Questions tagged [cardiology]

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

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Definition for different arrhythmia

I am wondering if there is an organization, a document or a research that standardize all the rhythms? Such as describing how long should the ECG be flatline to be considered as asystole? The rhythm I ...
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1answer
201 views

How are monocytes larger than capillaries?

I have read that the average size of a capillary is about 8 micrometers. How is it possible that the 15 micrometer or so monocytes in blood do not block these vessels? https://en.m.wikipedia.org/wiki/...
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26 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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0answers
15 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 ...
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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 ...
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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 ...
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1answer
70 views

Is returning cholesterol to the liver really performed by HDL?

Various answers in biology SE, including two quite upvoted ones (1, 2) claim that (in humans) returning cholesterol to the liver is done by HDL. If I understand correctly, Wikipedia's Reverse ...
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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 ...
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1answer
43 views

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 ...
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4answers
233 views

Can systemic intravascular thrombosis cause brain infarction?

I wonder if the thrombus can pass through the brain-blood barrier because I think small molecules like O2, CO2 and ethanol can pass it. Probably, in some diseases where the permeability of the barrier ...
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4answers
711 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
26k 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
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When endothelial cells in blood vessels (arteries or veins) are damaged, does atheroma form first or blood clot?

I have learnt from Khan Academy's video on atheresclerosis that when the endothelial cells of an artery are damaged, atheroma forms at the site, and if the atheroma’s fibrous cap is ruptured, ...
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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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1answer
44 views

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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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 ...
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14 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 ...
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1answer
696 views

The heart of a Pigmy Shrew beats 1300 per minute then why is it so fast?

A pygmy shrew is such a small animal. Even with such fast heart beats their average life span is 1.5 years. So can we consider faster heartbeats to not be good for health?
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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: ...
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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 ...
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1answer
48 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
33 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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2answers
286 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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1answer
26k views

Arm at Heart Level when Measuring Blood Pressure

How come that one's arm has to be at heart level so that the blood pressure can be measured accurately. I've tried researching this question, but most answers to it were just "if the arm is above the ...
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1answer
61 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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What is the cause that angina pectoris is felt in your left arm?

When someone has heart problems sometimes they feel pain in their left arm. But why is the left arm painful?
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1answer
108 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
153 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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19 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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2answers
13k views

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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0answers
69 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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2answers
21k 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
146 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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Is the amount of blood that flows through every vein and artery per minute really a constant?

I was listening lectures from Mark Saltzman via Open Yale Courses. Now, if I did not understand him wrong, he said that the amount of blood that travels through every vein and artery in our bodies per ...
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1answer
57 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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129 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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1answer
1k 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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182 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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2answers
534 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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2answers
393 views

Should heart-to-body energy consumption ratio equal oxygen consumption ratio?

The human heart pumps oxygen to the body, and the heart itself requires oxygen. Both the body and the heart use energy, usually expressed in calories or ergs. If we look at the energy consumption (...
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1answer
882 views

How can a heart of human work if one of its valve is not working?

Yesterday I went to a hospital and heard a doctor say that one of the heart valves of a patient is not working. However, the patient was still alive and was healthy; the patient could walk and talk ...
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1answer
60 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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115 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 saw ...
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0answers
175 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
883 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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1answer
4k views

Can humans live without their right atrium?

The right atrium is one of four chambers (two atria and two ventricles) in the hearts of mammals (including humans) and archosaurs (which include birds and crocodilians). It receives deoxygenated ...
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1answer
129 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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1answer
29k 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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3answers
526 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, ...