Long-term efficacy and health consumption before and after ablation of AF

Background

Atrial fibrillation (AF), the most common arrhythmia worldwide, is associated with increased morbidity and mortality. Catheter ablation of AF is the most effective treatment option for symptomatic patients. The long-term efficacy is however not very well studied nor is health consumption before and after an ablation of atrial fibrillation.

Purpose

To study the long-term efficacy and health consumption before and after an ablation of AF in 1453 consecutive patients undergoing ablation in our institution.

Methods

Consecutive patients undergoing radiofrequency ablation for AF were included prospectively. 4 mm irrigated ablation (Biosense Webster) catheters and Carto® were used for all procedures. After a mean period of 4 years a survey measuring arrhythmia symptoms was sent out to all patients who were treated with an ablation of AF between 1st of January 2010 and 31st of December 2016. Data was collected from local registries, the national registry for catheter ablations and the national health registry. Health consumption measured as in-hospital visits two years before and after the procedure was assessed.

Results

877 (72.7%) patients had no further symptomatic arrhythmia four years after the procedure. Among the 329 patients who still reported symptoms 237 (72%) had milder, 65 (20%) had unchanged and 20 (8%, 1.3% of total) had worsened symptoms after e ablation.

The total number of in-hospital visits 2 years before and after the ablation was 4067. There were 2594 in-hospital visits before and 1473 after the ablation, a decrease by 43%. The majority of the these were arrhythmia related, 2264 and 908, respectively, a decrease by 60%. Seven patients had a stroke before the ablation and five after. The median length of stay was 1 day both before and after the ablation.

Conclusion

Health consumption is significantly decreased after an ablation for AF. The long-term effect is good with freedom of symptomatic AF of approximately 70% after four years.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Biosense Webster Inc

Distribution of hospital care among pediatric and young adult Hodgkin lymphoma survivors-A population-based cohort study from Sweden and Denmark

The burden of late effects among Hodgkin lymphoma (HL) survivors treated according to contemporary protocols remains poorly characterized. We used nation‐wide registers to assess number of inpatient bed‐days and specialist outpatient visits among 1048 HL‐patients (<25 years, diagnosed 1990‐2010) and 5175 country‐, sex‐, and age‐matched comparators. We followed them for up to 24 years, with time‐dependent assessment of relapse status. International Classification of Diseases (ICD‐10) chapter‐specific hazard ratios (HRs) were assessed in Cox regression analyses, and nonparametric statistics described patterns of health‐care‐use. Relative to comparators, relapse‐free survivors were at increased risk of infections, diseases of the blood, endocrine, circulatory and respiratory systems, and unspecific symptoms, HRs ranging from 1.86 to 3.05. Relative to comparators, relapsed survivors had at statistically significantly increased risk of diseases reflecting practically all investigated disease‐chapters, HRs ranging from 1.60 to 18.7. Among relapse‐free survivors, 10% of the patients accounted for 80% of all hospital bed days, and 55% were never hospitalized during follow‐up. Among relapsed‐survivors, 10% of the patients accounted for 50% of the bed days, and only 24% were never hospitalized during follow‐up. In contrast, 10% of the comparators accounted for 90% of hospital bed days and 75% were never hospitalized. These findings challenge the impression of a uniformly distributed long‐term morbidity among all HL survivors and emphasize the need for early identification and attention to patients particularly susceptible to late effects, such as relapsed survivors.

Hodgkin lymphoma in children, adolescents and young adults - a comparative study of clinical presentation and treatment outcome

BACKGROUND

Hodgkin lymphoma (HL) treatment protocols for children, adolescents and young adults traditionally differ, but the biological and clinical justification for this remains uncertain.

MATERIAL AND METHODS

We compared age-dependent clinical presentation and treatment and outcome for 1072 classical HL patients 0-24 years diagnosed in Denmark (1990-2010) and Sweden (1992-2009) in pediatric (n = 315, Denmark <15 years, Sweden <18 years) or adult departments (n = 757). Distribution of clinical characteristics was assessed with Pearson's chi²-test and Mantel-Haenszel trend test. The Kaplan-Meier method was used for survival analyses. Hazard ratios (HR) were used to compare the different treatment groups and calculated using Cox regression.

RESULTS

Children (0-9 years) less often presented with advanced disease than adolescents (10-17 years) and young adults (18-24 years) (stage IIB-IV: children 32% vs. adolescents 50%, and adults 55%; p < .005). No variation in overall survival (OS) was seen between pediatric and adult departments or by country. Danish pediatric patients received radiotherapy (36%) less frequently than Swedish pediatric patients (71%) (p < .0001). Ten-year event-free survival (EFS) was lower among Danish pediatric patients (0-14 years) (0.79; 95% confidence interval (CI) 0.70-0.86) than among Swedish pediatric patients (0-17 years) (0.88; 95% CI 0.83-0.92), HR (1.93; 95% CI 1.08-3.46). A similar pattern was seen between adult patients in the two countries: Denmark 10-year EFS 0.85 (95% CI 0.81-0.88), Sweden 0.88 (95% CI 0.84-0.91), adjusted HR 1.51 (95% CI 1.03-2.22).

CONCLUSION

Adolescents and young adults shared similar clinical presentation suggesting a rationale of harmonized treatment for these groups. Both adult and pediatric protocols provided high OS with no significant difference between the departments. The less frequent use of radiotherapy in Danish pediatric patients corresponded to a lower EFS, but comparable OS in all groups confirmed effective rescue strategies for the relapsing patients.

