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Assessment of abnormal systolic intraventricular flow patterns by Doppler imaging in patients with left ventricular
P J Garrahy1, O L Kwan, D C Booth
1Division of Cardiovascular Medicine, University of Kentucky Medical Center, Lexington 40535.
Insights
Abnormal heart wall movement, known as left ventricular dyskinesis, causes paradoxical blood flow during systole. This abnormal flow correlates with reduced heart function, aiding diagnosis.
Area of Science:
- Cardiology
- Medical Imaging
- Physiology
Background:
- Limited data exist on how abnormal heart muscle contraction affects blood flow within the left ventricle.
- Color Doppler flow imaging now allows visualization of intraventricular blood flow patterns.
Purpose of the Study:
- To investigate intraventricular flow patterns using Doppler flow mapping in patients with varying degrees of left ventricular contraction abnormalities.
- To correlate Doppler findings with left ventriculography to assess regional and global left ventricular function.
Main Methods:
- Doppler flow mapping was performed on 41 patients: 12 with normal contraction, 8 with hypokinesis/akinesis, and 21 with dyskinesis.
- Findings were compared with left ventriculography to evaluate regional wall motion and ejection fraction.
Main Results:
- Normal contraction showed flow through the left ventricular outflow tract to the aorta.
- Paradoxical systolic flow toward abnormal segments was observed in 18/21 patients with dyskinesis, persisting for 77% of systole on average.
- Paradoxical flow was seen in 2/5 patients with akinesis but none with hypokinesis.
- The duration of paradoxical flow strongly correlated with regional wall motion (r=0.77) and global ejection fraction (r=0.79).
Conclusions:
- Paradoxical systolic flow is detectable in most patients with left ventricular dyskinesis.
- The presence and duration of paradoxical flow correlate with the severity of regional and global left ventricular dysfunction.
- Doppler flow mapping is a valuable tool for assessing the functional consequences of abnormal left ventricular contraction.
Abstract:
Few data exist regarding the consequences of abnormalities of segmental contraction on intraventricular flow patterns. The development of color Doppler flow imaging has now permitted the visualization of intraventricular blood flow patterns. Therefore, we performed Doppler flow mapping in 41 patients (12 with normal left ventricular contraction, eight with hypokinesis or akinesis, and 21 with dyskinesis) and compared these findings with left ventriculography. Systolic blood flow by Doppler mapping in subjects with normal ventricular contraction was characterized primarily by flow through the left ventricular outflow tract and into the aorta. In patients with dyskinesis, paradoxical systolic flow toward the abnormal segment was present, and persisted for at least 50% of systole in 18 of 21 patients. Mean duration of paradoxical flow in dyskinetic patients was 77% of systole. Paradoxical flow was also observed in two of five patients with akinesis but in no patients with hypokinesis. A good correlation was observed between the duration of paradoxical systolic flow and indexes of regional wall motion (radian shortening of the involved myocardium) (r = 0.77) and global ejection fraction derived from cineangiography (r = 0.79). Correlations between the area of the paradoxical systolic flow stream in midsystole and indexes of left ventricular function were less close, with r equaling 0.57 for both regional wall motion and ejection fraction. Thus, paradoxical systolic flow can be detected in most patients with left ventricular dyskinesis, and correlates with the magnitude of regional and global left ventricular dysfunction by cineangiography.