Cardiomyopathy in western Denmark

A gender perspective on diet, microbiome, and sex hormone interplay in cardiovascular disease

A unique interplay between body and environment embeds and reflects host-microbiome interactions that contribute to sex-differential disease susceptibility, symptomatology, and treatment outcomes. These differences derive from individual biological factors, such as sex hormone action, sex-divergent immune processes, X-linked gene dosage effects, and epigenetics, as well as from their interaction across the lifespan. The gut microbiome is increasingly recognized as a moderator of several body systems that are thus impacted by its function and composition. In humans, biological sex components further interact with gender-specific exposures such as dietary preferences, stressors, and life experiences to form a complex whole, requiring innovative methodologies to disentangle. Here, we summarize current knowledge of the interactions among sex hormones, gut microbiota, immune system, and vascular health and their relevance for sex-differential epidemiology of cardiovascular diseases. We outline clinical implications, identify knowledge gaps, and place emphasis on required future studies to address these gaps. In addition, we provide an overview of the caveats associated with conducting cardiovascular research that require consideration of sex/gender differences. While previous work has inspected several of these components separately, here we call attention to further translational utility of a combined perspective from cardiovascular translational research, gender medicine, and microbiome systems biology.

Sex and Age Characteristics in Acute or Chronic Myocarditis A Descriptive, Multicenter Cohort Study

BACKGROUND

Understanding the clinical features of myocarditis in various age groups is required to identify age-specific disease patterns.

OBJECTIVES

The objective of this study was to examine differences in sex distribution and clinical outcomes in patients with myocarditis of various ages.

METHODS

Patients with acute or chronic myocarditis in 3 centers in Berlin, Germany from 2005 to 2021 and in the United States (National Inpatient Sample) from 2010 to 2019 were included. Age groups examined included "prepubescent" (below 11 years for females and below 13 years for males), adolescents (11 [female] or 13 [male] to 18 years), young adults (18-35 years), "middle-aged adults" (35-54 years), and older adults (age >54 years). In patients admitted to the hospital, hospital mortality, length of stay, and medical complication rates were examined.

RESULTS

Overall, 6,023 cases in Berlin and 9,079 cases in the U.S. cohort were included. In both cohorts, there were differences in sex distribution among the 5 age categories, and differences in the distribution were most notable in adolescents (69.3% males vs 30.7% females) and in young adults (73.8% males vs 26.3% females). Prepubescent and older adults had the highest rates of in-hospital mortality, hospital length of stay, and medical complications. In the Berlin cohort, prepubescent patients had higher levels of leukocytes (P < 0.001), antistreptolysin antibody (P < 0.001), and NT-proBNP (P < 0.001) when compared to young adults.

CONCLUSIONS

In this study, we found that sex differences in myocarditis and clinical features of myocarditis were age-dependent.

Re-evaluating the Incidence and Prevalence of Clinical Hypertrophic Cardiomyopathy: An Epidemiological Study of Olmsted County, Minnesota

OBJECTIVE

To contemporaneously reappraise the incidence-rate, prevalence, and natural history of hypertrophic cardiomyopathy (HCM) in Olmsted County, Minnesota, from 1984 to 2015.

PATIENTS AND METHODS

A validated medical-record linkage system collecting information for residents of Olmsted County was used to identify all cases of HCM between January 1, 1984, and December 31, 2015. After adjudication of records from Mayo Clinic and Olmsted Medical Center, data relating to diagnoses and outcomes were abstracted. The calculated incidence rate and prevalence were standardized to the US 1980 White population (age- and sex-adjusted) and compared with a prior study examining the years 1975-1984.

RESULTS

Two hundred seventy subjects with HCM were identified. The age- and sex-adjusted incidence rate was 6.6 per 100,000 person-years, and the point prevalence of HCM on January 1, 2016, was 89 per 100,000 population. The incidence rate and point prevalence of HCM on January 1, 2016, standardized to the US 1980 White population (age- and sex-adjusted), were 6.7 (95% CI, 7.1 to 8.8) per 100,000 person-years and 81.5 per 100,000 population, respectively. The incidence rate of HCM increased each decade since the index study. Individuals with HCM had a higher overall standardized mortality rate than the general population with an observed to expected HR of 1.44 (95% CI, 1.21 to 1.71; P<.001) which improved by each decade.

