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Influence of left ventricular cavity size on clinical presentation in hypertrophic cardiomyopathy
F Manganelli1, S Betocchi, M A Losi
1Institute of Internal Medicine, Cardiology, and Cardiac Surgery, Federico II University School of Medicine, Naples, Italy.
Insights
In hypertrophic cardiomyopathy (HC), a smaller left ventricular (LV) cavity size is linked to reduced functional capacity and syncope. This finding highlights LV end-diastolic dimension as a key indicator for disease severity and patient outcomes.
Area of Science:
- Cardiology
- Cardiovascular Imaging
- Clinical Medicine
Background:
- Hypertrophic cardiomyopathy (HC) is a complex cardiac condition affecting myocardial structure and function.
- Left ventricular (LV) diastolic dysfunction is a known contributor to functional limitations in HC patients.
- The relationship between LV cavity size, diastolic properties, and clinical manifestations like syncope requires further elucidation.
Purpose of the Study:
- To investigate the association between left ventricular (LV) cavity size and functional impairment in patients with hypertrophic cardiomyopathy (HC).
- To determine if LV end-diastolic dimension is related to the occurrence of syncope in HC patients.
- To explore the role of LV diastolic dysfunction and reduced LV end-diastolic dimension in the pathophysiology of HC.
Main Methods:
- Eighty-two HC patients in sinus rhythm and off medication underwent echocardiography to measure LV end-diastolic dimension (indexed to body surface area).
- Radionuclide angiography was performed in 50 patients to assess peak filling rate.
- Statistical analyses, including correlation and regression, were used to identify predictors of functional limitation and syncope.
Main Results:
- Patients with higher New York Heart Association (NYHA) functional classes (II-IV) exhibited significantly smaller LV end-diastolic dimensions and lower peak filling rates compared to NYHA class I.
- LV end-diastolic dimension was independently associated with functional limitation (RR 0.63) and was the sole independent predictor of syncope (RR 0.77).
- A smaller LV cavity size was observed in patients with functional limitation, irrespective of obstruction and hypertrophy, and in those with a history of syncope.
Conclusions:
- Reduced left ventricular (LV) cavity size, specifically a smaller LV end-diastolic dimension, is significantly associated with functional limitation in hypertrophic cardiomyopathy (HC).
- A small LV cavity size is an independent predictor of syncope in patients with HC.
- These findings suggest that LV cavity dimensions are important clinical markers for assessing disease severity and predicting adverse outcomes in HC.
Abstract:
The aim of this study was to assess whether left ventricular (LV) cavity size relates to functional impairment and syncope in patients with hypertrophic cardiomyopathy (HC). LV diastolic dysfunction influences functional limitation in HC. A reduced LV end-diastolic dimension may underlie impaired diastolic properties and be implicated in hemodynamic syncope. Eighty-two consecutive patients with HC (off drugs, in sinus rhythm) underwent echocardiography to measure LV end-diastolic dimension in the short-axis view (indexed to the body surface area) and radionuclide angiography (n = 50) to calculate peak filling rate (normalized to stroke counts/s). Patients in New York Heart Association functional classes II to IV had smaller LV end-diastolic dimension (23.2 +/- 2.6 vs 25.5 +/- 2.5 mm/M2, p = 0.0001) and lower peak filling rate (4.3 +/- 1.4 vs 5.1 +/- 1.3 stroke counts/s, p = 0.036) than those in New York Heart Association class I. LV end-diastolic diameter was correlated to peak filling rate (r = 0.37; p = 0.008). The most potent predictors of functional limitation were LV end-diastolic dimension (relative risk [RR] 0.63, confidence interval [CI] 0.45 to 0.88; p = 0.008), age (RR 1.09, CI 1.03 to 1.17; p = 0.003), and LV thickness score (RR 1.08, CI 1.02 to 1.13; p = 0.003). LV cavity size was smaller in patients with functional limitation irrespective of obstruction and hypertrophy. Patients with differed from those without a history of syncope for a smaller LV end-diastolic dimension (23.2 +/- 2.5 vs 25.0 +/- 2.7 mm/M2, p = 0.008), which was the only independent predictor of syncope (RR 0.77, CI 0.63 to 0.95; p = 0.013). Thus, a small LV cavity size is associated with functional limitation and history of syncope in HC.