12-lead Electrocardiogram in Acute Coronary Syndrome - TamPub

147 Pages·2012·3.73 MB·English

KJELL NIKUS
12-lead Electrocardiogram in Acute Coronary Syndrome
Association with Coronary Angiography Findings and Outcome
ACADEMIC DISSERTATION
To be presented, with the permission of
the board of the School of Medicine of the University of Tampere,
for public discussion in the Main Auditorium of Building M,
Pirkanmaa Hospital District, Teiskontie 35,
Tampere, on November 23rd, 2012, at 12 o’clock.
UNIVERSITY OF TAMPERE
ACADEMIC DISSERTATION
University of Tampere, School of Medicine
Tampere University Hospital,
Cardiology Department, Heart Center
Finland
Supervised by Reviewed by
Professor Mika Kähönen Docent Mika Laine
University of Tampere University of Helsinki
Finland Finland
Docent Markku Eskola Docent Antti Saraste
University of Tampere University of Turku
Finland Finland
Copyright ©2012 Tampere University Press and the author
Distribution Tel. [phone]
Bookshop TAJU [email protected]
P.O. Box 617 www.uta.fi/taju
33014 University of Tampere http://granum.uta.fi
Finland
Cover design by
Mikko Reinikka
Acta Universitatis Tamperensis 1776 Acta Electronica Universitatis Tamperensis 1250
ISBN 978-951-44-8950-1 (print) ISBN 978-951-44-8951-8 (pdf)
ISSN-L 1455-1616 ISSN 1456-954X
ISSN 1455-1616 http://acta.uta.fi
Tampereen Yliopistopaino Oy – Juvenes Print
Tampere 2012
To my family
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Contents

CONTENTS ...................................................................................................................................................................... 5
LIST OF ORIGINAL COMMUNICATIONS ............................................................................................................... 9
ABBREVIATIONS ......................................................................................................................................................... 10
ABSTRACT .................................................................................................................................................................... 11
TIIVISTELMÄ (ABSTRACT IN FINNISH) ............................................................................................................... 14
INTRODUCTION .......................................................................................................................................................... 17
REVIEW OF THE LITERATURE .............................................................................................................................. 20
1. NON-ST-ELEVATION ACUTE CORONARY SYNDROME .......................................................................................... 20
1.1 Definition ....................................................................................................................................................... 20
1.2 Distribution and incidence ............................................................................................................................ 20
1.3 Prognosis ....................................................................................................................................................... 22
1.3.1 Non-ST-elevation myocardial infarction ..................................................................................................................... 22
1.3.2 Unstable angina pectoris .............................................................................................................................................. 24
2. DISTRIBUTION OF ECG CHANGES AT ADMISSION IN ACUTE CORONARY SYNDROME ........................................... 24
3. CORONARY ANATOMY ........................................................................................................................................ 26
3.1 Coronary artery dominance .............................................................................................................................. 26
3.2 Left coronary artery .......................................................................................................................................... 28
3.3 Right coronary artery ........................................................................................................................................ 29
3.4 Coronary collateral flow ................................................................................................................................... 29
4. SEVERE CORONARY ARTERY DISEASE ................................................................................................................. 30
4.1 Definition of significant coronary obstruction .................................................................................................. 30
4.2 Anatomical classification .................................................................................................................................. 31
4.3. Left main disease and its equivalent ................................................................................................................. 32
4.4 Scoring systems ................................................................................................................................................. 33
4.5 Prognosis .......................................................................................................................................................... 34
4.5.1 Single, double and triple vessel disease ....................................................................................................................... 34
4.5.2 Left main disease ......................................................................................................................................................... 34
4.5.3 Left main disease and cardiogenic shock ..................................................................................................................... 36
5. PATHOPHYSIOLOGY OF ECG CHANGES IN NON-ST ELEVATION ACUTE CORONARY SYNDROME .......................... 37

