虚血性心疾患における運動負荷時のdynamic systolic time intervals の臨床評価に関する研究
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概要
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With the purpose to estimate the left ventricular reserve function in the ischemic heart disease, easily and noninvasively, sequential measurement of the systolic time intervals (STI) as undertaken before, during and after double Master's two step exercise test and these were designated as dynamic systolic time intervals (DSTI). Measurement of DSTI was made with Ear Densitogram, which closely correlated with carotid pulse wave. DSTI were studied in the ischemic heart disease and compared with the findings in the left ventriculography, coronary angiography and the factors to affect DSTI were studied and following results were obtained. 1) Rate of shortening in PEP and rate of diminishment in PEP/ET by the exercise test were less in the ischemic heart disease, if compared to the normal subjects and these response patterns provided the possibilities to assess the left ventricular reserve function. 2) The value of PEP at 10 minutes after completing exercise was 99.0±3.1 msec in the normal group, 118.7 ±3.2 msec in the group with the ejection fraction exceeding 50% (PVFG) and 138.9±4.7 msec in the group with ejection fraction less than 50% (DVFG) in the ischemic heart disease, respectively, while PEP lET was 0.418±0.014, OA98±0.019 and 0.658±0.025 in the normal, PVFG and DVFG, respectively. Namely, PEP/ET was significantly larger at the standing position in the ischemic heart disease, if compared with normal group, and marked statistical difference was noted among each group. Both indices of PEP and PEP/ET had close correlation with EF, r=-0.725 and r=-0.77 (P<0.001) respectively. From the above findings, even though the indices of PEP and PEP lET were affected by preload, afterload and sympathetic activity and appear to be insufficient to be an index to specifically reflect the myocardial ischemia, both indices at the late recovery phase, 10 minutes after exercise could provide the possibilities to estimate the effects of myocardial ischemia. 3) Response pattern of the delta ETI (difference of ETI from the pre-exercise level) was observed to reveal the maximal value at 1 minute during the Master's exercise test, while it was constantly increasing during whole period of exercise in the group of documented left ventricular aneurysm or the group to reveal the ST elevation by the exercise test. Thus the delta ETI 1'→3', namely the difference of ETI at 1 minute and 3 minutes during Master's exercise test was setted as a new index to be studied. Delta ETI 1'→3' was -7.3±1.3 in the normal, -2.7±1.3 in the PVFG and 7.1±2.3 in DVFG, respectively. The group of multi vessel disease indicated 3.1 ±2.2, while the group of single vessel disease showed -6.0±3.9. △ETI 1'→3' was significantly larger in the severe ischemic heart disease than normals. This index was -3.3±2.0 and -4.3±2.3 before and after administration of beta-blocking agents whose difference was statistically insignificant. Delta ETI 1'→3' in the hypertensive group With PEP/ET exceeding 0.4 at the supine resting was-10.6±5.8 which revealed no significant statistical difference from the normal controls. From the above findings, △ETI 1'→3' was concluded to be an index to detect the abnormal wall motion of the left ventricle due to the myocardial ischemia. It was concluded in this study that DSTI were clinically useful indices to assess the reserve function and severity of the ischemic heart disease.
- 神戸大学の論文