Electrical and morphological changes of cardiac pressure over-load left ventricular hypertrophy in rabbits
10.16781/j.0258-879x.2017.01.0066
- Author:
Gui-Zhi LIU
1
Author Information
1. Department of Physical Diagnosis, First Affiliated Hospital of Zhengzhou University
- Publication Type:Journal Article
- Keywords:
Echocardiography;
Electrocardiography;
Left ventricular hypertrophy;
Pressure over-load
- From:
Academic Journal of Second Military Medical University
2017;38(1):66-73
- CountryChina
- Language:Chinese
-
Abstract:
Objective To observe whether the changes of electrocardiogram (ECG) is earlier than the morphological changes of ultrasonic cardiogram (UCG) during the development of cardiac pressure over-load left ventricular hypertrophy (LVH) in rabbits, so as to discuss the value of ECG in the early diagnosis of hypertensive LVH. Methods Forty male Japanese rabbits were randomly divided into experimental group (n=25) and control group (n=15). Rabbits in the experimental group were used to establish cardiac pressure over-load LVH model by subtotal ligation of suprarenal abdominal aorta. The control group received the same treatment as that in the experimental group except for the coarctation of abdominal aorta. Before operation and the 2nd, 4th, 6th, and 8th week after operation, 12-lead ECG were recorded to measure R-wave and QRS complex wave amplitude, heart electric axis, QRS duration and QTc period; UCG was performed to detect the thickness of left ventricular inferior wall (LVIW), posterior wall (LVPW) and interventricular septum (IVS), left ventricular end diastolic diameter (LVDd), left ventricular end systolic diameter (LVDs), E/A ratio and left ventricular ejection fraction (LVEF). Before operation and the 8th week after operation, chest X-ray examination was performed to detect cardiothoracic ratio. Then all the rabbits were sacrificed. Left ventricular mass indices (LVMI) were measured and cardiac pathological examination was performed. Results The blood pressure of rabbits increased gradually after operation in the experimental group, the cardiothoracic ratio and LVMI aggrandized, and the cardiomyocytes hypertrophy, denaturalization or necrosis were observed under microscope in the experimental group. The thickness of LVIW, LVPW and IVS of rabbits in the experimental group increased gradually, and the E/A ratio decreased gradually, showing significant difference when compared to those of the control group at the 4th week (P<0.05). LVDd and LVDs of rabbits in the experimental group increased from the 4th week, and were significantly larger than that of the control group after the 6th week (P<0.05). LVEF of rabbits in the experimental group decreased gradually, showing significant difference when compared with the control group at the 8th week (P<0.05). R-wave and QRS complex wave amplitudes in II, III, aVF and chest leads in ECG of the experimental group increased gradually, and became significantly higher than those of the control group at the 2th week (P<0.05). QRS duration and QTc increased gradually after operation, showing significant difference compared to that of the control group at the 4th week (P<0.05). The above mentioned indices had no significant change before or after operation in control group (P>0.05). Conclusion During the development of cardiac pressure over-load LVH of rabbits, the electrical changes of ECG are earlier than the morphologic changes of UCG, which indicates that ECG may has a value for early diagnosis of the hypertensive LVH.
