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Severe functional limitation in patients with hypertrophic cardiomyopathy and only mild localized left ventricular
Insights
This study identifies a subset of nonobstructive hypertrophic cardiomyopathy patients with mild hypertrophy experiencing severe heart failure. Many showed developing left ventricular dysfunction and thinning, suggesting a previously unrecognized aspect of this condition.
Area of Science:
- Cardiology
- Cardiovascular Medicine
- Medical Research
Background:
- Hypertrophic cardiomyopathy (HCM) is a complex heart muscle disease.
- Nonobstructive HCM with mild localized left ventricular hypertrophy can present with severe symptoms.
- The natural history and specific patient subsets require further elucidation.
Purpose of the Study:
- To describe a specific cohort of patients with nonobstructive hypertrophic cardiomyopathy.
- To investigate the clinical course and cardiac function in these patients over time.
- To identify potential novel phenotypes within hypertrophic cardiomyopathy.
Main Methods:
- Retrospective analysis of ten patients with nonobstructive HCM and mild localized left ventricular hypertrophy.
- Longitudinal assessment over a mean follow-up of 7 years.
- Echocardiography, M-mode echocardiography, and radionuclide angiography were utilized.
Main Results:
- Six of ten patients showed increased left ventricular internal dimension without absolute dilation.
- Four patients exhibited significant ventricular septal thinning.
- Eight of nine patients demonstrated impaired left ventricular diastolic function, and six had depressed systolic function.
Conclusions:
- A distinct subset of nonobstructive HCM patients with mild hypertrophy can develop severe cardiac failure.
- Progressive left ventricular internal dimension increase or septal thinning, coupled with systolic and diastolic dysfunction, characterizes this subset.
- These findings highlight an underappreciated aspect of hypertrophic cardiomyopathy progression.
Abstract:
Ten patients with nonobstructive hypertrophic cardiomyopathy and only mild localized left ventricular hypertrophy who had severe symptoms of cardiac failure are described. During a mean follow-up period of 7 years, 6 of these 10 patients showed a substantial increase in left ventricular internal dimension (6 to 15 mm, mean 10) as assessed with M-mode echocardiography, although absolute left ventricular cavity size remained within normal limits in 5 of the 6. Four patients demonstrated substantial septal thinning (5 to 14 mm, mean 8). Left ventricular diastolic function, assessed by radionuclide angiography in nine patients, was impaired in eight who showed decreased peak filling rate (less than 2.5 end-diastolic volumes/s) and prolonged time to peak rate of filling (greater than or equal to 180 ms). Furthermore, left ventricular systolic function, usually supernormal in patients with hypertrophic cardiomyopathy, was depressed (ejection fraction less than or equal to 45%) in six patients. Hence, a subset of patients was identified with nonobstructive hypertrophic cardiomyopathy and only mild localized left ventricular hypertrophy who experienced severe cardiac symptoms. The majority of these patients showed both systolic and diastolic left ventricular dysfunction in the presence of a progressive increase in left ventricular internal dimension (but without absolute left ventricular dilation) or ventricular septal thinning or both. Such patients may represent an important component of the natural history of hypertrophic cardiomyopathy which has not been previously fully appreciated.