the primary prevention of SCD in patients with LV systolic dysfunction without documented arrhythmia. However, the efficacy of ICD seems to be modest in patients with advanced heart failure. Individualized combined therapies such as ICD plus amiodarone and ICD plus cardiac resynchronization therapy are necessary for advanced heart failure patients. It is doubtful whether ICD is indicated for MADIT II and SCD -HeFT population in Japan, where the incidence of SCD is thought to be lower than the Western countries.     

Management of hyperlipidemia in the elderly population: an evidence-based approach

Coronary heart disease (CHD) is the leading cause of morbidity and mortality in patients more than 65 years old. Within this population, elevated cholesterol levels are prevalent and associated with increased risk of CHD. Despite increasing emphasis on lipid-lowering treatment in the elderly population, questions remain regarding secondary and primary prevention of CHD. According to current clinical trial evidence, lipid-lowering therapy, specifically with HMG-CoA-reductase inhibitors, can reduce CHD morbidity and mortality without increased adverse effects in the elderly population. Lipid-lowering treatment should be considered for patients aged 65 to 75 years with a history of CHD or who are at moderate to high risk for CHD. Estrogen replacement therapy (ERT), which has also been shown to lower cholesterol levels, raises special considerations for postmenopausal women. However, recent findings suggest that postmenopausal women with a history of CHD should not be given estrogen solely for secondary prevention of CHD events.     

Survival in Patients with Depressed Left Ventricular Function Treated by Implantable Cardioverter Defibrillator

Mortality in patients with cardiovascular disease is generally due to pump failure or lethal ventricular arrhythmias, In patients with ventricular tachycardia (VT) or ventricular fibrillation (VF) and poor left ventricular (LV) function the death rate is particularly high. The overall incidence of premature arrhythmic death rate in patients with poor LV function is not totally clear. Since implantable cardioverter defibrillator (ICD) could prevent arrhythmic death in any population, we proceeded to analyze mortalities in patients with poor LV function who received ICD. Among a total of 200 consecutive patients receiving ICD at our institution, 68 (34%) had LV ejection fraction (LVEF) of < 30%. Thirty-one of these (45%) experienced appropriate ICD discharges and 17/31 (55%) had multiple shocks. Survival curves in this population revealed a 5 year projected overall survival of 11% whereas an actual survival was 60%. Even those who ultimately died from nonsudden causes, life was prolonged by ICD in a significant number of cases. Based upon these findings it is concluded that ICD has a major impact on survival in patients with poor LV function suggesting that many of these patients die prematurely from arrhythmia causes.     

Implantation Trends and Patient Profiles for Pacemakers and Implantable Cardioverter Defibrillators in the United States: 1993–2006

Background: Prior studies of cardiac rhythm management devices (pacemakers [PM] and implantable cardioverter defibrillators [ICD]) utilization in the United States have been limited to the Medicare population. We evaluated the national trends for the implantation of PMs and ICDs including the burden of device replacement. Methods: The Nationwide Inpatient Sample was queried to identify PM and ICD patients between 1993 and 2006 using ICD‐9‐CM codes, including demographics, health profile, and economic data. The Charlson Comorbidity Index (CCI) and replacement burden were calculated, and changes over time studied. Results: From 1993 to 2006, 2.4 million patients received a primary PM and 0.8 million received an ICD, while there were 369,000 PM replacements and 74,000 ICD replacements. Women comprised 49% of PM and 24% of ICD patients. The mean ICD replacement burden was 8.4% (range 5–22%) and decreased significantly over time (P < 0.0001) while the replacement burden for PMs was constant (mean = 13.4%, range 11–16%). ICD patients had more comorbidities than PM patients (CCI: 0.8 vs 1.1, P < 0.0001). Conclusions: The replacement burden for PMs has remained constant, while the replacement burden for ICDs has decreased. This is likely due to the stability of the patient population receiving PMs and technology maturity. Alternatively, the indications for ICD implantation have broadened, resulting in an increased number of primary ICD implantations. The age and comorbidities are increasing in those patients receiving ICDs while the PM population is stable. These data suggest that monitoring of replacement burden is warranted, given the changing populations, their disparate clinical outcomes, and economic implications to the health care system. (PACE 2010; 33:705–711)     

Increased morbidity and mortality in very preterm/VLBW infants with congenital heart disease

Purpose

To study the association between congenital heart diseases (CHD) and in-hospital mortality and morbidity of very preterm/very low birth weight (VLBW) infants.

