The study of the physiology and pathology of the cardiovascular system, especially the heart.

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Elevated position effect on recovery times from upper respiratory infections at rest?

In nursing school, they advice for people with upper respiratory infections to be in a slightly elevated position at the head region when sleeping. My intuition of the reason is that the lymphatic ...
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27 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 ...
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27 views

Can Omega 3 Fatty Acids prevent chest pain in periodic Atrial Fibrillation?

It is debated if omega-3 polyunsaturated fatty acids (N3PUFa) may be effective in preventing AF (atrial fibrillation), meta-analysis here. However, much less has been considered this: Do N3-PUFAs ...
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59 views

What is the nature of action potentials in autonomic nervous system?

My conjecture is that the natures of sympathetic and parasympathetic action potentials are different. My findings propose me that sympathetic action potential is little longer lasting than ...
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1answer
29 views

What is the quality rate of intrinsic autoregulation in the heart?

Autoregulation is the maintenance of constant blood flow to an organ in spite of fluctuations in Blood pressure. It involves the relaxation of myocardium and contraction. It is local. I know that ...
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2answers
47 views

Are Purkinje Action Potentials Neuronal and Cardiac?

I first thought that action potentials of His-bundle i.e. Purkinje fibers are Cardiac. However, I started to think that this is not enough. I think now that they are neuronal and cardiac. My ...
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36 views

How is Calcium regulated in myocardic AP and plateau phase?

The plateau phase is maintained by influx of calcium and outflux of potassium in the second stage: My conjecture is that calcium transforms between two phases ionated phase (free calcium from i/c ...
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36 views

Spironolactone's role with adrenergic agents in heart failure?

I am studying the treatment plan of adrenergic agents for heart failure. Then, in the group discussion, spironolactone was included. But I cannot understand how it is relevant when considering ...
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25 views

Maximum heart rate increase/decrease while physically active [duplicate]

I'm a computer scientist and implementing a heart-rate monitor for physical exercise. While I try to improve my code, I stumbled over the question how fast the heart rate can change within a given ...
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11 views

Public Pacemaker database online?

I am looking for any database about pacemakers with the leads atria A right ventricle VR left ventricle VL I did not find any in Physionet. Is there any anonymous data about different ...
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1answer
47 views

Does physical exercise following lack of sleep increase the risk of sudden cardiac death (SCD)?

Is there any scientific evidence supporting the hypothesis that physical exercise following lack of sleep increases the risk of sudden cardiac death (SCD)? The only relevant research I could find is: ...
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53 views

To define the total Resistance of Systemic Blood Circulation

Some systems are in parallel. For instance, the resistance of lungs $R_{\text{lungs}}$. Assume here for simplicity that these parallel systems can be handled linearly. We also consider only Total ...
2
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1answer
63 views

Fast standing and the heart's insufficient accommodation of the increased venous return

Assume you are 45 minutes on the supine position. Furthermore: you stand all of a sudden and fast and without sympaticus activity. The venous return (smooth musculature of vessels) accommodates ...
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1answer
86 views

Sodium levels and blood pressure

Why does low Na+ levels cause hypotension (low blood pressure). Alternatively, why does excessive intake of Na+ cause hypertension or high blood pressure? From what I understand, there are ...
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17 views

To Study Interactions of two molecules in PubChem

Assume you have two substances Diosminum / Hesperidinum. The former strengthens vascular walls. The latter has role in some glycoside biosynthesis. From Biochemistry, I recall that glycodises have ...
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7 views

Does transplanted heart have full sympaticus without medication?

I am reading this and this where I am considering this sentence [N]o baseline parasympathetic innervation [in transplanted heart]. Does this sentence imply that ...
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30 views

ECG of heart transplant patients

I am studying ECGs of heart transplant patients. The difficult thing is that there is so little available data publicly. I must apply for data in my universities. It would be also great if ...
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1answer
27 views

why is heart failure treated as more critical than kidney failure?

The kidney filters blood whereas heart pumps the blood. Filtering blood is important. Therefor why is heart failure treated as more critical than kidney failure?
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0
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91 views

What is atrial fibrillation?

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 ...
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8 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 ...
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98 views

Can Panic disorder induce Atrial Fibrillation and Temporary Cardiac Asystole?

This question is partly based on the article "Asystolic pauses in atrial fibrillation. Incidence, dependence on the underlying disease and significance for pacemaker therapy", where the exact ...
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82 views

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

Assume that the heart is beating but no pacemaker cells is working for at least 15 seconds. This would be very long compensatory pause if extrasystole started it. There may be some low frequent ...
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1answer
29 views

Cardiac Excitation Threshold - in C++ modelling [closed]

So I am trying to write a code in C++ about the cardiac excitation threshold. I know that this excitation threshold is the shortest stimulus2 value at which it can conduct an action potential (known ...
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17 views

Recovering Coma patient with theoretical full knowledge of heart function

In coma, there is the medullary depression (stage of agony). Spontaneous respiration and circulation cease i.e. vasomotor center. There is no full circulatory and respiratory support. Assume you ...
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What effect does ambient temperature have on the cardiovascular system?

