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Questions tagged [cardiology]

the branch of medicine that deals with diseases and abnormalities of the heart.

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Myocardial and Pacemaker Action Potential

I recently learned the Myocardial and Pacemaker Action Potentials and had some doubts regarding them. Do structures other than the SAN and AVN (Bundle of HIS and purkinje fibres)exhibit the pacemaker ...
ynm1_1's user avatar
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5 votes
1 answer
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Hypoxia effects on circulatory system

In the latest edition of Harrison’s Principles of Internal Medicine it is said that “acute hypoxia stimulates the chemoreceptor reflex arc to induce venoconstriction and systemic arterial vasodilation”...
Andrés's user avatar
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How common is tachycardia as a symptom of COVID-19?

How common is tachycardia as a symptom of current COVID-19 infection? I have found quite a bit of information about tachycardia after COVID, such as this paper and this Cleveland Clinic article, but ...
Someone's user avatar
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2 votes
1 answer
79 views

ECG: vector perpendicular to lead axis and its pattern

I have come across a contradiction while learning about ECG. Some sources say that a biphasic deflection (two waves of same size but of opposite directions) is drawn on ECG tracing if the electrical ...
Mario Bedon's user avatar
1 vote
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Why is there a rapid ejection phase followed by a slow ejection phase in isotonic contraction, why isnt this a steady rate?

Trying to work our how the cardiac cycle works by gaining a deep understanding, would appreciate any explanations which go into such depth and what variations we may see if this was a pathological ...
Leona's user avatar
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3 votes
1 answer
107 views

What limits the VO2 (rate of oxygen consumption) in individuals?

I am quite confused regarding what limits the VO2 max, options are (1) number of mitochondria or (2) the ability of the cardiovascular system to deliver oxygen to tissues. I believe it should be the # ...
helplessstudent147's user avatar
1 vote
2 answers
214 views

How does blood flow change between systolic and diastolic phases?

Summary What is the change in flow between systolic and diastolic phases specifically in the muscular arteries? There is a lot of information on how pressure changes between these phases (see graph) ...
Luke Hamilton's user avatar
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40 views

Does an increased heart rate from stimulants train the heart as if the increase came from exercise?

Bottom line it will probably be unhealthy - but if the effect on heart fitness is viewed in isolation?
Adler's user avatar
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Should we invert other ECG leads if aVR was positive?

I would like to seek your kind guidance in understanding the right way of solving this question. (for the context, so far we only covered normal ECG and axis deviation) The question displays all 12 ...
helplessstudent147's user avatar
1 vote
1 answer
259 views

How to determine QRS voltage from ECG?

Attached below is a question from my textbook "Guyton and Hall Textbook of Medical Physiology Review, 4e" and I am confused because the solutions manual has the answer as B (0.5mV), implying ...
helplessstudent147's user avatar
0 votes
1 answer
38 views

Why are some guidewire's tips bend for endovascular interventions?

I am working in a medical-physics field and want to summarize some information about guidewires. I have read, that guidewires can sometimes have their tip bend slightly in one direction, in order for ...
the2second's user avatar
2 votes
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49 views

Are there any recent studies of the incidence of atrioesophageal fistula as a complication of cryoballon ablation for afib?

I have found some reports online after searching and although the paper is 2018 the studies referenced may actually be considerably older and the technique may have been improved since then. Surely I ...
Sedumjoy's user avatar
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1 answer
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Pressure volume curve; Is it wrong ESPVR?

ESPVR is a straight line passing through the upper left corner point of the pressure volume curve and such that the x-intercept is the dead volume of the ventricle; as far as this definition is ...
Blue Various's user avatar
1 vote
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61 views

What is the difference between the vasomotor center and cardiovascular center in the brain?

The vasomotor center is introduced as the following in our coursework: The vasomotor center is located bilaterally in the reticular substance of the medulla and lower third of pons. It contains the ...
Filthyscrub's user avatar
8 votes
2 answers
122 views

How is adding up action potentials equivalent to measuring the direction of depolarization vectors?

An ECG of the heart measured from lead II looks like this: I have seen two ways of arriving at this image, the first is by considering the depolarization and the repolarization vectors and their ...
Cosmic Dust's user avatar
9 votes
1 answer
1k views

Why doesn't water enter the venous system if injury happens far underwater?

If I expect a maximum central venous pressure of 5 mmHg in a peripheral vein, why doesn't water enter the system if a diver underwater injures themself?
Adler's user avatar
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Myocardial infarction treatment [closed]

During a myocardial infarction, as an immediate treatment, we must try to decrease the workload of the heart so that it will not require the extra oxygen that it would need and cannot get due to the ...
Drita Raci's user avatar
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1 answer
48 views

CAR-T therapy for cardiac sarcoidosis?