Methods

The area-based prospective cohort study ACTION included all infants with gestational age (GA) 22–31 weeks or birth weight <1,500 g admitted to neonatal care between July 2003 and June 2005 in six Italian regions (n = 3,684). CHD were coded according to ICD9-CM. Cluster multivariable logistic regression analyses were used to assess the relationship between CHD and mortality and selected morbidities [neonatal infection, ultrasound brain abnormalities, retinopathy of prematurity (ROP), and bronchopulmonary dysplasia (BPD)] adjusting for potential confounders.

Results

Seventy-one patients had CHD [19.3 ‰, 95 % confidence interval (CI) 15.1–24.2 ‰]. The most common lesions were isolated atrial and ventricular septal defects (31.1 and 26.8 %, respectively), pulmonary valvar stenosis (12.7 %), and tetralogy of Fallot (5.6 %). Compared with other infants, CHD patients showed significantly higher GA and frequency of small for gestational age (SGA, i.e., birth weight ≤3rd centile). After adjustment for GA, sex, SGA, presence of extracardiac malformations or chromosomal anomalies, and region of birth, CHD patients had a significantly higher likelihood of infection, BPD, ROP, and, after 27 weeks gestation only, hospital mortality. The increased risk of ROP appeared to be partly due to infection.

Conclusions

In very preterm/VLBW infants CHD are more prevalent than in the general liveborn population, and confer an increased risk of death and serious morbidities independently of other risk factors. These results may be useful to better tailor prognostic assessment and diagnostic and therapeutic interventions for these children.     

Experience of ICD management at a UK center: cardiovascularly stable VT presentation predicts higher risk for appropriate ICD therapy

BACKGROUND: It would be useful to identify patients at high risk of implantable cardioverter defibrillator (ICD) therapy via additional antiarrhythmic measures to minimize the morbidity of ICD therapies. OBJECTIVE: We assessed baseline characteristics for predictors of device therapy in a general ICD population. We also compared the likelihood of therapy delivery by replacement ICDs implanted for battery depletion with the original implants. METHODS: Clinical and ICD interrogation data from patients followed up at a UK center were analyzed looking for predictors of appropriate ICD therapy. Univariate and multivariate analysis was performed using Cox regression. We compared time to first appropriate therapy between first and second ICDs in patients who had undergone ICD replacement for battery depletion by log-rank testing. RESULTS: One hundred and sixty-one patients were studied (129 men, age 65.7 +/- 12.9 years, follow-up 908 +/- 676 days). Appropriate therapy was delivered in 68 patients (42%). Univariate risk factors for appropriate ICD therapy were presentation with stable ventricular tachycardia (VT) (P = 0.0002), ischemic etiology (P = 0.03), tiered therapy programmed ICDs (P = 0.01), and beta-blocker use (P = 0.001). Stable VT and beta blocker use were independent predictors of ICD therapy on multivariate analysis. Thirty-three patients (20%) had at least one ICD replacement. Time to first appropriate therapy was no different between first and second ICD implants (P = 0.8). CONCLUSION: Patients who present with cardiovascularly stable VT have a higher probability of receiving appropriate ICD therapy than those who do not. Following battery depletion of an original ICD, the replacement device is no less likely to administer therapy than the first.     

A higher than expected prevalence of AV nodal reentrant tachycardia in patients receiving implantable cardioverter-defibrillators

