Antibiotics for the primary prevention of acute rheumatic fever: a meta-analysis

BACKGROUND

Rheumatic fever continues to put a significant burden on the health of low socio-economic populations in low and middle-income countries despite the near disappearance of the disease in the developed world over the past century. Antibiotics have long been thought of as an effective method for preventing the onset of acute rheumatic fever following a Group-A streptococcal (GAS) throat infection; however, their use has not been widely adopted in developing countries for the treatment of sore throats. We have used the tools of systematic review and meta-analysis to quantify the effectiveness of antibiotic treatment for sore throat, with symptoms suggestive of group A streptococcal (GAS) infection, for the primary prevention of acute rheumatic fever.

METHODS

Trials were identified through a systematic search of titles and abstracts found in the Cochrane Central Register of Controlled Trials (Cochrane Library Issue 4, 2003), MEDLINE (1966-2003), EMBASE (1966-2003), and the reference lists of identified studies. The selection criteria included randomised or quasi-randomised controlled trials comparing the effectiveness of antibiotics versus no antibiotics for the prevention of rheumatic fever in patients presenting with a sore throat, with or without confirmation of GAS infection, and no history of rheumatic fever.

RESULTS

Ten trials (n = 7665) were eligible for inclusion in this review. The methodological quality of the studies, in general, was poor. All of the included trials were conducted during the period of 1950 and 1961 and in 8 of the 10 trials the study population consisted of young adult males living on United States military bases. Fixed effects, meta-analysis revealed an overall protective effect for the use of antibiotics against acute rheumatic fever of 70% (RR = 0.32; 95% CI = 0.21-0.48). The absolute risk reduction was 1.67% with an NNT of 53. When meta-analysis was restricted to include only trials evaluating penicillin, a protective effect of 80% was found (Fixed effect RR = 0.20, 95% CI = 0.11-0.36) with an NNT of 60. The marginal cost of preventing one case of rheumatic fever by a single intramuscular injection of penicillin is approximately USD 46 in South Africa.

CONCLUSION

Antibiotics appear to be effective in reducing the incidence of acute rheumatic fever following an episode of suspected GAS pharyngitis. This effect may be achieved at relatively low cost if a single intramuscular penicillin injection is administered.

Heterozygous disruption of SERCA2a is not associated with impairment of cardiac performance in humans: implications for SERCA2a as a therapeutic target in heart failure

OBJECTIVE

To verify whether a deficiency in the cardiac sarcoplasmic reticulum pump SERCA2a causes cardiac dysfunction in humans.

DESIGN

Cardiac performance was measured in a serendipitous human model of primary SERCA2a deficiency, Darier's disease, an autosomal dominant skin disorder caused by mutations inactivating one copy of the ATP2A2 gene, which encodes SERCA2a.

METHODS

Systolic and diastolic function and contractility were assessed by echocardiography at rest and during exercise in patients with Darier's disease with known mutations. Fourteen patients with Darier's disease were compared with 14 normal controls and six patients with dilated cardiomyopathy with stable heart failure.

RESULTS

Resting systolic and diastolic function was normal in patients with Darier's disease and in controls. The increase in systolic function during exercise was not different between patients with Darier's disease and normal controls; neither was there a difference in contractility. As expected, patients with dilated cardiomyopathy had impaired diastolic and systolic function with depressed contractility at rest and during exercise.

CONCLUSION

Contrary to expectations, heterozygous disruption of SERCA2a is not associated with the impairment of cardiac performance in humans. Attempts to increase SERCA2a levels in heart failure, although showing promise in rodent studies, may not be addressing a critical causal pathway in humans.

Pentoxifylline for heart failure: a systematic review

BACKGROUND

Recent trials have indicated a beneficial effect of pentoxifylline on measures of inflammation and markers of cardiac dysfunction in people with heart failure. However, it is uncertain whether pentoxifylline should be used routinely in the management of heart failure.

OBJECTIVE

To determine the effectiveness of pentoxifylline in heart failure.

DESIGN

Systematic review of randomised controlled trials.

METHODS

We searched MEDLINE (1 January 1966 - 20 November 2004), the Cochrane Controlled Trials Register (issue 4, 2004), and reference lists of related papers, for randomised controlled trials of pentoxifylline in the treatment of heart failure. Prospective, randomised, double-blind controlled trials were sought for inclusion in the study. The two reviewers independently assessed trial quality and extracted data, which were analysed using RevMan statistical software. The following outcome measures were evaluated: (i) New York Heart Association (NYHA) functional class; (ii) left ventricular ejection fraction (LVEF); (iii) frequency of hospitalisation; and (iv) death from all causes.