Cannabis-associated psychosis: Neural substrate and clinical impact

Prospective epidemiological studies have consistently demonstrated that cannabis use is associated with an increased subsequent risk of both psychotic symptoms and schizophrenia-like psychoses. Early onset of use, daily use of high-potency cannabis, and synthetic cannabinoids carry the greatest risk. The risk-increasing effects are not explained by shared genetic predisposition between schizophrenia and cannabis use. Experimental studies in healthy humans show that cannabis and its active ingredient, delta-9-tetrahydrocannabinol (THC), can produce transient, dose-dependent, psychotic symptoms, as well as an array of psychosis-relevant behavioral, cognitive and psychophysiological effects; the psychotogenic effects can be ameliorated by cannabidiol (CBD). Findings from structural imaging studies in cannabis users have been inconsistent but functional MRI studies have linked the psychotomimetic and cognitive effects of THC to activation in brain regions implicated in psychosis. Human PET studies have shown that acute administration of THC weakly releases dopamine in the striatum but that chronic users are characterised by low striatal dopamine. We are beginning to understand how cannabis use impacts on the endocannabinoid system but there is much still to learn about the biological mechanisms underlying how cannabis increases risk of psychosis. This article is part of the Special Issue entitled "A New Dawn in Cannabinoid Neurobiology".

Hodgkin lymphoma--a survey of children and adolescents treated in Sweden 1985-2009

BACKGROUND

Hodgkin lymphoma (HL) in children constitutes approximately 30% of all pediatric lymphomas in Sweden. The chance of cure is high, but the frequency of late effects has been considerable. Over recent years, efforts have been made to reduce treatment with maintained survival.

MATERIAL AND METHODS

All patients 0-17 years, identified in the Swedish Childhood Cancer Register as diagnosed between 1985 and 2009, were included. The material was analyzed using descriptive statistics and for survival estimates the Kaplan-Meier method was used.

RESULTS

Three hundred and thirty-four patients were identified during this time period. The median age was 14 years. Male sex was over-represented, especially in lower age groups and in nodular lymphocyte predominant Hodgkin lymphoma (NLPHL). In nodular sclerosis and in age group 15-17 years, female sex dominated. Most of the cases presented in stages I or II. B-symptoms were present in 38% of cHL, but only in 7% of NLPHL. The number of patients receiving radiotherapy has been significantly reduced during the period studied. The relapse rate in cHL was 10 ± 2% and in NLPHL 16 ± 7%. The relapse rate was significantly higher in cHL stage IIB compared to other stages in the same therapy group. In cHL 6% died, and in NLPHL 0%. The 5-, 10- and 20-year overall survival estimates in cHL were 96 ± 1%, 95 ± 1% and 90 ± 3%, respectively, with no significant difference when comparing different treatment regimens and time periods. The 5- and 10-year overall survival after relapse in cHL was 81 ± 8% and 75 ± 10%, respectively.

CONCLUSION

During the period studied there is no indication of a decline in survival despite changes in treatment. Survival rates in Sweden are high, and even after relapse chances of cure are high. We were not able to identify any characteristics specific for the group of patients that did not survive.

Citrulline concentration in routinely collected neonatal dried blood spots cannot be used to predict necrotising enterocolitis

AIM

Low citrulline concentration is a marker of low functional enterocyte mass, which may predispose neonates to necrotising enterocolitis (NEC). We hypothesised that citrulline could be used to assess the NEC risk that could not be accounted for by gestational age and birthweight. This study investigated whether citrulline concentrations routinely measured in neonatal dried blood spots (DBS) could predict NEC.

METHODS

We used national Danish registries to retrospectively identify all 361 babies born between 2003 and 2009 who were diagnosed with NEC and had a valid citrulline concentration measured from a DBS sample. The control group comprised 1083 healthy newborns, with three controls for every newborn with NEC, matched for birthweight and gestational age.

RESULTS

Neonatal dried blood spots were collected between 2 and 21 days of life, with a median of 8 days. The results showed that NEC was not associated with low citrulline concentration, either in a direct comparison between the NEC and control groups or in a multivariate logistic regression (p = 0.73).

CONCLUSION

The findings of this study show that the citrulline concentrations found in routine DBS samples between 2003 and 2009 did not predict NEC in newborn babies.

Changes in mortality and causes of death in the Swedish Down syndrome population

During the past few decades age at death for individuals with Down syndrome (DS) has increased dramatically. The birth frequency of infants with DS has long been constant in Sweden. Thus, the prevalence of DS in the population is increasing. The aim of the present study was to analyze mortality and causes of death in individuals with DS during the period 1969-2003. All individuals with DS that died between 1969 and 2003 in Sweden, and all individuals born with DS in Sweden between 1974 and 2003 were included. Data were obtained from the Swedish Medical Birth Register, the Swedish Birth Defects Register, and the National Cause of Death Register. Median age at death has increased by 1.8 years per year. The main cause of death was pneumonia. Death from congenital heart defects decreased. Death from atherosclerosis was rare but more frequent than reported previously. Dementia was not reported in any subjects with DS before 40 years of age, but was a main or contributing cause of death in 30% of the older subjects. Except for childhood leukemia, cancer as a cause of death was rare in all age groups. Mortality in DS, particularly infant mortality, has decreased markedly during the past decades. Median age at death is increasing and is now almost 60 years. Death from cancer is rare in DS, but death from dementia is common.

The safety of flecainide treatment of atrial fibrillation: long-term incidence of sudden cardiac death and proarrhythmic events

OBJECTIVE

To assess the safety of long-term treatment with flecainide in patients with atrial fibrillation (AF), particularly with regard to sudden cardiac death (SCD) and proarrhythmic events.

DESIGN

Retrospective, observational cohort study.

