Epidemiology of dilated cardiomyopathy. A prospective post-mortem study of 5252 necropsies. The Heart Muscle Disease Study Group

Therapeutic left ventricular assist device and apheresis on dilated cardiomyopathy

Pathogenesis and therapies of dilated cardiomyopathy (DCM) have been discussed for a long time, but both of the ultimate answers are still unknown. In the last decade, the pathogenic role of immunological factors, such as cardiac autoimmune antibodies and cytokines, have been discussed attentively. This has led to one possible new therapy, immunoadsorption, which removes antibodies, and it has made a remarkable effect. However, there are other factors to remove. For the removal of cytokines and neurohormones, the most effective method is hemofiltration (HF). Also, double-filtration plasmapheresis (DFPP) removes immunoglobulin as well as low-density lipoprotein (LDL) and coagulation factors that may improve blood circulation, including the coronary arteries. Therefore, to eliminate all deteriorative factors, both apheresis therapies, HF and DFPP, should be performed. Due to the shortage of donor hearts, left ventricular assist systems (LVAD) have been used as a bridge to transplantation. It has now been reported that the total unloading of the left ventricle does not only maintain, but also recovers, the cardiac function, even from end-stage heart failure. However, the patients who have obtained a long-lasting recovery of cardiac function from an LVAD are still in a minority. To make this the majority, therapeutic LVAD should be combined with the apheresis therapies, DFPP and HF. We believe that this concept, a combination of HF and DFPP with therapeutic LVAD, will be the next generation of treatment that has a potential to postpone, or even avoid, heart transplantation.

The prevalence of calcified carotid atheromas on the panoramic radiographs of patients with dilated cardiomyopathy

OBJECTIVE

Individuals with dilated cardiomyopathy (DCM) often die from heart failure without a transplant. Of those who do receive a transplant, a significant number suffer a perioperative stroke, although the cause is often in doubt. Our study attempts to determine whether the prevalence of calcified carotid artery atheromas, a known cause of stroke, is greater on the panoramic radiographs of individuals with DCM than it is among controls.

STUDY DESIGN

Twenty-seven persons [mean age 62.3 years] enrolled in the UCLA Cardiac Transplantation Program were provided a panoramic radiograph. An age-matched, atherogenic risk-matched cohort of 54 patients free of DCM served as controls. The radiographs of patients in each group were examined for the presence of calcified carotid atheromas.

RESULTS

Nine of the 27 patients with DCM had calcified atheromas, whereas only 2 of the 54 patients in the control group had such lesions. This difference was statistically significant (P<.001).

CONCLUSIONS

Panoramic radiographs may be helpful in identifying some DCM patients with occult carotid artery atherosclerosis who may be at risk for a subsequent stroke.

Idiopathic dilated cardiomyopathy in an Omani population of the Arabian Peninsula: prevalence, clinical profile and natural history

We have analysed prospectively the prevalence and clinical profile of idiopathic dilated cardiomyopathy (IDC) in a circumscribed native population of the Sultanate of Oman over 3 years (1992-1994). Identified patients were followed up for a period ranging from 1 to 8 years (median 4 years) and the variables related to outcome determined. IDC was diagnosed in 97 patients, giving a prevalence of 43.2/100,000 population during the study period. 84.5% of patients were aged over 35 years and males outnumbered females (M/F=1.4:1). Factors related to poor outcome were an initial left ventricular ejection fraction </=30% (P=0.01), severe symptoms, i.e. NYHA functional class III or IV at presentation (P=0.04), and significant ventricular tachycardia during follow up (P=0.02). However, multivariate regression analysis yielded only low LVEF as the predictor of poor outcome (P=0.01). When analysed from age of onset of symptoms, survival figures were 94% at 1 year (95% CI 88 to 99%), 76% at 5 years (95% CI 67 to 86%) and 68% at 8 years (95% CI 54 to 82%). Mean survival was 6.5 years (95% CI 6 to 7 years). Patients were still at risk of fatal ventricular arrhythmia even when haemodynamically stable and had left ventricular ejection fraction >30%.

Incidence and epidemiology of heart failure

Epidemiologic data from the Framingham Study provide insights into the population burden of heart failure (CHF), its prognosis and modifiable risk factors that promote it. In the general population CHF is chiefly the end stage of hypertensive, coronary and valvular cardiovascular disease. It is a major and growing problem in most affluent countries because of aging populations of increased size, and the prolongation of the lives of cardiac patients by modern therapy. Once clinically manifest, CHF, despite recent innovations in therapy, carries an unacceptably high mortality rate. In the Framingham Study, median survival is only 1.7 y for men and 3.2 y for women, with only 25% of men and 38% of women surviving 5 y. This is a mortality rate 4-8 times that of the general population of the same age. This poor outlook is observed for all etiologies of CHF and sudden death is a prominent feature of the mortality. Based on population attributable risks, hypertension has the greatest impact, accounting for 39% of CHF events in men and 59% in women. Despite its much lower prevalence in the population (3-10%) myocardial infarction also has a high attributable risk in men (34%) and women (13%). Valvular heart disease only accounted for 7-8% of CHF. Hypertension increased the age and risk factor adjusted hazard of CHF 2-fold in men and 3-fold in women, with a greater impact of the systolic than diastolic blood pressure. Diabetes increased CHF risk 2-8 fold with risk ratios twice as large in women as men. About 19% of CHF cases have diabetes. It accounted for 6-12% of the CHF in the Framingham Study cohort. Dyslipidemia characterized by a high total/HDL cholesterol ratio, but not the total cholesterol alone was a risk factor for CHF. An enlarged heart on X-Ray, ECG-LVH, a reduced vital capacity and rapid heart rate usually signified deteriorating cardiac function. CHF risk associated with ECG-LVH was independent of X-Ray cardiomegaly but risk was further augmented when both coexist. Echocardiographic left ventricular hypertrophy signifies a high risk of CHF proportional to the degree of increase in left ventricular mass without a critical value that delineates compensatory from pathological hypertrophy. Risk of CHF in persons predisposed by hypertension, diabetes or cardiac conditions varies over a 10-fold range depending on the aforementioned modifiable risk factors and indicators of deteriorating left ventricular function. Using multivariate risk formulations it is possible to identify 20% of the population from which 70% of the CHF will evolve. Those in the upper quintile of multivariate risk are good candidates for echocardiographic testing to delineate those needing aggressive preventive measures to delay the onset of CHF. Therapy of CHF must begin with treatment of presymptomatic left ventricular dysfunction to reverse the dysfunctional maladaptive changes.

