Questions tagged [electrocardiography]

The study of the electrical activity of the heart.

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83 views

ECG detection using minimal number of electrodes

Disclaimer: Hello, I'm someone from an electrical engineering background, so this question may sound dumb. I wish to make a wearable ECG monitoring device for arrhythmia detection. Since the device ...
1k views

Can a mathematical function be assigned to ECG diagram?

This is a 12 lead electeocardiogram of a 26 year old male: This is the graph of function $5sin(7x)sin(.5x)cos(3.25x)$ This graph look quite similar to the ECG diagram.After sketching this graph, I ...
15 views

Is there a way to derive Bazett's formula to correct QT interval in ECG?

As we know that QT interval in ECG is a function of heart rate (HR) and to comment on the pathology associated with altered QT interval, we must neutralise the effect of HR. For this Bazett's formula ...
96 views

Why is the current flow shown to be flowing from the negative area towards the positive area?

When I was studying the ECG chapter in the book "Guyton and Hall Textbook of Medical Physiology", I noticed something odd in one of the pictures: As you can see the current is shown to be ...
13 views

Relationship between blood pressure time series and ventricular dynamics of the heart

The answer to this question is probably very straightforward, but I have actually had some difficulty finding an explicit answer online. To what extent does the oscillatory pattern of arterial blood ...
19 views

Is there any case in which excitability increases with lowering the RMP?

My professor says , at a more negative RMP, less sodium ion channels are inactivated, so if you take 2 of the exact same neuron with the same threshold potentials, and try to excite them starting from ...
19 views

Understanding the ECG waveform with respect to Lead Positions

I am really confused about the Representation of potential in an ECG graph. First i will ask what is on the vertical axis? (I guess it is electrical potential in millivolts) But again it changes for ...
97 views

Why are P and T waves curved and not straight (ECG)

The P and T wave are in shape of a curve while the QRS complex is in straight lines. What is the reason this is happening?
70 views

In the PR segment of an ECG, how come there's no current flowing?

I don't really know how to phrase the question, but to put it as clearly as I can, I don't get why it is the P wave "flattens down" when the atria have completely depolarized. I get that the ...
59 views

Can anybody recognize this cardiac waveform? [closed]

Is this an artifact or an arrhythmia?
1k views

Difference between Premature Atrial Contraction and Atrial Fibrillation

what is the difference between Premature Atrial Contraction and Atrial Fibrillation. I know that both have irregular heart beat but have normal QRS complex. Both have abnormal or absence P waves but a ...
290 views

Understanding beat annotations of arrhythmia ECG dataset

I'm trying to understand the rhythm changes in the MIT BIH dataset. In annotations, there are 2 main types. Beat annotations and rhythm annotations. Rhythm annotations (aux_notes field) contains ...
140 views

Electrocardiogram: Difference between Atrial Fibrillation and Atrial Flutter

I have been working on analyzing Electrocardiogram data. I have read several documents related to conditions of the Atria during fibrillation and flutter, the most lucid being that atria quiver with ...
189 views

How to obtain normalised ECG given ECG readings across lead 1, 2, and 3?

I saw this youtube video on ECG readings and cardiac dipole vector locus of the heart across the three leads. Posting screenshots from it: My question is how to obtain the graph (2nd image) from the ...
1k views

Can an electrocardiogram be recorded with a single electrode?

Is it possible to do an electrocardiogram with one electrode? Or is it neccesary to have multiple electrodes? I do not understand much about EKG, so I am sorry if this question sounds naive.
18k views

What does the 'V' stand for in ECG electrode names?

In electrocardiography, electrodes have the typical names of: RA (Right Arm) LA (Left Arm) RL (Right Leg) LL (Left Leg) V1, V2, V3, V4, V5 and V6 What does the V stand for? Is it perhaps from vector,...
503 views

what is the difference between osciloscope and electrocardiograph?

I am completely confused about these two devices! as far as I know, oscilloscope and electrocardiograph, both, show the heat waves(P, QRS, T) so what is the difference between their job?
351 views

why do sodium channels close with excessive extracellular potassium ions in cardiac myocytes?

When there is an excessive concentration of potassium ions outside cardiac myocytes, the membrane potential surely goes up. I would have thought that this would make it easier for the membrane ...
132 views

Is this an ectopic beat? [closed]

First of all, I am unclear as to whether the answer to this question is a matter of fact or of opinion. Nevertheless, I hope to find the answer. In the image below, is the green beat considered ...
23 views

Why does the posterior region and the right ventricle of the heart are not well represented in standard 12 leads?

When assessing an ECG we divide our 12-lead into four main contiguous lead groups: inferior, lateral, septal, and anterior. Regions not well represented on a standard 12-lead are the posterior region ...
19k views

How long do the periods of systole and diastole last?

The background to this is i'm doing some work using ECGs for an animation of the heart and i'm having trouble defining the end points of these periods, particularly diastole. Currently, the only ...
476 views

Normal ECG/EKG Measurement?

