Appropriate therapies predict long-term mortality in primary and secondary prevention of sudden cardiac death.

BACKGROUND: Less than 50% of patients implanted with an implantable cardioverter-defibrillator (ICD) receive device therapy during the follow-up. The aim of our study was to prospectively evaluate the predictive role of appropriate ICD therapy on long-term survival of patients implanted for primary or secondary sudden death prevention. METHODS: From 2002 to 2003, 139 consecutive patients [mean age 66±9 years, male 77%, ischemic heart disease 56%, New York Heart Association functional class >II (74%), primary prevention 74%, mean left ventricular ejection fraction 30±9%, cardiac resynchronization ICD 65%] were enrolled. We collected and evaluated device therapies for at least 18 months and recorded survival status for more than 5 years. RESULTS: Over a median follow-up of 18 months, 54 (39%) patients received at least one ICD intervention, with 28 patients receiving only appropriate ICD therapies, 13 only inappropriate therapies and 13 receiving both therapies. At a mean follow-up of 63±12 months, 30 deaths occurred in 130 patients (23%); for nine patients, we had no survival status information. Death was classified as cardiac in 22 (73%) patients, the most common cause was progressive heart failure. In a Cox proportional regression model, an appropriate ICD therapy was associated with a significant increase in the subsequent risk of death (hazard ratio 3.02, P=0.003). CONCLUSION: In patients implanted with ICD or cardiac resynchronization therapy with ICD devices, for primary or secondary sudden cardiac death prevention, appropriate ICD therapy predicts a three-fold greater risk of death.

Methodological lessons and pilot data on the effect of proximity of homes and schools to highways on pediatric asthma and lung function.

PURPOSE: Numerous studies have found that either living or attending school near highways or exposure to pollutants associated with heavy motor vehicle traffic are associated with a high prevalence of asthma and reduced lung function. Yet, few investigations have assessed school and home exposure in the same study. METHODS: We recruited children aged 5-19 years from a pediatric clinic in an urban center (Boston Chinatown) for many of whom housing and school were located immediately adjacent to two major highways. A questionnaire was used to assess self-report of diagnosis of asthma and the proximity of schools and homes to highways, as well as basic demographic information. Spirometric lung function data were obtained and reviewed by a pediatric pulmonologist blinded to survey responses. During this review, we excluded lung function tests of low quality. RESULTS: The analyses did not demonstrate any associations or mean differences between near-highway exposure at school, at home, or both with diagnosed asthma (p>0.10, n=124). For the lung function data (n=87), neither direct measures (FEV1, FVC, and FEF(25-75)) nor ratio measures (FEV1/FVC and FEF(25-75)/FVC) had a significant association with near-highway exposure (p>0.10). Certain predisposing factors, such as diagnosed allergies and family history of asthma, were strongly associated with diagnosed asthma (p<0.05 and p=0.001, respectively), findings we have seen consistently in other work with children recruited from the same clinic. We also found that exposure to pests was significantly correlated with a smaller FEF(25-75)/FVC ratio (p=0.02). CONCLUSIONS: Our findings suggest that either limitations in our study design restricted our ability to see the associations reported by others or that such associations do not exist in this population. One possibility is that in this community, with heavy street traffic and many street canyons, the gradient of exposure next to the highway is not very well delineated by simple proximity.

Lessons for primary prevention of asthma: foreign-born children have less association of SES and pests with asthma diagnosis.

There are no proven interventions for primary prevention of asthma. As asthma prevalence varies globally, comparing asthma in native and foreign-born children might provide insights. We pooled data from five cross sectional asthma surveys (N = 962). Place of birth was associated with asthma (OR = 3.4, P < 0.001). In children not born in the US, lower socio-economic status had no significant effect on asthma (OR = 0.71, P = 0.53), while for children born in the US, the effect was significant (OR = 2.1, P = 0.001). The odds ratio for exposure to household pests was significant (OR = 1.6, P < 0.008) for children born in the US but was non-significant for children born outside the US (OR = 0.29, P = 0.11). Our findings are consistent with foreign-born children experiencing protective factors or US born children experiencing detrimental environmental exposures.