CONCLUSION

The incidence and prevalence of HCM are higher than rates reported from a prior study in the same community examining the years 1975-1984, but lower than other study cohorts. The risk of mortality in HCM remains higher than expected, albeit with improvement in rates of mortality observed each decade during the study period.

Epidemiology of Cardiomyopathy in Taiwanese Population Aged Younger Than 65 Years

BACKGROUND

Few studies have investigated the epidemiology of cardiomyopathy (CMP) in the general population in Taiwan. The aim of this study was to investigate this issue.

METHODS

We identified patients aged < 65 years and diagnosed with CMP between 2001 and 2014 from the National Health Insurance Database of Taiwan 2000-2014. Those with known or presumed causes of CMP were further identified.

RESULTS

We identified 38,868 CMP patients (male/female = 2.13). Half had known or presumed causes of CMP, including coronary artery disease (23.6%), congenital heart disease (1.6%), metabolic disease (8.4%), conduction disturbance/dyssynchrony (2.2%), myocarditis (0.5%), muscular dystrophy (1.42%), Kawasaki disease (0.2%), nutrition problems or alcoholism (2.9%), and unspecified causes (12.4%). The incidence rates of CMP without known causes were 1.13 and 8.70 per 100,000 person-years in pediatric (0-19 years) and adult (20-64 years) populations, respectively. After an initial peak during infancy (9.16 per 100,000 person-years), the incidence declined to a nadir in those aged from 5 to 14 years, and then steadily increased during adulthood (26.51 per 100,000 person-years in those aged 60-64 years). Although mortality was higher in the pediatric (11.4%) than in the adult (1.5%) patients, the proportion of sudden death to all deaths was similar in the pediatric (9.9%) and adult (10.5%) patients.

CONCLUSIONS

This study provides an epidemiological continuum of CMP in a Taiwanese population aged < 65 years. The results revealed an initial peak during infancy, followed by a decline in adolescence and a subsequent steady rise. The prognosis was poorer in the pediatric patients, and poorest in the infants. However, the risk of sudden death was the same in the adult and pediatric patients.

Incidence rates of dilated cardiomyopathy in adult first-degree relatives versus matched controls

Background

The incidence rates and importance of traditional risk factors in dilated cardiomyopathy among first-degree relatives are unknown.

Methods and Results

We identified all probands with dilated cardiomyopathy (n = 13,714, mean age at diagnosis 63 years) from the Danish nationwide registries between 1994 and 2017. Incidence rates among first-degree relatives (n = 29,671, mean age 38 years) and for up to 10 age- and sex-matched controls were calculated. Totally 233 (0.8%) first-degree relatives and 285 (0.1%) controls developed dilated cardiomyopathy during a median follow-up of 8.2 (Q1-Q3 4.4-13.3) years. Incidence rates (per 100,000 person-years) were 86.4 (95% confidence interval 73.9-101.0) and 111.1 (79.4-128.7) for first-degree relatives aged < 50 and ≥ 50 years, respectively, versus 7.5 (6.4-8.9) and 19.7 (16.8-23.2) for controls. Atrial fibrillation, diabetes, ischemic heart disease, and hypertension were associated with increased risks of developing dilated cardiomyopathy both in first-degree relatives and controls. Population attributable fractions for the 4 risk factors were 27.7% for first-degree relatives and 37.3% for controls aged < 50 years, and 46.4% versus 58.4% for first-degree relatives and controls among people aged ≥ 50 years, respectively.

Conclusions

The absolute incidence rates of dilated cardiomyopathy in first-degree relatives to patients with dilated cardiomyopathy were low, but significantly higher than in matched controls and elevated by the presence of additional risk factors, especially atrial fibrillation. Additional investigations are warranted to assess whether aggressive treatment of risk factors translates into a reduction of dilated cardiomyopathy in first-degree relatives.

