Questions tagged [cardiology]

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

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51 views

Will being very muscular (to the point that one is characterised as obese by BMI) increase blood pressure?

It is widely accepted that obesity/overweight (which I believe refers to people with a high amount of fat cells instead of bodybuilders who weigh a lot due to lots of muscle cells) have higher blood ...
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1answer
37 views

Why does atheroma contain thromplastin/tissue factor?

From my understanding, when the endothelial lining of arteries is damaged, atheroma is formed at the site of the damaged area. If the atheromas is ruptured, thromboplastin contained in atheroma is ...
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1answer
103 views

Alcohol effect on heart and vascular system

How does alcohol weaken heart muscles and why does it increase blood pressure both temporarily and long term? Is the long term effect due to increase of plaque or is it due to other effects?
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134 views

Can the heart generate its own rhythm independent to the SAN?

My textbook and a revision guide, which I believe is a reinterpretation of the textbook, state that: The SAN initiates waves of excitation that usually override the myogenic action of the cardiac ...
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3answers
219 views

Why do our bodies maintain blood pressure but not the flow rate?

This might be a silly question but i'm not not clear I'm always told that blood pressure is homeostatic parameter and can't not be changed but isn't what important is the flow rate to the organs? ...
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1answer
26 views

The detail about the exact time of heart attack

Storage of cholesterol in coronary artery tends to heart attack. But in which phase heart attack occurs? Why only a definite time is called heart attack? Why this is the extreme point of coronary ...
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1answer
78 views

ECG detection using minimal number of electrodes

Disclaimer: Hello, I'm someone from an electrical engineering background, so this question may sound dumb. I wish to make a wearable ECG monitoring device for arrhythmia detection. Since the device ...
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2answers
334 views

Does blood clot reduce blood flow?

I read that blood clot reduces blood flow from few website and from doing an A level biology question; and if this blood clot is formed in pulmonary thrombosis, this can reduce gas exchange in lung. ...
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0answers
89 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 ...
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1answer
168 views

How does the cardiac cycle and electrical activity all relate to blood pressure in the heart? [closed]

I know how the cardiac cycle works and understand the electrical activity in the heart such as the AV nodes, SA nodes and Bundles, but how do they work together in relation to blood pressure?
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1answer
68 views

Structure separating the left atrium from the ascending aorta?

With reference to the (adult) anatomy of the human heart: The left atrium (LA) and the proximal part of the ascending aorta (Ao) abut one another, as shown nicely in this image [1]. Is there a name ...
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219 views

How does vasoconstriction retain heat?

I am reading on vasoconstriction on wikipedia. The article states that: When blood vessels constrict, the flow of blood is restricted or decreased, thus retaining body heat or increasing vascular ...
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326 views

What does “dissipated” mean here?

This is the context: You know cardiac muscle cells are small cells relative to skeletal muscle cells, but unlike skeletal muscle cells that are arranged in parallel and their contraction is ...
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86 views

Turbulence in blood

Turbulence in blood flow is known to indicate diseased or obstructed arteries. Techniques to measure turbulence in blood flow are mostly based on turbulence kinetic energy measurments using MRI [e.g., ...
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285 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 ...
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1answer
2k views

Heart rate vs body size

It is known that large animals have lower heart rates (beats per minute) than small animals. Is it the same situation in humans? That is: if we have a group women, about the same age and fitness, ...
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187 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 ...
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1answer
36 views

Using formulas to explain why contraction of blood vessels leads to increased blood pressure

I know, I know this is probably a question too simple to be asked on a forum like biology stack exchange. Problem is, I looked many places and can't seem to find a more mathematical approach to ...
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3answers
684 views

Why is the heart adversely impacted by chronic psychological stress, yet it benefits from routine physical exercise?

Chronic psychological stress is commonly said to be deleterious to the heart, and predispose one to cardiovascular disease. Yet the opposite is said about regular aerobic exercise. Physiologically, ...
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56 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 ...
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1answer
472 views

The 4-chambered heart

Birds and humans have a four chambered heart. All animals having 4-chambered hearts are warm-blooded. Why are crocodiles an exception? Why are they cold-blooded even though they have a 4-chambered ...
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1answer
485 views

what is the difference between osciloscope and electrocardiograph?