Do you know whether CAR-T therapy to replace fibrotic cells in the heart might apply to scarring from cardiac sarcoidosis? The articles below are from Penn research that shows they are able to replace ...
M Katz's user avatar
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EKG reading question [closed]

Can someone tell me what "ETRSR1-RSR' in V1 or V2, right VCD or RVH-QRS area positive & R' V1/V2 " means? In other comments it also said "otherwise normal EKG"
Ashely Cox's user avatar
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24 views

What happens to cations after depolarization/repolarization in cardiac muscle?

In the depolarization/repolarization of the cardiac cell cations such as sodium, calcium, and potassium flow in and out of the cell creating an action potential. My question is what happens to these ...
webworm's user avatar
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21 views

Cardiac events/Myocardial infarction from 1 clinic or 1 large city daily data

Requesting help in finding a DAILY data about cardiac events/myocardial infarction from 1 clinic or 1 large city, i.e. day by day number of events for at least a month. It is very easy to find this ...
Kostya's user avatar
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Cardiopulmonary capacity assessment

Is it possible to determine someone's cardiopulmonary capacity from organ/tissue/blood samples alone? No other clues allowed. Think about a non cooperative patient, who can lie in an anamnesis, or ...
rslemos's user avatar
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3 votes
1 answer
109 views

How does a cardiopulmonary bypass machine continue circulation without cutting off circulation to the pulmonary veins and artery?

So, my first stop in trying to answer this question was on Johns Hopkins website, but they are way too vague about the procedure, especially the use of a cardiopulmonary bypass machine. The only ...
Curious Layman's user avatar
0 votes
1 answer
59 views

Phases of cardiac cycle

what is the correct sequence for cardiac cycle Sequence 1: a. Atrial systole b. Ventricular systole c. Combined diastole Sequence2 a. Atrial systole/Ventricular diastole b. Ventricular systole/atrial ...
CREATIVITY Unleashed's user avatar
3 votes
1 answer
280 views

How does a prosthetic heart valve "burst"?

I have a friend who's father died suddenly, and the coroner described the cause as his prosthetic heart valve "bursting." Can someone illustrate in words what that means, and would heart ...
Chris Fedele's user avatar
1 vote
1 answer
53 views

How do I measure my resting heart rate?

I measured my sitting down, relaxed, not moving heart rate, which is around 65-80BPM. If I do the same measurement laying down, it's anywhere from 50-65BPM. While asleep, it dips into the 40s. The ...
eddiewastaken's user avatar
1 vote
0 answers
15 views

Why in Brockenbrough-Braunwald-Morrow there is a paradoxical decrease in arterial pulse pressure?

The article here tells that in HCM due to ventricular premature contraction there is enough time for dilatation of ventricular filling which increases end diastolic volume thereby increasing ...
Sikander's user avatar
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5 votes
1 answer
104 views

Bradyarrhythmia & Bradycardia- same or different?

Do Bradyarrhythmia & Bradycardia denote same abnormality or are there some finer differences between the two?? In text provided by my college, it appears bradycardia condition comes under the ...
Pearl Dua's user avatar
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0 answers
14 views

Why does LDH-1 peak later than CK-MB in acute myocardial infarction?

As a marker of AMI, different enzymes are used. Creatine Kinase-MB peaks within 24 hrs and returns to normal relatively quickly. Where as LDH-1 peak appears later (~72 hrs) and stays high for a week. ...
ANA negative's user avatar
2 votes
0 answers
106 views

Bulbus aortae is a part of aortic root, then where are the two measurements taken?

I would like to clarify my understanding because anatomy atlases do not provide me an explanation. As far as I know, the aortic bulbus is a part (the widest, the sinuses of Valsalva) of the aortic ...
John V's user avatar
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-1 votes
1 answer
53 views

Could an increase in heart strength result in an increase in systolic blood pressure? [closed]

If someone begins intense cardio training and develops their heart muscle, it seems to me that the increase in volume of blood that the heart can pump with every beat might manifest as a higher ...
Nathan Wailes's user avatar
1 vote
1 answer
804 views

What does primary, secondary and safety outcome of a drug study mean?

I was reading a research article and came across this: We studied 55 outcomes of interest, including both effectiveness and safety endpoints. We divided effectiveness outcomes into three primary ...
The Great's user avatar
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2 votes
0 answers
39 views

Why can't JVP be measured in a standing or supine position?

While carrying out the jugular venous pressure (JVP) examination, the patient is kept at a 45 degree angle with respect to the ground. Why can't it be measured in a standing or supine position?
chinmai's user avatar
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1 vote
0 answers
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How to differentiate Split S2 from Mitral valve prolapse murmur?