Dilated cardiomyopathy: a new insight into the rare but common cause of heart failure

Heart failure is a global health burden responsible for high morbidity and mortality with a prevalence of greater than 60 million individuals worldwide. One of the major causes of heart failure is dilated cardiomyopathy (DCM), characterized by associated systolic dysfunction. During the last few decades, there have been remarkable advances in our understanding about the genetics of dilated cardiomyopathy. The genetic causes were initially thought to be associated with mutations in genes encoding proteins that are localized to cytoskeleton and sarcomere only; however, with the advancement in mechanistic understanding, the roles of ion channels, Z-disc, mitochondria, nuclear proteins, cardiac transcription factors (e.g., NKX-2.5, TBX20, GATA4), and the factors involved in calcium homeostasis have also been identified and found to be implicated in both familial and sporadic DCM cases. During past few years, next-generation sequencing (NGS) has been established as a diagnostic tool for genetic analysis and it has added significantly to the existing candidate gene list for DCM. The animal models have also provided novel insights to develop a better treatment strategy based on phenotype-genotype correlation, epigenetic and phenomic profiling. Most of the DCM biomarkers that are used in routine genetic and clinical testing are structural proteins, but during the last few years, the role of mi-RNA has also emerged as a biomarker due to their accessibility through noninvasive methods. Our increasing genetic knowledge can improve the clinical management of DCM by bringing clinicians and geneticists on one platform, thereby influencing the individualized clinical decision making and leading to precision medicine.

Sex Differences, Genetic and Environmental Influences on Dilated Cardiomyopathy

Dilated cardiomyopathy (DCM) is characterized by dilatation of the left ventricle and impaired systolic function and is the second most common cause of heart failure after coronary heart disease. The etiology of DCM is diverse including genetic pathogenic variants, infection, inflammation, autoimmune diseases, exposure to chemicals/toxins as well as endocrine and neuromuscular causes. DCM is inherited in 20–50% of cases where more than 30 genes have been implicated in the development of DCM with pathogenic variants in TTN (Titin) most frequently associated with disease. Even though male sex is a risk factor for heart failure, few studies have examined sex differences in the pathogenesis of DCM. We searched the literature for studies examining idiopathic or familial/genetic DCM that reported data by sex in order to determine the sex ratio of disease. We found 31 studies that reported data by sex for non-genetic DCM with an average overall sex ratio of 2.5:1 male to female and 7 studies for familial/genetic DCM with an overall average sex ratio of 1.7:1 male to female. No manuscripts that we found had more females than males in their studies. We describe basic and clinical research findings that may explain the increase in DCM in males over females based on sex differences in basic physiology and the immune and fibrotic response to damage caused by mutations, infections, chemotherapy agents and autoimmune responses.

Epidemiology of cardiomyopathies: essential context knowledge for a tailored clinical work-up

Cardiomyopathies (CMPs) are primary disorders of myocardial structure and function in the absence of coronary artery disease, hypertension, valvular disease, and congenital heart disease. Knowledge of the incidence and prevalence of CMPs may help clinicians to compare their observations in clinical practice with expected cases per person-year and to avoid under-reporting in clinical context. Currently, available estimates of prevalence and incidence of CMPs are based on clinical data, collected with a wide variability in population-source, and before the genetic testing evolved as a standard diagnostic tool. This review focuses on the epidemiology of CMPs in subjects aged between 18 and 55 years. A structured up-to-date diagnostic flow-chart for CMPs diagnosis and assessment is proposed to avoid misdiagnosis of CMPs in the young population and in subjects with unexplained cardiac disorders.

Incidence of idiopathic cardiomyopathy in patients with type 2 diabetes in Taiwan: age, sex, and urbanization status-stratified analysis

BACKGROUND

The epidemiology of diabetes and idiopathic cardiomyopathy have limited data. We investigated the overall and the age-, sex-, and urbanization-specific incidence and relative hazard of idiopathic cardiomyopathy in association with type 2 diabetes and various anti-diabetic medications used in Taiwan.

METHODS

A total of 474,268 patients with type 2 diabetes were identified from ambulatory care and inpatient claims in 2007-2009 from Taiwan's National Health Insurance (NHI) database. We randomly selected 474,266 age-, sex-, and diagnosis date-matched controls from the registry of NHI beneficiaries. All study subjects were linked to ambulatory care and inpatient claims (up to the end of 2016) to identify the possible diagnosis of idiopathic cardiomyopathy. The person-year approach with Poisson assumption was used to estimate the incidence, and Cox proportional hazard regression model with Fine and Gray's method was used to estimate the relative hazards of idiopathic cardiomyopathy in relation to type 2 diabetes.

