A novel echocardiographic method closely agrees with cardiac magnetic resonance in the assessment of left ventricular function in infarcted mice

Figure 1. ECHO pLAX and ECHO pSAX methods. Schematic representation of ECHO pLAX (A) and ECHO pSAX (B) acquisition. (A) 2D ECHO cine-loops were taken from parasternal long axis view and endocardial diastolic and systolic areas were traced according to the maximal and minimal LV expansion. (B) transducer was rotated approximately 90 degrees clockwise from the parasternal long axis until left ventricle appeared circular. Serial cine-loops of 2D images from parasternal short axis view were acquired from base to apex by translating the ultrasound probe by 1 mm using a customized system. The figure was drawn using Servier Medical Art (https://smart.servier.com).

Figure 2. ECHO and CMR images. In vivo echocardiographic images of infarcted heart taken from 2D parasternal long axis (A) and from serial consecutive parasternal short axis (B) and used to apply the ECHO pLAX and the ECHO pSAX methods, respectively. Both echocardiographic methods were used to calculate LV volumes and ejection fraction and were compared to CMR (C). Corresponding ex-vivo photographs of anterior and posterior walls of the left ventricle in corresponding animals are presented in the bottom of the panel. AW, anterior wall; FW, free wall; IVS, interventricular septum; LV, left ventricle; PW, posterior wall; HLA, horizontal long axis; MID-PAP, mid-papillary level; VLA, vertical long axis. *Indicates papillary muscles.

Figure 3. Acquisition time. Comparison between ECHO and CMR imaging duration considering all 34 animals. Data are expressed as mean ± SE. P value from Student’s t-test.

Figure 4. Bland and Altman plots for SHAM and CAL mice. The agreements between CMR and ECHO pLAX (A,C) and between CMR and ECHO pSAX (B,D) in SHAM and CAL mice are presented. See corresponding Table 3 for each mean difference. Single CMR and ECHO parameters are presented in Table 2.