Functional and histological assessment of an experimental model of Takotsubo's cardiomyopathy.
Bottom Line: Pretreatment with propranolol and metoprolol improved survival to 90% and 100% respectively, compared with 60% in the ISO group, but did not reduce the incidence and extent of akinesis or the structural damage.TC can be mimicked in a rat model of ISO exposure that demonstrates apical akinesis on days 2 to 3 with full recovery of systolic regional wall motion abnormality despite the presence of persistent foci of necrosis and fibrosis on day 8.Pretreatment with beta-blockers improved survival but did not affect structural and functional alterations.
Affiliation: Heart Institute of Good Samaritan Hospital and Division of Cardiovascular Medicine of the Keck School of Medicine, University of Southern California, Los Angeles, CA (J.S., W.D., R.A.K.).Show MeSH
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Mentions: To determine the time course of recovery of wall motion abnormalities and whether it was affected by percentage of akinesis, 8 ISO‐treated rats that showed apical akinesis on echo 24 hours after the last dose of ISO were monitored and sacrificed after 1 week. In the ISO‐treated group, 4 rats of the akinesis ≥10% subgroup (larger akinetic LV circumference) and 4 of the akinesis <10% subgroup (smaller akinetic LV circumference) were included. One week post‐ISO, echocardiography revealed normal wall motion in all of the ISO‐treated rats irrespective of the percent akinesis at 24 hours. Noticeably, apical FS was markedly increased whereas the basal FS was similar as compared with the control group (Figure 3C and 3D). Hemodynamic parameters such as Pes, Ped, and +dP/dt were comparable with the control group, whereas, MAP and −dP/dt remained significantly decreased (P<0.05) at 1 week post‐ISO. Heart rate was significantly depressed (P<0.05) in the akinesis ≥10% subgroup (Table 4). Despite the full recovery of the wall motion abnormality, histopathological analysis showed widespread necrosis, interstitial edema, inflammatory cells infiltration and vacuoles in the ISO‐treated rats (Figure 8). The semi‐quantitative score for picrosirius red staining was 3.5 [2.0] in the ISO‐treated group which indicates marked collagen deposition (Figure 5C, Table 6).
Affiliation: Heart Institute of Good Samaritan Hospital and Division of Cardiovascular Medicine of the Keck School of Medicine, University of Southern California, Los Angeles, CA (J.S., W.D., R.A.K.).