Early vectorcardiographic monitoring provides prognostic information in patients with ST-elevation myocardial infarction

The electrocardiographic reperfusion peak in patients with ST-elevation myocardial infarction

OBJECTIVES

To analyse the incidence and the prognostic value of the reperfusion peak in a population of patients with AMI treated with thrombolysis.

DESIGN

Two hundred and sixty-nine patients with ST-elevation myocardial infarction treated with thrombolysis were monitored with continuous on-line vectorcardiography.

RESULTS

A reperfusion peak defined as a transiently increased ST-VM of >50 microV followed by an immediate decrease to a level lower than the starting point was seen in 112 of all 269 (42%) patients and in 111 of 149 (75%) of the patients with successful ST-resolution. A reperfusion peak was an independent predictor of better prognosis both in the short- and the long term but had no implications on the prognosis in the subgroup with successful ST-resolution.

CONCLUSION

A reperfusion peak was equally common in patients treated with thrombolysis having a successful ST-resolution as observed in studies of patients with successful primary coronary angioplasty. The reperfusion peak was associated with better prognosis and should be recognised as a possible marker of successful reperfusion but can mimic aggravated ischemia.

Characterization of the location and extent of myocardial infarction using heart vector analysis

An innovative method was proposed on the basis of vectorcardiography to characterize the location and extent of moderate to large, relatively compact infarcts using ECG evidence. It is assumed that heart vector is proportional to relevant active depolarization area(s). The normal VCG was then used to examine our ideas based on the information of location, amplitude, and direction of heart vector at any instant that is included in it. The model-based comparison of cases under study and relevant normal VCGs gives region and extent of myocardial infarction. Three criteria were finally defined to evaluate the presented method based on Physionet database. EPD, which is the percentage discrepancy between the extent of the infarct as estimated from our proposed method and as determined from the gold standard. SO, which was defined as the overlap between the sets of infarct segments as estimated and as determined from the gold standard. And CED, which is the distance between the centroid (geometrical center) of the infarct as estimated from our method and as determined from the gold standard. Finally, we gained the values of EPD equal to 32, SO equal to 0.933 and CED equal to 1. The presented method is not applicable in cases of hypertrophy, Bundle Branch Block (BBB) and arrhythmia which can be a plan for future work.

The influence of acute-phase levels of haemostatic factors on reperfusion and mortality in patients with acute myocardial infarction treated with streptokinase

BACKGROUND

The fibrinolytic system and von Willebrand factor (vWF) have been shown to play a role as risk factors for myocardial infarction. We performed this prospective cohort study to determine if components in the fibrinolytic system or vWF before or during treatment of AMI with streptokinase (SK) could predict reperfusion, recurrent ischaemia, reinfarction or mortality at one year, or mortality at five years. Reperfusion and recurrent ischaemia were assessed by continuous vectorcardiography. The setting was Umeå university hospital and Skellefteå county hospital, Sweden.

RESULTS

139 patients were included; successful reperfusion was obtained in 53%. tPA activity, PAI-activity, PAI-mass concentration and vWF were analysed immediately on arrival and after 4 and 10 h. High fibrinolytic activity, measured as tPA activity > 25 U/L after the start of treatment, was associated with reperfusion. No significant associations between pre-treatment levels of the fibrinolytic variables or vWF and reperfusion or recurrent ischaemia were found. Elevated levels of PAI-1 mass concentration and PAI-1 activity after the start of SK treatment were associated with a higher risk for death at one year, but not at five years. High levels of vWF were associated with worse prognosis but not when corrected for age.

CONCLUSION

Pre-treatment levels of PAI-1, vWF and tPA activity showed no association with reperfusion or recurrent ischaemia. Elevated levels of PAI-1 activity after the start of treatment were associated with worse prognosis.