RESULTS

Four studies with a total of 144 participants met the inclusion criteria. Statistical pooling (or meta-analysis) was not performed owing to the significant clinical heterogeneity and differences in reporting of the outcomes in the included studies; instead, the trials were analysed separately for the outcomes of interest. The four studies tested the use of pentoxifylline versus placebo in patients with heart failure of varying aetiology (idiopathic dilated cardiomyopathy, 3 studies; ischaemic cardiomyopathy, 1 study). In 2 of the idiopathic dilated cardiomyopathy studies, patients were classified as NYHA class II or III, while the study population in another idiopathic cardiomyopathy study was in NYHA class IV. The trial of patients with ischaemic cardiomyopathy included patients in NYHA functional classes I - IV. The use of pentoxifylline was associated with significant improvement in symptoms (i.e. NYHA functional class) and cardiac function (i.e. LVEF) in 3 out of 4 studies. The beneficial effect on symptoms of heart failure and cardiac function was seen in all grades of severity of heart failure and in patients with ischaemic and idiopathic dilated cardiomyopathy. All 4 studies showed a trend towards reduction of mortality, but this effect was not statistically significant. The effect of pentoxifylline on the frequency of hospitalisation has not been tested in randomised controlled trials.

INTERPRETATION

Pentoxifylline may have a beneficial effect on NYHA functional class, ejection fraction and mortality in heart failure, but published trials are too small to provide conclusive evidence. There is a need for large, placebo-controlled trials of pentoxifylline in heart failure, involving a diverse group of patients with regard to cause and severity of heart failure.

Lack of adherence to the national guidelines on the prevention of rheumatic fever

OBJECTIVES

To explore the extent to which current practices for the secondary prevention of rheumatic fever (RF) in Cape Town adhere to those outlined in the national guidelines on the primary prevention and prophylaxis of RF and rheumatic heart disease (RHD) for health professionals at primary level.

METHODS

A combination of qualitative tools was used to evaluate the four priority issues identified in the guidelines as fundamental elements of a comprehensive programme for the secondary prophylaxis of RF/RHD: (i) health education and promotion; (ii) case detection of RF and RHD; (iii) secondary prophylaxis every 3-4 weeks at primary level; and (iv) notification of acute rheumatic fever (ARF). The qualitative tools included parent/child interviews of cases diagnosed with ARF in the Cape metropole area during the period 1999-2003; a physician questionnaire focused on awareness and adherence to the national guidelines; and a review of the records on acute rheumatic fever notification in the Cape metropole area from 1999 to 2003.

RESULTS

The evaluation revealed four key findings. First, patient knowledge on the disease was almost non-existent. Despite this lack of knowledge, adherence to secondary prophylactic treatment was good. Second, the physicians most likely to encounter a case of rheumatic fever were least likely to be aware of and to comply with the national guideline. Third, the guidelines do not clearly state how increased detection of ARF will be achieved. Finally, the RF notification system is dysfunctional, with discrepancies in the reporting of cases at hospital, city and provincial levels.

CONCLUSIONS

Since the publication of the national guidelines in 1997, little progress has been made towards achieving the implementation of a comprehensive programme for the secondary prevention of RF/RHD.

Cardiac involvement in HIV-infected people living in Africa: a review

The primary objective of this study was to review and summarise the literature on the spectrum and management of cardiac disease in HIV-infected people living in Africa. We searched MEDLINE (January 1980 to February 2003), reference lists of papers, and reviews on the subject, and contacted experts working in the field for information on relevant references. The review was limited to papers that were published in peer-reviewed journals and indexed on MEDLINE. Seventeen of the 21 studies identified met the inclusion criteria for analysis. The studies confirmed that cardiac abnormalities are more common in HIV-infected people, compare to normal controls, and that about half of hospitalized patients and a significant proportion of patients followed up over several years develop cardiac abnormalities. The commonest HIV-related cardiac abnormalities were cardiomyopathy and pericardial disease. Tuberculosis was the major cause of large pericardial effusion in Africa. Myocarditis was the commonest pathological abnormality in HIV-associated cardiomyopathy, and non-viral opportunistic infections such as toxoplasmosis and cryptococcosis may account for up to 50% of cases of HIV-associated cardiomyopathy in Africa. Echocardiography is indicated in HIV-positive patients with cardiac symptoms or signs. If cardiomyopathy or pericardial disease is identified, further investigation must be considered to exclude potentially treatable opportunistic infections. Further research in large numbers of patients is needed to determine the value of endomyocardial biopsy in the management of patients with HIV-associated cardiomyopathy, and to establish the place of adjuvant steroids in the treatment of HIV-associated tuberculous pericarditis.

