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Sonicated albumin for evaluating midventricular obstruction in hypertrophic cardiomyopathy
1The First Department of Internal Medicine, Kobe University School of Medicine.
Insights
Sonicated albumin injection clarified flow dynamics in hypertrophic cardiomyopathy patients with midventricular obstruction. This method improved visualization of flow profiles, aiding hemodynamic assessment.
Area of Science:
- Cardiology
- Medical Imaging
- Hemodynamics
Background:
- Hypertrophic cardiomyopathy (HCM) can cause midventricular obstruction, leading to complex flow dynamics.
- Conventional Doppler echocardiography sometimes yields vague velocity profiles in these patients.
- Accurate assessment of flow dynamics is crucial for understanding HCM severity.
Purpose of the Study:
- To evaluate the utility of sonicated albumin injection in delineating flow dynamics of midventricular obstruction in HCM.
- To characterize the Doppler flow profiles obtained after sonicated albumin administration.
Main Methods:
- Intravenous injection of sonicated albumin in 14 HCM patients with unclear Doppler velocity profiles.
- Analysis of continuous wave Doppler echocardiography to identify flow patterns.
- Calculation of peak pressure gradients using the modified Bernoulli equation.
Main Results:
- Sonicated albumin injection clarified Doppler envelopes in 64% of patients.
- Three distinct flow profile patterns were observed: monophasic, biphasic with diastolic flow, and biphasic with a notch.
- Presence of diastolic flow or obstruction site did not significantly alter pressure gradient calculations, indicating their independence as severity parameters.
Conclusions:
- Sonicated albumin injection is a valuable tool for visualizing flow dynamics in midventricular obstruction within HCM.
- The method aids in a more precise hemodynamic evaluation of HCM.
- Distinct flow patterns identified can provide further insights into obstruction characteristics.
Abstract:
The flow dynamics of midventricular obstruction in hypertrophic cardiomyopathy were evaluated with intravenous injection of sonicated albumin in 14 patients with vague velocity profiles on conventional continuous wave Doppler echocardiography. Nine patients (64%) demonstrated a clear envelope after the injection. The following three patterns of continuous Doppler profiles were obtained : 1) a monophasic flow profile with a brief and sharp increase in peak velocity in late systole, 2) a late-peaking systolic flow and a diastolic flow during isovolumic relaxation time emerging after sonicated albumin injection (biphasic flow profile), 3) a biphasic flow profile with systolic and diastolic flow waves having a notch around the second heart sound. The calculated peak pressure gradients from the modified Bernoulli equation did not differ significantly with the presence of diastolic wave or the site of obstruction. Therefore, these are independent parameters for estimating the severity of midventricular obstruction. Therefore, these are independent parameters for estimating the severity of midventricular obstruction. The sonicated albumin method was useful in delineating the flow profile, and thus evaluating the hemodynamics of midventricular obstruction in hypertrophic cardiomyopathy.