Background: Epidemiologic studies have indicated that the prevalence of paroxysmal supraventricular tachycardia (SVT) is approximately two to three of 1000 persons, of whom 50–60% have atrioventricular node reentrant tachycardia (AVNRT). Although SVT has been reported to account for a significant portion of inappropriate shocks in patients receiving implantable cardioverter‐defibrillators (ICDs), the incidence of AVNRT is unknown. Objective: To define the incidence of AVNRT in patients with ICDs. Methods and Results: Of 426 patients followed with an ICD, 15 patients with AVNRT were identified (3.5%). AVNRT was noted preimplant in eight patients. One had remote AVNRT and had undergone radiofrequency (RF) ablation several years prior to ICD implantation. Three patients had known episodes and underwent RF ablation prior to ICD implant. Four had AVNRT induced at preimplant electrophysiology study and three had RF ablation prior to ICD implant. Seven patients had clinical episodes of AVNRT after ICD implant and six of seven received inappropriate ICD therapy for AVNRT. All seven patients underwent RF ablation for treatment of AVNRT. No patient who underwent RF ablation had further clinical episodes of SVT, and only one had further inappropriate ICD therapy for sinus tachycardia. Conclusion: The substantially higher prevalence of AVNRT in our followed ICD population (3.5%) compared to the general population may be due to detection bias or electroanatomic changes in the atrioventricular nodal area induced by the accompanying heart disease. In any case, further studies to evaluate the inducibility of AVNRT prior to ICD implant, its prognostic implications, and the role of RF ablation to prevent inappropriate shocks are warranted. (PACE 2011; 34:584–586)     

Implantable cardioverter defibrillators in diabetics: efficacy and safety in patients at risk of sudden cardiac death

Diabetes mellitus is a major risk factor for arrhythmogenesis and is associated with a two-fold increase in all-cause mortality and a four-fold increase in cardiovascular mortality including sudden cardiac death when compared with nondiabetics. Implantable cardioverter defibrillators (ICD) have been shown to effectively reduce arrhythmic death and all-cause mortality in patients with severe myocardial dysfunction. With a high competing risk of nonarrhythmic cardiac and noncardiac death, survival benefit of ICD in patients with diabetes mellitus could be reduced, but the subanalysis of diabetic patients in randomized clinical trials provides reassurance regarding a similar beneficial survival effect of ICD and cardiac resynchronization therapy in diabetics, as observed in the overall population with advanced heart disease. In this article, the authors highlight some of the clinical issues related to diabetes, summarize the data on the efficacy of ICD in diabetics when compared with nondiabetics and discuss concerns related to ICD implantation in patients with diabetes.     

Survival and Appropriate Device Interventions in Recipients of Cardioverter Defibrillators Implanted for the Primary Versus Secondary Prevention of Sudden Cardiac Death

Background: Implantable cardioverter-defibrillators (ICD) implanted after an episode of ventricular tachyarrhythmia (VTA) or in patients at high risk of VTA lower the long-term mortality. Comparisons of the clinical outcomes of the two indications are scarce.
Methods: The study enrolled 360 consecutive ICD recipients. The device was implanted for secondary prevention in 150 patients, whose mean age was 60 ± 14 years, and mean left ventricular ejection fraction (LVEF) was 40 ± 16%, and for primary prevention in 210 patients, whose mean age was 61 ± 11 years, and mean LVEF was 31 ± 13%. All-cause mortality and time to first appropriate ICD therapy were measured.
Results: The two study groups were similar with respect to age and prevalence of coronary artery disease. Mean LVEF was higher in the secondary prevention group (P = 0.001). Cox regression analysis revealed a significantly shorter time to first appropriate ICD therapy in the secondary prevention group (HR = 0.51, 95% CI = 0.30 – 0.87, P = 0.01). Over a mean follow-up of 37 ± 19 months, the all-cause mortality in the overall population was 12.7%, and was similar in both subgroups (HR = 0.99, 95% CI = 0.55–1.77, P = 0.97).
Conclusions: The long-term mortality in this unselected population of ICD recipients was low. Patients treated for secondary prevention received earlier appropriate ICD therapy than patients treated for primary prevention. Long-term mortality was similar in both groups. The higher VT incidence of VTA was effectively treated by the ICD and was not associated with a higher mortality.     

Readability and Content of Patient Education Material Related to Implantable Cardioverter Defibrillators

