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Electrocardiographic predictors of clinical outcome in ST-elevation myocardial infarction

Demidova, Marina LU (2015) In Lund University Faculty of Medicine Doctoral Dissertation Series 2015:88.
Abstract
Malignant ventricular arrhythmias, particularly ventricular fibrillation (VF), remain an important contributor to mortality in

ST-elevation myocardial infarction (STEMI). The size of myocardial injury is one more important factor influencing the

prognosis of STEMI patients. The search for new non-invasive markers, which can be relatively simply calculated using

conventional ECG recording and can predict the degree of myocardial injury and impending VF, is promising. This work is

aimed at investigating cardiac repolarization and depolarization abnormalities and predictors and prognosis of ventricular

arrhythmias during the course of STEMI.

The thesis is composed of the experimental part... (More)
Malignant ventricular arrhythmias, particularly ventricular fibrillation (VF), remain an important contributor to mortality in

ST-elevation myocardial infarction (STEMI). The size of myocardial injury is one more important factor influencing the

prognosis of STEMI patients. The search for new non-invasive markers, which can be relatively simply calculated using

conventional ECG recording and can predict the degree of myocardial injury and impending VF, is promising. This work is

aimed at investigating cardiac repolarization and depolarization abnormalities and predictors and prognosis of ventricular

arrhythmias during the course of STEMI.

The thesis is composed of the experimental part (Studies I, II, III) and clinical register-based retrospective studies (Studies IV

and V). Closed-chest porcine model of myocardial infarction (MI) was used in the experimental part. Occlusion of left

descending artery (LAD) lasted 40 minutes and was followed by reperfusion, and ECG was continuously recorded. QRSduration

and morphology, dynamics of ST-segment and T-wave alternans (TWA) were calculated, and myocardial area at

risk (MaR) and infarct size (IS) were assessed. Predictors and prognostic impact of early VF in STEMI was assessed in a

register-based study of 1,718 consecutive patients admitted for primary PCI during 2007-2009 who were followed up for

one year.

In experimental MI, the maximal level of TWA during occlusion period was associated with both MaR and IS (Study II).

Rapid and marked transient increase in QRS duration associated with appearance of J-wave pattern predicted impending VF

in acute ischemia (Study III). Restoration of blood flow in infarct-related artery was accompanied by reperfusion peak in all

animals, and the magnitude of ST elevation at reperfusion peak was associated with infarct size (Study I). In clinical studies

IV and V, the risk of VF in acute period of STEMI was higher in patients with MI history, cardiovascular risk factors such as

smoking and left main stenosis, resulting in a large infarct area. Besides MI history and left main stenosis, the risk of VF at

reperfusion was associated with inferior localization of STEMI, hypokalemia, high ST-elevation and shorter symptom-toballoon

time. The magnitude of ST-elevation before PCI for STEMI independently predicted reperfusion VF. Patients

successfully resuscitated after VF and alive at 48 hours had higher in-hospital mortality (12% vs. 2%, p<0.001). However, in

VF patients who were discharged alive, 1-year mortality did not differ compared with patients without VF (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Lombardi, Federico, University of Milan
organization
publishing date
type
Thesis
publication status
published
subject
in
Lund University Faculty of Medicine Doctoral Dissertation Series
volume
2015:88
pages
79 pages
publisher
Cardiology, Clinical Science, Lund, Lund University
defense location
Segerfalksalen, Wallenberg Neurocentrum, BMC A10, Sölvegatan 17, Lund
defense date
2015-09-18 09:00
ISSN
1652-8220
ISBN
978-91-7619-167-5
language
English
LU publication?
yes
id
6639817c-b0b9-41d7-b65a-1138d311ccf4 (old id 8034420)
date added to LUP
2015-10-01 09:59:31
date last changed
2016-09-19 08:44:46
@phdthesis{6639817c-b0b9-41d7-b65a-1138d311ccf4,
  abstract     = {Malignant ventricular arrhythmias, particularly ventricular fibrillation (VF), remain an important contributor to mortality in<br/><br>
ST-elevation myocardial infarction (STEMI). The size of myocardial injury is one more important factor influencing the<br/><br>
prognosis of STEMI patients. The search for new non-invasive markers, which can be relatively simply calculated using<br/><br>
conventional ECG recording and can predict the degree of myocardial injury and impending VF, is promising. This work is<br/><br>
aimed at investigating cardiac repolarization and depolarization abnormalities and predictors and prognosis of ventricular<br/><br>
arrhythmias during the course of STEMI.<br/><br>
The thesis is composed of the experimental part (Studies I, II, III) and clinical register-based retrospective studies (Studies IV<br/><br>
and V). Closed-chest porcine model of myocardial infarction (MI) was used in the experimental part. Occlusion of left<br/><br>
descending artery (LAD) lasted 40 minutes and was followed by reperfusion, and ECG was continuously recorded. QRSduration<br/><br>
and morphology, dynamics of ST-segment and T-wave alternans (TWA) were calculated, and myocardial area at<br/><br>
risk (MaR) and infarct size (IS) were assessed. Predictors and prognostic impact of early VF in STEMI was assessed in a<br/><br>
register-based study of 1,718 consecutive patients admitted for primary PCI during 2007-2009 who were followed up for<br/><br>
one year.<br/><br>
In experimental MI, the maximal level of TWA during occlusion period was associated with both MaR and IS (Study II).<br/><br>
Rapid and marked transient increase in QRS duration associated with appearance of J-wave pattern predicted impending VF<br/><br>
in acute ischemia (Study III). Restoration of blood flow in infarct-related artery was accompanied by reperfusion peak in all<br/><br>
animals, and the magnitude of ST elevation at reperfusion peak was associated with infarct size (Study I). In clinical studies<br/><br>
IV and V, the risk of VF in acute period of STEMI was higher in patients with MI history, cardiovascular risk factors such as<br/><br>
smoking and left main stenosis, resulting in a large infarct area. Besides MI history and left main stenosis, the risk of VF at<br/><br>
reperfusion was associated with inferior localization of STEMI, hypokalemia, high ST-elevation and shorter symptom-toballoon<br/><br>
time. The magnitude of ST-elevation before PCI for STEMI independently predicted reperfusion VF. Patients<br/><br>
successfully resuscitated after VF and alive at 48 hours had higher in-hospital mortality (12% vs. 2%, p&lt;0.001). However, in<br/><br>
VF patients who were discharged alive, 1-year mortality did not differ compared with patients without VF},
  author       = {Demidova, Marina},
  isbn         = {978-91-7619-167-5},
  issn         = {1652-8220},
  language     = {eng},
  pages        = {79},
  publisher    = {Cardiology, Clinical Science, Lund, Lund University},
  school       = {Lund University},
  series       = {Lund University Faculty of Medicine Doctoral Dissertation Series},
  title        = {Electrocardiographic predictors of clinical outcome in ST-elevation myocardial infarction},
  volume       = {2015:88},
  year         = {2015},
}