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5.1 ST segment ........................................................................................................................................................ 37
5.1.1 Biochemical changes during myocardial ischemia ...................................................................................................... 37
5.1.2 ST-segment depression in subendocardial ischemia .................................................................................................... 38
5.1.3 ST-segment depression in subendocardial infarction ................................................................................................... 39
5.1.4 Reciprocal ST-segment depression .............................................................................................................................. 40
5.2 T wave ............................................................................................................................................................... 41
6. ECG PATTERNS DURING ISCHEMIA AND CORRELATION WITH CORONARY ANGIOGRAPHIC FINDINGS ................... 42
6.1 Regional subendocardial ischemia ................................................................................................................... 42
6.1.1 Definition ..................................................................................................................................................................... 42
6.1.2 Study observations ....................................................................................................................................................... 43
6.2 Circumferential subendocardial ischemia ........................................................................................................ 45
6.2.1 Definition ..................................................................................................................................................................... 45
6.2.2 Clinical study observations .......................................................................................................................................... 45
6.2.3 Autopsy study observations ......................................................................................................................................... 49
6.2.4 Differential diagnosis of the ECG pattern of circumferential subendocardial ischemia............................................... 50
6.2.5 Similarities with ECG changes during the exercise test ............................................................................................... 50
6.3 Pre-existing changes ......................................................................................................................................... 52
7. ECG IN RISK STRATIFICATION ............................................................................................................................. 53
7.1 Prognostic value of ST-segment depression ...................................................................................................... 53
7.1.1 Presence of ST-segment depression ............................................................................................................................. 54
7.1.2 Sum of ST-segment depression .................................................................................................................................... 56
7.1.3 Localization of ST-segment deviation ......................................................................................................................... 57
7.2 Prognostic value of the T wave ......................................................................................................................... 59
7.2.1 Isolated T-wave inversion ............................................................................................................................................ 60
7.3 Prognostic value of regional subendocardial ischemia .................................................................................... 61
7.4 Prognostic value of circumferential subendocardial ischemia ......................................................................... 62
AIMS OF THE STUDY ................................................................................................................................................. 64
MATERIALS .................................................................................................................................................................. 65
1. PATIENTS ............................................................................................................................................................ 65
1.1 Study I .............................................................................................................................................................. 65
1.2 Studies II and III ................................................................................................................................................ 65
1.3 Study IV ............................................................................................................................................................. 66

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2. ETHICAL ASPECTS .................................................................................................................................................... 67
METHODS ...................................................................................................................................................................... 68
1. ECG ANALYSIS ................................................................................................................................................... 68
1.1 Study I ............................................................................................................................................................... 68
1.2 Study II .............................................................................................................................................................. 69
1.3 Study III ............................................................................................................................................................. 69
1.3.1 Classification of ECG categories ................................................................................................................................. 69
1.4 Study IV ............................................................................................................................................................. 70
1.5 Regional subendocardial ischemia ................................................................................................................... 70
1.6 Circumferential subendocardial ischemia ........................................................................................................ 71
2. ECHOCARDIOGRAPHY ......................................................................................................................................... 71
3. CORONARY ANGIOGRAPHY ................................................................................................................................. 71
4. CLASSIFICATION OF ACUTE CORONARY SYNDROME CATEGORIES (II) ................................................................. 72
5. STATISTICAL METHODS ....................................................................................................................................... 72
RESULTS ........................................................................................................................................................................ 74
1. BASELINE DEMOGRAPHICS AND DISTRIBUTION OF ACUTE CORONARY SYNDROME CATEGORIES .............................. 74
1.1 Baseline data in all-comers ............................................................................................................................... 74
1.2 Distribution of ECG changes in all-comers ...................................................................................................... 74
1.3 Baseline data in coronary artery bypass grafting patients (IV) ........................................................................ 75
1.4 Acute coronary syndrome categories in patients undergoing urgent or emergent bypass grafting (IV) ........... 76
2. CORRELATION OF THE ECG PATTERN OF CIRCUMFERENTIAL SUBENDOCARDIAL ISCHEMIA WITH ANGIOGRAPHIC
FINDINGS ...................................................................................................................................................................... 76
3. OUTCOME IN ACUTE CORONARY SYNDROME ............................................................................................................ 77
3.1 According to acute coronary syndrome categories ........................................................................................... 77
3.1.1 Predictors of mortality ................................................................................................................................................. 78
3.2 According to ECG patterns ............................................................................................................................... 80
3.2.1 All-comers ................................................................................................................................................................ 80
3.2.2 Regional and circumferential subendocardial ischemia ............................................................................................... 82
DISCUSSION .................................................................................................................................................................. 83
1. GENERAL CONSIDERATIONS ................................................................................................................................ 83
2. OUTCOME PREDICTORS IN NON-ST ELEVATION ACUTE CORONARY SYNDROME .................................................. 85