SETTING

Single-centre study at Örebro University Hospital, Sweden. Subjects.  A total of 112 patients with paroxysmal (51%) or persistent (49%) AF (mean age 60 ± 11 years) were included after identifying all patients with AF who initiated oral flecainide treatment (mean dose 203 ± 43 mg per day) between 1998 and 2006. Standard exclusion/inclusion criteria for flecainide were used, and flecainide treatment was usually combined with an atrioventricular-blocking agent (89%).

MAIN OUTCOME MEASURE

Death was classified as sudden or nonsudden according to standard definitions. Proarrhythmia was defined as cardiac syncope or life-threatening arrhythmia.

RESULTS

Eight deaths were reported during a mean follow-up of 3.4 ± 2.4 years. Compared to the general population, the standardized mortality ratios were 1.57 (95% confidence interval (CI) 0.68-3.09) for all-cause mortality and 4.16 (95% CI 1.53-9.06) for death from cardiovascular disease. Three deaths were classified as SCDs. Proarrhythmic events occurred in six patients (two each with wide QRS tachycardia, 1 : 1 conducted atrial flutter and syncope during exercise).

CONCLUSION

We found an increased incidence of SCD or proarrhythmic events in this real-world study of flecainide used for the treatment of AF. The findings suggest that further investigation into the safety of flecainide for the treatment of patients with AF is warranted.

Long-term prognosis in patients with bifascicular block--the predictive value of noninvasive and invasive assessment

OBJECTIVES

Patients with bifascicular block (BFB) have a high mortality rate. The purpose of the present study was to identify high-risk patients in a BFB population by performing an extensive cardiac evaluation including noninvasive and invasive tests.

DESIGN

Population-based study.

SUBJECTS

A total of 100 patients with BFB, of whom 41 had a history of unexplained syncope, were prospectively studied. The mean age was 68 +/- 12. All patients were investigated with Holter-monitoring, an exercise test, an echocardiography, and an invasive electrophysiological study. The severity of congestive heart failure (CHF) was assessed by New York Heart Association (NYHA) classification. Patients in NYHA class IV were excluded.

INTERVENTIONS

Patients with syncope were recommended prophylactic pacemaker treatment, which was accepted by 31 patients (76%). Main outcome measures. All-cause mortality and sudden cardiac death (SCD).

RESULTS

During a median follow-up of 84 months, 33 patients died, of whom 14 in SCD. In a univariate analysis, high age, a previous myocardial infarction, and CHF were associated with a significantly increased risk of all-cause mortality and SCD. In a Cox multiple regression analysis, CHF was the only independent predictor of all-cause mortality and SCD (P < 0.01).

CONCLUSION

Patients with BFB have a poor long-term prognosis. The predictive value of noninvasive and invasive investigations is limited. The only independent predictor of all-cause mortality and SCD in this population was the presence of CHF.

Dispersion in ventricular repolarization in patients with severe intraventricular conduction disturbances

Increased dispersion of repolarization, measured invasively or by QT interval measurements, is associated with an increased risk for ventricular arrhythmias and sudden death. Most studies on this issue have included patients with normal intraventricular conduction, and it is not known if this finding has a predictive value also in patients with intraventricular conduction disorders. An invasive electrophysiological study, including programmed ventricular stimulation and assessment of effective refractory periods at two RV sites, was performed in 103 patients with bifascicular block (mean age 67 +/- 12 years). QT dispersion was measured from standard 12-lead ECGs. In patients with inducible sustained polymorphic VT or VF the dispersion in refractoriness between the two RV sites was significantly greater (46 +/- 11 ms, n = 13) than in noninducible patients (14 +/- 14 ms, n = 84) and in patients with inducible sustained monomorphic VT (16 +/- 5 ms, n = 6) (P < 0.01). Similarly, QT dispersion was 104 +/- 46 ms, 66 +/- 31 ms, and 77 +/- 33 ms, respectively, in the three groups (P < 0.05). Dispersion in repolarization, neither measured invasively nor by QT interval measurements, predicted sudden death, all cause mortality, or ventricular arrhythmia during a mean follow-up period of 3 years. In patients with bifascicular block, there is a relation between the degree of dispersion of ventricular repolarization and the inducibility of polymorphic ventricular arrhythmia, but this outcome did not occur during follow-up.

Circadian variation of malignant ventricular arrhythmias in patients with ischemic and nonischemic heart disease after cardioverter defibrillator implantation. European 7219 Jewel Investigators

OBJECTIVES

The purpose of this study was to examine the circadian variation of ventricular arrhythmias detected by an implantable cardioverter defibrillator in patients with and without ischemic heart disease.

BACKGROUND

Previous studies have shown a circadian variation of ventricular arrhythmias, sudden death and myocardial infarction with a peak occurrence in the morning hours. The circadian pattern, which is similar for both arrhythmic and ischemic events, suggests that ischemia may play a critical role in the genesis of ventricular arrhythmias and sudden death. We hypothesized that, if ischemia plays an important role in the triggering of ventricular arrhythmias, the circadian pattern should be different in patients with ischemic heart disease compared with patients with nonischemic heart disease.

METHODS

The circadian variation of ventricular arrhythmias recorded by an implantable cardioverter defibrillator was studied in 310 patients during a mean follow-up of 181 +/- 163 days. Two hundred four patients had a history of ischemic heart disease and 106 patients had nonischemic heart disease. The times of the episodes of ventricular arrhythmias were retrieved from the data log of each device during follow-up, and the circadian pattern was compared between the two groups.

RESULTS

During follow-up, 1,061 episodes of ventricular arrhythmias were recorded by the device in the 310 patients. Six hundred eighty-two episodes occurred in the group of patients with ischemic heart disease and 379 occurred in the nonischemic heart disease group. The circadian variation of the episodes showed a typical pattern with a morning and afternoon peak in both groups of patients with ischemic and nonischemic heart disease, but there was no significant difference between the two groups.