I am completely confused about these two devices! as far as I know, oscilloscope and electrocardiograph, both, show the heat waves(P, QRS, T) so what is the difference between their job?
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52 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 ...
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102 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 ...
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1k views

Why is the body cooled during cardiac surgery?

When undergoing cardiac surgery, the heart is disconnected from the blood circulation and blood is passed through a heart-lung machine and cooled so that the body temperature of the patient is reduced....
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347 views

why do sodium channels close with excessive extracellular potassium ions in cardiac myocytes?

When there is an excessive concentration of potassium ions outside cardiac myocytes, the membrane potential surely goes up. I would have thought that this would make it easier for the membrane ...
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201 views

Cardiac pacemaker: how can different nodes have different frequencies?

Primary SA node creates 70 beats per minute and secondary AV node 40-60 beats per minute. Is the AV node inactive (and other subsequent nodes) while the SA node is functional? If the primary, ...
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Effect of hemoglobin on colloidal osmotic pressure

If Hemoglobin gets out of RBCs, my book says that colloidal osmotic pressure of plasma increases. Hence, filtration of fluid across capillaries is prevented. So the heart increases its work to be ...
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30 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 ...
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42 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 ...
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1answer
132 views

Is this an ectopic beat? [closed]

First of all, I am unclear as to whether the answer to this question is a matter of fact or of opinion. Nevertheless, I hope to find the answer. In the image below, is the green beat considered ...
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1answer
55 views

Seizures and blood pressure

A seizure is basically a synchronized firing of neurons as opposed to the more common unsynchronized firing taking place during normal neural activities. However, I am uncertain if the exact technical ...
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23 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 ...
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1answer
593 views

Why is the pressure pulse bigger after exercise?

Right after exercise, is the amplitude of the pulse smaller or bigger than resting period? And why is that ?
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1k views

Why repolarization in ventricles start in last area which is depolarized “epicardium ” rather than first area “endocardium” [closed]

About ventricular repolarization , l know it start in the last area which is depolarized ( that is why it has positive deflection on ECG ) but the question is why it start in that area ( epicardium ) ...
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1answer
198 views

Is a one ventricle heart feasible?

So this is derived from a lesson at Khan Academy. The mind activity assumes that the one ventricle heart pumps blood to the lungs for oxygenation then rest of the body. However, the problem is that ...
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1answer
864 views

Pressure change in atria

Background:It is said that during the phase of isovolumetric contraction , due to sharp rise in the ventricular pressure, there occurs bulging of AV valves into the atria producing a small but sharp ...
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4answers
900 views

Why does an increased heart rate mean increased blood pressure?

Say a person starts exercising. If their cardiac volume remains the same but their heart rate increases so that the overall result is an increase in cardiac output, will their blood pressure increase ...
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2answers
27k views

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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1answer
695 views

Human anti animal antibodies issues in blood testing

Do people have to be exposed to animals to get HAMA antibodies? Can these antibodies impact blood tests with false negatives as well as false positives?
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2answers
120 views

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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2answers
510 views

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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1answer
37k views

How can heart disease cause excessive sweating?

According to google: What can cause sudden sweating? Excessive Sweating. A person with excessive sweating has a condition called hyperhidrosis. ... In adults, the most common cause of ...
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132 views

Trying to determine Heart Condition? ECG show no P Wave [closed]

A young woman was at the gym doing great her normal workout. She would spend 45 minutes on the elliptical and then 15 minutes doing weight training. This was the regular routine for her as she did ...
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0answers
300 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. ...
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1answer
1k 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 ...
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3answers
8k views

What prevents backflow of blood from right atrium to vena cava during atrial systole

Vena cava is valve less. So, during atrial systole what prevents backflow of blood to them?
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4answers
1k views

Why heart beats increase when we are in a state of tension even though it is a disadvantage?

Suppose a poisonous snake bites you; this will likely cause hypertension, and it will result in your heart rate increasing dramatically. Because of the high rate of heart beats, your body will make ...
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2answers
6k views

ECG wave names origin

Why do electrocardiogram waves go P, Q, R, S, T and not like A, B, C, D? Is there any specific reason behind this?