RESULTS

The overall incidence of idiopathic cardiomyopathy for men and women patients, respectively, was 3.83 and 2.94 per 10,000 person-years, which were higher than the corresponding men and women controls (2.00 and 1.34 per 10,000 person-years). Compared with the control group, patients with type 2 diabetes were significantly associated with an increased hazard of idiopathic cardiomyopathy (adjusted hazard ratio [aHR]: 1.60, 95% confidence interval [CI]: 1.45-1.77] in all age and sex stratifications except in those men aged > 64 years. Patients with type 2 diabetes aged < 45 years confronted the greatest increase in the hazard of idiopathic cardiomyopathy, with an aHR of 3.35 (95% CI 2.21-5.06) and 3.48 (95% CI 1.60-7.56) for men and women, respectively. The usage of some anti-diabetic medications revealed lower risks of idiopathic cardiomyopathy.

CONCLUSIONS

In Taiwan, diabetes increased the risk of idiopathic cardiomyopathy in both sexes and in all age groups, except in men aged > 64 years. Younger patients were vulnerable to have higher HRs of idiopathic cardiomyopathy. Some anti-diabetic medications may reduce the risks of cardiomyopathy.

Body Mass Index in Young Women and Risk of Cardiomyopathy: A Long-Term Follow-Up Study in Sweden

Supplemental Digital Content is available in the text.

Incidence rates of cardiomyopathies, which are a common cause of heart failure in young people, have increased during the last decades. An association between body weight in adolescence and future cardiomyopathy among men was recently identified. Whether or not this holds true also for women is unknown. The aim was therefore to determine whether for young women being overweight or obese is associated with a higher risk of developing cardiomyopathy.

Unsettled Issues and Future Directions for Research on Cardiovascular Diseases in Women

Biological sex (being female or male) significantly influences the course of disease. This simple fact must be considered in all cardiovascular diagnosis and therapy. However, major gaps in knowledge about and awareness of cardiovascular disease in women still impede the implementation of sex-specific strategies. Among the gaps are a lack of understanding of the pathophysiology of women-biased coronary artery disease syndromes (spasms, dissections, Takotsubo syndrome), sex differences in cardiomyopathies and heart failure, a higher prevalence of cardiomyopathies with sarcomeric mutations in men, a higher prevalence of heart failure with preserved ejection fraction in women, and sex-specific disease mechanisms, as well as sex differences in sudden cardiac arrest and long QT syndrome. Basic research strategies must do more to include female-specific aspects of disease such as the genetic imbalance of 2 versus one X chromosome and the effects of sex hormones. Drug therapy in women also needs more attention. Furthermore, pregnancy-associated cardiovascular disease must be considered a potential risk factor in women, including pregnancy-related coronary artery dissection, preeclampsia, and peripartum cardiomyopathy. Finally, the sociocultural dimension of gender should be included in research efforts. The organization of gender medicine must be established as a cross-sectional discipline but also as a centered structure with its own research resources, methods, and questions.

Mechanistic Pathways of Sex Differences in Cardiovascular Disease

Major differences between men and women exist in epidemiology, manifestation, pathophysiology, treatment, and outcome of cardiovascular diseases (CVD), such as coronary artery disease, pressure overload, hypertension, cardiomyopathy, and heart failure. Corresponding sex differences have been studied in a number of animal models, and mechanistic investigations have been undertaken to analyze the observed sex differences. We summarize the biological mechanisms of sex differences in CVD focusing on three main areas, i.e., genetic mechanisms, epigenetic mechanisms, as well as sex hormones and their receptors. We discuss relevant subtypes of sex hormone receptors, as well as genomic and nongenomic, activational and organizational effects of sex hormones. We describe the interaction of sex hormones with intracellular signaling relevant for cardiovascular cells and the cardiovascular system. Sex, sex hormones, and their receptors may affect a number of cellular processes by their synergistic action on multiple targets. We discuss in detail sex differences in organelle function and in biological processes. We conclude that there is a need for a more detailed understanding of sex differences and their underlying mechanisms, which holds the potential to design new drugs that target sex-specific cardiovascular mechanisms and affect phenotypes. The comparison of both sexes may lead to the identification of protective or maladaptive mechanisms in one sex that could serve as a novel therapeutic target in one sex or in both.

Sex and gender differences in myocarditis and dilated cardiomyopathy

Heart failure due to nonischemic dilated cardiomyopathy (DCM) contributes significantly to the global burden of cardiovascular disease. Myocarditis is, in turn, a major cause of acute DCM in both men and women. However, recent clinical and experimental evidence suggests that the pathogenesis and prognosis of DCM differ between the sexes. This seminar provides a contemporary perspective on the immune mediators of myocarditis, including interdependent elements of the innate and adaptive immune response. The heart's acute response to injury is influenced by sex hormones that appear to determine the subsequent risk of chronic DCM. Preliminary data suggest additional genetic variations may account for some of the differences in epidemiology, left ventricular recovery, and survival between men and women. We highlight the gaps in our knowledge regarding the management of women with acute DCM and discuss emerging therapies, including bromocriptine for the treatment of peripartum cardiomyopathy.

