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The dilated cardiomyopathies: clinical aspects
1UCLA School of Medicine, UCLA Medical Center.
Insights
Dilated cardiomyopathies involve enlarged heart ventricles, often idiopathic, leading to heart failure. Optimal medical management, including diuretics and vasodilators, is crucial for managing symptoms and improving function in most patients.
Area of Science:
- Cardiology
- Internal Medicine
- Pathology
Background:
- Dilated cardiomyopathies (DCM) are defined by increased left ventricular dimensions without compensatory wall thickening.
- Myocardial injury in DCM is often subclinical until advanced stages.
- Etiologies include idiopathic causes, viral infections, autoimmune factors, genetics, and coronary microvascular dysfunction.
Purpose of the Study:
- To review the pathophysiology, diagnosis, and management of dilated cardiomyopathies.
- To emphasize the importance of medical management in heart failure due to DCM.
Main Methods:
- Literature review of dilated cardiomyopathies.
- Analysis of hemodynamic factors and therapeutic strategies.
- Discussion of outcomes including sudden death and transplantation.
Main Results:
- Compensated dysfunction can persist despite impaired contractility.
- Progressive hemodynamic deterioration is driven by fluid retention, neurohumoral activation, and vasoconstriction.
- Diuretic and vasodilator therapy can restore functional capacity by normalizing filling pressures.
Conclusions:
- Optimal medical management is essential for the majority of patients with dilated cardiomyopathy.
- While cardiac transplantation improves survival, its limited availability necessitates focus on medical therapy.
- Sudden death from arrhythmias and emboli remain significant risks, with prophylactic therapies lacking proven efficacy.
Abstract:
The dilated cardiomyopathies are characterized by an increase in left ventricular internal dimensions without an appropriate increase in ventricular wall thickness. The myocardial injury often goes unrecognized until the offending cause is no longer apparent. Although specific diagnoses and treatment can sometimes be established, the majority of cases are designated idiopathic but are believed to result from previous viral infections, autoimmune or genetic predisposition, or abnormalities of the coronary microvasculature. Despite impaired contractility and ventricular dilatation, compensated dysfunction may prevail for some time. Excessive fluid retention, neurohumoral activation, systemic vasoconstriction, and atrioventricular valve regurgitation promote progressive hemodynamic deterioration. The meticulous matching of diuretic and vasodilator therapy to specific hemodynamic goals, particularly the normalization of ventricular filling pressure, frequently allows restoration and maintenance of reasonable functional capacity even in patients with severe heart failure. Nevertheless, sudden death due to ventricular arrhythmias and occasionally to systemic emboli remains a major threat. Prophylactic use of antiarrhythmic agents and anticoagulant therapy is not of proven efficacy. Cardiac transplantation results in significant improvement in life expectancy for patients with dilated heart failure but is available only to a relatively small number of patients because of the limited donor supply. Accordingly, programs providing cardiac transplantation should be equally committed to providing optimal medical management that is the only option for the majority of patients with dilated cardiomyopathy.