CONCLUSIONS

The circadian rhythm of ventricular arrhythmias in patients with ischemic heart disease is similar to patients with nonischemic heart disease, suggesting that the trigger mechanisms of the initiation of ventricular tachyarrhythmias may be similar, irrespective of the underlying heart disease.

Increased QT dispersion during hypoglycaemia in patients with type 2 diabetes mellitus

OBJECTIVES

To study effects of insulin-induced hypoglycaemia on the cardiac repolarization, using QT interval measurements, in patients with type 2 diabetes.

DESIGN

Hypoglycaemia was induced by an i.v. insulin-infusion and blood glucose was clamped at 2.7 mmol L-1 for 60 min (T = 90-150 min) in two experiments, with (+GLIB) and without (-GLIB) glibenclamide. In a third experiment, with similar hyperinsulinaemia, glucose was clamped at a euglycaemic level (;5 mmol L-1). ECG was continuously recorded for arrhythmia-monitoring, and 12-lead ECGs were recorded at T = 0 and 150 min. QT intervals were measured, and we determined QT dispersion (difference between the maximum and the minimum QT interval) reflecting interlead variability of repolarization.

SUBJECTS

Thirteen patients with type 2 diabetes, on combined insulin and glibenclamide treatment, were studied during hypoglycaemia, and eight of them participated in the euglycaemic experiment.

RESULTS

No significant arrhythmias were seen during hypoglycaemia but the mean QT intervals and QT dispersion increased significantly (P < 0.001), with no differences between -GLIB and +GLIB. During the euglycaemic clamp all QT measurements remained unchanged. Serum potassium decreased significantly (P < 0.001) during all three clamps, but the decrease was more pronounced during hypoglycaemia. The change in potassium was not correlated to the degree of QT prolongation or QT dispersion.

CONCLUSIONS

Significant changes in the repolarization of the heart can be seen during hypoglycaemia in patients with type 2 diabetes, indicating an increased risk of arrhythmia at low blood glucose levels.

Pleural mesothelioma in Sweden: an analysis of the incidence according to the use of asbestos

OBJECTIVE

To investigate if the preventive measures taken to reduce the occupational exposure to asbestos have resulted in a decreased incidence of pleural mesothelioma in Sweden.

METHODS

The incidence of pleural mesothelioma between 1958 and 1995 for birth cohorts born between 1885 and 1964 was investigated. The cases of pleural mesothelioma were identified through the Swedish Cancer Register.

RESULTS

In 1995, around 80 cases of pleural mesothelioma could be attributed to occupational exposure to asbestos. There is an increasing incidence in more recent birth cohorts in men. The incidence was considerably higher in the male cohort born between 1935 and 1944 than in men born earlier.

CONCLUSIONS

The annual incidence of pleural mesothelioma attributable to occupational exposure to asbestos is today larger than all fatal occupational accidents in Sweden. The first asbestos regulation was adopted in 1964 and in the mid 1970s imports of raw asbestos decreased drastically. Yet there is no obvious indication that the preventive measures have decreased the risk of pleural mesothelioma. The long latency indicates that the effects of preventive measures in the 1970s could first be evaluated around 2005.

Use of spectral turbulence analysis for the identification of patients at high risk for ventricular fibrillation and sudden death in patients with hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy carries an increased risk of sudden death. The aim of the present study was to assess the predictive value of the signal-averaged ECG, analysed in the time domain and using a new method, spectral turbulence analysis, for the identification of high-risk patients. Two-hundred and forty-six patients with hypertrophic cardiomyopathy were studied. During a mean follow-up of 68 +/- 17 months, 17 patients died suddenly. Patients with sudden death (SD) and/or a history of ventricular fibrillation (VF; n = 25) were compared to patients without SD/VF (n = 221) and to patients without any recognised risk factors for SD (n = 82). There were no differences in mean values of the time domain or spectral turbulence parameters analysed between patients in the SD/VF group and the patients without SD/VF or in the low-risk group. It is concluded that the clinical usefulness of the signal-averaged ECG, analysed in the time domain or as spectral turbulence analysis, is limited in identifying high-risk patients with hypertrophic cardiomyopathy.

Pharmacological stress testing of the His-Purkinje system in patients with bifascicular block

This literature review, based mainly on the English-language literature, focuses on pharmacological stress testing of the His-Purkinje system as part of an invasive electrophysiological study. The main target group for this investigation is patients with bifascicular block and syncope in which intermittent high grade AV block is suspected. Several drugs have been used for this purpose, mainly Class I antiarrhythmic agents such as ajmaline, procainamide, disopyramide, and flecainide. Most studies, unfortunately, suffer from limited patient numbers, lack of adequate control groups, and/or adequate follow-up. The sensitivity of the disopyramide stress test has been shown to be 75%-100% for prediction of impending high grade AV block. The specificity was > 90%. Studies on procainamide have shown a sensitivity of 60% but the specificity has not been assessed. There are no studies allowing a strict comparison of the diagnostic value of pharmacological provocation with different drugs. Based on the similarities of the electrophysiological effects on the His-Purkinje system of the above Class I agents, it is reasonable to assume that all of them might be of diagnostic value in the present clinical context, provided atrial and ventricular stimulation after drug is included in the protocol.

Wavelet decomposition analysis of the signal averaged electrocardiogram used for risk stratification of patients with hypertrophic cardiomyopathy

AIMS

To study the predictive value of wavelet decomposition, as demonstrated by the signal-averaged ECG, in order to identify patients with hypertrophic cardiomyopathy at increased risk for malignant ventricular arrhythmias or sudden death.

