Preliminary reference values for electrocardiography, echocardiography and myocardial morphometry in the European brown hare (Lepus europaeus)

Abstract

The study aimed at defining reference values for electrocardiographic (ECG) and echocardiographic parameters as well as macroscopic dimensions of the heart and microscopic dimensions of cardiomyocytes in the European brown hare. The studies were conducted on 30 adult, clinically healthy hares of either sex caught in Poland. ECG and echocardiography were performed supravitally on anaesthetized hares. After euthanasia, gross and microscopic myocardial and cardiomyocyte dimensions were determined. Heart rate amounted to 140 ± 37.5 beats/min, the leading rhythm involved the sinus rhythm. P wave time was 26 ± 5 ms, PQ time was 80 ms, QRS time was 29 ± 3.5 ms, and ST was 97.5 ± 7 ms. Echocardiography determined a left ventricular wall end-diastolic diameter of 8.6 ± 2.0 mm and an intraventricular septum end-diastolic diameter of 5.75 ± 1.0 mm. The thickness of the interventricular septum corresponded to that of the free wall of the left ventricle, a finding consistent with physiological hypertrophy. Preliminary reference values were established for echocardiography. The findings were similar to those obtained at necropsy. The ECG and echocardiographic studies represent the first supravital examination of cardiac function in the hare. The obtained results illustrate adaptation of hare's myocardium to its mode of life. The cardiac findings resemble the athlete's heart syndrome described in humans. The findings may prove useful in further studies on the physiology of the cardio-vascular system in the hare. FindingsStudies on the physiology of the European brown hare (Lepus europaeus) have focused on organ morphology, blood biochemical parameters, methods of blood sampling, coagulation parameters and cardiovascular disorders [1][2][3][4][5][6]. Physiological and morphological studies of the heart have not been performed, so the electrocardiographic (ECG) and echocardiographic variables remain unknown. Also, cardiomyocyte morphology remains to be reported.

Normal Values for Heart Electrophysiology Parameters of Healthy Swine Determined on Electrophysiology Study

“…To this date, normal values for electrocardiographic (ECG) parameters were published for brown hares [5], dogs [6], cats [7], and swine [8], and the reference values for echocardiographic parameters were established for dogs [9], cattle [10], ferrets [11], sheep [12], monkeys [13], Syrian hamsters [14], mice [15], rats [16], and swine [8]. However, despite the widespread use of porcine models in experimental electrophysiology, still no reference values for intracardiac electrical activity and conduction parameters determined during an invasive electrophysiology study (EPS) have been developed in this species thus far.…”

Thoracic cage plasticity in prepubertal New Zealand white rabbits submitted to T1–T12 dorsal arthrodesis: computed tomography evaluation, echocardiographic assessment and cardio-pulmonary measurements

“…At completion of skeletal maturity CD was reduced in operated compared to sham-operated rabbits (p \ 0.05) %FS and EF (p \ 0.05). Echocardiographic data were all within normal limits [35,36].…”

“…However, operated rabbits showed a tendency to have greater PaO 2 reduction and PaCO 2 increase compared to sham-operated rabbits, thus highlighting a possible modification of gas exchanges. Furthermore, %FS and EF were significantly higher in operated rabbits, but remained within the normal range [36,37]. Rabbits were housed in stainless steel cages, in compliance with national and international animal care regulations.…”

Chronic liquid nutrition feeding affects blood pressure, heart and kidney morphology, and serum lipid profile in Wistar rats

“…Diameter of cardiomyocytes was measured along a line intercepting the cell nucleus in 100 cells per animal (Farah et al 2009). Length of the cardiomyocyte nucleus was measured along a line that intercepted the respective nucleus in 100 cells per animal (Noszczyk-Nowak et al 2009). The wall thickness of the aorta (tunica intima and tunica media) was measured and the mean values were calculated from 10 measurements per each rat.…”