Adjuvant corticosteroids for tuberculous pericarditis: promising, but not proven

BACKGROUND

There is controversy regarding the effectiveness of corticosteroids in tuberculous pericarditis, particularly in patients who are immunocompromised by HIV.

AIM

To determine the effectiveness of adjuvant corticosteroids in tuberculous pericarditis.

DESIGN

Systematic review of randomized controlled trials.

METHODS

We searched the Cochrane Infectious Diseases Group trials register (June 2002), the Cochrane Controlled Trials Register (Issue 2, 2002), MEDLINE (January 1966 to March 2003), EMBASE (1980 to May 2002), and the reference lists of existing reviews, for randomized and quasi-randomized controlled trials of adjuvant corticosteroids in the treatment of suspected tuberculous pericarditis. We also contacted organizations and individuals working in the field. Two reviewers independently assessed trial quality and extracted data. We used meta-analysis with a fixed effects model to calculate the summary statistics, provided there was no statistically significant heterogeneity, and expressed results as relative risk.

RESULTS

Four trials with a total of 469 participants met our criteria. Three (total n = 411) tested adjuvant steroids in participants with suspected tuberculous pericarditis in the pre-HIV era. Fewer participants died in the intervention group, but the potentially large reduction in mortality was not statistically significant (relative risk RR 0.65, 95%CI 0.36-1.16, n = 350; p = 0.14). One trial with 58 patients that enrolled HIV-positive individuals also showed a promising but non-significant trend on mortality (RR 0.50, 95%CI 0.19-1.28; p = 0.15). There was no significant beneficial effect of steroids on re-accumulation of pericardial effusion or progression to constrictive pericarditis. Patients with pericardial effusion were significantly more likely to be alive with no functional impairment at 2 years following treatment. However, the effect was not sustained in a sensitivity analysis that included patients who were lost to follow-up.

DISCUSSION

Steroids could have large beneficial effects on mortality and morbidity in tuberculous pericarditis, but published trials are too small to be conclusive. Large placebo-controlled trials are required, and should include sufficient numbers of HIV-positive and HIV-negative participants, and an adequate adjuvant steroid dose.

Molecular genetics of cardiomyopathy: changing times, shifting paradigms

Congestive heart failure is a major problem in developed and developing countries alike. Primary dysfunction of the heart muscle accounts for a significant proportion of patients with a non-ischaemic cause of heart failure. Application of genetic techniques has facilitated identification of some molecular causes of the inherited form of these diseases, dramatically increasing our understanding of the pathogenesis of these primary, previously termed 'idiopathic', cardiomyopathies over the last few decades. Knowledge of the different causes is beginning to coalesce into aetiological principles underlying the clinically distinguished cardiomyopathies. Hypertrophic cardiomyopathy (HCM) now appears to be a disease caused by a dysfunctional sarcomere, dilated cardiomyopathy (DCM), a disease of myocytic structural instability, and arrhythmogenic right ventricular cardiomyopathy, a disease of accelerated myocyte death. The aetiology of both HCM and DCM probably also involves cardiac energy imbalances, while additional factors modify the clinical expression in all cardiomyopathies. Even though our knowledge of the genetic aetiology of the cardiomyopathies is still incomplete, it already has relevant clinical significance. Elucidation of the full genetic contribution to the development and progression of the cardiomyopathies represents a new challenge in the study of these diseases, and will undoubtedly lead to new therapeutic approaches in the not-too-distant future.

Measured haplotype analysis of the aldosterone synthase gene and heart size

Gene-association studies of heart size and the aldosterone synthase (CYP11B2) gene have produced inconsistent results, possibly because of limitations in the sample size and/or the number and location of the polymorphisms. An analysis of six polymorphisms spanning 6 kb of the CYP11B2 gene in Caucasian British families revealed a limited number of haplotypes because of strong linkage disequilibrium over this small region. The genotype and haplotype information was used in an association study involving 955 members of 229 families phenotyped for echocardiographic measures of heart size. In a mixed effects linear modelling analysis, the G5937C polymorphism was associated with cardiac wall thickness (P=0.02), and the intron conversion and A4550C polymorphisms were associated with left ventricular cavity size (P=0.02 and 0.002, respectively). Measured haplotype analyses confirmed the association of alleles at the intron conversion and G5937C polymorphisms with cardiac wall thickness (P=0.02), and alleles at the intron conversion polymorphism with left ventricular cavity size (P=0.04). The polymorphisms contributed to 2.0-3.4% of the variability in these traits. In summary, genetic polymorphisms at the CYP11B2 gene make a small contribution to quantitative variation in echocardiographic measures of heart size. These results point to the importance of analysing the full extent of genetic variation that captures the haplotype structure of a locus in gene association studies.