METHODS AND RESULTS

Two hundred and forty-six patients with hypertrophic cardiomyopathy were studied. During a mean follow-up of 68 +/- 17 months 32 patients died, of whom 17 died suddenly. Patients with sudden death, together with eight patients with a history of ventricular fibrillation (sudden death/ventricular fibrillation group) were analysed and compared to the other 221 patients as well as to a subgroup of 82 patients without a history of syncope, ventricular arrhythmias on a long-term ECG recording or a family history of sudden death. There were no differences in mean values of the four wavelet decomposition parameters among patients in the sudden death/ ventricular fibrillation group, those without sudden death/ ventricular fibrillation or patients in the low risk group. There were, however, significant differences between patients dying non-suddenly and patients being alive at the end of follow-up. Eighty-seven patients (35%) demonstrated evidence of non-sustained ventricular tachycardia on a long-term ECG. Analysis of wavelet decomposition resulted in abnormal findings in these patients more often than in those without ventricular arrhythmias.

CONCLUSION

The usefulness of wavelet decomposition analysis in predicting sudden death or ventricular fibrillation is limited in patients with hypertrophic cardiomyopathy. It may, however, play a role in identifying patients at risk of dying non-suddenly and of patients with non-sustained ventricular tachycardia.

Smoking and the risk of leukemia, lymphoma, and multiple myeloma (Sweden)

While several epidemiologic studies have indicated a link between smoking and the risk of developing hematolymphoproliferative cancers (chiefly leukemias, lymphomas, and multiple myelomas), in particular myeloid leukemia, the role of tobacco in the etiology of these neoplasms remains unclear. To evaluate the potential impact of tobacco use on development of leukemia, lymphoma, and multiple myeloma, we conducted a cohort study of 334,957 Swedish construction workers using prospectively collected exposure-information with complete long-term follow-up. A total of 1,322 incident neoplasms occurred during the study period, 1971-91. We found no significant association between smoking status, number of cigarettes smoked, or duration of smoking and the risk of developing leukemias, lymphomas, or multiple myeloma. There was a suggestion of a positive association between smoking and the risk of developing Hodgkin's disease, although the rate ratios were not significantly elevated, except for young current smokers. No positive dose-risk trends emerged. Our study provides no evidence that smoking bears any major relationship to the occurrence of leukemias, non-Hodgkin's lymphomas, or multiple myeloma.

[ECG findings with poor prognosis. Bifascicular block as a warning sign in cases of syncope]

Of 517 emergency room admissions for syncope at four Stockholm hospitals, 36 (7 per cent) were found to be cases of bifascicular block. Of these 36 patients, 34 underwent ambulatory electrocardiography (ECG) in hospital, which showed significant arrhythmia to be present in three cases [high-grade atrioventricular block (n = 2), or sustained ventricular tachycardia (n = 1)]. After a mean follow-up of 32 months, eight more patients had developed high-grade atrioventricular block, and 13 patients had died (eight of them suddenly). It is concluded that patients with bisfascicular block constitute a high-risk category, and would benefit from thorough investigation, including an invasive electrophysiological study, in order to identify those at risk of progression to high-grade atrioventricular block or malignant ventricular arrhythmia.

Body size and prostate cancer: a 20-year follow-up study among 135006 Swedish construction workers

BACKGROUND

Obesity is associated with endocrine changes (e.g., increased estrogen and decreased testosterone in the blood) that have been implicated in the cause of prostate cancer and, therefore, an association between body weight and the risk of developing prostate cancer would be expected. However, because of bias or low statistical power in previous epidemiologic studies, associations between anthropometric measurements (height and weight), body mass index (BMI), and the risk of prostate cancer may have been inadvertently overlooked.

PURPOSE

We performed a large, retrospective cohort study among Swedish construction workers to evaluate possible associations of adult weight, height, BMI, and lean body mass (LBM) by age at entry in the study with the incidence and mortality rate of prostate cancer.

METHODS

We analyzed data that had been compiled in a computerized central register on a cohort of approximately 135000 male construction workers. Information on height and weight had been collected with the use of a comprehensive questionnaire filled out by nurses at the time of enrollment in the cohort, from 1971 through 1975. Complete follow-up was achieved through 1991 by means of record linkage to the Swedish National Cancer Register, the Death Register, and the Migration Register. A total of 2368 incident cases and 708 deaths from prostate cancer occurred in the cohort during a follow-up period averaging 18 years. We used only information obtained at the index visit from 1971 through 1975 to determine age-adjusted rate ratios (RRs) in a Poisson-based multiplicative multivariate model with age and the relevant exposure variable (e.g., weight, height, BMI, and LBM) as independent variables.

RESULTS

All anthropometric measurements were positively associated with the risk of prostate cancer and were more strongly related to mortality than to incidence. The excess risk of death from prostate cancer was statistically significant in all BMI categories above the reference category: RR = 1.40 (95% confidence interval [CI] = 1.09-1.81) in the highest category compared with the lowest (P for trend = .04). For height and LBM, the excess risk in the highest compared with the lowest categories was somewhat less pronounced: RR = 1.28 (95% CI = 1.02-1.60) and RR = 1.26 (95% CI = 1.02-1.57), respectively. Statistically significant linear dose-response relationships were also found with the incidence of prostate cancer, with the exception of BMI (P for trend = .10).

CONCLUSION

Our large cohort study indicates that various aspects of body size are related to the risk of prostate cancer and that future studies are needed to study the role of body size and prostate cancer.

