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Related Concept Videos

Electrocardiogram Fundamentals01:28

Electrocardiogram Fundamentals

Introduction
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...
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...
Correlation between ECG and Cardiac Cycle01:25

Correlation between ECG and Cardiac Cycle

The electrical signals recorded on an electrocardiogram (ECG) occur before the mechanical processes of contraction and relaxation during the cardiac cycle.
A cardiac action potential originates in the SA node and spreads throughout the atria and the AV node in approximately 0.03 seconds. This results in the P wave in an ECG and triggers atrial contraction. The action potential is then briefly slowed at the AV node, allowing the atria to contract and fill the ventricles with blood before...
Cardiac Action Potential01:30

Cardiac Action Potential

Cardiac action potentials are essential for proper heart function, enabling the rhythmic contractions needed for adequate blood circulation. Nodal cells and Purkinje fibers, specialized for electrical conduction, generate these action potentials.
The cardiac action potential process involves a series of phases characterized by the movement of ions across the cardiac cell membranes, leading to the depolarization and repolarization of the cardiac myocytes.
Ionic Basis of Cardiac Action Potentials
Electrophysiology of Normal Cardiac Rhythm01:19

Electrophysiology of Normal Cardiac Rhythm

The normal cardiac rhythm is a synchronized electrical activity that facilitates the regular and coordinated contraction of the heart muscle. This process is essential for efficient blood circulation throughout the body. The fundamental elements involved in establishing and maintaining this rhythm include the unique electrical properties of cardiac muscle cells, the sinoatrial (SA) node's pacemaker function, the specialized conducting system, and the ionic mechanisms underlying each phase of...
Dysrhythmias III: Characteristics of Dysrhythmias01:29

Dysrhythmias III: Characteristics of Dysrhythmias

Dysrhythmias, also known as arrhythmias, are irregular heart rhythms that result from abnormal electrical activity in the heart, affecting its ability to circulate blood efficiently. Tachyarrhythmias, a subset of dysrhythmias, are characterized by abnormally fast heart rates exceeding 100 beats per minute. Here are some types of tachyarrhythmias with their distinct ECG features:Sinus Tachycardia:Sinus tachycardia presents a regular heart rhythm with an increased rate of 101-180 beats per minute.

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Electrocardiographic patterns during left ventricular epicardial pacing.

Marek Jastrzebski1, Kamil Fijorek, Danuta Czarnecka

  • 1First Department of Cardiology and Hypertension, University Hospital, Cracow, Poland Department of Statistics, Cracow University of Economics, Cracow, Poland. mcjastrz@cyf-kr.edu.pl

Pacing and Clinical Electrophysiology : PACE
|September 6, 2012
PubMed
Summary

Electrocardiogram (ECG) patterns can identify left ventricular (LV) lead positions during LV-only pacing. Specific posterolateral and anteroapical ECG patterns accurately predict LV lead placement in cardiac resynchronization therapy patients.

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Published on: January 31, 2019

Area of Science:

  • Cardiology
  • Electrophysiology
  • Medical Imaging

Background:

  • Limited data exists on using QRS morphology for identifying left ventricular (LV) epicardial pacing sites in biventricular device patients.
  • Understanding these patterns is crucial for optimizing cardiac resynchronization therapy (CRT) lead placement.

Purpose of the Study:

  • To identify QRS morphology patterns during LV-only pacing.
  • To correlate these ECG patterns with LV lead position.
  • To validate the diagnostic accuracy of ECG patterns for predicting specific LV pacing sites (e.g., posterolateral vs. anterior, apical vs. nonapical).

Main Methods:

  • Retrospective analysis of 376 CRT device patients.
  • Inclusion of ECGs from LV-only VVI pacing, fluoroscopy, and chest roentgenograms for LV lead position documentation.
  • Two-phase study: initial ECG pattern categorization followed by association analysis with lead position.

Main Results:

  • A trend of more negative precordial QRS complexes was observed as LV epicardial pacing sites moved anteroapically.
  • Three distinct ECG patterns (posterolateral, intermediate, anteroapical) were identified and significantly associated with LV lead position (P < 0.001).
  • The posterolateral pattern showed 89.1% accuracy for nonapical LV lead prediction; the anteroapical pattern demonstrated 98.5% specificity and 89.1% accuracy for anteroapical pacing.

Conclusions:

  • Distinct ECG patterns, specifically posterolateral and anteroapical, are highly predictive of LV lead position.
  • These findings offer a non-invasive method for confirming LV lead placement accuracy.