-
[show abstract]
[hide abstract]
ABSTRACT: 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.
Retrospective, observational cohort study.
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%).
Death was classified as sudden or nonsudden according to standard definitions. Proarrhythmia was defined as cardiac syncope or life-threatening arrhythmia.
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).
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.
Journal of Internal Medicine 06/2011; 270(3):281-90. · 5.48 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: 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.
Population-based study.
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.
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).
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).
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.
Journal of Internal Medicine 08/2006; 260(1):31-8. · 5.48 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: 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.
Pacing and Clinical Electrophysiology 08/2001; 24(7):1067-75. · 1.35 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: 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.
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.
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.
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.
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.
Journal of the American College of Cardiology 12/1999; 34(5):1560-8. · 14.16 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: To study effects of insulin-induced hypoglycaemia on the cardiac repolarization, using QT interval measurements, in patients with type 2 diabetes.
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.
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.
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.
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.
Journal of Internal Medicine 09/1999; 246(3):299-307. · 5.48 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: 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.
Cardiology 11/1998; 90(2):79-82. · 1.71 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: 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.
Pacing and Clinical Electrophysiology 11/1998; 21(10):1979-87. · 1.35 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: 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.
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.
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.
European Heart Journal 10/1998; 19(9):1383-90. · 10.48 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: 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.
Lakartidningen 11/1997; 94(41):3626, 3629-30, 3632.
-
[show abstract]
[hide abstract]
ABSTRACT: 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.
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.
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.
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).
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.
JNCI Journal of the National Cancer Institute 04/1997; 89(5):385-9. · 13.76 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: 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.
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.
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.
Circulation 03/1997; 95(4):951-4. · 14.74 Impact Factor
-
A Englund
[show abstract]
[hide abstract]
ABSTRACT: 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.
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.
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.
European Heart Journal 02/1997; 18(2):311-7. · 10.48 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: 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.
International Journal of Cancer 10/1996; 67(6):764-8. · 5.44 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: 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.
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.
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%.
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.
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.
Heart 01/1996; 74(6):650-5.
-
Lakartidningen 01/1996; 92(50):4784-7.
-
[show abstract]
[hide abstract]
ABSTRACT: 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.
European Heart Journal 12/1995; 16(12):1936-42. · 10.48 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: 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%.
American Heart Journal 09/1995; 130(3 Pt 1):481-8. · 4.65 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: 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.
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.
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.
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.
American Journal of Public Health 04/1994; 84(3):399-404. · 3.93 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: 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.
International Journal of Epidemiology 02/1993; 22 Suppl 2:S29-35. · 6.41 Impact Factor
-
Annals of Occupational Hygiene 02/1987; 31(4B):663-75. · 1.95 Impact Factor