BACKGROUND:: Implantable cardioverter defibrillators (ICDs) are increasingly offered to patients for primary prevention of sudden cardiac death. Candidates for ICD receive ICD-related patient education material when they make decisions to consent or decline a primary prevention ICD. Printed patient education material directed at ICD candidates has not been the focus of direct appraisal. OBJECTIVE:: We evaluated the readability and content of ICD-related print education materials made available to patients who were enrolled in a study involving patient decision making for ICD from 3 ICD sites in southern Ontario, Canada. METHODS:: All ICD print materials referred to during interviews and/or that were available in ICD site waiting rooms were collected for analysis. Readability testing was conducted using the "simple measurement of gobbledygook" and Fry methods. The material was evaluated according to selected plain-language criteria, thematic content analysis, and rhetoric analysis. RESULTS:: Twenty-one print materials were identified and analyzed. Documents were authored by device manufacturers, tertiary care hospitals, and cardiac support organizations. Although many documents adhered to plain-language recommendations, text-reading levels were higher than recommended. Twelve major content themes were identified. Content focused heavily on the positive aspects of living with the device to the exclusion of other possible information that could be relevant to the decisions that patients made. CONCLUSIONS:: Print-based patient education materials for ICD candidates are geared to a highly literate population. The focus on positive information to the exclusion of potentially negative aspects of the ICD, or alternatives to accepting 1, could influence and/or confuse patients about the purpose and implications of this medical device. Development of print materials is indicated that includes information about possible problems and that would be relevant for the multicultural and debilitated population who may require ICDs. The findings are highly relevant for nurses who care for primary prevention ICD candidates.     

Poor prognosis for patients with chronic kidney disease despite ICD therapy for the primary prevention of sudden death

INTRODUCTION: Chronic kidney disease (CKD) has been independently associated with increased cardiovascular mortality. Little is known about the benefit of implantable cardioverter defibrillator (ICD) therapy for prevention of sudden death in this large, high-risk population. We sought to evaluate the impact of CKD on survival in patients who received an ICD for primary prevention of sudden death. METHODS AND RESULTS: In this retrospective study of patients who underwent ICD implantation for primary prevention of sudden death, patients were stratified by CKD, defined as serum creatinine > or = 2 mg/dL or dialysis use. Primary endpoint was mortality. CKD was identified in 35 of 229 patients (15.3%). There were 33 deaths during a follow-up period of 18.0 +/- 15.2 months: 17 of 35 CKD patients and 16 of 194 patients without CKD (48.6% vs 8.2%, P < 0.00001 by log-rank). One-year survival for patients with and without CKD was 61.2% and 96.3%, respectively. Cox regression analysis controlling for age, sex, comorbidities, ejection fraction, and medications proved CKD to be the strongest independent predictor of death (hazard ratio 10.5; 95% confidence interval 4.8-23.1; P = 0.0001). This risk was dependant on severity of CKD; a 10 mL/min reduction in creatinine clearance was associated with a 55% increase in hazard of death (P < 0.0001). CONCLUSIONS: In patients receiving an ICD for primary prevention of sudden death, CKD significantly reduced long-term survival. This poor prognosis may limit the impact of primary prevention ICD therapy in this patient population.     

Fear of exercise and health-related quality of life in patients with an implantable cardioverter defibrillator

Several studies have reported improved survival rates thanks to the use of an implantable cardioverter defibrillator (ICD) in the treatment of patients with life-threatening arrhythmia. However, the effects of the ICD on health-related quality of life (HR-QoL) of these patients are not clear. The aim of this study is to describe HR-QoL and fear of exercise in ICD patients. Eighty-nine ICD patients from the University Hospital in Groningen, the Netherlands, participated in this study. HR-QoL was measured using the Rand-36 and the Quality of Life After Myocardial Infarction Dutch language version questionnaires. Fear of exercise was measured using the Tampa Scale for Kinesiophobia, Dutch version and the Fear Avoidance Beliefs Questionnaire, Dutch version. Association between outcome variables was analysed by linear regression analyses. Study results show that the HR-QoL of patients with ICDs in our study population is significantly worse than that of normal healthy people. Furthermore, fear of exercise is negatively associated with HR-QoL corrected for sex, age and number of years living with an ICD. After implantation of the ICD, patients with a clear fear of exercise should be identified and interventions should be considered in order to increase their HR-QoL.     

