[Electrocardiographic diagnosis of left main coronary artery obstruction using ST-segment and QRS-complex vector
José A Prieto-Solís1, Natividad Benito, Rafael Martín-Durán
1Servicio de Cardiología, Unidad Coronaria, Hospital Universitario Marqués de Valdecilla, Santander, Cantabria, España. ucopsj@humv.es
Introduction And Objectives:
It is vital that obstruction of the left main coronary artery (LMCA) is diagnosed early. We investigated the value of ST-segment and QRS-complex vector analysis in identifying LMCA obstruction in acute coronary syndrome.
Methods:
The study involved 57 consecutive patients with electrocardiographic features suggestive of LMCA obstruction. Both ST-segment and QRS-complex parameter vectors were analyzed.
Results:
Coronary angiography showed that the obstructed vessel was the LMCA in 20 patients, the left circumflex artery in 19, the right coronary artery in 10, and the left anterior descending artery in three. Five patients had three-vessel disease. An ST vector that was directed between -90 degrees and 180 degrees in the frontal plane was observed in 100% of patients with an LMCA obstruction (P< .001). The specificity of this observation was 78%. An ST vector directed anteriorly or parallel to the horizontal plane was present in 95% of patients (19/20) with an LMCA obstruction (P< .001; specificity 92%). A QRS vector with a left shift é-30 degrees was observed in 75% (15/20) with LMCA disease (P< .001; specificity 95%). An ST vector directed between -90 degrees and 180 degrees and anteriorly had a sensitivity of 95% and specificity of 100% for LMCA obstruction. An ST vector directed between -90 degrees and 180 degrees combined with a left QRS vector shift > or =-30 degrees had a sensitivity of 75% and a specificity of 100% for LMCA obstruction. A simple algorithm combining these observation was able to predict LMCA obstruction in 100% of patients.
Conclusions:
In acute coronary syndrome, ST-segment and QRS-complex vector analysis can predict the presence of LMCA obstruction.
More Related Videos
10:17Real-Time Cardiac Mapping with a Noninvasive Imageless Electrocardiographic Imaging System
Published on: April 11, 2025
06:57Ablation of Ischemic Ventricular Tachycardia Using a Multipolar Catheter and 3-dimensional Mapping System for High-density Electro-anatomical Reconstruction
Published on: January 31, 2019
Related Concept Videos
01:29Electrocardiogram
Three major waveforms are present in a typical ECG recording: the P wave, the QRS complex, and the T...
01:28Electrocardiogram Fundamentals
An electrocardiogram (ECG) is a diagnostic tool for identifying cardiac conditions such as arrhythmias, conduction abnormalities, and myocardial ischemia.
Definition
An electrocardiogram (ECG) visualizes the heart's electrical activity by tracing the electrical movement associated with each heartbeat on a graph or monitor. As the heart beats, an electrical wave passes through it, correlating with the cardiac cycle events.
Parts of an ECG
An ECG utilizes electrodes on the skin to...
01:30Acute Coronary Syndrome III: Diagnostic Studies
01:23Mitral Stenosis II: Clinical features and Diagnostic Tests
01:19Acute Coronary Syndrome II: Pathophysiology and Clinical Manifestations
01:24ECG Interpretation of Rhythms
Components of the Electrocardiogram
The primary components of a normal ECG waveform in Normal sinus rhythm(NSR) include the P wave, PR interval, QRS complex, ST segment, T wave, and occasionally a U wave.
ECG waveforms are divided by vertical and horizontal lines at standard intervals.
The horizontal axis measures time and rate, and the vertical axis measures amplitude or voltage. When...