If history is not available or doesn't gives a clue about the pathology, is it still possible to tell whether it is MVP or Split S2 due to pulmonary valve problems? Both split S2 and MVP's murmur( the ...
Physicsapproval's user avatar
1 vote
1 answer
63 views

Can I calculate the blood pressure and pulse based on a given blood loss

Is there a function, graph, guideline or rule where I can see how a change in blood volume changes other relevant values? E. g. for every 1% of blood volume lost, heart rate rises 2 beats per minute, ...
Maritn Ge's user avatar
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0 votes
1 answer
33 views

What does NKX2-5 do?

Where is the gene 'NKX2-5' located and what is its function? How is it relevant to developmental disorders?
Andrew's user avatar
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3 votes
1 answer
2k views

Why do semilunar valves not need tendinae but atrioventricular valves do?

Inside the heart the atrioventricular valves (AV) have chordae tendineae to prevent the backflow of blood into the atrium when the ventricle contracts. Since the AV and semilunar valves are ...
John Hon's user avatar
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2 votes
0 answers
114 views

Should people with tachycardia avoid choline supplements?

After doing some brief research online it appears choline can have an effect on the electrical system of the heart, there are several medical papers online that discuss this topic, however I'm not ...
bobwiley's user avatar
5 votes
2 answers
654 views

Does COVID-19 cause myocardial infarctions?

I heard that NYC hospitals are seeing an increased cases of myocardial infarction with higher mortality than normal during this COVID-19 pandemic. What the connection is between COVID-19 and ...
D.Tan's user avatar
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1 vote
2 answers
51 views

Can aortic stenosis lead to arrhythmia?

As I understand, Aortic stenosis restricts the blood flow from the left ventricle to the aorta, this restriction should cause a disruption in the pumping of blood. That would cause the heart to beat ...
Neel Shukla's user avatar
1 vote
0 answers
28 views

Beginner runner/jogger heart rate question [closed]

I am an it guy 220 lbs 6ft1 35 years old. With chest strap measurement my maximum heart rate is around 192 bpm. (Did warmup and 3 minutes thread mill intervals to measure) For a long period of time, ...
tekrunner2k's user avatar
1 vote
0 answers
13 views

Why do changes in Effective Refractory Period in Response to Antiarrhytmics occur and how do they help in treating the arrhythmia?

I am having trouble understanding two related concepts. First, why changes in ERP occur when there is the administration of certain antiarrhythmics (eg: Class IC). A neat explanation that I have ...
abacus143's user avatar
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1 vote
0 answers
23 views

Difference in heart muscle tissue growth (cardio vs low-rep intense weight lifting)

Below is a quote from a subreddit that says: I haven't kept up on the research, but the last thing I read back in college looked at weight lifters and long distance runners. Both types had larger ...
ZenVentzi's user avatar
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1 vote
1 answer
34 views

What is the functional difference between cardio-pulmonary and the baroreceptors in the regulation of Blood pressure?

Guyton mentions two types of receptor- the baroreceptors and the cardiopulmonary receptors- that are involved in the maintenance of the acute changes in blood pressure. I just wanted to know how these ...
abacus143's user avatar
  • 453
3 votes
1 answer
86 views

What causes a notch in the atrial pressure?

I wanted to know why there is a sort of fluctuation in "E" in the tracing of the atrial pressure right before the mitral valve opens (not the notch because of the Aortic valve closure). Source for ...
abacus143's user avatar
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1 vote
1 answer
78 views

Heart Sound Samples

Does anybody have helpful sources/links that are basically recordings and playbacks of heart sounds (normal/ abnormal/ etc.) that I could just listen to while in my spare time? I am looking for ...
abacus143's user avatar
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1 vote
1 answer
130 views

Do cardiologists learn nutrition as part of their expertise in Cardiology?

Almost all physicians I recognized as suggesting medicinal nutrition either as direct therapy, preventive medicine and via "popular medicine" as with books and articles, were Cardiologists; to a ...
user avatar
3 votes
1 answer
289 views

Ventricular diastolic pressure?

So, I have been wondering and couldn't find texts explaining this, but why is the diastolic volume of the circulation ~80, while that of the ventricles is almost 0. To phrase it another way, why does ...
abacus143's user avatar
  • 453
2 votes
2 answers
79 views

Are defibrillator leads actually clashed against each other?

In movies or television, the doctor gets giant heavy clothing iron sized leads. Clashes them together and uses them on the patient that has a flat lined heart and after doing it 1 times per second ...
Delta Oscar Uniform's user avatar
1 vote
1 answer
255 views

Acceptable Macronutrient Distribution Range [closed]

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2674146/ I found some papers suggesting AMDR is not the optimum and it is too high on carbohydrates in particular. Is it generally safe to undergo a 27....
George Ntoulos's user avatar