Genetics of dilated cardiomyopathy

Dilated cardiomyopathy (DCM) is a myocardial disease characterized by dilatation and impaired systolic function of the left or both ventricles. The etiology of DCM is multifactorial, and many different clinical conditions can lead to the phenotype of DCM. During recent years it has become evident that genetic factors play an important role in the etiology and pathogenesis of idiopathic DCM. The genetics of DCM have been under intensive investigation lately, and thereby the knowledge on the genetic basis of DCM has increased rapidly. The genetic background of the disease seems to be relatively heterogeneous, and the disease-associated mutations concern mostly single families and only few affected patients. Disease-associated mutations have been detected e.g. in genes encoding sarcomere, cytoskeletal, and nuclear proteins, as well as proteins involved with regulation of Ca(2+) metabolism. The mechanisms, by which mutations eventually result in clinical heart failure, are complex and not yet totally resolved. DCM causes considerable morbidity and mortality. Better knowledge of the genetic background and disease-causing mechanisms would probably help us in focusing early treatment on right subjects and potentially also developing new treatment modalities and improving cardiac outcome in the affected patients. This review deals with DCM of genetic origin.

Epidemiology of idiopathic cardiomyopathy in Qatar during 1996-2003

OBJECTIVES

To report the rates of cardiomyopathies in the population below 50 years of age in Qatar.

SUBJECTS AND METHODS

We conducted a retrospective review of clinical data on patients with cardiomyopathy who were hospitalized in Hamad General Hospital, Doha. Data were collected from medical records during the 1996-2002 period and prospectively from the patients who were hospitalized during the year 2003. All cardiomyopathy patients below 50 years of age who were citizens or permanent residents in Qatar were included in this study.

RESULTS

During the study period, a total of 132 cases were recorded with idiopathic cardiomyopathies. Among these, 67.4% were males and 32.6% females; Qatari 31.8%, non-Qatari 68.2%. The consanguinity rate was high among Qatari patients. In the first 7-year study period, 1996-2002, the incidence rate of all types of cardiomyopathies was 2.5/100,000 population per year (95% CI: 1.4-3.5). It increased to 5.2/100,000 population during the year 2003 (95% CI: 3.6-6.7). Dilated cardiomyopathy was most prevalent (75.8%) in all age groups, and the incidence increased remarkably with age. Lower prevalence of hypertrophic cardiomyopathy (13.6%) and left ventricle noncompaction cardiomyopathy (6.1%) was found. In children below 15 years of age, the incidence rate for all types of cardiomyopathies was 2.7/100,000 population. The overall mortality rate was 5.3%.

CONCLUSION

Most cases of cardiomyopathy were identified at an early age: below 15 years and above 35 years of age. Introducing preventive and early diagnosis programs may have an impact on reducing the mortality and morbidity from idiopathic cardiomyopathy.

Heart failure in women

Women who experience heart failure (HF) exhibit distinct differences from men. Because women are a minority in major HF trials and because diagnostic criteria have been variable in epidemiologic surveys, many questions remain unanswered. This article describes differences in sex hormone effects and responses to injury, pressure overload, and aging, which may account for differences observed in epidemiology, risk factors and causes, mechanisms for disease development, response to treatment, and outcomes. Hypertension,diastolic dysfunction, diabetes, obesity, and inactivity are more important factors in women, whereas ischemic heart disease and systolic dysfunction are more important factors in men. Women appear to benefit less from established treatments but have better survival. Future studies directed exclusively at women may be warranted to confirm or establish benefits of existing and future treatments.

Sex differences in the causes and natural history of heart failure

Heart failure is a clinical syndrome of increasing prevalence in the United States, with significant morbidity and mortality. Although men have a higher annual mortality rate, more women than men die from heart failure each year. Optimal disease management is critical in limiting the impact of heart failure on life quality, quantity, and health care expenditures. Women have a unique risk-factor profile and different clinical manifestations of heart failure than men. Understanding inherent sex differences in heart failure epidemiology, pathophysiology, and natural history is imperative in determining whether the optimal therapy for this prevalent and important syndrome is affected by sex.

