Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [cardiology]

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

17
votes
0answers
203 views

Effect of Aging on SA node's sympathetic fibers

I am trying to understand the effect of aging on the sympathetic fibers of SA node. I know that aging shifts the vagal curve to left in frequency due to aging. However, I am interested if aging has ...
5
votes
0answers
111 views

Evolutionary explanation of the bicuspid on the left and tricuspid on the right

The left heart handles more pressure and logically it would make sens to have a valve with three leafs on the left (If I had got to choose, I'd have put three on both sides). Other than being more ...
4
votes
0answers
173 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 ...
4
votes
0answers
836 views

What's so special about Chassaignac tubercle?

1-How does massaging of carotid artery at chassaignac tubercle( anterior tubercle of transverse process of C6 vertebra ) can relieve the symptoms of Supraventricular Tachycardia? My attempt: I think ...
4
votes
0answers
130 views

Is there a naturally occurring mechanism in the body for cleaning plaque buildup in arteries?

Is there a naturally occurring mechanism in the body for cleaning plaque buildup in arteries ?
3
votes
0answers
21 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 ...
3
votes
0answers
900 views

Why is there a structural difference between the bicuspid and tricuspid valve?

There are three cusps in the tricuspid valve and only two in the bicuspid valve? Why is there such a structural difference? Does it have anything to do with that there is oxygenated blood on the left ...
3
votes
0answers
103 views

How do cellphones calculate heart rate?

How do cellphones calculate heart rate ? I understand that the cameras there try to count undulation in blood flow, but is the method of calculation same as that of professional SpO2 monitors ?
2
votes
0answers
263 views

What drives max heart rate on beta blockers?

In a healthy human being, the increase in heart rate from rest to around 100 to 110 beats per minute at low intensity exercise is due to withdrawal of the parasympathetic nervous system's influence. ...
2
votes
0answers
77 views

How much do arteries expand during pulse?

Arteries expand during a pulse. The amount of expansion may differ from artery to artery. How much do arteries expand? I understand it might be a range. Inform the same. Even values specific to some ...
2
votes
0answers
192 views

Why does fetal distress (hypoxia) cause bradycardia?

In a non stress test performed in the labor room, fetal bradycardia is a danger sign indicating fetal distress (hypoxia). Why does fetal hypoxia cause bradycardia while hypoxia in adults cause ...
2
votes
0answers
22 views

Why are valves preferentially affected in endocarditis?

The inside of the heart is covered by endothelium throughout. Why are valves predisposed to endocarditis? I know it can affect other structires like the septum, chordae etc. But why the valves? ...
2
votes
0answers
102 views

Plaque rupture flow chart reading

I am having a bit of trouble interpreting flow charts given in my biology question sets. Given the following stimulus The Question is : In which of the following options does each substance play ...
2
votes
0answers
610 views

Why do earthworms have 4 hearts?

I was reading about earthworms and came to know that they have 4 hearts. Why is there a need for a 4 heart system? What advantages would it have over a 1 heart circulatory system except for pumping ...
2
votes
0answers
45 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, ...
2
votes
0answers
92 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 ...
2
votes
0answers
348 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
votes
0answers
55 views

If a receptor is inhibited throughout embryogenesis, could there be observable phenotypic differences in the adult?

So I read a journal article entitled "Maternal hypoxia and caffeine exposure depress fetal CV function during primary organogenesis" (Momoi, et al., 2012) and in essence the article speaks of the ...
2
votes
0answers
69 views

Can we make any judgements about sleep or readiness to sleep from a heart rate metric and/or pulse oxymetry?

I'm looking at inexpensive and un-intrusive ways to quantify the state of human body/mind . One of these is Actigraphy, which is a study of human motion over time. This can be done with an iPhone ...
1
vote
0answers
21 views

Is the medium which transmits the electrical impulse through the heart different to a nerve?

According to Nerve A nerve is an enclosed, cable-like bundle of nerve fibres called axons Being an Axon An axon (from Greek ἄξων áxōn, axis), or nerve fiber, is a long, slender projection of a ...
1
vote
0answers
68 views

How does alcohol interact with sympathomimetics to affect the cardiovascular system?

There is a fair amount of information on the cardiovascular effects of alcohol, and of sympathomimetics. How do they work? And how do their mechanisms interact? We know that similar pathologies ...
1
vote
0answers
67 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 ...
1
vote
0answers
46 views

Pain and Angina Pectoris

What causes pain in an angina pectoris? Ok, heart muscles may lack oxygen, but what is the role of pain here? Is it being beneficial? I'd like to know the physiological process of induction of pain ...
1
vote
0answers
44 views

effect of arterial vasocontriction on the pressure in arteries

if experimentally one induces smooth muscle contraction on an artery and cause it to constrict, keeping the cardiac output same and also the arteriolar resistance(total peripheral resistance) the same ...
1
vote
0answers
90 views

law of laplace and pressure developed in arteries

in arterioles the pressure depends on the impedance of the vessel(elasticity and youngs modulus) cardiac output pre arteriolar resistance what i want to ask is will the pressure also depend on law of ...
1
vote
0answers
28 views

How does heart rate change when entering N1 sleep?

I would like to know how the heart rate changes as a person enters N1 (NREM 1) sleep from a wakeful state. The focus is on entering N1, and it would be great to have time-series data to see the ...
1
vote
0answers
37 views

Do blood vessels expand during angiogenesis?

