Dilated cardiomyopathy

Referred to as global left ventricular systolic dysfunction in the absence of hypertension, valve disease, or significant coronary artery disease. and systolic dysfunction with normal left ventricular wall thickness, and left ventricular function.

Heart failure associated with reduced ejection fraction.

Characterized by left ventricular chamber enlargement and systolic dysfunction with normal left ventricular wall thickness.

A leading cause of advanced heart failure accounting for more than half of all heart transplantations.

Associated with myocyte death, and myocardial fibrosis.

While right ventricular dilation and dysfunction may be present, they are not necessary for the diagnosis.

Estimated prevalence, 1:2500.

Autopsy studies estimate 4.5 cases per hundred thousand population.

Clinical incidence about 2.45 cases per hundred thousand population per year.

Causes of nonischemic dilated cardiomyopathy include: valvular disease, and green disorders, exposure to myocardial toxins, but no clinical cause is identified for most patients.

Classification are primary without familial association, familial or secondary.

Two thirds have no family history and are referred to as sporadic cases.

More than 40 diseased genes associated.

Mutations in 8 sarcomere-protein genes in 40-70% of patients with hypertrophic cardiomyopathy.

30-50%-with dilated cardiomyopathy have relative who is affected or is likely to be affected, indicating a genetic causation.

In a study of 1220 patients with DCM and their 1693 family members, estimated familial DCM prevalence was almost 30% and the estimated TCM risk by age 80 years and family member members was 19% (Huggins GS).

Pathogenic mutations have been found in only 20-30% of patients.

Most common mode of inheritance is autosomal dominance, although autosomal recessive and x-linked forms have been reported.

May be inherited with other phenotype changes, cardiac and non-cardiac.

Fibrosis in dilated cardiomyopathy is associated with impaired left ventricular contraction and is a substrate for ventricular reentrant arrhythmias.

Fibrosis can be demonstrated and quantified as to myocardial replacement, in vivo, with the use of a late gadolinium enhancement cardiovascular magnetic resonance (LGE-CMR).

Caused by gene mutations encoding for a number of pathways and cellular components:nuclear envelope, contractile proteins, force transduction, gene transcription, splicing machinery and calcium handling.

In a series of 1230 patients 50% of cases idiopathic (Felker GM).

20-35% of patients have an affected family member (Goerss JB).

Recommended patients with a diagnosis of idiopathic dilated cardiomyoapthy should have siblings, parents and children undergo 2-D ECHO to be screened for this process, and they may require serially examinations over time to confirm a diagnosis.

The diagnosis of a single additional member of a family confirms the diagnosis of familial dilated cardiomyopathy, in the absence of an any other associated etiologic factor.

15% of sporadic cases arise from chronic myocarditis.

Viral diseases associated with myocarditis include Coxsackie virus, adenovirus, parvovirus and HIV.

Other etiologies include alcoholism, anthracycline chemotherapy agents, metals, autoimmune and systemic disorders and mitochondrial abnormalities.

Isolated cases with idiopathic disease may have de novo gene mutations, recessive inheritance or reduced penetrance.

The recognition of familial dilated cardiomyopathy is complicated by age dependence of this process, small families and difficulty in tracking down family histories: 20-30% of idiopathic patients, at a minimum, have genetic disease.

Distinction between primary and secondary disease may be difficult.

Family history a risk factor with familial aggregation ranging from 12.5-35%.

Familial disease is usually autosomal dominant, with X-linked autosomal recessive and mitochondrial related disease occurring less frequently.

The cause of 45% of heart transplantations.

Uncommon cause of congestive heart failure.

The diseases associated with significant morbidity and mortality due to heart failure and sudden cardiac death.

Five-year mortality remains as high as 20%.

No clear etiology.

Deficient trace element selenium and excess cobalt can induce clinically progressive cardiac dysfunction and dilation indistinguishable from dilated cardiomyopathy.

Studies of Left Ventricular Dysfunction (SOLVD)prevention trial indicated that the risk of developing CHF was reduced by early treatment with enalapril in asymptomatic patients with an ejection fraction less than or equal to 35%.

Present therapy includes: angiotensin-converting enzyme, angiotensin II receptor blockers, beta blockers, mineralocorticoid receptor blockers, and angiotensin receptor neprilyssin inhibitors can lead to a return of left ventricular ejection fraction and ventricular geometry to normal it up to 40% of patients with dilated cardiomyopathy.

Left ventricular ejection fraction is an important prognostic factor, but most patients who experience sudden cardiac death do not have severely reduced LVEF.

Many patients with significant impairment of left ventricular function may still be at low risk for sudden cardiac death.

CD34 cell transplant therapy maybe affecive as transendocardial therapy.

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