Sudden cardiac death and implantable cardioverter-defibrillators

Sudden cardiac death is a major public health problem, affecting 500,000 patients in the United States annually. An implantable cardioverter-defibrillator (ICD) can terminate malignant ventricular arrhythmias and has been shown to improve survival in high-risk populations. Although sudden cardiac death is a heterogeneous condition, left ventricular ejection fraction of 35 percent or less remains the single best factor to stratify patients for prophylactic ICD implantation, and randomized trials have shown mortality benefit in this population. Therefore, in patients with heart disease, assessment of ejection fraction remains the most important step to identify patients at risk of sudden cardiac death who would benefit from ICD implantation. Physician understanding of each patient's ICD type, indication, etiology of heart disease, and cardiovascular status is essential for optimal care. If the ICD was placed for secondary prevention, the circumstances relating to the index event should be explored. Evaluation of defibrillator shocks merits careful assessment of the patient's cardiovascular status. Consultation with a subspecialist and interrogation of the ICD can determine if shocks were appropriate or inappropriate and can facilitate management.     

Patient Acceptance of the Implantable Cardioverter Defibrillator in Ventricular Tachyarrhythmias

Besides surgical problems, recipierifs of implantable cardioverter defibrillators (ICDs) are faced with psychological and social adjustments. Successful ICD therapy is influenced by the patients' perceived concerns regarding device, discharge, changes in life style, and complications. In order to assess patients' acceptance of the ICD, the psychological profile of 57 consecutive patients was evaluated using a specifically designed questionnaire and the State Trait Anxiety Inventory (STAI). The results showed that 20 patients staled fear of ICD discharge, 12 patients revealed physical discomfort due to the device, and limited quality-of-life occurred in 8 patients. Fifty-five of 57 patients answered that it was worth having an ICD device implanted, 30 (53%) patients returned to active life, and 56 (98%) would advise another patient to undergo implantation if necessary. Overall, there was only a slight, but insignificant, decrease in the level of anxiety within the total patient population after ICD implantation. However, a comparison of two subgroups indicated that the state of anxiety was significantly higher in patients < 50 years of age as well as in patients having received > 5 shocks versus those > 50 years of age and having experienced < 5 shocks. In general, the acceptance of the ICD as a tool in managing life-threatening ventricular tachyarrhythmias is high. Besides the increased survival rate, quality-of-life and patient acceptance are important criteria for successful ICD therapy.     

Chronotropic incompetence in patients with an implantable cardioverter defibrillator: prevalence and predicting factors

Chronotropic incompetence (CI), which has not been systematically examined in the ICD patient population, may have implications for device programming. A total of 123 ICD patients were classified into three groups: single-chamber ICD with sinus rhythm, dual-chamber ICD with sinus rhythm, and single-chamber ICD with permanent atrial fibrillation. Heart rate response, maximum oxygen uptake, and oxygen uptake at the anaerobic threshold were measured during treadmill exercise testing. In addition, clinical variables such as antiarrhythmic drug therapy, underlying heart disease, and left-ventricular (LV) ejection fraction were recorded. Of the patients studied, 38% were chronotropically incompetent (47/123). Significant predictors of CI were as follows: presence of a coronary disease (P = 0.036), prior cardiac surgery (P = 0.037), chronic drug therapy with beta-blockers (P = 0.032), administration of amiodarone (P = 0.025), and a combination of these two forms of treatment (P = 0.01). Spiroergometry revealed reduced exercise capacity (P = 0.041) and lessened VO2max (P = 0.034) among chronotropically incompetent patients. A large percentage of ICD patients demonstrates CI with subsequently reduced physical stress tolerance. In light of the DAVID study, we believe that a closer examination of rate-adaptive modes for ICD patients is warranted under enhanced conditions: (1) optimized AV interval programming; (2) utilization of new algorithms to reduce ventricular pacing in combination with rate-adaptive atrial pacing, with the goal of addressing CI while minimizing ventricular pacing; and (3) an optimized upper heart-rate limit.     