The group B coxsackieviruses and myocarditis

The six serotypes of the group B coxsackieviruses (CVB) are common human enteroviruses linked etiologically to inflammatory cardiomyopathies. This has been demonstrated by molecular detection of enteroviral RNA in human heart tissue, serologic associations with disease, and virus isolation from cases of fulminant myocarditis. The murine model of CVB-associated myocarditis has demonstrated that CVB can be attenuated through mutations at different genomic sites. Human CVB3 isolates demonstrate varying degrees of cardiovirulence in the murine model; one site of virulence determination has been mapped to domain II of the 5' non-translated region. The interplay of CVB replication and the immune response to that replication in the heart is a complex interaction determining the extent to which the virus replication is limited and the degree to which a pathogenic inflammation of cardiac muscle occurs. Studies of CVB3-induced myocarditis in murine strains lacking subsets of the immune system or genes regulating the immune response have demonstrated a pivotal role of the T cell response to the generation of myocarditis. While CVB are associated with 20-25% of cases of myocarditis or cardiomyopathy, the severity of the disease and the existence of attenuated strains shown to generate protective immunity in animal models indicates that vaccination against the CVBs would be valuable.

An echocardiographic evaluation of patients with idiopathic heart failure

The primary myocardial disease idiopathic dilated cardiomyopathy (IDCM) is not clearly defined in the literature. The description is both morphologic and etiologic. We examined consecutive patients with congestive heart failure (CHF) of unknown cause to identify possible cases of IDCM and to give a detailed description of echocardiographic data and possible diastolic dysfunction in this group. The hospital records of patients aged 16 to 65 years hospitalized due to CHF or IDCM during a 6-year period (N = 2,711) were evaluated in a defined region of western Sweden. Twenty-two percent (584/2,711) of these records contained no plausible cause of CHF or IDCM, and among patients being alive, obvious cause was lacking in 411 of 1,516 (27%). These 411 patients were offered a diagnostic investigation, including echocardiography, and they were compared with a randomly selected control group (n = 103) from the general population. Of 411 patients, 293 accepted investigation. From the control group, we defined the reference level for left ventricular (LV) dilatation to be > 32 mm/m2, and reduced ejection fraction according to Teichholz formula to be < 50%. Applying these borderlines, we identified LV dilatation and systolic dysfunction to be present in 30%, either dilatation or systolic dysfunction in 36%, and neither in 34%. In patients without any signs of systolic dysfunction 44% (26/59) showed signs of diastolic dysfunction. In a multivariate analysis, LV dimension was not independently correlated to disease, although LV dimension was univariately correlated to ejection fraction (EF) (r = -0.59; p < 0.0001). However, EF (p < 0.0001), left atrial dimension (p < 0.0001), and the first third filling fraction (p < 0.0001) were the constellation of parameters that most accurately separated patients from controls. By using these three parameters, a positive and negative predictive accuracy of 98% and 61%, respectively, was achieved. Thus, in a consecutive group of patients with idiopathic CHF recruited from a nonselected group of hospitalized patients with CHF, all grades of ventricular function were found. In this group, 30% were identified as having IDCM. We give reference values for the diagnosis of idiopathic IDCM and a simple tool to identify patients with systolic and diastolic dysfunction.

Predictors of coronary angiography in patients with idiopathic dilated cardiomyopathy: the Washington, DC Dilated Cardiomyopathy Study

Although a number of clinical and demographic factors have been associated with the performance of angiography in cardiac patients, clinical studies of idiopathic dilated cardiomyopathy (DCM) have often excluded patients who have not undergone coronary angiography to rule out coronary artery disease (CAD). To examine the impact of this diagnostic criterion on population-based studies of idiopathic DCM, we examined characteristics of probable cases of DCM who did or did not have a recorded history of angiography. The cases (n = 129) were ascertained from five medical centers in the Washington, DC metropolitan area over the period 1 July 1990 through 29 February 1992. All of these cases had evidence of ventricular dilation and hypokinesis, with a left ventricular ejection fraction of less than 40%. Cases with a history of known CAD, congenital heart disease, valvular heart disease, or secondary cardiomyopathy were excluded. Sixty-two (48%) of the cases had a recorded history of angiography. Age, educational level, diabetes, alcohol use, insurance status, and type of hospital were significantly associated with angiography in bivariate analysis (p < 0.05). Diabetes and hypertension were inversely associated with history of angiography among black cases, and positively associated with angiography among whites. In logistic regression analysis, age was the strongest independent predictor of angiography (p < 0.025). The associations with educational attainment and alcohol use were of borderline significance (p < 0.10). Thus, in epidemiologic studies of idiopathic DCM, particularly in biracial populations, the exclusion of cases who have not undergone angiography may bias risk estimates and result in the underestimation of incidence and prevalence.

