Early prediction of 30-day mortality after Q-wave myocardial infarction by echocardiographic assessment of left ventricular function--a pilot investigation

A new simplified immediate prognostic risk score for patients with acute myocardial infarction

BACKGROUND

Immediate risk stratification of patients with myocardial infarction in the emergency department (ED) at the time of initial presentation is important for their optimal emergency treatment. Current risk scores for predicting mortality following acute myocardial infarction (AMI) are potentially flawed, having been derived from clinical trials with highly selective patient enrollment and requiring data not readily available in the ED. These scores may not accurately represent the spectrum of patients in clinical practice and may lead to inappropriate decision making.

METHODS

This study cohort included 1212 consecutive patients with AMI who were admitted to the Mayo Clinic coronary care unit between 1988 and 2000. A risk score model was developed for predicting 30 day mortality using parameters available at initial hospital presentation in the ED. The model was developed on patients from the first era (training set--before 1997) and validated on patients in the second era (validation set-during or after 1997).

RESULTS

The risk score included age, sex, systolic blood pressure, admission serum creatinine, extent of ST segment depression, QRS duration, Killip class, and infarct location. The predictive ability of the model in the validation set was strong (c = 0.78).

CONCLUSION

The Mayo risk score for 30 day mortality showed excellent predictive capacity in a population based cohort of patients with a wide range of risk profiles. The present results suggest that even amidst changing patient profiles, treatment, and disease definitions, the Mayo model is useful for 30 day risk assessment following AMI.

Echocardiographic comparison of cardiopulmonary resuscitation (CPR) using periodic acceleration (pGz) versus chest compression

OBJECTIVE

This investigation compared the effects of conventional cardiopulmonary resuscitation (CPR) using an automated Thumper chest compression device to periodic acceleration CPR (pGz-CPR) on early post-resuscitation ventricular function assessed by echocardiography, in an adult pig model of CPR.

BACKGROUND

Whole body periodic acceleration along the spinal axis (pGz) is a new method of cardiopulmonary resuscitation (CPR). Biomechanical forces and biochemical release produced by pGz impart ventilation and increase blood flow. Our laboratory has reported normal neurological and cardiovascular function 48 h after return of spontaneous circulation in animals that have undergone 22 min of pGz-CPR.

METHODS

Ventricular fibrillation (VF) was induced in 16 animals (25-35 kg). After 3 min of non-interventional period, the animals were randomized to receive either pGz-CPR or Thumper-CPR for 15 min. After 18 min of VF, a single dose of vasopressin and bicarbonate were administered and defibrillation attempted. An echocardiogram was performed at baseline and serially for 6h. Ejection fraction (EF), fractional shortening (FS) and wall motion were assessed by 2D and M-mode echocardiography.

RESULTS

Return of spontaneous circulation to 360 min occurred in 5/8 (62%) of the animals receiving Thumper-CPR and in 7/8 (88%) receiving pGz-CPR. FS and EF were impaired after CPR, but pGz-CPR animals had less impairment than Thumper-CPR animals. Further, wall motion score index (WMSI) was more impaired after Thumper-CPR and remained as such even 6h post-CPR.

CONCLUSION

pGz holds promise as a new method for CPR with better left ventricular (LV) function post-CPR than the more traditional chest compression method.

Specific tissue Doppler predictors of preserved systolic and diastolic left ventricular function after an acute anterior myocardial infarction

The degree of left ventricular (LV) dysfunction determines the outcome of patients suffering an acute anterior myocardial infarction (AAMI). Many recent studies have utilized tissue Doppler echocardiography (TDE) parameters in the assessment of LV function. We sought to investigate whether some variables easily obtained from TDE profiles of mitral annulus corners would predict a relatively preserved LV global function traditionally assessed with ejection fraction (EF) and deceleration time (DT), within the acute phase of AAMI. Included were 50 consecutive patients with a first AAMI. Standard echocardiography and TDE of mitral annulus were performed within 36 hours of admission. Pulsed wave sample volumes were set at the septal, lateral, anterior, and inferior corners of the mitral annulus. Preserved LV function was defined as an EF > 40% together with a DT > or = 140 ms and < 220 ms. An inferior annular systolic velocity of > 7.5 cm/s predicts preserved global left ventricular function with a sensitivity of 81% and specificity of 71%. An anterior mitral annular early diastolic velocity of > 8cm/s had a sensitivity of 69% and specificity of 85%. When these two velocities both exceed the limits above, such a combined index yielded a sensitivity of 69%, specificity of 94%, and an overall diagnostic accuracy of 86% for the estimation of preserved LV global function. The parameters derived from TDE profiles of inferior and anterior mitral annulus comers provide valuable information to predict preserved global left ventricular function during the early period of AAMI.