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[Secondary atypical hypertrophy: hypertrophic cardiomyopathy with acquired risk factors (author's transl)]
Insights
A new concept, "secondary atypical hypertrophy," is proposed for hypertrophic cardiomyopathy (HCM) linked to acquired factors like hypertension. This condition presents distinct clinical features and a favorable prognosis, differing from familial HCM.
Area of Science:
- Cardiology
- Clinical Medicine
- Pathophysiology
Context:
- Hypertrophic cardiomyopathy (HCM) is a complex condition with diverse etiologies.
- Acquired risk factors, including hypertension and strenuous exercise, are increasingly recognized in HCM development.
- Distinguishing between acquired and genetic forms of HCM is crucial for accurate diagnosis and management.
Purpose:
- To introduce and validate the clinical concept of "secondary atypical hypertrophy" in hypertrophic cardiomyopathy.
- To identify acquired risk factors contributing to HCM, such as hypertension and physical exertion.
- To differentiate secondary atypical hypertrophy from familial HCM based on clinical features, prognosis, and management strategies.
Summary:
- A case-control study identified hypertension, physical labor, and weight gain as risk factors for apical hypertrophy, with hypertension strongly linked to HCM in older adults.
- Transient hypertension during exercise was observed in non-obstructive HCM cases, suggesting its role as a risk factor.
- Secondary atypical hypertrophy, associated with acquired factors, presents differently from familial HCM, being more prevalent in older males and showing less impaired left ventricular function.
- Follow-up studies indicate a favorable prognosis for secondary atypical hypertrophy, characterized by an absence of sudden death.
Impact:
- Establishes a new clinical concept, "secondary atypical hypertrophy," for HCM related to acquired risk factors.
- Highlights the significant role of hypertension as a causal factor in HCM, particularly in older individuals.
- Suggests distinct clinical characteristics and a more favorable prognosis for secondary atypical hypertrophy, guiding clinical practice and patient management.
- Provides a framework for differentiating acquired HCM from genetic forms, improving diagnostic accuracy and therapeutic approaches.
Abstract:
New clinical concept of "secondary atypical hypertrophy" was proposed for hypertrophic cardiomyopathy (HCM) associated with an acquired risk factors such as hypertension, strenuous exercise, etc, based on the following findings. 1) Case-control study suggested that history of hypertension, physical labor and weight gain were thought to be risk factors of apical hypertrophy. History of hypertension was also demonstrated in 55% of older cases of HCM (greater than 35 yrs) with asymmetric septal hypertrophy, and this figure was appreciably higher than that in general population (around 26% in our population survey). Thus hypertension was suggested to have a causal relationship to HCM as an important risk factor in older cases. 2) Even in cases without hypertension, 29% of non-obstructive HCM exhibited a marked increase in systolic blood pressure on bicycle ergometer stress test, suggesting an important of transient hypertension during exercise as a risk factor of unusual hypertrophy. 3) The cases of HCM with definite family history and the cases of HCM with secondary atypical hypertrophy, with acquired risk factors such as hypertension, presented different clinical features. The latter is older and predominant in males. In the former, QRS pattern was les distorted, suggesting milder congenital defect of the myocardium. Left ventricular function was less impaired in cases with secondary atypical hypertrophy if judged from diastolic descent rate of the mitral valve, left ventricular enddiastolic pressure and functional aerobic impairment (FAI). On the other hand, no differences were observed between cases with ventricular septal hypertrophy and left ventricular outflow obstruction. 4) Follow-up study demonstrated rather favorable prognosis in cases with secondary atypical hypertrophy because of the absence of sudden death despite of their older age. These distinctive difference in clinical features, prognosis and then management in cases with HCM with acquired risk factors suggested a validity of the concept of secondary atypical hypertrophy in clinical practice.