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2.1 Clinical markers ................................................................................................................................................ 85
2.2 Acute coronary syndrome categories ................................................................................................................ 86
2.3 Severity of angiographic disease ....................................................................................................................... 89
2.4 Conventional ECG changes associated with myocardial ischemia................................................................... 89
2.4.1 Lead aVR ST-segment elevation ................................................................................................................................. 91
3. PREDICTIVE ACCURACY OF THE ECG PATTERN OF CIRCUMFERENTIAL SUBENDOCARDIAL ISCHEMIA ................. 92
4. THE ECG PATTERN OF CIRCUMFERENTIAL SUBENDOCARDIAL ISCHEMIA AND ANGIOGRAPHIC FINDINGS ............ 94
5. PATHOPHYSIOLOGICAL MECHANISMS OF CIRCUMFERENTIAL SUBENDOCARDIAL ISCHEMIA ................................ 95
6. MAJOR FINDINGS OF THE STUDY ......................................................................................................................... 96
6.1 Poor outcome in real life non-ST elevation acute coronary syndrome patients................................................ 96
6.2 An ECG marker of severe coronary artery disease in non-ST elevation acute coronary syndrome ................. 97
6.3 Impact of the present study on current treatment strategies ............................................................................. 97
SUMMARY AND CONCLUSIONS ............................................................................................................................. 99
ACKNOWLEDGEMENTS ......................................................................................................................................... 100
REFERENCES ............................................................................................................................................................. 102
ORIGINAL COMMUNICATIONS ............................................................................................................................ 113

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LIST OF ORIGINAL COMMUNICATIONS

This dissertation is based on the following four original publications, referred to in the text by their
Roman numerals I-IV.

I Nikus KC, Eskola MJ, Virtanen VK, Vikman S, Niemelä KO, Huhtala H, Sclarovsky S
(2004). ST-Depression with Negative T Waves in Leads V -V - A Marker of Severe
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Coronary Artery Disease in Non-ST Elevation Acute Coronary Syndrome: A Prospective
Study of Angina at Rest, with Troponin, Clinical, Electrocardiographic, and Angiographic
Correlation. Ann Noninvasive Electrocardiol 9:207-214.

II Nikus KC, Eskola MJ, Virtanen VK, Harju J, Huhtala H, Mikkelsson J, Karhunen PJ,
Niemelä KO (2007). Mortality of patients with acute coronary syndromes still remains high:
A follow-up study of 1188 consecutive patients admitted to a university hospital. Ann Med
39:63-71.

III Nikus KC, Sclarovsky S, Huhtala H, Niemelä K, Karhunen P, Eskola MJ (2012).
Electrocardiographic presentation of global ischemia in acute coronary syndrome predicts
poor outcome. Ann Med 44:494-502.

IV Nikus K, Järvinen O, Sclarovsky S, Huhtala H, Tarkka M, Eskola M (2011):
Electrocardiographic presentation of left main disease in patients undergoing urgent or
emergent coronary artery bypass grafting. Postgrad Med 123:42-48.

The original publications are reprinted with the permission of the copyright holders.

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ABBREVIATIONS

ACS acute coronary syndrome
ACUITY Acute Catheterization and Urgent Intervention Triage Strategy
AMI acute myocardial infarction
BARI Bypass Angioplasty Revascularization Investigation
CABG coronary artery bypass grafting
CAD coronary artery disease
CI 95% confidence interval
CSI circumferential subendocardial ischemia
ECG electrocardiogram
ESSENCE The Enoxaparin in Non-Q-Wave Coronary Events
FRISC Fragmin during Instability in Coronary Artery Disease
GRACE Global Registry of Acute Coronary Events
GUSTO Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries
HR hazard ratio
IQR inter-quartile range
LAD left anterior descending coronary artery
LBBB left bundle branch block
LCx left circumflex coronary artery
LM left main
LV left ventricle
LVH left ventricular hypertrophy
MI myocardial infarction
NPV negative predictive value
NSTE non-ST-elevation
NSTE-ACS non-ST elevation acute coronary syndrome
NSTEMI non-ST-elevation myocardial infarction
OR odds ratio
PCI percutaneous coronary intervention
PPV positive predictive value
RCA right coronary artery
RBBB right bundle branch block
RR relative risk
STE-ACS ST-segment elevation acute coronary syndrome
STEMI ST-segment elevation myocardial infarction
TACTICS Treat Angina with Aggrastat and determine Cost of Therapy with an Invasive or
Conservative Strategy
TIMI Thrombolysis in Myocardial Infarction
UA unstable angina pectoris

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