Head-up tilt test. A nonspecific method of evaluating patients with bifascicular block

BACKGROUND

Patients with bifascicular block have an increased risk of syncopal attacks, but the underlying mechanism often remains unclear despite an extensive diagnostic workup. The head-up tilt test has been established as an important diagnostic tool in the unmasking of vasovagal syncope in patients with unexplained syncope. Its role in the evaluation of patients with bifascicular block has not been studied.

METHODS AND RESULTS

A head-up tilt test, using a 60 degrees angle of tilt for 45 minutes without pharmacological provocation, was performed in 25 patients with bifascicular block and syncope that remained unexplained after an extensive invasive and noninvasive electrophysiological investigation. As a control group, 25 subjects with bifascicular block without syncope, matched for age, sex, left ventricular function, and underlying heart disease, were included. A positive head-up tilt test was found in 7 (28%) of the syncope patients and in 8 (32%) of the control subjects (P = NS). Six patients, of whom 3 had a positive tilt test, had recurrent syncopal attacks during 32 months of follow-up. None of the control subjects had syncope during follow-up.

CONCLUSIONS

This study gives rise to serious concern regarding the specificity of the head-up tilt test in patients with bifascicular block. A head-up tilt test should therefore be interpreted with caution, and its role as a diagnostic tool in this patient category remains to be established.

The RR index test for the differentiation of atrioventricular nodal block from His-Purkinje block during incremental atrial pacing in patients with bifascicular block

AIMS

His-Purkinje block induced by incremental atrial pacing is highly predictive of an impending high degree atrioventricular block in patients with bifascicular block. The His potential is, however, sometimes not measurable or is lost in the ventricular depolarization. The aim of this study was to evaluate whether the comparison of RR intervals before and after atrioventricular block, induced by incremental atrial pacing, could differentiate between atrioventricular nodal and His-Purkinje block in patients with bifascicular block.

METHODS AND RESULTS

In 98 patients, with bifascicular block, incremental atrial pacing was performed as part of an invasive electrophysiological study. An "RR index' was constructed by calculating the numerical difference between the RR interval immediately before and after the atrioventricular block divided by the RR interval immediately before the pacing induced block. Endocavitary recording of the His bundle potential was used for defining the level of atrioventricular block. The median RR index was 0.98 (range 0.88-1.02) in recordings with His-Purkinje block and 0.49 (range 0.11-0.89) in recordings with atrioventricular nodal block (P < 0.001). An RR index of > or = 0.85 had a sensitivity of 100% and a specificity of 99% for the identification of atrioventricular block localized to the His Purkinje system.

CONCLUSION

The use of an RR index is a helpful tool in the differentiation of His-Purkinje from atrioventricular nodal block in patients with bifascicular block undergoing incremental atrial pacing as part of an invasive electrophysical study.

A prospective study of smoking and risk of prostate cancer

We evaluated the hypothesis that smoking increases the incidence of and mortality from prostate cancer. High-quality smoking information was collected in 1971-1975 in a nation-wide cohort of 135,006 male construction workers in Sweden. We achieved virtually complete follow-up through record linkages and ascertained as of December 1991 2,368 incident cases of prostate cancer and 709 deaths due to this disease. Rate ratios (RR) of prostate cancer incidence and mortality, with 95% confidence intervals (CI), were estimated in Poisson-based age-adjusted models, with amount and duration of smoking as independent variables. We found no convincing association between current smoking status, number of cigarettes smoked or years since onset and risk of prostatic cancer. The age-adjusted incidence RR among previous smokers was 1.09 and among current smokers 1.11 compared with non-smokers. Weak and inconsistent trends were seen with increasing number of cigarettes smoked per day and increasing duration among current smokers. Smokers of 15 or more cigarettes daily for at least 30 years experienced an incidence RR of 1.30. Mortality in ex-smokers was similar to that in never-smokers; it was, however, slightly increased among current smokers without any trend with amount smoked or duration. The weak and inconsistent associations between smoking and prostate cancer could easily have arisen due to bias or confounding. We therefore conclude that smoking is most likely not causally linked to the occurrence of prostate cancer.

Spectral turbulence analysis of the signal-averaged electrocardiogram for predicting inducible sustained monomorphic ventricular tachycardia in patients with and without bundle branch block

Spectral turbulence analysis of the signal-averaged electrocardiogram is a new method for identifying patients prone to sustained monomorphic ventricular tachycardia. In contrast to analysis in the time domain, it has been claimed to be applicable in patients with bundle branch block. The aim of this study was to assess the predictive value of spectral turbulence analysis, in relation to the inducibility of sustained monomorphic ventricular tachycardia, in patients with and without bundle branch block. One hundred and sixty nine patients, of whom 120 had a QRS duration > or = 120 ms, were studied. Forty-seven patients had inducible sustained monomorphic ventricular tachycardia and were compared to 122 control patients. The overall sensitivity of the spectral turbulence analysis for predicting inducible ventricular tachycardia was 77%, the specificity 35% and the total predictive accuracy 47%. The limited predictive accuracy was mainly due to a lack of difference between patients with and without ventricular tachycardia in patients with a QRS duration > or = 120 ms. In patients with QRS < 120 ms, however, there were significant differences in all spectral turbulence parameters and the method had a sensitivity of 75%, a specificity of 72% and a total predictive accuracy of 73%. The diagnostic usefulness of spectral turbulence analysis is dependent upon normal QRS duration and the method is applicable only to patients without bundle branch block.

Disopyramide stress test: a sensitive and specific tool for predicting impending high degree atrioventricular block in patients with bifascicular block

OBJECTIVE

To study the value of intravenous disopyramide as part of an invasive electrophysiological study in predicting impending high degree atrioventricular block in patients with bifascicular block.