I am sorry if this is not appropriate for this site, but I think it fits so I am asking it here: I went for a run yesterday, and it was about -8⁰C. I was wearing a couple pairs of shorts, a t-shirt ...
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2answers
103 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?
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24 views

Potassium's Effect on Cardiac Syncytium [on hold]

I am trying to find databases about the effect of potassium on the architecture of the proteins (syncytium) and excitability of the heart. AAMI-standard database would be great. However, I think the ...
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1answer
47 views

Normal Frequencies in Heart

I am trying to visualise possible ranges of frequencies from different structures of heart: different valves and their possible frequencies heart sounds I - IV and their normal frequencties what can ...
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1answer
39 views

What are the benefits of statins in terms of prolonging life?

Recently the UK government suggested that all adults over the age of 50, without exception, would benefit from taking statins. I have an elderly female relative who may, or may not have had a minor ...
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95 views

Why shouldn't you defibrillate a flat line (asystole)?

In most popular medical dramas, when a patient is in cardiac arrest and has a flatline the doctors use a defibrillator to 'shock their heart into rhythm'. I know that actually, the proper protocol is ...
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350 views

What is the ratio of breathing rate to heart rate?

Breathing rate and heart rate are directly connected. This is because the heart is connected to the lungs via the pulmonary artery. I first thought that breathing rate would be half of the heart rate ...
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1answer
77 views

Why does the arch of aorta coils?

My study materials use the word vesselcompression chamber of aorta to emphasize aorta's elastic property. The arch of the aorta only coils, not its straight part. I think the reason why the arch ...
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1answer
34 views

Why is Aorta sometimes called Compression chamber?

I find this statement that Aorta is called Compression Chamber in my study materials. Aorta can it keeps blood flowing it can accumulate potential energy for bumping and compression However, why ...
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2answers
616 views

Why there is a very high drop in pressure from arteries to arterioles?

Laplace law explains why the pressure is the same in aorta and arteries (100). I am thinking why there is so big drop in pressure when going from arteries to arterioles (40-60). Why there is a great ...
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136 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 ...
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Is there any relationship between heartbeat rate and life span of an animal?

Is there any relationship between heartbeat rate and life span of an animal? Do they belong to a cause-and-effect relationship or are they both caused by some phenomenons or a common cause?
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352 views

What is the effect of extra-cellular potassium concentration on heart rate and conduction velocity?

If the extracellular potassium concentration surrounding a myocyte increases, then the potassium gradient accross the cell membrane decreases, and therefore the resting membrane potential will become ...
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297 views

What does irregular heartbeat mean in simple language?

I bought a blood pressure monitor (A&D UA-851) which has the option to measure irregular heartbeat. I do understand what 'irregular' means, but why do irregular heartbeats happen and what are ...
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60 views

People say the cardiac cycle depends on blood pressure? How so?

I know what the cardiac cycle is. There are two phases diastole and systole. One is the relaxed, and the other is the contracted form of the heart. The diastole is where blood is pumped to the ...
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23 views

To measure Na/K channel activation in membrane level?

Assume that there are two different signals going on in the ECG - during depolarisation and repolarisation in the standard ECG. I got an advice that do not use the standard ECG in measuring exactly ...
4
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1answer
55 views

Can you measure ECG from a single location?

I want to make a DIY bracelet to measure my ECG. All I need is the interbeat interval. Can I design a bracelet on one arm only, with two electrodes slightly spaced from one another, and figure out ...
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55 views

What is the correct medical procedure(s) for taking a resting heart rate?

Note: I thought the Biology stack exchange would suit this question better than the Fitness stack exchange. Please let me know in the comments if this is not suitable here. I am interested in ...
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1answer
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Function of the Auricle in heart

What is the function of the auricles (conical appendages through the atria) present in the heart? Do they have any other function than increasing the volume of blood the heart can hold?
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84 views

Why does max heart rate decrease with age?

I have heard that max heart rate declines steadily with age, and can be approximated by the equation Max Rate = 220 - Age. What is the physiological reason for this decline, and how is it ...
4
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1answer
96 views

What percentage of human capillaries are located in the skin?

As in the subject line, what percentage of capillaries in a human (expressed in terms of total length, I suppose) are located in the skin, as opposed to internal organs? Google scholar has not turned ...
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1answer
75 views

Is this ventricular tachycardia?

I am investigating the public data of this. Its specification ...
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31 views

To determine no beating cardiomyocytes from ECG or video recording

I am trying to find data and some method by which I can see and say that there are some cardiomyocytes not working. I have reviewed many arrythmia data where I think I can see much cardiomyocetes ...
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1answer
51 views

Calling for Free Online Data for Paediatric ECG?

I need free online data about heart murmurs to study these: heart murmur frequency , S2 heart sound frequency and its split, murmur timing, and duration, murmur intensity, S3 sound presence and ...
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About the Heart and cancer [duplicate]

I read cancerous growth in the heart is rare . Why is that? Cancer cells are very unstable yet can function somehow. Could the Heart's intense pulses of electromagnetic energy make it alot harder for ...