2001 Fiscal Year Final Research Report Summary
Evaluation of Cardiac Contractility by means of Q-D and D-S Time Intervals
| Project/Area Number |
12671496
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Anesthesiology/Resuscitation studies
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| Research Institution | Kyoto Prefectural University of Medicine |
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Principal Investigator |
TANAKA Yoshifumi Kyoto Prefectural University of Medicine, Anesthesiology, Professor, 医学部, 教授 (50079935)
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| Project Period (FY) |
2000 – 2001
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| Keywords | Cardiac Contractility / Continuous Measurement / ECG / Arterial Pressure / Q-D Interval / D-S Interval |
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| Research Abstract |
Q-D time is the time interval between the beginning of electrical Q wave in ECG and the period of diastolic pressure. It is regarded as the time lag of electrical action and mechanical action of the heart muscle. D-S time is the time interval between the period of the diastolic pressure and that of the systolic pressure. We measured both time intervals in patients undergoing the cardiac surgery.
In the normal cardiac condition, Q-D time and D-S time was almost 100 m second and these time intervals did not affected by the heart rate. When the patient was under the extra corporeal cardiac perfusion (ECC) with hypothermia, these time intervals extended two or three times significantly. Changes of D-S time was more significant compared with that of Q-D time.
Physical power of cardiac muscle is evaluated by multiplied value of force and duration time. Therefore the more the contractility of the heart muscle decreases, the more the duration time is needed for the ejection of the same amount of blood in the left ventricle. The cardiac work during Q-D time is regarded an accumulating the potential energy from the level of atrial pressure to that of diastolic pressure. There is no external work to the systemic circulation during Q-D time. D-S time is, however, obviously the loading time interval of the cardiac function. The stroke volume is ejected and the systemic blood pressure is increased from diastole to systole. Hence, we conclude that the load of cardiac muscle during the D-S time is heavier than that of during Q-D time.
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