"Mirror-lake" serial relationship of electrocardiographic and biochemical indices for the detection of reperfusion and the prediction of salvage in patients with acute myocardial infarction

Background

Serial observations of biochemical markers in the blood and bioelectric markers on the electrocardiogram (ECG) have been used to evaluate the effectiveness of reperfusion therapy in acute myocardial infarction (AMI). This study presents a combined method for clinical use, based on the “mirror-lake” tendency of the serial changes in these markers.

Methods

Consecutive thrombolytic-treated patients with AMI (n = 43) had ST-segment monitoring (Mortara Eli 100) and frequent serum sampling of myoglobin (MG) concentration. Their acutely predicted and finally estimated AMI sizes and myocardial salvage extents were calculated from the 12-lead standard ECG. Patients having 2 positive reperfusion indices (ST resolution at least 50%, and an increase in MG at least 2.4 fold) at 2 hours after initiation of thrombolytic therapy were considered the “complete reperfusion” group, and patients with discordant or 2 negative reperfusion indices after 2 hours of thrombolytic therapy were considered the “limited reperfusion” group.

Results

Patients with complete reperfusion (n = 22) versus patients with limited reperfusion (n = 21) had +12% versus −1% myocardial salvage (P < .0001). The serial changes in the ST segment mirrored the serial changes in the MG concentration, and the rates of increase in MG correlated with the rates of resolution of the ST-segment elevation.

Conclusion

Myocardial salvage (measured by ECG indices) is greatest when an early increase in serum MG is “mirrored” by early resolution of ST-segment elevation.     

Relative contributions of a single-admission 12-lead electrocardiogram and early 24-hour continuous electrocardiographic monitoring for early risk stratification in patients with unstable coronary artery disease

Patients with unstable coronary syndromes are a heterogeneous group with varying degrees of ischemia and prognosis. The present study compares the prognostic value of a standard electrocardiogram (ECG) obtained at admission to the hospital with the information from 24-hour continuous electrocardiographic monitoring obtained immediately after admission. The admission ECGs and 24 hours of vectorcardiographic (VCG) monitoring from 308 patients admitted with unstable coronary artery disease were analyzed centrally regarding standard electrocardiographic ST-T changes, ST-vector magnitude (ST-VM), and ST change vector magnitude episodes. End points were death, acute myocardial infarction, and refractory angina pectoris within a 30-day follow-up period. ST-VM episodes (> or = 50 microV for > or = 1 minute) during VCG monitoring was the only independent predictor of death or acute myocardial infarction by multivariate analysis. ST-VM episodes during vectorcardiography was associated with a relative risk of 12.7 for having a cardiac event, hypertension was associated with a relative risk of 1.7, and ST depression on the admission ECG was associated with a relative risk of 5.7. Patients with ST depression at admission had an event rate (death or acute myocardial infarction) of 17% at 30-day follow-up. Patients without ST depression could further be risk stratified by 24 hours of VCG monitoring into a subgroup with ST-VM episodes at similar (8%) risk and a subgroup without ST-VM episodes at low (1%) risk (p = 0.00005). Continuous VCG monitoring provides important information for evaluating patients with unstable coronary artery disease. It is recommended that patients not initially estimated at high risk based on the admission ECG are referred for 24 hours of VCG monitoring for further risk stratification.     

Cerebrospinal fluid creatine kinase isoenzyme BB levels do not predict the clinical outcome in patients unconscious following cardiac resuscitation

It has recently been claimed that an increase in creatine kinase isoenzyme BB(CK-BB) in cerebrospinal fluid (CSF) is well correlated with the cerebral outcome in patients resuscitated after cardiac arrest. Twenty-one such patients consecutively admitted from outside this hospital participated in the study. The patients were divided into two groups: 6 survivors and 15 nonsurvivors. The median CSF-CK-BB value was 5 U/L among nonsurvivors and below detection limit among survivors (NS). However, the predictive value of a positive test is limited, since only 6 of 15 nonsurvivors (40%) had an increase in CSF-CK-BB (predictive value of positive test = 67%). The predictive value of a negative test is limited, since 3 of 6 survivors (50%) showed no rise in CSF-CK-BB (predictive value of negative test = 25%). No relationship between cerebral dysfunction and CSF-CK-BB values was revealed. Thus, CSF-CK-BB does not predict the clinical outcome in patients resuscitated after cardiac arrest.     

Prehospital electrocardiographic acuteness score of ischemia is inversely associated with neurohormonal activation in STEMI patients with severe ischemia

Background

Elevated levels of N-terminal pro brain natriuretic peptide (NT-proBNP) are associated with adverse cardiovascular outcome after ST elevation myocardial infarction (STEMI). We hypothesized that decreasing acuteness-score (based on the electrocardiographic score by Anderson-Wilkins acuteness score of myocardial ischemia) is associated with increasing NT-proBNP levels and the impact of decreasing acuteness-score on NT-proBNP levels is substantial in STEMI patients with severe ischemia.

Serum myoglobin for the early non-invasive detection of coronary reperfusion in patients with acute myocardial infarction

The ideal non-invasive method for detectmg coronary reperfusionhas not yet been established. In 63 patients with acute myocardialinfarction, serum myoglobin and creatine kinase-MB were measuredevery 15mm. Thrombolytic treatment was given (n=52) and acutecoronary angiography showed a patent infarct-related arteryin 49 patients while 14 patients had no coronary reperfusion.Median time to peak serum myoglobin was shorter (reperfusiongroup 178 mm vs no reperfusion group 480 min, P<0·0001)than time to peak serum creatine kinase-MB (reperfusion group550 mm vs no reperfusion group 1080 min, P<0·0001),P<0·0001. Myoglobin appearance rate, calculated asthe concentration at 2 h divided by baseline values (Mb₂/Mb₀)was highest in the reperfusion group (4·0 vs 1·6),P<0·001. An earlier proposed index, Mb₂/Mb₀>2·4 for identificationof reperfusion 2 h after thrombolytic therapy, showed predictivevalues of positive and negative tests of 0·94 and 0·44,respectively. Combining this mdex with signs of medium to largerinfarct size (Mb₂>200 µg . 1^–1)increased thepredictive value of the negative test to 1·00. In patientswith signs of minor mfarcts (Mb₂ <200 .µg .1^–1)the predictive values of positive and negative tests were 0·94and 0·79 respectively, 5 h after onset of thrombolytictherapy. An early rise and a peak in serum myoglobin values seems tobe a reliable and simple non-invasive indicator of successfuland unsuccessful reperfusion therapy. (Eur Heart J 1996; 17: 399–406)