Intramuscular penicillin is more effective than oral penicillin in secondary prevention of rheumatic fever--a systematic review

BACKGROUND

People with a history of rheumatic fever (RF) are at high risk of recurrent attacks and of developing rheumatic heart disease following a streptococcal throat infection. Giving penicillin to these people can prevent recurrent attacks of RF and subsequent rheumatic heart disease. However, there is no agreement on the most effective method of giving penicillin.

OBJECTIVES

To assess the effects of different penicillin regimens and formulations for preventing streptococcal infection and RF recurrence.

SEARCH STRATEGY

We searched the Controlled Trials Register (Cochrane Library Issue 2, 2001), Medline (January 1966-July 2000), Embase (January 1985-July 2000), reference lists of articles, and contacted experts in the field.

SELECTION CRITERIA

Randomised and quasi-randomised studies comparing: (i) oral with intramuscular penicillin; and (ii) 2- or 3-weekly with 4-weekly intramuscular penicillin in patients with previous RF.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data.

MAIN RESULTS

Six studies were included (1,707 patients). Data were not pooled because of clinical and methodological heterogeneity of the trials. Four trials (1,098 patients) compared intramuscular with oral penicillin and all showed that intramuscular penicillin was more effective in reducing RF recurrence and streptococcal throat infections than oral penicillin. One trial (360 patients) compared 2-weekly with 4-weekly intramuscular penicillin. Penicillin given every 2 weeks was better at reducing RF recurrence (relative risk (RR) 0.52, 95% confidence interval (CI): 0.33-0.83) and streptococcal throat infections (RR 0.60, 95% CI: 0.42-0.85). One trial (249 patients) showed that 3-weekly intramuscular penicillin injections reduced streptococcal throat infections (RR 0.67, 95% CI: 0.48-0.92) compared with 4-weekly intramuscular penicillin.

CONCLUSIONS

Intramuscular penicillin seemed to be more effective than oral penicillin in preventing RF recurrence and streptococcal throat infections. Two-weekly or 3-weekly injections appeared to be more effective than 4-weekly injections. However, the evidence is based on poor-quality trials and the use of outdated formulations of oral penicillin.

Utilization of implantable defibrillators in Africa

Sub-Saharan Africa is dominated by diseases of poverty. HIV/AIDS affects 28.5 out of a total of 600 million in the region. South Africa is the only country in sub-Saharan Africa in which implantable cardiovertor defibrillators (ICDs) are implanted (0.8/million in 2001). Only 3 of the 35 new ICDs were implanted in state-funded public hospitals. The pacemaker implantation rate for South Africa was 41/million in 2001. Approximately 20% of the population consume 56% of the health care expenditure, mainly funded by Medical Insurance. A tax-funded state health care system serves the rest of the population, but is concentrated on improving sanitation and primary health care. Diversion of funds from academic tertiary hospitals has reduced specialised services, particularly cardiology and cardiac surgery, and has resulted in an exodus of skilled personnel to the private sector. In the rest of sub-Saharan Africa, tertiary health care is mainly privately funded. Cardiology and cardiac surgery is not widely available. Many countries are crippled by debt and chronic local conflicts. Only one state hospital (Groote Schuur, Cape Town) provides an electrophysiology (EP) service including catheter ablation and ICD implantation, and training in EP, by two electrophysiologists. EP services are available privately in 3 centres. No EP service exists in the rest of sub-Saharan Africa.

Electrocardiographic measures of left ventricular hypertrophy show greater heritability than echocardiographic left ventricular mass

AIMS

To assess the heritability (i.e. relative contribution of genetic factors to the variability) of continuous measures of left ventricular hypertrophy determined by electrocardiography and echocardiography.

