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Diagnosis and natural history of congested (dilated) cardiomyopathies
Insights
Primary dilated cardiomyopathy involves a weakened, enlarged left ventricle without a known cause. Its progression and symptoms, like heart failure, vary greatly, with some patients showing recovery.
Area of Science:
- Cardiology
- Internal Medicine
Background:
- Primary dilated cardiomyopathy is characterized by a dilated, poorly contracting left ventricle.
- Diagnosis requires excluding secondary causes and structural heart disease.
Purpose of the Study:
- To define the diagnostic criteria for primary dilated cardiomyopathy.
- To explore the natural history and variability of the condition.
- To illustrate the interplay between hypertension and dilated cardiomyopathy.
Main Methods:
- Diagnostic criteria based on left ventricular morphology and function.
- Exclusion of secondary causes of heart muscle disorders.
- Observational analysis of clinical presentation and progression.
Main Results:
- The condition presents as a dilated, poorly contracting left ventricle with increased volumes.
- Symptoms, including heart failure, dysrhythmia, and mitral regurgitation, may develop late.
- Natural history is variable, with some patients recovering cardiac function.
Conclusions:
- Primary dilated cardiomyopathy diagnosis relies on excluding other causes.
- The condition's course is unpredictable, ranging from latency to heart failure.
- Hypertension and dilated cardiomyopathy show complex interactions influencing patient outcomes.
Abstract:
The diagnosis of primary dilated cardiomyopathy depends on the recognition of a dilated poorly contracting left ventricle with increased end-diastolic and end-systolic volumes in the absence of a detectable cause. The diagnosis is made only after exclusion both of structural heart disease and of known causes of secondary heart muscle disorder. The natural history is still largely unknown and is probably as variable as the likely causes. The left ventricular disorder does not cause symptoms until heart failure supervenes except for occasional patients who develop an early atrial or ventricular dysrhythmia, conduction defect, chest pain or murmur of mitral regurgitation. This period of latency may be short, prolonged or even permanent since it is unlikely that all cases progess to the point of failure. A few patients recover normal or near-normal cardiac function. The interplay between high blood pressure, hypertensive heart failure and dilated cardiomyopathy is illustrated by patients who recover from heart failure to become hypertensive and vice versa and in current treatment with vasodilators and diuretics for patients at either end of the spectrum.