DESIGN

An invasive electrophysiological study was performed in the basal state and after the infusion of disopyramide (2 mg/kg body weight). The progression to high degree atrioventricular block was assessed by bradycardia-detecting pacemakers or repeated 12-lead electrocardiogram recordings, or both.

PATIENTS

73 patients with bifascicular block were included, of whom 25 had a history of unexplained syncope. The remaining 48 patients had no arrhythmia related symptoms and were included as controls. All patients had an ejection fraction of > 35%.

RESULTS

After a mean follow up of 23 months, seven patients in the syncope group and three in the non-syncope group had a documented high degree atrioventricular block or pacemaker-detected bradycardia of < or = 30 beats/min for > or = 6 s. The sensitivity of the disopyramide test was 71% and the specificity 98%. The corresponding figures for an abnormal electrophysiological study in the basal state were 14% and 91%, respectively.

CONCLUSIONS

The sensitivity of an invasive electrophysiological study in patients with bifascicular block and syncope can be markedly increased by the use of intravenous disopyramide. A positive test is a highly specific finding and warrants pacemaker implantation.

Diagnostic value of programmed ventricular stimulation in patients with bifascicular block: a prospective study of patients with and without syncope

OBJECTIVES

The aim of this study was to examine the inducibility of ventricular arrhythmias in patients with bifascicular block both with and without a history of syncope and to relate the findings to clinical events during follow-up.

BACKGROUND

Patients with bifascicular block have an increased risk of sudden death that is not reduced by pacemaker treatment. This risk could be related to a high incidence of ventricular arrhythmias.

METHOD

Programmed ventricular stimulation was performed in 101 patients with bifascicular block: 41 had a history of unexplained syncope, and 60 were asymptomatic.

RESULTS

Programmed ventricular stimulation resulted in a sustained ventricular arrhythmia in 18 patients (18%), 8 in the syncope group and 10 in the nonsyncope group (p = NS). Three patients in each group had an inducible sustained monomorphic ventricular tachycardia. During a mean follow-up of 21 months, 10 patients experienced a clinical event defined as sudden death (n = 4), syncope (n = 5) or appropriate discharges from an implantable cardioverter-defibrillator (n = 1). Only one of these patients had an inducible ventricular arrhythmia at baseline.

CONCLUSIONS

The inducibility of ventricular arrhythmias is high in patients with bifascicular block and of the same magnitude in patients with and without a history of syncope. Clinical events during follow-up were not predicted by programmed ventricular stimulation in either of the two groups. The finding of inducible ventricular arrhythmia in patients with bifascicular block should therefore be interpreted with caution.

Use of signal-averaged electrocardiography for predicting inducible sustained monomorphic ventricular tachycardia in patients with bundle branch block with and without a history of syncope

The aim of this study was to examine the utility of signal-averaged electrocardiography in relation to inducible sustained monomorphic ventricular tachycardia in patients with bundle branch block. One hundred fourteen patients with bundle branch block underwent signal-averaged electrocardiography in the time domain and programmed ventricular stimulation. Sustained monomorphic ventricular tachycardia was induced in 17 patients. The mean values of the three signal-averaged electrocardiographic variables analyzed differed significantly between the inducible and the noninducible group. The filtered QRS duration showed the most prominent difference between the two groups, and a filtered QRS duration > or = 155 msec had a sensitivity of approximately 80%, a specificity of 60%, and a total predictive value of 65%. In the subgroup of patients with syncope, a combination of these criteria with a history of coronary artery disease had a sensitivity of 100% and a specificity of 90%.

Recent data on cancer due to asbestos in Sweden

Asbestos exposure in Sweden rapidly grew in the '50s and '60s, and then began to drop at the beginning of the '70s. The number of pleural mesotheliomas due to this exposure increased to some 80 a year during the second half of the '80s, and is rapidly increasing. The jobs with the highest risk are the wood and pulp industry, plumbing, shipbuilding, and, most of all, railroad manufacturing and sugar refineries. Data dealing with peritoneal mesotheliomas are more uncertain, and possibly misleading. As far as lung cancer incidence is concerned, it remains high in plumbers and insulators, while it declined to the expected levels in the other categories of exposed workers.

Safety and health in the construction industry

Workers in the building, renovation, and demolition of roads and commercial structures in the U.S. suffer a disproportionate share of occupational fatalities and lost-time injuries. Nearly all of the injuries and deaths are preventable. The fatality rate from work-related ailments, such as cancers and silicosis, is believed to be excessive, but is not generally computed. The safety and health problems are tied largely to the construction industry's organization and how the work is performed. Many hazardous exposures result from inadequacies in access to information, measurement technology, and personal protective equipment. Potential solutions are in labor-management site safety and health planning and management, education and training of workers and supervisors, new technologies, federal regulation, workers' compensation law, medical monitoring, and occupational health delivery. Public health opportunities involve health care delivery systems, improved preventive medicine, disability determination and rehabilitation programs, and research, beginning with the standardization of data to monitor these problems.

Health insurance and workers' compensation: the delivery of medical and rehabilitation services for construction workers

The construction industry has one of the highest proportions of workers without health insurance. The authors review the two types of insurance systems that are generally used to cover the cost of health care for construction workers in the U.S.: health and welfare funds and workers' compensation. Recent developments in health care delivery in the U.S. are discussed, as are the more comprehensive occupational medicine services offered in France, Germany, The Netherlands, and Sweden.

Why construction is different

Construction differs markedly from many other types of manufacturing in that the nature of the work exacerbates the safety and health risks faced by workers. Even for workers who have health care coverage, the authors point out, the transient nature of the industry makes it difficult to trace an individual's exposure to health hazards.