METHODS AND RESULTS

We studied 955 members of 229 Caucasian families, ascertained through a hypertensive proband. Electrocardiographic measurements were performed manually on resting 12-lead electrocardiograms, and echocardiographic measurements were made on M-mode images. Sex-specific residuals for the left ventricular phenotypes were calculated, adjusted for age, systolic blood pressure, weight, height, waist-hip ratio, and presence of diabetes. Heritability was estimated in two ways: firstly, from familial correlations with adjustment for spouse resemblance; and secondly by using variance components methods with ascertainment correction for proband status. The heritability estimates (given as a range derived from the two methods) were higher for Sokolow-Lyon voltage (39-41%) than for echocardiographic left ventricular mass (23-29%). Electrocardiographic left ventricular mass, Cornell voltage, and Cornell product had heritability estimates of 12-18%, 19-25%, and 28-32%, respectively.

CONCLUSIONS

Genetic factors may explain a substantial proportion of variability in quantitative electrocardiographic and echocardiographic measures of left ventricular hypertrophy. The greater heritability of Sokolow-Lyon voltage suggests that electrocardiographic phenotypes may be particularly important for the molecular investigation of the genetic susceptibility to cardiac hypertrophy.

Genotype at a promoter polymorphism of the interleukin-6 gene is associated with baseline levels of plasma C-reactive protein

OBJECTIVE

Baseline concentrations of plasma C-reactive protein (CRP) are associated with coronary heart disease. Interleukin-6 (IL-6) regulates CRP gene expression; a promoter polymorphism (-174G/C) of the IL-6 gene has been shown to influence IL-6 transcription but the relationship between genotype at this polymorphism and circulating levels of inflammatory markers remains unclear. We hypothesised that plasma CRP would be a heritable phenotype that would be influenced by genotype at this polymorphism.

METHODS

We measured baseline plasma CRP and determined genotypes at the -174G/C polymorphism of the IL-6 gene in 588 members of 98 nuclear families. The heritability of plasma CRP and the association of plasma CRP with genotype were determined using variance components methods.

RESULTS

Baseline CRP levels were highly heritable (h(2)=0.39, P<0.0000001). Presence of the -174C allele was associated with higher baseline CRP levels, both in the whole population (P=0.01), and in the founders only (n=128, P=0.001). Family-based analyses confirmed the association (P=0.02) suggesting that it arises from chromosomal proximity or identity of the typed polymorphism with a genetic variant influencing baseline CRP levels.

CONCLUSIONS

Baseline plasma CRP is a significantly heritable cardiovascular risk factor. Levels are associated with genotype at the -174G/C polymorphism of the IL-6 gene.

Interventions for treating tuberculous pericarditis

BACKGROUND

Tuberculous pericarditis - tuberculosis infection of the pericardial membrane (pericardium) covering the heart - is becoming more common. The infection can result in fluid around the heart or fibrosis of the pericardium, which can be fatal.

OBJECTIVES

In people with tuberculous pericarditis, to evaluate the effects on death, life-threatening conditions, and persistent disability of: (1) 6-month antituberculous drug regimens compared with regimens of 9 months or more; (2) corticosteroids; (3) pericardial drainage; and (4) pericardiectomy.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group trials register (June 2002), the Cochrane Controlled Trials Register (Issue 2, 2002), MEDLINE (1966 to June 2002), EMBASE (1980 to May 2002), and checked the reference lists of existing reviews. We also contacted organizations and individuals working in the field.

SELECTION CRITERIA

Randomized and quasi-randomized controlled trials of treatments for tuberculous pericarditis.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. Meta-analysis using fixed effects models calculated summary statistics, provided there was no statistically significant heterogeneity, and expressed results as relative risk. Study authors were contacted for additional information.

MAIN RESULTS

Four trials met the inclusion criteria, with a total of 469 participants. Treatments tested were adjuvant steroids and surgical drainage. Two trials with a total of 383 participants tested adjuvant steroids in participants with suspected tuberculous pericarditis in the pre-HIV era. Fewer participants died in the intervention group, but numbers were small (relative risk [RR] 0.65; 95% confidence interval [CI] 0.36 to 1.16, n = 350). One small trial tested steroids in HIV positive participants with effusion showed a similar pattern (RR 0.50; 95% CI 0.19 to 1.28, n = 58). One trial examined open surgical drainage compared with conservative management, and showed surgery relieved cardiac tamponade.

REVIEWER'S CONCLUSIONS

Steroids could have important clinical benefits, but the trials published to date are too small to demonstrate an effect. This requires large placebo controlled trials. Subgroup analysis could explore whether effusion or fibrosis modify the effects. Therapeutic pericardiocentesis under local anaesthesia and pericardiectomy also require further evaluation.

