Questions tagged [cardiology]

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

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2
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1answer
231 views

Physiology of tricuspid and bicuspid(mitral) valves

The tricuspid and bicuspid valves are atrioventricular valves. Both are valves that prevent backflow of blood pumped from the atria to the ventricles. However, the former has 3 "flaps" while the ...
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3answers
30k views

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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1answer
674 views

Does our heart stop when we sneeze?

Is it fact or myth that our heart stops beating for moments when we sneeze? If it is fact, what drives the heart to start beating again?
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4answers
43k views

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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1answer
2k views

How does amiodarone act as an alpha and beta blocker?

Amiodarone is potassium channel blocker but also voltage-gated Na+ channel blocker according to Pubchem. However, upon reading my notes I discovered Amiodarone blocks potassium channels and block ...
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1answer
40 views

What does this sentence about angina mean?

I do not understand this sentence Angina can be treated ambulatory (in out-patient) in stable angina. I think ambulatory refers to ambulatory ECG monitoring. So I understand this that you can ...
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1answer
5k views

Why is Electrical Cardioversion contraindicated in AF and Digitalis Poisoning?

I am thinking why electrical cardioversion is contraindicated in atrial fibrillation with digitalis toxicity/poisoning. Cardiac digitalis is also called digoxin and cardiac glycoside. It is ...
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1answer
1k views

Is missing Q wave characteristic for Wolff-Parkinson-White Syndrome?

No my study books says about that no Q waves in WPW syndrome. They are about wide QRS complex often however. I heard today that the characteristic property of WPW is often a missing Q wave, like here ...
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1answer
500 views

Explanation of ECG in MI using an electrostatic model

I found a paper presenting an electrostatic model to explain the ECG recorded in various leads. This model essentially calls for considering the depolarization wavefront to be the major contributing ...
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1answer
1k 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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0answers
1k views

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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4answers
1k views

How to analyse an ECG?

I have a project about extracting features from a homemade ECG. I need the PQRST points from the signal of the heart beat. The ECG I'm using has 3 electrodes that attach to the chest. The problem is ...
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2answers
19k views

How long do the periods of systole and diastole last?

The background to this is i'm doing some work using ECGs for an animation of the heart and i'm having trouble defining the end points of these periods, particularly diastole. Currently, the only ...
2
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1answer
484 views

What is the insight of Frank Starling law of the heart?

The Frank Starling law appears to be a trivial observation: stroke volume is directly related to the end diastolic volume In everyday language, as more blood fills the heart, the heart pumps more ...
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1answer
872 views

What causes a small bump in the arterial pressure plot?

In my book there is a plot of the arterial pressure against time. From the plot, during heart contraction, there is greater pressure on the artery and during heart relaxation, there is lower amount ...
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1answer
431 views

Similarity between a heart attack and a spasm

When someone is having a heart attack, could it be considered , in some situations, a spasm? Below, I have written how I believe the process may work. The heart is basically a muscle working ...
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4answers
2k views

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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2answers
2k views

Is hands-only CPR as effective as traditional CPR?

Is hands-only CPR as effective as traditional CPR ? Wouldn't 30 chest compressions + 2 rescue breaths be more effective if the person doesn't have a pulse AND not breathing? From my understanding (...
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1answer
476 views

Normal ECG/EKG Measurement?

I'm getting started using ECG using a 3 lead system by iWorx. I have place the leads on my two wrists and the ground on my ankle and have recorded some data into the provided LabScribe 3 software ...
3
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1answer
28k 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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0answers
102 views

What's Incomplete atrioventricular heart block (AV)? [closed]

This is unclear for me and I can not understand differences between complete and incomplete atrioventricular heart block.also I want an electrocardiograph of incomplete atrioventricular heart block.
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46 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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1answer
1k views

Biphasic T wave caused by digitalis toxicity

Digitalis is a drug that can be used during coronary insufficiency to increase the strength of cardiac muscle contraction. But when overdosages of digitalis are given, depolarization duration in ...
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1answer
5k views

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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1answer
3k views

How can heart disease cause dizziness after eating?

