Investigation of Myocardial Stunning after Cardiopulmonary Resuscitation in Pigs

Key words: 
• Myocardial stunning /
• Systolic and diastolic dysfunctions /
• Cardiopulmonary resuscitation

Abstract: Objective To investigate cardiac function and myocardial perfusion during 48 h after cardiopulmonary resuscitation (CPR), further to test myocardial stunning and seek indicators for long-term survival after CPR. Methods After 4 min of untreated ventricular fibrillation, fifteen anesthetized pigs were studied at baseline and 2 h, 4 h, 24 h, and 48 h after restoration of spontaneous circulation (ROSC). Hemodynamic data, echocardiography and gated-single photon emission computed tomography myocardial perfusion images were carried out. Results Mean arterial pressure (MAP), coronary perfusion pressure (CPP) and cardiac troponin I (CTNI) showed significant differences between eventual survival animals and non-survival animals at 4 h after ROSC (109.2±10.7 mmHg vs. 94.8±12.3 mmHg, P=0.048; 100.8±6.9 mmHg vs. 84.4±12.6 mmHg, P=0.011; 1.60±0.13 ug/L vs. 1.75±0.10 ug/L, P=0.046). Mitral valve early-to-late diastolic peak velocity ratio, mitral valve deceleration time recovered 24 h; ejection faction and the summed rest score recovered 48 h after ROSC. Conclusion Cardiac systolic and early active relaxation dysfunctions were reversible within survival animals; cardiac stunning might be potentially adaptive and protective after CPR. The recovery of MAP, CPP, and CTNI could be the indicators for long-term survival after CPR.