Questions tagged [cardiology]
The study of the physiology and pathology of the heart and the cardiovascular system.
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How did the cardiovascular system evolve?
How has evolution created our blood, lungs and the heart?
We can't exist without blood, which transports the oxygen to all areas of our body. However, the blood needs a lung, which gives it the ...
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Extremely rare occurence of Heart cancer?
The occurrence of Heart cancer (similar, but not the same as Rhabdomyosarcoma) is extremely rare, about 1 per year according to MayoClinic. The reason for this rarity is explained to be the post-...
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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 it'...
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How quickly can the human heart rate rise and fall?
How quickly can the human heart rate rise and lower?
For example lets say a human heart rate is rested and is at 60BPM and that person is suddenly scared to trigger their fight or flight reaction. ...
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Why is blood pressure higher the more distal an artery is?
Why is blood pressure generally higher in more distal arteries?
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Why does the apex of the human heart usually point to the left?
In the majority of human beings, the apex of the heart (left ventricle) points towards the left side of the body. Sometimes however (approx. 1/12000 births), a person is born with a condition known ...
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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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Why is the heart not in the middle of the body?
All mammals that I can think of have a high degree of bilateral symmetry (In fact, almost every animal I can think of is like this).
So why is the human heart not exactly in the middle of the body? ...
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How is the blood volume of a living organism measured without killing it?
How is the blood-volume of an organism measured without killing it?
Note:The blood-volume of an organism is defined as the total volume of blood present inside that organism.
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Why does the face turn pale in dangerous situations?
I know what the effects are of a dangerous situation on the brain, i.e., an activation of the hypothalamic-pituitary-adrenal (HPA) axis which eventually results in an increased heart rate and elevated ...
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Will the heart keep beating if it's separated from the body?
The heart is a vital organ in our body, as it drives blood circulation. I was wondering if a heart keeps beating if it is separated from the body? If yes, then why?
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How does sodium in one's diet affect blood pressure?
Due to high blood pressure, my doctor has recommended I go on a low-sodium diet. So, that got me wondering what it is about sodium that drives this recommendation?
What does sodium do to a body that,...
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How does Bernoulli’s Principle apply to the cardiovascular system?
Below are graphs which illustrate the cross-sectional area, velocity, and fluid pressure through each vascular segment of the cardiovascular system.
It makes sense that velocity and cross-sectional ...
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Why do people say that trans fatty acids are bad for your health?
I've heard from several sources that trans FAs are bad for you and their consumption will lead to cardiac problems, and that they are indigestible.
But I also learned from biochemistry that they are ...
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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 ...
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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 ...
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Why can't we defibrillate the heart within 1 minute after ventricular fibrillation by electroshock?
We mostly can defibrillate the heart before 1 min of ventricular fibrillation by electroshock.Then we often can't do defibrillate it with electroshock.
What's the reason and What's the best way to ...
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Why do the size of the phase 1 notch vary among cardiac cells?
The size of the phase 1 notch varies among cardiac cells. It is prominent in myocytes in the
epicardial and midmyocardial regions of the left ventricular wall and in ventricular Purkinje fibers. ...
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How can we measure cardiac output?
I could find a way which could find it by body oxygen consumption and there is another way to measure it by injecting drugs — measuring cardiac output by the so-called “indicator dilution method,” a ...
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How does heart beat faster while doing a strenuous task?
I know that when we do tasks which require extra physical effort (like running etc.), our heart beats faster.
I also know that the reason behind this is that these jobs require more energy than usual ...
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How do veins's valve pocket sinus tend to become hypoxic?
For context, this question relates to the formation of deep vein thrombosis as I read that hypoxemia in vein can trigger coagulation cascade and cause a thrombus to form in vein.
I read that vein's ...
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Why do people perceive blood pressure as the force that moves the blood forwards (see details)?
For example "Veins contain a lot of valves because the blood pressure inside them is low.". This wouldn't make any sense unless if blood pressure was perceived as the force that drives the blood ...
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Can stress echocardiography show coronary blood flow difference before and after exercise?
Stress echocardiography means a pair of cardiac ultrasound imaging examinations, before and after exercise. I assume that coronary blood flow is increased after exercise. Is cardiac ultrasound ...
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Why is elevated homocysteine considered a risk factor for angina?
Elevated homocysteine levels are listed among risk factors for angina. How is homocysteine related to the heart? Or the coronary arteries? How do these relationships make it a risk factor for angina?
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Why can we control our breath rate but not our heart rate? [closed]
Even though we cannot survive for more than few minutes if we stop breathing or if our heart stops, why is it so that our heart beat is controlled involuntarily while breathing can be voluntarily ...
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Why is pericardium muscle repolarizated earlier than endocardium? [closed]
I was reading about heat muscle contraction and I read:
The endocardium depolarization happens earlier than pericardium , but
pericarduim repolarization happens earlier, therefore the T wave in
...
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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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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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At what stage is the nervous system developed enough to interpret neuronal signals as 'pain'?
According to this article in Live Science, one of the reasons the fetus can't feel pain until 19 weeks is because the nervous system isn't fully developed.
But according to this article, the heart ...
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Are there any forms of heart failure where cell size decreases?
I think hypertrophy happens in most of the cases. However, I am not sure if hypertrophy always happens. I started to think about wet lungs (pulmonary reason for the left-sided heart failure).
Can the ...
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Which ionic channels of Pacemakers can work in very low frequencies in extrasystole?
At frequency 0-3 Hz.
Like computer processors which can work at low frequencies and controlling under- and overvoltage.
Normal most significant channels are Ca2+ and K+ that are changing.
However, I ...
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Manifestations of open foramen ovale in adults
I read that foramen ovale opens in 30% of adults.
I do not know how much of these openings can then close again.
Probably, none.
It is not pathogenic if no symptoms.
It allows blood to enter from ...
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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 (...
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What's seen when stress echocardiography shows ischaemia? Can this happen without angina?
What can be seen on the screen when stress echocardiography (a pair of heart ultrasounds before and after exercise) suggests ischaemia? Can this happen without chest pain?
Illustration from Wikipedia:...
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Cardiac cycle and atrial contraction
During atrial contraction ("a" in the figure), why does the ventricular pressure match the atrial pressure? The ventricular pressure generally stays the same throughout passive filling until it ...