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[Left ventricular relaxation and filling abnormalities in patients with HOCM and left ventricular pressure overload
Insights
Delayed mitral valve opening is not specific to hypertrophic obstructive cardiomyopathy (HOCM). Abnormal relaxation, causing delayed mitral valve opening, is also observed in chronic pressure overload, indicating it
Area of Science:
- Cardiovascular Physiology
- Echocardiography
- Cardiac Diastology
Context:
- Hypertrophic obstructive cardiomyopathy (HOCM) is a condition characterized by left ventricular hypertrophy.
- Assessing diastolic function is crucial for understanding cardiac mechanics in various heart conditions.
- Delayed mitral valve opening is a potential indicator of diastolic dysfunction.
Purpose:
- To investigate whether the timing of mitral valve opening relative to end-systole is specific to HOCM.
- To compare the timing of mitral valve opening in HOCM patients versus those with chronic pressure overload (CPO) and healthy individuals.
Summary:
- Echocardiograms of HOCM, CPO, and normal subjects were analyzed for the time from end-systole to mitral valve opening (t DS-MO).
- Both HOCM and CPO groups exhibited significantly delayed t DS-MO compared to normals, attributed to abnormal relaxation.
- This prolonged relaxation led to increased ventricular diameter during isovolumic relaxation and rapid filling phases in both HOCM and CPO groups.
Impact:
- The echocardiographic signs of abnormal relaxation, including delayed mitral valve opening, are not exclusive to HOCM.
- These findings are also present in secondary left ventricular hypertrophy due to CPO.
- Changes in diastolic filling patterns accompany these relaxation abnormalities, highlighting the complexity of diastolic dysfunction.
Abstract:
In order to test the hypothesis that delayed mitral valve opening (MO) with regard to endsystolic dimension (t DS-MO) is specific for hypertrophic obstructive cardiomyopathy (HOCM), LV echograms of patients with different forms of LV hypertrophy due to chronic pressure overload (CPO; aortic stenosis + arterial hypertension, n = 24) and hypertrophic obstructive cardiomyopathy (n = 24) were recorded, digitized and compared with those of normals (N :n = 28(. In patients with HOCM (93 +/- 37 ms; p less than 0.0001) and CPO (66 +/- 31 ms; p less than 0.0001) the time t DS-MO was significantly delayed compared with N (13 +/- 15 MS), due to abnormal relaxation. This prolonged relaxation time resulted in an abnormal diameter increase (delta D) during the isovolumic relaxation phase (HOCM: 4.0 +/- 2.2 MM/CPO: 3.0 +/- 1.8 mm; p less than 0.0001/N:0.6 +/- 0.5 mm) and the rapid filling phase (HOCM 7.6 +/- 2.7 mm; p less than 0.0001/CPO 9.2 +/- 2.9 mm; p less than 0.05 / N: 10.7 +/- 2.2 mm). The echocardiographical signs of an abnormal relaxation are not specific for HOCM, they can be seen in different forms of secondary LV hypertrophy and are accompanied by changes in the diastolic filling pattern.