Penicillin for secondary prevention of rheumatic fever

BACKGROUND

People with a history of rheumatic fever are at high risk of recurrent attacks of rheumatic fever and developing rheumatic heart disease following a streptococcal throat infection. Giving penicillin to these people can prevent recurrent attacks of rheumatic fever and subsequent rheumatic heart disease. However, there is no agreement on the most effective method of giving penicillin.

OBJECTIVES

To assess the effects of penicillin compared to placebo and the effects of different penicillin regimens and formulations for preventing streptococcal infection and rheumatic fever recurrence.

SEARCH STRATEGY

We searched the Controlled Trials Register (Cochrane Library Issue 2, 2001), MEDLINE (1997 to July 2000), EMBASE (1998 to July 2000), reference lists of articles and we contacted experts in the field.

SELECTION CRITERIA

Randomised and quasi-randomised studies comparing (i) penicillin with control, (ii) oral with intramuscular penicillin (iii) 2- or 3-weekly with 4-weekly intramuscular penicillin in patients with previous rheumatic fever.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data.

MAIN RESULTS

Nine studies were included (n=3008). Data were not pooled because of heterogeneity. Overall, the methodological quality of included studies was poor. Three trials (n= 1301) compared penicillin with control. Only one of three studies showed that penicillin reduced rheumatic fever recurrence (RR 0.45, 95% CI 0.22 to 0.92) and streptococcal throat infection (RR 0.84, 95% CI 0.72 to 0.97). Four trials (n=1098) compared intramuscular with oral penicillin and all showed that intramuscular penicillin reduced rheumatic fever recurrence and streptococcal throat infections compared to oral penicillin. One trial (n= 360) compared 2-weekly with 4-weekly intramuscular penicillin. Penicillin given every two-weeks was better at reducing rheumatic fever recurrence (RR 0.52, 95% CI 0.33 to 0.83) and streptococcal throat infections (RR 0.60, 95% CI 0.42 to 0.85). One trial (n= 249) showed 3-weekly intramuscular penicillin injections reduced streptococcal throat infections (RR 0.67, 95% CI 0.48 to 0.92) compared to 4-weekly intramuscular penicillin.

REVIEWER'S CONCLUSIONS

Intramuscular penicillin seemed to be more effective than oral penicillin in preventing rheumatic fever recurrence and streptococcal throat infections. Two-weekly or 3-weekly injections appeared to be more effective than 4-weekly injections. However, the evidence is based on poor quality of trials.

A common mitochondrial DNA variant associated with susceptibility to dilated cardiomyopathy in two different populations

Idiopathic dilated cardiomyopathy is a recognised manifestation of mitochondrial disease due to specific mitochondrial (mt) DNA mutations. However, whether mtDNA polymorphisms predispose to sporadic dilated cardiomyopathy is not known. We analysed two populations with this disorder for a general mtDNA variant (T16189C), previously implicated in susceptibility to type 2 diabetes. We noted an increased frequency of the polymorphism in both populations compared with controls (p=0.002). The polymorphism occurred on different mtDNA backgrounds, suggesting that it might be a functional variant. This association of an mtDNA variant with increased susceptibility to dilated cardiomyopathy provides evidence for a mitochondrial cause in sporadic disease.

Long-term survival after permanent pacemaker implantation in young adults: 30 year experience

The goal of the present study was to determine the etiology of conduction disease and long-term outcome for young adults who undergo permanent pacemaker implantation. Permanent pacing was performed in 232 patients aged 21-50 years, 135 males and 97 females, from 1965 through 1995. One hundred and twenty-six subjects (54%) had evidence of structural heart disease, while idiopathic conduction disease accounted for 46%. About half (54%) of 106 patients with structural heart disease had surgically induced heart block. Pacing mode at primary implantation was single chamber in 65% and dual chamber in 35%. Follow-up ranged from 12-387 months, with a mean of 104-months. At the last follow-up, 133 of 232 patients (57%) were alive, 40 (17%) had died, 30 (13%) were lost to follow-up, 26 (11%) were transferred elsewhere, and 3 (1%) explanted. Patients with sick sinus syndrome had similar outcomes to those with AV block. There was a sharp decline in survival during the first six months; 7.5% of the sample died within the first year following their first pacemaker operation. After the first year, the decline in survival slowed and 70% of the patients could be expected to survive beyond 20 years. The overall survival of young patients without structural heart disease who received a permanent pacemaker was comparable to an age- and sex-matched control population, while patients with structural heart disease performed significantly worse than the control population.