Postresuscitation myocardial dysfunction: correlated factors and prognostic implications

Objective: To evaluate the clinical factors correlated with postresuscitation myocardial dysfunction and the prognostic implication such dysfunction may have. Design and setting: Prospective observational study in a university medical center Patients: 58 adult patients successfully resuscitated from nontraumatic out-of-hospital cardiac arrest over 2 years. Measments and results: Echocardiographic evaluation of the left ventricular systolic and diastolic functions was performed 6 h postresuscitation and was analyzed in correlation to the clinical features and resuscitation factors. Univariate analysis revealed left ventricular ejection fraction (LVEF) to be significantly lower in patients with hypertension, past history of myocardial infarction, resuscitation duration longer than 20 min, defibrillation, and use of more than 5 mg epinephrine. Isovolumic relaxation time (IVRT) was significantly longer in patients with noncardiac cause and initial rhythm of nonventricular fibrillation/ tachycardia. Multiple regression analysis showed epinephrine dose and past history of myocardial infarction to be independent factors for LVEF, while the cause of cardiac arrest was independently associated with IVRT. For prognosis, 27 patients survived to hospital discharge. Both LVEF under 40% and IVRT 100 ms or longer were associated with poor survival outcomes. In Cox regression analysis IVRT 100 ms or longer served as an independent factor predicting poor survival prognosis. Conclusions: Postresuscitation left ventricular dysfunction is correlated with a number of clinical factors, among which past history of myocardial infarction, epinephrine dose, and the cause of cardiac arrest play independent roles. Meanwhile, IVRT 100 ms or longer 6 h postresuscitation predicts poor survival outcomes and serves as a marker of poor prognosis.