24
votes
Accepted
ECG wave names origin
Interesting question! I searched briefly and came up with an answer from this short paper.
I won't repeat all the details of the paper, but to be not a completely link-only answer I will give a brief ...
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6
votes
ECG wave names origin
According to this site: http://www.ecglibrary.com/ecghist.html
Originally the waves were designated as A,B,C& D but after correction they were termed as P,QRS, T.
Why PQRST and not ABCDE? The ...
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5
votes
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Why is the current flow shown to be flowing from the negative area towards the positive area?
By convention, positive current is assumed to be the direction of flow of positive charges. The trouble is that in many common situations (like this one), the current is actually carried by electrons ...
- 3,131
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votes
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Can an electrocardiogram be recorded with a single electrode?
Short answer
Any electrophysiological recording of potentials, including the electrocardiogram (ECG or EKG), measures a potential difference. Hence, two or more electrodes are necessary.
Background
...
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5
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What does the 'V' stand for in ECG electrode names?
Short answer
V stands for voltage.
Background
The various leads in an ECG montage are shown below:
ECG electrodes. Source: American Heart Association
I am not an expert in ECGs, but as far as I ...
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5
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How to analyse an ECG?
First bump is called P point, middle is QRS wave (as in Q-down, R-up, S-down), and last bump is T. Every feature is representation of electrical activity in certain region of heart. E.g. P bump is ...
4
votes
How does sepsis affect heart function?
While the heart is affected during septic shock, it is the result of the chain of events that occur as a result of a systemic release of the pro-inflammatory cytokine Tumor Necrosis Factor alpha (TNF-$...
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3
votes
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Difference between Premature Atrial Contraction and Atrial Fibrillation
Atrial Fibrillation is a dysrhythmia while PAC is an early depolarization coming from the atria. An occasional PAC can be normal for some people. In that case their heart rhythm would be a sinus ...
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Explanation of ECG in MI using an electrostatic model
The concentration of K+ inside the cell is 30 time more than outside. Hypoxia causes loss of this intracellular Kalium and consequent/premature repolarization when measuring the potential of action.
...
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3
votes
Accepted
How long do the periods of systole and diastole last?
The following image from wikipedia answer what you need. You can check corresponding page for details.
The top part shows the details of the different processes during a heart beat. Corresponding to ...
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Normal ECG/EKG Measurement?
If you're looking for an explanation of the parts of the waveform you recorded, here's an annotated version:
I hope that helps you map it back to the "standard" QRS you saw. The AV delay is the time ...
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2
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How long do the periods of systole and diastole last?
Systole lasts about 3/8 and diastole 5/8 of a cardiac cycle.
Keep in mind though that such values vary with heart rate. The higher the heart rate, the shorter the fraction of diastolic time compared ...
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2
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How to analyse an ECG?
The only abnormality which can be seen on the ECG curve is a prolonged PR Interval but only when acute alcohol poisoning has been done.
In the referenced paper the patient had consumed 3.7 g/l (3.7 ...
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What does the 'V' stand for in ECG electrode names?
As a paramedic who does EKGs every day, I can tell you it stands for "VECTOR" meaning the direction the electrode monitors electricity from the heart.
RA, LA, RL, and LL electrodes are ALL the ...
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Is there any case in which excitability increases with lowering the RMP?
A typical voltage-gated sodium channel has 3 gating states: open, closed, and inactivated. The third category is the important one here.
Open channels are open: they let ions through.
Closed ...
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In the PR segment of an ECG, how come there's no current flowing?
I'd suggest reading the rest of the Wikipedia article on EKG rather than focusing on the particular cartoon you are using right now, because that cartoon does not depict the dipoles that are measured.
...
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1
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Why are P and T waves curved and not straight (ECG)
P wave represents atrial depolarization (hence atrial contraction).
Atrial depolarization takes only a split second, therefore its corresponding wave will be smooth and rounded.
Variations from this ...
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1
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ECG detection using minimal number of electrodes
First, let's talk about electrodes.
Background
What do the electrodes measure?
When we talk about ECG signals, we generally talk about leads - that is, difference of electrical potential between two ...
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1
vote
what is the difference between osciloscope and electrocardiograph?
I would say that electrocardiograph is a specific case of oscilloscope. The main difference, perhaps is that "oscilloscope" is a device for visualization on a display ("scope" from greek "look out"), ...
1
vote
Accepted
why do sodium channels close with excessive extracellular potassium ions in cardiac myocytes?
Short Answer
Depolarization block keeps sodium channels in a different state where they aren't available to open.
Longer Answer
The answer here applies equally to cardiac myocytes and neurons, and ...
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Electrocardiogram: Difference between Atrial Fibrillation and Atrial Flutter
A-Flutter will have discernible waves that can be counted, usually. The R-R interval will be regular or maybe slightly irregular if there's a variable conduction block in the AV Node. A-Fib will ...
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vote
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Electrocardiogram: Missed beats in presence of Ectopic beats or Premature Atrial/Ventricular Contraction beats
After developing and checking the algorithm with simulated ECG data, i found out that premature beats (as the name suggests) itself arrive prematurely i.e. their R-R peak interval is less then the R-R ...
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vote
Accepted
Why is Electrical Cardioversion contraindicated in AF and Digitalis Poisoning?
The mechanism of action of digitalis-like preparations based on inhibition of myocardial NA+/K+-ATPase as well as of cardiac conducting tissue. The inhibition of latter (conducting) is 2.5 greater ...
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How to analyse an ECG?
Beautiful work!
Whether the PR is prolonged depends on timescale om x axis (which i cannot find...).
I didn't really get the scope of this task. If you are attempting to create a computer automated ...
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Any databases with AAMI ECG and ECHO?
One possibility is PTB Diagnostic ECG database here.
However, its AAMI verification is still under process here.
Some ECHO findings also there.
Only top scored, non community-wiki answers of a minimum length are eligible