Economic analysis of a randomized trial of biventricular pacing in Canada

BACKGROUND: Congestive heart failure (CHF) has been shown to affect 5% of the Canadian adult population, and leads to 9.5 deaths per 100 cardiac-related hospitalizations in Canada. The economic outcomes from biventricular pacing for heart failure are not well understood. This study analyzes resource utilization and related costs associated with CHF for patients who receive standard implantable cardiac defibrillators (ICDs) versus those who receive ICD plus biventricular pacing or cardiac resynchronization therapy (CRT). METHODS: The Canadian analysis of resynchronization therapy in heart failure (CART-HF) study included 72 patients with New York Heart Association class II-IV CHF requiring an ICD. Patients were randomized to receive either ICD + CRT treatment or ICD treatment alone. Medical resource utilization data were collected for 6 months following treatment and were applied to representative costs for the provinces of Quebec and Ontario. Resource utilization was subcategorized into pharmacological therapy, physician visits, hospitalizations, adverse events, and productivity losses. RESULTS: Post-treatment, per patient costs for the CRT + ICD treatment group were less than the follow-up costs for patients receiving ICD treatment only in each province. Mean savings for patients receiving biventricular therapy were CAD 2,420 dollars in Quebec and CAD 2,085 dollars in Ontario during the 6-month follow-up. CONCLUSIONS: These analyses indicate that savings in post-implant health-care utilization (hospitalizations and pharmacological therapy) can offset some of the device and procedural costs associated with CRT devices.     

Apolipoprotein(a) phenotypes, Lp(a) concentration and plasma lipid levels in relation to coronary heart disease in a Chinese population: evidence for the role of the apo(a) gene in coronary heart disease.

Elevated lipoprotein(a) (Lp[a]) concentrations are associated with premature coronary heart disease (CHD). In the general population, Lp(a) levels are largely determined by alleles at the hypervariable apolipoprotein(a) (apo[a]) gene locus, but other genetic and environmental factors also affect plasma Lp(a) levels. In addition, Lp(a) has been hypothesized to be an acute phase protein. It is therefore unclear whether the association of Lp(a) concentrations with CHD is primary in nature. We have analyzed apo(a) phenotypes, Lp(a) levels, total cholesterol, and HDL-cholesterol in patients with CHD, and in controls from the general population. Both samples were Chinese individuals residing in Singapore. Lp(a) concentrations were significantly higher in the patients than in the population (mean 20.7 +/- 23.9 mg/dl vs 8.9 +/- 12.9 mg/dl). Apo(a) isoforms associated with high Lp(a) levels (B, S1, S2) were significantly more frequent in the CHD patients than in the population sample (15.9% vs 8.5%, P less than 0.01). Higher Lp(a) concentrations in the patients were in part explained by this difference in apo(a) allele frequencies. Results from stepwise logistic regression analysis indicate that apo(a) type was a significant predictor of CHD, independent of total cholesterol and HDL cholesterol, but not independent of Lp(a) levels. The data demonstrate that alleles at the apo(a) locus determine the risk for CHD through their effects on Lp(a) levels, and firmly establish the role of Lp(a) as a primary genetic risk factor for CHD.     

Implantable Cardioverter Defibrillator-Related Complications in the Pediatric Population

Background: The recognition that implantable cardioverter-defibrillator (ICD) therapy in children can prolong life coupled with the development of smaller devices and transvenous lead technology has increased the number of ICDs implanted in children and young adults.
Methods: ICD complications in the pediatric population are reviewed.
Results: ICD complications in the pediatric population include those related to the implantation procedure, the ICD system, as well as psychosocial issues. Inappropriate ICD therapy and ICD lead failures are the most frequent complications.
Conclusion: Identifying complications is the prerequisite for advances in ICD technology and effective management strategies need to be developed to avoid their recurrence.     

Lower observed versus expected (based on U.S. age and gender specific rates) survival in patients treated for near-fatal ventricular arrhythmias

Implantable cardioverter defibrillators (ICDs) have improved survival for patients with ventricular fibrillation (VF) or sustained vertricular tachycardia (VT). However, the survival of these patients compared to the general population has not been assessed. Observed survival rates for patients randomized to either antiarrhythmic drug therapy (mainly amiodarone) arm or ICD arm were compared to expected rates, calculated using age and sex-specific survival rates derived from the 1989-1991 US population life tables and applied to the age and sex distribution of patients in each arm. Consistent with the results of the Antiarrhythmics Versus Implantable Defibrillators (AVID) trial, patients randomized to receive ICDs experienced significantly higher survival than those in the drug arm; however, both groups experienced significantly lower survival than expected using age and gender matched U.S. survival rates. Within arms, the difference between the observed and expected rates increased over 3 years of follow-up from 7.7% to 15.3% for the ICD arm, and from 14.6% to 26.4% for the drug arm. These results quantify the improvements in survival that can be expected for VF or VT patients using drug or ICD therapies and underscore the need for continued research into methods for further improving the overall level of health of these patients.