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

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158 views

What is the effect of persistent hypothermia on cardiac performance?

I define persistent hypothermia in this thread about the mechanisms of persistent hypothermia. The Graph of Katzung et al. in Pharmacology about Heart Failure: I am thinking which parts here are ...
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73 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 ...
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56 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 ...
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0answers
53 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 ...
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106 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 ...
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37 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, ...
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57 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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41 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 ...
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10 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 ...
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16 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 ...
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13 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 ...
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78 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 ...
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15 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 ...
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61 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 ...
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37 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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32 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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288 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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51 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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42 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 ...
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74 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 ?
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105 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 ...
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56 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 ...
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38 views

Can defibrillation (cardiac arrest treatment) be done with a vehicle spark plug?

Can successful defibrillation (restarting the heart after cardiac arrest) be done with a spark plug from a vehicle (possibly offroad vehicle)? Is it POSSIBLE for this to work? Let's say you are stuck ...
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10 views

Is there any range for Aortic Valve Gradient?

I understand aortic valve gradient is pressure on the value (measured in mmHg). What I would like to know is if there has been any research that identified a minimum and maximum pressure value as the ...
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13 views

reduced rate of blood flow and thrombus

How does reduced rate of blood flow cause thrombus formation? Although thrombus is usually caused due to hematoma (clotted blood mass). So, in this regard, we can say that due to thrombus formation ...
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10 views

ECG Atlases of Many Years?

I am looking for ECG data/atlases of Many years in healthy individuals of age from 6 to 40 years old. I would like to study several processes/effects occurring in years. Note the long-term ECG data ...
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5 views

How does the Sensitivity of Sokolev-Lyon indicators 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 Sokolev-Lyon indicator and/...
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51 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 ...
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8 views

Placental Adherence and Premature Heartbeat

I am studying the placental adherence in premature fetuses i.e. from 22nd week to 38th week of gestational age. About 60% of placental adherences are diagnosed during labour, which increases the risk ...
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29 views

What is the function of the Moderator band?

The moderator band in the right ventricle is a band sorts of muscle which consists of a significant branch of the AV bundle. Does it mean it delivers impulses to the anterior papillary muscle faster? ...
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24 views

Determination of Ageing by ECG inclusions/exclusions?

I am studying ageing and considering ECG signal because of its high sensitivity in theory (escardio). Some factors Sensitivity Gender Medical treatment ... Benchmark: RTG dental + wrist ...
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17 views

ECG Calibration by Infusion Pump?

I am trying to understand how to calibrate 5-lead ECG device with an infusion pump before the human calibration as described here. The system uses 5 electrodes (RA, RL, LA, LL and Chest). The monitor ...
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18 views

What is the realationship between arterial pressure and stroke volume

Frank-Starling Law says , When keep const Pvp (pulmonary venous pressure) and T ( heart period) and we increase Psa(aortic pressure or arterial pressure), Vd(end-diastolic volume) and Vr(residual ...
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63 views

What does the term pre potential mean in the pacemaker cells of the heart?

I recently read about the concept of the pacemaker potential in the heart . In this what does the term pre potential refer to ? Is it the same as the pacemaker potential. This is because one of the ...
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6 views

How much potential from heart reaches the chest

I learn about the ECG waveform of heart potential.How much voltage will actually reach our skin which is developed in the heart(from Sinoatrial node).What will be the approximate voltage range when it ...
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56 views

Is the molecule nitric oxide responsible for healing blood vessels?

Is the molecule nitric oxide responsible for healing blood vessels? How does nitric oxide heal the blood vessels? I watched a documentary about the healing effects of nitric oxide. In the video I ...
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80 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 ...