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[Left ventricular volume decrease during isovolumic relaxation period in gated blood pool scintigraphy: observations
T Furuta1, K Kodera, H Tabuchi
1Second Department of Internal Medicine, Kagoshima University School of Medicine.
Insights
In patients with old myocardial infarction (OMI), a specific left ventricular (LV) volume decrease during isovolumetric relaxation was linked to asynchronous LV relaxation. This finding aids in understanding OMI complications.
Area of Science:
- Cardiology
- Nuclear Medicine
- Cardiovascular Imaging
Background:
- Old myocardial infarction (OMI) can lead to complex left ventricular (LV) dysfunction.
- Gated blood pool scintigraphy (GBPS) is used to assess LV volume dynamics.
Purpose of the Study:
- To investigate the mechanism and clinical significance of LV volume decrease during isovolumetric relaxation in OMI patients.
- To correlate this phenomenon with wall motion abnormalities and abnormal diastolic flow.
Main Methods:
- Studied 113 OMI patients using GBPS, left ventriculography, and Doppler echocardiography.
- Analyzed time-activity curves from GBPS for LV volume changes during isovolumetric relaxation.
- Compared patients with (Group I) and without (Group II) the observed phenomenon.
Main Results:
- The LV volume decrease phenomenon was observed in 25% of anterior OMI patients.
- Group I showed significantly more dyskinetic/aneurysmal anterior/apical wall motion (85% vs. 39%) on ventriculography.
- Abnormal reversed LV flow during isovolumetric relaxation was more frequent in Group I (54% vs. 8%) via Doppler echocardiography.
Conclusions:
- The observed LV volume decrease is likely due to asynchronous LV relaxation.
- This phenomenon is a potential indicator of asynchronous relaxation in OMI patients.
Abstract:
We studied left ventricular (LV) volume decrease, namely, the downward displacement of the LV volume curve, during the isovolumic relaxation period on the time-activity curves obtained from gated blood pool scintigraphy in patients with old myocardial infarction (OMI). To evaluate the mechanism and clinical significance of this phenomenon, 113 consecutive patients with OMI undergoing gated blood pool scintigraphy, left ventriculography, and Doppler echocardiography were studied. 1. This phenomenon was observed only in patients with anterior OMI (13 of 51 patients: 25%). Presence (Group I) or absence (Group II) of this phenomenon was examined. 2. On left ventriculography, dyskinetic or aneurysmal wall motion was observed in the anterior or apical region more frequently in Group I (11 of 13 patients: 85%) than in Group II (20 of 51 patients: 39%) (p < 0.001). 3. Doppler echocardiography showed that the presence of abnormal LV reversed flow over 20 cm/sec from the apex to the base during the isovolumic relaxation period is more frequent in Group I (7 of 13: 54%) than in Group II (4 of 51: 8%) (p < 0.001). These results suggested that this blood shift in the left ventricle is attributed to asynchronous LV relaxation occurring simultaneously with LV volume decrease on gated blood pool scintigraphy. In conclusion, this phenomenon suggests the presence of asynchronous LV relaxation.