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Electrocardiogram

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...

ECG Interpretation of Rhythms

ECG Interpretation of Rhythms

An electrocardiogram (ECG)graphically represents the heart's electrical activity on ECG paper or a monitor.
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....

Correlation between ECG and Cardiac Cycle

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...

Electrocardiogram Fundamentals

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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...

Cardiac Action Potential

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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

Dysrhythmias III: Characteristics of Dysrhythmias

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...

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Electrophysiological Analysis of human Pluripotent Stem Cell-derived Cardiomyocytes hPSC-CMs Using Multi-electrode Arrays MEAs

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R-Peak Time: An Electrocardiographic Parameter with Multiple Clinical Applications.

Andrés Ricardo Pérez-Riera¹, Luiz Carlos de Abreu¹, Raimundo Barbosa-Barros^2,3

¹Laboratory Design of Studies and Scientific Writing, ABC Faculty of Medicine, ABC Foundation, Santo André, São Paulo, Brazil.

Annals of Noninvasive Electrocardiology : the Official Journal of the International Society for Holter and Noninvasive Electrocardiology, Inc

|November 3, 2015

Summary

Ventricular activation time (VAT), also known as R-peak time, measures the electrical activity from the start of the QRS complex to the R wave peak. This review explores its clinical uses in electrocardiography.

Keywords:

R wave peak time R-peak time intrinsicoid deflection ventricular activation time

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Area of Science:

Cardiology
Electrophysiology
Medical Diagnostics

Background:

The 12-lead electrocardiogram (ECG) provides insights into cardiac electrical activity.
Ventricular activation time (VAT), or R-peak time, reflects the duration of ventricular depolarization.
Understanding normal VAT ranges is crucial for interpreting ECG findings.

Purpose of the Study:

To define ventricular activation time (VAT) and its measurement on an ECG.
To outline the normal R-peak time values for the right and left ventricles.
To review the clinical applications of VAT in medical diagnostics.

Main Methods:

Defining VAT as the interval from QRS onset to R wave peak.
Specifying measurement techniques using various ECG leads (precordial, limb).
Establishing normal upper limits: 35 ms for the right ventricle (V1-V2) and 45 ms for the left ventricle (V5-V6).

Main Results:

VAT quantifies the time for electrical activation from endocardium to epicardium.
Normal VAT values differ between the right and left ventricles.
The parameter's clinical utility is established through its diagnostic potential.

Conclusions:

R-peak time is a valuable ECG parameter reflecting ventricular depolarization.
Normal ranges for right and left ventricular activation times are established.
This review highlights the diverse clinical applications of VAT.