Related Experiment Video

Updated: Aug 9, 2026

A Research Method For Detecting Transient Myocardial Ischemia In Patients With Suspected Acute Coronary Syndrome Using Continuous ST-segment Analysis
18:11

A Research Method For Detecting Transient Myocardial Ischemia In Patients With Suspected Acute Coronary Syndrome Using Continuous ST-segment Analysis

Published on: December 28, 2012

Clinical features of emergency electrocardiography in patients with acute myocardial infarction caused by left main

Tomohisa Hirano1, Kunihiko Tsuchiya, Kazuhiko Nishigaki

  • 1Department of Regenerative and Cardiovascular Medicine, Gifu University Graduate School of Medicine, Gifu, Japan.

Circulation Journal : Official Journal of the Japanese Circulation Society
|April 26, 2006
PubMed

Insights

Diagnosing left main trunk (LMT) infarction using electrocardiograms (ECGs) is crucial. Key ECG indicators include ST-segment elevation in lead aVR, prolonged QTc intervals, and abnormal QRS axis deviation, aiding emergency diagnosis.

Area of Science:

  • Cardiology
  • Emergency Medicine
  • Diagnostic Electrocardiography

Background:

  • Diagnosing left main trunk (LMT) infarction via standard 12-lead ECG is a critical emergency procedure.
  • Specific ECG features for LMT infarction require clarification.

Purpose of the Study:

  • To identify and clarify distinct electrocardiogram (ECG) features indicative of left main trunk (LMT) infarction.

Main Methods:

  • 140 subjects were analyzed, divided into four groups based on culprit artery: LMT, LAD, RCA, and LCx (35 each).
  • ECG parameters including QTc interval, QRS axis, and ST-segment changes were meticulously analyzed.

Main Results:

  • LMT infarction group showed a significantly longer average QTc interval (0.51 ± 0.06 s) and a marked leftward QRS axis deviation (-10 ± 77 degrees).
  • ST-segment elevation in lead aVR was observed in 80% of LMT infarction patients.
  • Two primary ECG patterns emerged: RBBB with left axis deviation, and ST elevation in anterior precordial leads with a normal axis.

Conclusions:

  • ST-segment elevation in lead aVR combined with prolonged QRS width and QTc interval, and abnormal axis deviation, strongly suggests LMT infarction.
  • Alternatively, ST-segment elevation across broad anterior precordial leads with a normal QRS axis also indicates LMT infarction.
Abstract

More Related Videos

Confirmation of Myocardial Ischemia and Reperfusion Injury in Mice Using Surface Pad Electrocardiography09:23

Confirmation of Myocardial Ischemia and Reperfusion Injury in Mice Using Surface Pad Electrocardiography

Published on: November 24, 2016

Myocardial Infarction and Functional Outcome Assessment in Pigs12:03

Myocardial Infarction and Functional Outcome Assessment in Pigs

Published on: April 25, 2014

Related Concept Videos

Introduction Cardiac Emergencies01:30

Introduction Cardiac Emergencies

Cardiac emergencies are critical situations involving the heart that require immediate medical intervention to prevent severe complications or death. These emergencies often arise from underlying heart conditions that impair the heart's ability to function correctly.Types of Cardiac EmergenciesThe most common types of cardiac emergencies include Acute Coronary Syndrome (ACS), myocardial infarction (MI), cardiac arrest, and heart failure.Acute Coronary Syndrome (ACS)Acute Coronary Syndrome (ACS)...
Acute Coronary Syndrome II: Pathophysiology and Clinical Manifestations01:19

Acute Coronary Syndrome II: Pathophysiology and Clinical Manifestations

The pathophysiology of Acute Coronary Syndrome [ACD] involves several key processes:The main underlying cause of ACD is atherosclerosis, a chronic inflammatory disease characterized by the buildup of lipid-laden plaques within the coronary arteries.As the atherosclerotic plaque grows in the coronary artery, it may become unstable due to the formation of a lipid-rich core and a thin fibrous cap. Inflammatory cells within the plaque, such as macrophages, secrete enzymes that degrade the...
Acute Coronary Syndrome III: Diagnostic Studies01:30

Acute Coronary Syndrome III: Diagnostic Studies

Diagnosing acute coronary syndrome or ACS begins with a thorough patient history. Notable symptoms include central, crushing chest pain radiating to the left arm, neck, jaw, or back, along with shortness of breath, sweating (diaphoresis), nausea, vomiting, dizziness, and palpitations.It is crucial to note any history of cardiac illnesses and assess risk factors, including age, gender, smoking, hypertension, diabetes, hyperlipidemia, and a sedentary lifestyle.During physical examination, vital...
Acute Coronary Syndrome I: Introduction01:30

Acute Coronary Syndrome I: Introduction

Acute Coronary Syndrome (ACS) encompasses a spectrum of heart conditions caused by sudden obstruction of coronary arteries, typically resulting from the rupture of an atherosclerotic plaque and subsequent thrombus (blood clot) formation. This obstruction can lead to partial or complete blockage of blood flow, causing varying degrees of myocardial ischemia or infarction.ACS includes the following clinical entities:Unstable Angina (UA)Non-ST-Elevation Myocardial Infarction (NSTEMI)ST-Elevation...
Aortic Regurgitation II: Clinical Features and Diagnostic Tests01:22

Aortic Regurgitation II: Clinical Features and Diagnostic Tests

Aortic valve regurgitation (AR) occurs when the aortic valve fails to close properly, allowing blood to flow backward from the aorta into the left ventricle. This backflow can result in two distinct clinical presentations: acute and chronic AR, each characterized by its own set of symptoms and physical findings.Acute Aortic RegurgitationAcute AR presents with a sudden onset of severe symptoms. Patients typically experience profound dyspnea (shortness of breath), chest pain, and signs of left...
Electrocardiogram01:29

Electrocardiogram

An electrocardiogram (ECG or EKG) is a critical diagnostic tool that records the electrical signals produced by the heart during each heartbeat. This recording is achieved through electrodes placed strategically on the arms, legs, and chest. The electrocardiograph amplifies these signals and produces 12 distinct tracings, offering a comprehensive understanding of the heart's electrical activity.
Three major waveforms are present in a typical ECG recording: the P wave, the QRS complex, and the T...