I'm getting started using ECG using a 3 lead system by iWorx. I have place the leads on my two wrists and the ground on my ankle and have recorded some data into the provided LabScribe 3 software ...
1k views

How to analyse an ECG?

I have a project about extracting features from a homemade ECG. I need the PQRST points from the signal of the heart beat. The ECG I'm using has 3 electrodes that attach to the chest. The problem is ...
6k views

ECG wave names origin

Why do electrocardiogram waves go P, Q, R, S, T and not like A, B, C, D? Is there any specific reason behind this?
378 views

Which leads are abbreviated typically as channel ECG 1 and ECG 2?

I want make sure about the fact in the documentation of MIT-BIH NSRDB here. They just say ECG 1 and ECG 2 but not what particularly. I think they are the frontal plane channel and transverse plane ...
128 views

How to measure Na/K channel activation at the membrane level?

Assume that there are two different signals occurring on the ECG - during depolarization and repolarization in the standard ECG. I was advised not to use the standard ECG in measuring the exact ...
1k views

What is atrial fibrillation? [closed]

I am wondering exactly what a-fib is (causes and symptoms). I would really appreciate having a sample of an EKG with it (because in my limited research, I have found it nearly impossible to find just ...
2k views

Is Sinus node conduction necessary for heart beating?

Assume a patient with previous cardial infaction which SA node not possible to activate action potential anymore. However, SA trying to beat unsuccessfully repeatedly waisting energy. Therefore, I ...
2k views

What are the highest and lowest amplitude values in ECG for humans?

I'm currently trying to parse the records captured from an ECG device and display them on a mobile application. I am wondering what the highest and lowest possible amplitude values for ECGs are in ...
180 views

Electrocardiogram: Missed beats in presence of Ectopic beats or Premature Atrial/Ventricular Contraction beats

I have been working on analyzing Electrocardiogram data. So far, i have identified Ectopic beats and Premature Atrial/Ventricular Contraction beats. I am working on identifying Missed Beat in the ...
2k views

How does sepsis affect heart function?

I have intuition that sepsis with infection can cause: spastic functioning of heart during systole heart working spontaneously in snatches during systole atrial fibrillation first contraction of ...
88 views

Can I simply take the trend of heart rate amplitude to get breathing rate in an ECG?

I processed an ECG signal using findpeaks in Octave. Then, I plotted the amplitude of the "peaks" found by that function and got the followinge result (original ...
503 views

Explanation of ECG in MI using an electrostatic model

I found a paper presenting an electrostatic model to explain the ECG recorded in various leads. This model essentially calls for considering the depolarization wavefront to be the major contributing ...
72 views

Any databases with AAMI ECG and ECHO?

There is no AAMI 12-lead ECG databases available online. All of them have problems. I and my friends finally finalised our tests with St Petersburg. It is not AAMI. So the next step is to search ...
5k views

Why is Electrical Cardioversion contraindicated in AF and Digitalis Poisoning?

I am thinking why electrical cardioversion is contraindicated in atrial fibrillation with digitalis toxicity/poisoning. Cardiac digitalis is also called digoxin and cardiac glycoside. It is ...
40 views

Non-cumbersome respiration sensor for sleep study?

I'm working on a project where I collect ECG signal from multiple volunteers, derive ECG derived respiration(EDR) from the timestamped ECG signal and calculate the cross correlation between EDR and ...
536 views

To get Standard ECG from PhysioNet?

I am trying to get standard ECG by using PhysioNet's ATM with parameters but I get It should be something like How can you get complete standard 12-lead ECG out of Physionet database?
47 views

Neural correlates of the function of the cardiovascular system?

Are there any known neural correlates of the function of the cardiovascular system? I'm looking for research results that use standard brain imaging techniques (e.g. electroencephalography, ...
657 views

What is the name of the condition where no pacemaker cells are active in the heart for a short-time?

Assume that the heart is beating, but no pacemaker cells are working for at least 15 seconds. This would be a very long compensatory pause if extrasystole started it. There may be some low frequent ...
547 views

Is a raised baseline between T and QRS normal in any ECG lead?

Here are excerpts from an unknown ECG lead. I find it weird that the "baseline" changes after the T wave and doesn't return until after the following QRS complex. Is that normal/expected for any lead? ...
238 views

What are the mechanisms of disabling extrinsic control of heart?

I started this thread by thinking this question but I developed it further below What is the mechanism maintaining refractory period of pacemakers? My conjecture is that the mechanism is the ...
219 views

Normal position of Electrical axis only in the III lead?

I found this sentence in my notes which is not exact enough: Electrical axes Excitatory processes have definite direction and magnitude and could therefore be represented as vectors. At any ...
6k views

How does strength of a pulse related to EKG(ECG)?

There are variabilities in the heart rate as well as strength of heartbeats. I want to know if one can predict which heartbeat will be strong or weak based on the corresponding EKG/ECG signal. I am ...