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Relationship between instantaneous trans-mitral blood flow velocity and instantaneous left ventricular volume in
J Kenny1, T Plappert, M S Sutton
1Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.
Insights
Doppler echocardiography reveals that mitral flow velocities, specifically the A wave, correlate with left ventricular muscle-to-cavity size in hypertrophied hearts. This finding is crucial for understanding diastolic function in conditions like aortic stenosis and dilated cardiomyopathy.
Area of Science:
- Cardiology
- Echocardiography
- Physiology
Background:
- Left ventricular hypertrophy (LVH) alters cardiac structure and function.
- Trans-mitral blood flow velocity is a key indicator of diastolic function.
- Understanding the relationship between flow dynamics and ventricular geometry is essential for diagnosing and managing heart conditions.
Purpose of the Study:
- To investigate the correlation between trans-mitral blood flow velocity and left ventricular (LV) volume in normal and hypertrophied hearts.
- To assess differences in mitral flow patterns among normal subjects, patients with aortic stenosis, and those with dilated cardiomyopathy.
Main Methods:
- Cross-sectional Doppler echocardiography was used in 10 normal subjects and 19 patients with LVH (9 aortic stenosis, 10 dilated cardiomyopathy).
- Digitized echocardiograms provided instantaneous mitral flow velocity, LV volume, LV mass, and LV mass/volume ratio.
- Peak E wave and A wave velocities, A/E ratio, and LV filling percentages were analyzed.
Main Results:
- Peak E wave velocities were similar across all groups.
- Peak A wave velocities were significantly increased in aortic stenosis but not in dilated cardiomyopathy compared to normal.
- The peak A/E velocity ratio was elevated in aortic stenosis but similar to normal in dilated cardiomyopathy.
- No correlation was found between flow velocities (E wave, A wave, A/E ratio) and LV volume or mass.
- A significant correlation was observed between peak A velocities and LV muscle/cavity areas (r=0.81) and between peak A/E velocity ratios and LV muscle/cavity areas (r=0.80).
Conclusions:
- Trans-mitral flow velocities, particularly the A wave and A/E ratio, are significantly correlated with left ventricular muscle-to-cavity areas in hypertrophied hearts.
- These findings suggest that ventricular geometry plays a crucial role in shaping diastolic flow patterns, especially in conditions like aortic stenosis.
- Doppler echocardiography provides valuable insights into the interplay between cardiac structure and diastolic function.
Abstract:
We examined the relationship between trans-mitral blood flow velocity and left ventricular volume in normal and hypertrophied hearts using cross-sectional Doppler echocardiography. We studied 10 normal subjects and 19 patients with left ventricular hypertrophy, 9 with aortic stenosis and 10 with dilated cardiomyopathy. Trans-mitral Doppler flow velocity signals and cross-sectional echocardiograms of the left ventricular short and long axes were digitized in each patient to obtain instantaneous mitral flow velocity, instantaneous left ventricular volume, left ventricular mass, and left ventricular mass/volume ratio at end-diastole. Peak velocities during rapid filling (E wave) were similar in all three groups. Peak velocities during atrial systole (A wave) were significantly increased in aortic stenosis, (124 +/- 28 cm/sec); but were not different from normal in dilated cardiomyopathy (43 +/- 20 cm/sec versus 32 +/- 9 cm/sec). The peak A/E velocity ratio was elevated in aortic stenosis 1.47 +/- 0.30, but in dilated cardiomyopathy it was similar to normal hearts (0.47 +/- 0.23 versus 0.54 +/- 0.15). The percentages of left ventricular filling achieved at the time of the peak E wave, the end of rapid filling, and at the time of the peak A wave were similar in all three patient groups. There was no correlation between blood flow velocities at peak E wave, peak A wave or the A/E velocity ratio and left ventricular volume or mass. There was a significant correlation between peak A velocities and left ventricular muscle/cavity areas (r = 0.81; P less than 0.001). There was a similarly close correlation between the peak A/E velocity ratios and left ventricular muscle/cavity areas (r = 0.80; P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)