Post-cardiac arrest temporal evolution of left ventricular function in a rat model. Speckle tracking Echocardiography and cardiac circulating biomarkers

There is little information from experimental studies regarding the evolution of post-resuscitation cardiac arrest (post-ROSC) myocardial dysfunction during mid-term follow-up. For this purpose, we assessed left ventricular (LV) function and circulating cardiac biomarkers at different time points in a rat model of cardiac arrest (CA). Rats were divided into two groups: control and post-ROSC rats. Eight min of untreated ventricular fibrillation were followed by 8 min of CPR. Conventional and speckle tracking (STE) echocardiographic parameters and cardiac circulating biomarkers concentrations were assessed, at 3-4-72-96h post-ROSC. At 3-and-4h post-ROSC LV systolic function resulted severely impaired and hs-cTnT and NT-pro ANP plasma concentrations were significantly increased, compared to control rats (p<0.0001 for all). At 72 and 96h post-ROSC left ventricular ejection fraction (LVEF) normalized. At 96h, the following variables were significantly different from control rats: early-trans-mitral-peak-velocity, 56.8 ± 3.1 vs. 87.8 ± 3.8 cm/sec, p<0.0001; late-trans-mitral-peak-velocity, 50.6±4.7 vs. 73.7±4.2 cm/sec, p<0.0001; mean s’ wave velocity, 4.6±0.3 vs. 5.9±0.3 cm/sec, p<0.0001, global longitudinal strain (GLS) -7.5±0.5 and vs. -11±1.2%, p<0.01, global longitudinal strain rate (GLSR): -0-9±0.4 and -2.3±0.2 1/sec, p<0.01 and NT-proANP concentration, 2.5[0.2; 6.0] vs 0.4 [0.01; 1.0] nmol/L, p<0.01. s’ velocity, GLS and GLSR, indicated that LV systolic function was still impaired 96h post-ROSC. These findings agree with NT-proANP concentrations which continue high. Normalization of LVEF supports the use of STE for its greater sensitivity for monitoring post-CA cardiac function. Further investigations are needed to provide evidence of the post-ROSC LV diastolic function pattern.