Morbidity and mortality patterns in Sweden

This extensive review of morbidity and mortality patterns cites data from Bygghälsan, a Swedish program that has followed a quarter of a million construction workers for two decades. Comparisons are made among different types of workers, and standardized mortality ratios and standardized incidence ratios are presented.

Perspectives on the future

There is a growing trend toward new forms of labor-management cooperation, through negotiated agreements involving job-site safety and health, workers' compensation, and preventive medicine (see chapter 14). These developments are likely to change safety and health in the industry. At the same time, they provide opportunities for practitioners and researchers in occupational safety and health. If we can venture to express a professional wish, it would be to find answers to the following: How can we, as the professions concerned with the well being of workers, help preserve the characteristics of construction work that are positive while reducing the aspects of the industry's functioning that are so deleterious to health? How do we preserve the crafts with their fostering of self-esteem: through individual freedom on the job, team work, or empowerment? Meanwhile, how do we reduce the destructive patterns of work, not just on the work site, but also involving the pressures and lifestyle associated with intermittent and uncertain employment? The rewards for safety and health professionals in the construction industry are immediate and striking. Whether through the practice of safety and health or through research, results can be measured in short order. That is a professional benefit afforded by few other industries. To structure occupational safety and health programs for construction workers, the safety and health professions need to engage in the labor-management processes that are changing the industry. In construction, it is not enough to think about what needs to be done in individual workplaces. In construction, we must think industry-wide, because that is how workers are employed.(ABSTRACT TRUNCATED AT 250 WORDS)

Smokeless tobacco use and increased cardiovascular mortality among Swedish construction workers

OBJECTIVES

Little is known about the risks of cardiovascular disease associated with the use of smokeless tobacco, which produces blood nicotine levels similar to those caused by cigarette smoking.

METHODS

Male Swedish construction industry employees (n = 135,036) who attended a health examination were followed by studying cause-specific mortality during a 12-year period. The study population comprised 6297 smokeless tobacco users, 14,983 smokers of fewer than 15 cigarettes per day, 13,518 smokers of 15 or more cigarettes per day, 17,437 ex-smokers, 50,255 "other" tobacco users, and 32,546 nonusers.

RESULTS

The age-adjusted relative risk of dying from cardiovascular disease was 1.4 for smokeless tobacco users and 1.9 for smokers of 15 or more cigarettes per day, compared with nonusers. Among men aged 35 through 54 years at the start of follow-up, the relative risk was 2.1 for smokeless tobacco users and 3.2 for smokers. When data were adjusted for body mass index, blood pressure, and history of heart symptoms, the results were essentially unchanged. Cancer mortality was not raised in smokeless tobacco users.

CONCLUSIONS

Both smokeless tobacco users and smokers face a higher risk of dying from cardiovascular disease than nonusers. Although the risk is lower for smokeless tobacco users than for smokers, the excess risk gives cause for preventive actions.

A simplified assay for the specific diagnosis of paroxysmal nocturnal hemoglobinuria: detection of DAF(CD55)- and HRF20(CD59)- erythrocytes in microtyping cards

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disease that is caused by a monoclonal stem cell defect. The affected cells lack the carbohydrate linkage between phosphatidylinositol and a group of membrane proteins of which three protect the cell against complement lysis. The absence of these three proteins, DAF(CD55), C8BP and HRF20(CD59), makes cells from the erythropoiesis, thrombopoiesis and myelopoiesis extensively sensitive to complement attack and affected patients suffer from intravascular hemolysis, thrombosis and increased susceptibility to infections. In this study we describe a swift and specific assay for the detection of CD55- and CD59- erythrocytes, which is suitable for screening of possible PNH patients.

The risk of lung cancer from asbestos among Swedish construction workers: self-reported exposure and a job exposure matrix compared

A total of 719 lung cancers were identified in a follow-up of 135,000 Swedish construction workers interviewed during 1971-1974 by occupational health nurses as part of a routine health check-up. These were analysed in a matched case-control study nested within this cohort, to compare different methods of characterizing exposure to asbestos. Self-reported exposure was contrasted with a job exposure matrix (JEM) of five levels of exposure intensity, applied to the job at the time of health check-up. Smoking adjusted odds ratios were computed and the JEM performed better than self-reported exposure, in being able to discriminate high risk subgroups. The same pattern was evident in a parallel analysis of 41 mesotheliomas. However both measures appeared subject to misclassification, and the question put seemed to pick up the use of asbestos cement products more effectively than asbestos insulation products. It is concluded that a simple JEM can be more reliable than a simple question, but that both should be much more detailed, to take account of different types of asbestos exposure and their variation over time.

Safety evaluation in both short- and long-term treatment of schizophrenia with remoxipride

Results for laboratory and cardiovascular variables in both short-term (4-6 weeks) and long-term (greater than 6 weeks) double-blind studies in schizophrenic patients consistently showed comparably low incidences of both transient treatment-emergent changes and changes present at last rating for both remoxipride and haloperidol. The total incidence of serious adverse events in the short-term double-blind programme was approximately 2% for both remoxipride and haloperidol. The corresponding figure for remoxipride (n = 434) in long-term treatment was approximately 6%. Compared to those on haloperidol, fewer patients on remoxipride had trough plasma prolactin levels above the normal range in short-term treatment. The results with long-term treatment with remoxipride were similar. Breast swelling and galactorrhoea were infrequent treatment-emergent side effects with either drug. It was impossible to evaluate menstrual disturbance in short-term studies but in long-term use the incidence of treatment-emergent menstrual disorder was low in remoxipride patients. Too few patients continued treatment with haloperidol for a comparative long-term evaluation. Overall, based on the information available at present, remoxipride appears to offer a high degree of safety in both short-term and long-term treatment of schizophrenia.