抄録
The time-left ventricular ejection phase volume curve (LV curve) obtained from a M-mode echocardiogram was best fitted on the quadratic function in the form of the non-linear least square method. New parameters derived from the quadratic analysis were compared among 28 healthy volunteers, 32 patients with ischemic heart disease and 9 with cardiac enlargement. The effects of 0.1 mg β-methyldigoxin, 10 mg nifedipine (sublingual), physical exercise (cycle ergometory) and 20 mg propranolol (administered before physical exercise) on the parameters were analyzed in 19 patients and 8 healthy volunteers. The parameters obtained from the study can be explained as follows:
1) a (cm3/s2): Acceleration factor. β-methyldigoxin increased “a”, while propranolol inhibited the exercise induced increase. “a” was most influenced by cardiac contractility. The average in normal subjects was 883.4 + 281.2 cm3/s2.
2) b (cm3/s): Velocity factor. Quadratic analysis showed the velocity was largest at the beginning of systolic ejection. The value was usually negative. (-480.2 + 23.2 cm3, in normal subjects).
3) c (cm3): End diastolic volume. (90.2 + 23.2 cm3, in normal subjects).
4) EFref: This was similar to the ejection fraction (EF), but more characteristic in expressing LV curvature. (0.46 + 0.06, in normal subjects).
5) MNSERref: This was similar to the mean normalized systolic ejection rate (MNSER). Both parameters were characterized by a “Time” factor, but MNSERref was easily detected. (1.89 + 0.23, in normal subjects).
6) MNSEHE (P/(SV·tl)): This was the most distinctive among the new parameters in this study. P/(SV⋅tl) was the only parameter which expressed hysteresis of the LV curve. This level was increased by β-methyldigoxin in patients with congestive heart failure. (0.14 + 0.04, in normal subjects).
