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Left ventricular systolic and diastolic flow abnormalities determined by Doppler echocardiography in obstructive
Insights
Systolic anterior motion (SAM) of the mitral valve is present in all patients with obstructive hypertrophic cardiomyopathy (HC). This condition significantly impacts left ventricular outflow tract velocity and aortic flow dynamics.
Area of Science:
- Cardiology
- Echocardiography
- Cardiovascular Physiology
Background:
- Obstructive hypertrophic cardiomyopathy (HC) is characterized by dynamic left ventricular outflow tract (LVOT) obstruction.
- Systolic anterior motion (SAM) of the mitral valve is a key echocardiographic finding in HC, contributing to obstruction.
Purpose of the Study:
- To analyze the relationship between SAM, peak LVOT velocity, and aortic/mitral flow in patients with obstructive HC.
- To compare these parameters with findings in age-matched normal subjects.
Main Methods:
- Utilized M-mode, 2D echocardiography, and Doppler (pulsed and continuous-wave) in 17 HC patients and 18 controls.
- Measured time to peak LVOT velocity, aortic flow cessation, and diastolic filling velocities.
Main Results:
- SAM was present in all HC patients, absent in controls.
- Time to peak LVOT velocity as a percentage of ejection time was significantly higher in HC (63%) vs. controls (29%).
- Early to late diastolic filling ratio was significantly lower in HC patients without mitral regurgitation (0.99) compared to controls (1.47).
Conclusions:
- SAM is a consistent finding in obstructive HC and correlates with altered LVOT flow dynamics.
- Diastolic filling patterns are affected in HC, particularly in the absence of mitral regurgitation.
- Echocardiographic parameters provide insights into the pathophysiology of LVOT obstruction in HC.
Abstract:
To analyze the relation of systolic anterior motion (SAM) of the mitral valve, peak left ventricular (LV) outflow tract velocity, aortic flow and mitral flow, 17 patients with obstructive hypertrophic cardiomyopathy (HC) (8 men, 9 women), aged 19 to 88 years (mean 45), were studied using M-mode and 2-dimensional echocardiography and pulsed and continuous-wave Doppler echocardiography and results were compared with those from 18 age-matched normal subjects. SAM was present in all patients with HC and absent in normal subjects. Time to peak outflow velocity as a percentage of LV ejection time was 63% in patients with HC and 29% in normal subjects (p less than 0.001). In 13 patients, time from the R-wave peak to the closest approximation of the mitral valve to the ventricular septum or initial contact during SAM was determined and was 242 +/- 66 ms and time from the R-wave peak to the peak LV outflow tract velocity was 242 +/- 73 ms (r = 0.90). In 11 patients time from the R-wave peak to cessation of flow in the ascending aorta was measured and was 286 +/- 80 ms; time from the R-wave peak to the peak LV outflow tract velocity was 246 +/- 75 ms. The ratio of early to late diastolic filling velocities of the left ventricle was 1.47 +/- 0.40 in the normal subjects and 1.26 +/- 0.84 in patients with HC (difference not significant). The early to late ratio of the 12 patients without mitral regurgitation was 0.99 +/- 0.52 (p less than 0.01 vs normal subjects).(ABSTRACT TRUNCATED AT 250 WORDS)