Comparison of clinical findings in idiopathic dilated cardiomyopathy in women versus men. The Italian Multicenter Cardiomyopathy Study Group (SPIC)

Clinical and laboratory findings were compared in 65 women and 238 men with invasively documented idiopathic dilated cardiomyopathy. Women had more severe symptoms (New York Heart Association class > or = III in 48 vs 39%; p < 0.05), presented more frequently with heart failure signs (63 vs 41%; p < 0.01), and had a higher cardiothoracic ratio (0.56 +/- 0.06 vs 0.53 +/- 0.06; p < 0.05) and higher frequency of left bundle branch block (41 vs 29%; p < 0.05). Echocardiographic measurements in women showed significantly greater left ventricular (LV) end-diastolic (42 +/- 7 vs 39 +/- 6 mm/m2; p < 0.0001) and end-systolic (36 +/- 7 vs 33 +/- 6 mm/m2; p < 0.001) diameters, and mean myocardial thickness (11 +/- 2 vs 10 +/- 2 mm; p < 0.05). Exercise duration was shorter in women than in men (7 +/- 3 vs 10 +/- 4 minutes; p < 0.001). After 18 +/- 16 months, 9 women and 27 men died, and 7 and 17, respectively, received transplants. Transplant-free survival was not significantly different according to gender. By Cox multivariate analysis, LV ejection fraction was a significant independent predictor of cardiac death or heart transplantation in both sexes (p < 0.05 in men, and p < 0.005 in women), together with left atrial diameter index (p < 0.01) in women, and mean pulmonary artery pressure (p < 0.001) in men. In conclusion, women with idiopathic dilated cardiomyopathy present a more advanced phase of the disease with greater LV dilation, but do not have a different prognosis.

Descriptive epidemiology of idiopathic dilated cardiomyopathy in Washington County, Maryland, 1975-1991

Estimates of the incidence of idiopathic dilated cardiomyopathy (IDC) were obtained by identifying cases from Washington County, Maryland who were hospitalized at local and regional hospitals over a recent 17 year period. All of the verified cases had evidence of ventricular dilatation and hypokinesis, with a left ventricular ejection fraction of less than 40%. A total of 26 cases were hospitalized over the period 1975-1991. The average age of the cases at the time of diagnosis was 55.5 years (range 22-80 years of age). About 58% of the subjects were males. A marked increase in newly diagnosed cases of IDC occurred in this population in recent years; 38% of the cases (10 of 26) were newly diagnosed during 1991 alone. Over the period 1975-1991, the average annual incidence rate of hospitalized cases was 1.6 per 100,000 among men and 1.2 per 100,000 among women. During the last 7 years of the case ascertainment period (1985-1991), the average annual incidence rate was 3.5 per 100,000 among men and 2.5 per 100,000 among women. These results provide additional evidence that IDC is being increasingly recognized by clinicians, and underscore the need for an improved understanding of the distribution and determinants of this often fatal condition.

The prevalence of hypertrophic cardiomyopathy in men: an echocardiographic population screening study with a review of death records

The purpose of this study was to estimate the prevalence of hypertrophic cardiomyopathy (HCM) in 3607 men from the Reykjavik study of 1979-81. Of these, 452 men had an abnormal (group A) and 3155 a normal electrocardiogram. An echocardiographic control group of 128 men was selected from cohorts with a normal electrocardiogram (group B). Until 1987, 189 deaths had occurred, 59 from group A and 130 from cohorts with a normal ECG including 4 from group B. To identify subjects with HCM, survivors of groups A and B were examined by echocardiography and by review of all autopsy data and death certificates. HCM was found in 14 subjects from group A but none in group B. Two additional cases were found at autopsy in cohorts with a normal ECG. The prevalence of HCM in men with an abnormal and normal ECG was 3.6% and 0.8%, respectively. The overall prevalence was calculated to be 1.1% with a 95% confidence interval of 0.3-3.2%. Men with HCM reported more symptoms than others in groups A and B (P < 0.05-0.001). 25% were without symptoms. Asymptomatic ventricular arrhythmias were detected by Holter monitoring in 45% of men with HCM. The total annual mortality was 1.6% compared with 0.5% in the group with a normal ECG (P < 0.001).