I have been reading several articles explaining dizziness after eating (see here and here), and both articles gloss over something that I found pretty remarkable. Both articles claim that "heart ...
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1answer
281 views

Heart Rate being normal when under treatment for the bends

When you surface from diving too quickly; you get "bends" - these are caused by gas bubbles forming in your lungs (especially nitrogen). This causes breathing problems if not treated since the bubbles ...
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2answers
1k views

What happens when the brain is no longer capable of co-ordinating or regulating the heart and breathing rates? [closed]

Does the heart no longer function? Does it go into ventricular fibrillation? What happens?
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3answers
4k views

How does vasoconstriction/vasodilation change blood pressure?

Background: I am coming at this question from an electrical engineering background, and I feel like I am missing certain assumptions that are going into the statement found in my physiology textbook, "...
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1answer
242 views

What shows how healthy someone is by their heart rate? [closed]

What shows how healthy someone is by their heart rate - how low it is at resting pulse or how low it is during exercise or how large the difference is between the resting rate and rate with load? Any ...
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2answers
10k views

What’s the reason for isovolumic contraction and isovolumic relaxation?

During cardiac cycle, there are two periods in which the heart volume doesn’t change, but there is a change in tension/pressure. It takes about 0.25-0.35 second to achieve this change. I searched in ...
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2answers
539 views

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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1answer
593 views

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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119 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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1answer
544 views

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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1answer
137 views

Why is sarcoma more prevalent and common in right heart?

Ewing's sarcoma or Ewing sarcoma is a malignant small, round, blue cell tumor. It is a rare disease in which cancer cells are found in the bone or in soft tissue. It is more common in right heart than ...
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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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2answers
919 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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2answers
729 views

Why don't we see turbulence in the aorta even in normal situations?

I read about the Windkessel effect. Then I read about pulse pressure waves getting reflected from the periphery. If the pulse pressure wave is reflected during diastole and at the same time blood is ...
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1answer
185 views

Spironolactone's role with adrenergic agents in heart failure?

I am studying the treatment plan of adrenergic agents for heart failure. Then, in the group discussion, spironolactone was included. But I cannot understand how it is relevant when considering ...
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0answers
56 views

Maximum heart rate increase/decrease while physically active [duplicate]

I'm a computer scientist and implementing a heart-rate monitor for physical exercise. While I try to improve my code, I stumbled over the question how fast the heart rate can change within a given ...
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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 ...
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1answer
2k views

Does physical exercise following lack of sleep increase the risk of sudden cardiac death (SCD)?

Is there any scientific evidence supporting the hypothesis that physical exercise following lack of sleep increases the risk of sudden cardiac death (SCD)? The only relevant research I could find is: ...
4
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1answer
242 views

Does transplanted heart have full sympaticus without medication?

I am reading this and this where I am considering this sentence [N]o baseline parasympathetic innervation [in transplanted heart]. Does this sentence imply that the heart work then in full ...
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0answers
103 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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1answer
130 views

Why is heart failure treated as more critical than kidney failure?

The heart pumps the blood to supply tissues and kidney always filters the blood to remove urea,extra water and etc. And all these are vital,so the kidney is as important as heart: and my question is: ...
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2answers
187 views

Are Purkinje Action Potentials Neuronal and Cardiac?

I first thought that action potentials of His-bundle i.e. Purkinje fibers are Cardiac. However, I started to think that this is not enough. I think now that they are neuronal and cardiac. My ...
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0answers
133 views

Why does a pacemaker have a negative pulse? [closed]

Why is the first phase of the pulse from a pacemaker cathodic?
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1answer
89 views

Can Omega 3 Fatty Acids prevent chest pain in periodic Atrial Fibrillation?

It is debated if omega-3 polyunsaturated fatty acids (N3PUFa) may be effective in preventing AF (atrial fibrillation), meta-analysis here. However, much less has been considered this: Do N3-PUFAs ...
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1answer
72 views

Any databases with AAMI ECG and ECHO?

There is no AAMI 12-lead ECG databases available online. All of them have problems. I and my friends finally finalised our tests with St Petersburg. It is not AAMI. So the next step is to search ...
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2answers
653 views

What is the name of the condition where no pacemaker cells are active in the heart for a short-time?

Assume that the heart is beating, but no pacemaker cells are working for at least 15 seconds. This would be a very long compensatory pause if extrasystole started it. There may be some low frequent ...