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Clinical course of middle-aged asymptomatic patients with hypertrophic cardiomyopathy
G M Hecht1, J A Panza, B J Maron
1Echocardiography Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892.
Insights
Middle-aged patients with hypertrophic cardiomyopathy (HC) who are initially asymptomatic often remain symptom-free for years. However, these individuals still face risks of sudden cardiac death and symptom progression.
Area of Science:
- Cardiology
- Genetics
- Internal Medicine
Background:
- Hypertrophic cardiomyopathy (HC) presents diverse clinical and morphological features.
- The natural history of HC is partially understood, but specific subgroups require further investigation.
Purpose of the Study:
- To define the initial presentation and clinical course of middle-aged patients with HC who are asymptomatic.
- To compare the morphology of asymptomatic and symptomatic HC patients.
Main Methods:
- Analysis of 241 middle-aged HC patients (35-55 years).
- Focus on 31 initially asymptomatic patients, with 29 followed for >= 2 years (mean 8 years).
- Morphological comparison with 30 age- and gender-matched symptomatic HC control subjects.
Main Results:
- 76% of initially asymptomatic patients remained symptom-free during follow-up.
- 3 patients showed symptom progression, and 4 experienced sudden cardiac death (1.7% annual mortality).
- Asymptomatic patients were more likely to have localized left ventricular hypertrophy (58% vs. 30%, p=0.02).
Conclusions:
- Middle-aged patients with HC who are asymptomatic at presentation often remain so for approximately 8 years.
- Despite mild hypertrophy and lack of outflow obstruction, these patients are not fully protected from adverse events.
- Localized hypertrophy may be a distinguishing feature in asymptomatic HC patients.
Abstract:
Patients with hypertrophic cardiomyopathy (HC) may present a wide spectrum of clinical and morphologic manifestations. Although many aspects of the natural history of HC are understood, the initial presentation and subsequent clinical course of certain subgroups are not yet well defined. To further our understanding in this regard, 241 middle-aged patients with HC (aged 35 to 55 years) were analyzed. The vast majority of patients (210) had already experienced symptoms, whereas the remaining 31 initially presented with no or minimal symptoms and are the focus of this investigation; 29 of these were followed for greater than or equal to 2 years (range to 11.5 years, mean 8). A separate group of 30 moderately symptomatic age- and gender-matched patients with HC were selected as control subjects for morphologic comparisons. Of the 29 study patients with follow-up, 22 (76%) are presently free of important cardiac symptoms, but 3 showed progression of symptoms, and 4 have died suddenly. Annual mortality rate was 1.7%. Eighteen of the middle-aged asymptomatic patients with HC (58%) had localized left ventricular hypertrophy, usually involving only the anterior ventricular septum; in contrast, only 9 of the 30 symptomatic control subjects (30%) had such localized hypertrophy (p = 0.02). In conclusion, of those patients with HC who achieved middle-age without developing important cardiac symptoms, approximately 75% remained asymptomatic during the ensuing average 8-year follow-up. However, such patients are not protected in absolute terms from unfavorable clinical events (despite relatively mild left ventricular hypertrophy and in most cases absence of outflow obstruction.(ABSTRACT TRUNCATED AT 250 WORDS)