I know that there are two usual ways of creating new blood vessels: A new vessel sprouts from the wall of an old one, A wall of cells grows down the middle of a vessel, splitting it into two. I also ...
1
vote
0answers
60 views

Different number of flaps in heart valves

Can anyone tell me why the different valves of heart have different number of flaps is it in any way related to evolution of homo sapiens.
1
vote
0answers
23k views

Exsanguination Time from Damage to Major Arteries

For a game project, I need to study how much blood loss is suffered when the major arteries of the human body are severed. I believe there are medical textbooks that have collected data on blood ...
1
vote
0answers
35 views

State of voltage gated sodium channels in depolarised potentials

Case 1 We learn in Physiology that during the depolarization phase in the membrane, more sodium channels tend to open as the membrane potential increases i.e., less negative. This is a kind of ...
1
vote
0answers
59 views

How much Cardiomyocyte Move in Relation to its Neurons?

I am trying to estimate how much cardiomyocyte and its things (mitochondria) move in relation to neurons Movement of neurons (1) Movement of cardiomyocytes Movement of cardiomyocytes' mitochondrias (...
1
vote
0answers
38 views

Pathogenesis of Cardiac Atypia?

I am studying the pathogenesis of atypia in cardiac cells where the etiology is most commonly irritation or infection and where the precancerous risk depends on the context of diagnosis. This fact ...
1
vote
0answers
31 views

Membrane conductance in phase 1 of the cardiac action potential

Correct me if I am wrong, but in phase 1 of the cardiac action potential (for ventricle cells) there is flow of potassium ions due to the opening of transdent potassium channels. To me this would ...
1
vote
0answers
246 views

Reasons for strange heart rate graph following exercise (line going up and down)?

Following a 2 minute general jumping and movement exercise designed to involve the entire body, the pulse was taken every minute for ten seconds. Strangely, the graph appears to jump up and down, for ...
1
vote
0answers
33 views

How can hyperplasia occur in non-fetal hypokinesis?

I have read that the hypoplasia can occur in fetal hypertrophic cardiomyocytes. However, I am interested if this can be theoretically be possible in non-fetal cardiomyocytes which are hypokinetic. I ...
1
vote
0answers
76 views

Can bigger persons generally resist g-forces better?

I've seen a claim that bigger persons generally resist g-forces worse than smaller in an undergraduate biology book. However this claim was supported by the argument that blood has to travel a longer ...
1
vote
0answers
66 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 situations ...
1
vote
0answers
76 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 ...
1
vote
0answers
775 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 ...
1
vote
0answers
209 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 ...
1
vote
0answers
81 views

Which reflex arcs work in Heart with extrasystoles?

I am researching what is triggering the extrasystoles - initial idea from this thread about Which ionic channels of Pacemakers can work in very low frequencies in extrasystole? I am interested in the ...
0
votes
0answers
6 views

For how long can the heart be in asystole and then restart itself?

The medication Adenosine is used for the treatment of some abnormal heart rhythms. However, according to Wikipedia, it can cause asystole for a few seconds: Because of the effects of adenosine on ...
0
votes
0answers
12 views

Why does repolarisation of the heart start from the point where depolarisation ends?

Depolarisation moves from the atria to the ventricles and ends near the atrioventricular fibrous tissue after completing a swooping motion However, repolarisation first begins where depolarisation ...
0
votes
0answers
17 views

what are best methods for mrsa screening in hospital?

methods for screening MRSA are based on PCR (mecA detection) and MRSA latex test and culture. I need to know sensitive, specific and cost-effective methods for diagnosis MRSA infection on one work day ...
0
votes
0answers
17 views

Can the heart and other muscles function without creatine/phosphocreatine?

Skeletal muscles in the body have a small reserve of ATP. During the first few seconds after contraction, phosphocreatine is used by the enzyme creatine kinase in order to phosphorylate ADP to ATP ...
0
votes
0answers
13 views

How does a stronger heart reduce the risk of CVD?

I read from websites and articles that exercise will make your heart stronger thus your heart will use less effort to pump blood around the body per heartbeat thus reduce risk of CVD. However, how ...
0
votes
0answers
14 views

Cardiopulmonary reflex

Cardiopulmonary receptors (CPR) locate in the junction of great veins (IVC/SVC/PV) to atria. They are also known as low-pressure receptors. They detect the increase of preload to atria. Statement 1: ...
0
votes
0answers
31 views

Are there toxins that cause heart attack and/or stroke in multiple individuals in short time frames?

Are there any known environmental factors that would cause more than one person to have a heart attack or stroke within a short period of time (e.g. 2-3 months) of one another? I'm particularly ...
0
votes
0answers
22 views

How does the Sensitivity of Sokolow-Lyon indexes change by age?

I am studying the indicator and how diseases/age affect its sensitivity. However, no publication about it in PubMed and no luck in Escardio. How does the sensitivity of Sokolow-Lyon index and/or ...
0
votes
0answers
130 views

Average Beginning of Action Potential in ECG by t-f HRV

I have some ECG data where I am estimating the average beginning of the action potential. I am interested in the discrete Fourier analysis of joint t-f HRV when input data is ECG. Frequency domain ...