Figure 1.
Representative slides of MRI and echocardiography-gained heart slides.
Short axis view gained with A) MRI and D) echocardiography. Seven short axis slices were used for calculation of left ventricular volumes with MRI. B) Shows MRI-gained and E) echocardiography-gained long axis view. C) Shows 4-chamber view (MRI). F) Shows M-mode based calculation of LVEF (echocardiography). LV: left ventricle; RV: right ventricle; LA: left atrium; RA: right atrium; Ao: aorta.
Table 1.
Left ventricular function parameters of CVB3-infected mice compared to age matched healthy controls at baseline.
Table 2.
Comparison of MRI devices and results on cardiac function in small animals and in humans.
Figure 2.
Echocardiography confirms values obtained by MRI.
A) Echocardiography was able to reproduce the low LVEF values we obtained from MMF anesthetized mice investigated by MRI. B) Heart rates (HR) and C) cardiac output (CO) measured by our Vevo2100 system did not significantly differ from those in the MRI study. D) Anesthesia with isoflurane revealed the cardiodepressive effects of MMF. n.s.: not significant; **: p<0.01; ***: p<0.001.
Figure 3.
Anesthesia with isoflurane reduces variability of data.
Compared to MMF, isoflurane is able to reduce the variability of the results. Additionally, isoflurane at higher concentrations than commonly used might further reduce the variability of heart rate and heart rate dependent values such as cardiac output and cardiac index. However, compared with lower isoflurane concentrations (1.75%), high isoflurane concentrations (3%) show no significant cardiodepressive effects. A) Shows percentual standard deviations of single cycle values, and B) of mean values (average of 3 consecutive cycles). (C) Shows percentual standard deviations for cardiac output and cardiac index obtained with either MMF, 1.75% isoflurane or 3% isoflurane. D) Shows heart rate, E) cardiac output and F) cardiac index under different anesthetic regimens. EF = LVEF, EDV = end diastolic volume, ESV = end systolic volume, SV = stroke volume, HR = heart rate, CO = cardiac output, CI = cardiac index. 100 µl MMF: n = 6, 1.75% isoflurane and 3% isoflurane: n = 7. ***: p<0.001.
Table 3.
Left ventricular function parameters in healthy mice under different anesthetic regimen.
Figure 4.
Calculation of an average LVEF value reduces variability of data independently from the anesthetic regimen.
For evaluation of cardiac function parameters, 3 consecutive cycles were measured and averaged. Mean values showed a reduced variability compared to values obtained by single cycle measurements. A) Shows single cycle and mean values for the group anesthetized with 1.75% isoflurane, B) for the group anesthetized with 3% isoflurane and C) for the group anesthetized with 100 µl MMF. EF = LVEF, EDV = end diastolic volume, ESV = end systolic volume, SV = stroke volume, HR = heart rate, CO = cardiac output, CI = cardiac index. 100 µl MMF: n = 6, 1.75% isoflurane and 3% isoflurane: n = 7.