Vital epidemiologic clues in heart failure

The epidemiologic investigation of heart failure evolution by the Framingham Heart Study has provided vital clues concerning the pathogenesis, predisposing conditions, other predictive risk factors, and indicators of deteriorating ventricular function related to the disease. This information is important in the early detection of those susceptible to heart failure who are candidates for preventive measures-of importance because the prevalence of the disease has not declined despite the recent therapeutic advances. Epidemiologic investigation has identified useful indicators for the disease including a low or falling vital capacity suggesting diastolic dysfunction, a rapid resting heart rate in compensation for a decreased stroke volume, and cardiomegaly indicating myocardial hypertrophy or dilatation. Hypertension and coronary disease remain the leading causes of the disease, and heart failure due to myocardial infarction has increased in prevalence. Hypertension and coronary disease often coexist in individuals who develop heart failure so that correction and prevention of these conditions deserve a high priority. Early detection and correction of insulin resistance is important because a threefold increase in the prevalence of diabetes in the general population has serious implications for the incidence of heart failure. In patients with hypertension, the occurrence of a myocardial infarction increases the risk of developing heart failure five to sixfold, whereas angina increases it less than twofold. In these patients, the presence of left ventricular hypertrophy increases the risk of developing heart failure two- to threefold. Heart failure-related mortality remains unacceptably high, despite improvements in treatment, indicating a need for early detection and treatment of predisposing conditions.

Investigation of a family with autosomal dominant dilated cardiomyopathy defines a novel locus on chromosome 2q14-q22

Dilated cardiomyopathy (DCM) is a leading cause of heart failure and the most frequent indication for heart transplantation in young patients. Probably >25% of DCM cases are of familial etiology. We report here genetic localization in a three-generation German family with 12 affected individuals with autosomal dominant familial DCM characterized by ventricular dilatation, impaired systolic function, and conduction disease. After exclusion of known DCM loci, we performed a whole-genome screen and detected linkage of DCM to chromosome 2q14-q22. Investigation of only affected individuals defines a 24-cM interval between markers D2S2224 and D2S2324; when unaffected individuals are also included, the critical region decreases to 11 cM between markers D2S2224 and D2S112, with a peak LOD score of 3.73 at recombination fraction 0 at D2S2339. The identification of an additional locus for familial autosomal dominant DCM underlines the genetic heterogeneity and may assist in the elucidation of the causes of this disease.

Nonischemic heart failure: epidemiology, pathophysiology, and progression of disease

The prevalence of nonischemic heart failure including idiopathic dilative cardiomyopathy is not well known. It may vary considerably in different population sub-groups and geographic areas. In ambulatory and hospitalized patients with clinically manifest heart failure primary cardiomyopathy is diagnosed in 2-15%, while in recent large scale therapeutic trials the proportion of patients with nonischemic heart failure ranged from 18% to 53%. There is a relation between sex, age and etiology of chronic heart failure, nonischemic cardiomyopathy being more frequent in women and in younger individuals. In contrast to ischemic heart failure, where the severity usually correlates with the extent of coronary artery lesions, the pathophysiology of cardiomyopathy is less clear. Genetic factors, myocarditis from infectious agents, auto-immune mechanisms, cytokine activation, hormonal and metabolic influences can play a role. The functional consequences of myocardial damage in nonischemic heart failure is a global instead of localized abnormality of ventricular contractility. There is epidemiological evidence that in general the prognosis of nonischemic heart failure is better than in ischemic heart failure. The mortality of patients with ischemic heart failure was usually higher in the placebo groups of recent heart failure trials than in patients with nonischemic etiology. Furthermore, therapeutic responses to angiotensin-converting enzyme (ACE) inhibitors, beta-blockers, amlodipine and amiodarone were also different in some studies. The outcome of nonischemic heart failure is better even in transplant candidates with the most advanced stages of heart failure, they survive longer and respond better to intensified drug regimens than patients with similar clinical severity of ischemic heart failure. Thus, an early and precise diagnosis of the etiology of heart failure should be encouraged not only in clinical trials but also in every day patient management. As more therapeutic options are developed, individualized drug selection for patients with various etiologies of heart failure may become possible.