Prevalence and etiology of idiopathic dilated cardiomyopathy (summary of a National Heart, Lung, and Blood Institute workshop

Idiopathic dilated cardiomyopathy (IDC) is the primary indication for cardiac transplantation, with associated costs of approximately $177 million per year. Recognizing the economic implications of IDC, the increasing incidence, and the limited information on pathogenesis and prognosis, the National Heart, Lung, and Blood Institute convened a workshop on the Prevalence and Etiology of Idiopathic Dilated Cardiomyopathy on June 13 to 14, 1991. The difficulties of studying the disease were reviewed, including its relatively low prevalence, its potentially pluricausal nature, and the fact that it is often a diagnosis of exclusion. Still, it presents significant challenges to the cardiovascular scientific community, since the mechanism of myocardial damage and related etiologic and prognostic factors are virtually unknown. The development of more reliable measures of immune-mediated damage and noninvasive measures of impaired cardiac function present new research opportunities in this disorder. Standardized diagnostic criteria for use in observational and interventional trials were developed, and priorities for future research were proposed. Population-based registries and nested case-control studies, where feasible, are appropriate study designs for tracking incidence and prevalence, and for identifying risk factors, respectively. Interventional studies should focus on secondary prevention, through modifying immune-mediated damage in clinically evident dilated cardiomyopathy, and through prevention of sudden death in patients with the disorder. Primary prevention trials must await the identification of modifiable risk factors and of appropriate and effective interventions.

The natural history of dilated cardiomyopathy--a community study

The incidence, clinical features and natural history of dilated cardiomyopathy within a clearly defined population of Scotland was studied retrospectively. From 1982 to 1986, 57 cases were recorded in a population of 145,00, representing an annual incidence of 7.9 per 100,000 per year. This incidence rate is higher than that reported from other centres, and the overall survival rates were poorer.

Epidemiology of idiopathic dilated and hypertrophic cardiomyopathy. A population-based study in Olmsted County, Minnesota, 1975-1984

Using the records linkage system of the Mayo Clinic and of the Rochester Epidemiology Project, which accesses diagnostic data on the entire population of Olmsted County, Minnesota, we identified 45 new cases of idiopathic dilated cardiomyopathy (DCM) and 19 new cases of hypertrophic cardiomyopathy (HCM) among county residents for the years 1975-1984. Overall age- and sex-adjusted incidence rates were 6.0/100,000 and 2.5/100,000 person-years, respectively. The incidence of DCM doubled from 3.9/100,000 in the first 5 years to 7.9/100,000 person-years in the last 5 years of study. The corresponding change for HCM was from 1.4 to 3.6/100,000 person-years. Age- and sex-adjusted prevalence rates as of January 1, 1985, for DCM and HCM were 36.5/100,000 and 19.7/100,000 population, respectively. The prevalence of DCM in persons less than 55 years old was 17.9/100,000, over a third of whom were New York Heart Association functional Class III or IV at diagnosis. These estimates may be of value in determining the potential use of health care resources, particularly cardiac transplantation.

Dilated cardiomyopathy and myocarditis: natural history, etiology, clinical manifestations, and management

This monograph begins and ends with a statement of uncertainty regarding many aspects of dilated cardiomyopathy. Natural history studies identify patients with widely differing outcomes. A host of prognostic factors have emerged, yet it would appear that the major determinants of survival are as yet unrecognized. The diagnosis remains primarily one of exclusion, and management is largely nonspecific and supportive. The frequency of sudden cardiac death is well documented, but the ability to accurately identify patients at risk and the efficacy of antiarrhythmic therapy is unestablished. The emerging success of cardiac transplantation is a source of encouragement. The causes of dilated cardiomyopathy remain a source of intense investigation. Accumulating evidence (much of it circumstantial) does, however, implicate a viral etiology and perhaps altered function of the immunoregulatory system. However, the disparity between the severity of functional disturbance with the relative lack of histologic markers of cellular necrosis implies a disturbance at a cellular level. The etiology or etiologies remain elusive. Future investigation directed at fundamental aspects of cardiac cellular biology may provide the answers.