Cardiovascular System Flashcards
First heart sound
Closing of the AV valves. First mitral than tricuspid.
Systole
Events associated with ventricular contraction and ejection, short part of the cardiac cycle.
Diastole
Events associated with ventricular relaxation and filling, long part of the cardiac cycle.
Chronotropic
That influence the heart rate.
Dromotropic
Affect the conduction speed in the AV node, therefore the rate of electrical impulse on of the heart.
Inotropic
Affect the force/energy of the contraction of the heart.
Vagal / parasympathetic activation of the heart
Decrease chronotropy, decrease dromotropy and decrease inotropy by releasing acetylcholine.
Sympathetic activation of the heart
Increase in chronotropy, increase in dromotropy, increase in inotropy by releasing noradrenaline.
What controls the heart rate ?
The sinoatrial node is the pacemaker of the heart, it is innervated by the vagal efferent fibres to prevent the heart from having a too high frequency of beat.
What happen to the duration of the cardiac cycle when the heart rate increase.
The diastole phase shorten, the cardiac cycle last less than 1s.
Third heart sound
Pathological signs after 40 of fatigue of the ventricles that became too stiff. Heard during the filling phase.
What method do you use to auscultate the heart ?
All Patient Take Med
Aorta (right up), Pulmonary (left up), Tricuspid (right down), Mitral (left down)
Second heart sound
Closing of semilunar valve. First aortic valve then pulmonary valve.
How do the AV valves close ?
Pressure in the ventricles exceed pressure in the atrial, then the papillary muscle and their attached chordae tendinae contract preventing the AV valves leaflets from bulging back.
What does the Frank-starling law say ?
Preload volume increase ==> EDV increase ==> pressure increase
Preload volume decrease ==> EDV decrease ==> pressure decrease
Afterload volume increase ==> pressure increase ==> stroke volume decrease
Afterload volume decrease ==> pressure decrease ==> stroke volume increase
What does the preload affect ?
It influences the interaction between the myosin and actin forming the muscle contraction. The higher it is, the stronger the connection between the two will be.
Parasympathetic efferent fibres
Vagus nerve
Sympathetic efferent fibres
Cardiac nerve from the lower cervical and the upper thoracic ganglia.
Autonomic nervous system
Both the sympathetic and the parasympathetic. Consist of autonomic nerves conducting impulse from the central nervous system to the glands, smooth muscle and cardiac muscles.
Cardiac output
Total blood flow pumped per minute
Stroke volume
EDV minus ESV
Pressure gradient
Difference between the atrial and ventricular pressure.
Total energy of blood
Sum of the pressure energy and the kinetic energy (which is the square velocity of the blood flow).
What is a physiological shock ? What are the major causes ? What are the main symptoms ?
Life threatening clinical state characterised by deficiency of blood supply.
Caused by allergic reaction, significant blood loss, heart failure, blood infection,dehydration poisoning and burn.
Symptoms : low blood pressure, weak pulse, confusion, thirst, low glucose level, bone fracture, organ rupture,…
What is hypovolemic shock ?
A problem in circulatory blood volume. There isn’t enough blood in the vessel to carry the oxygen. Caused by internal or external blood loss.
What is angina ?
Chest pain caused by reduced blood flow to the heart muscle.
What are the most common symptoms of myocardial infraction ?
Chest pain (burning, squeezing, heaving feeling) and dyspnea.
What is the relationship between the levels of troponin and the cardiovascular system ?
One hour after myocardial damage, the level of troponin 1 can be detected.
When would crackles be heard ?
Heard in the lungs of patient when they have a left sided heart failure.
What is cardiac tamponade ?
A pathology where the pericardium is filled with fluid, more often blood.
What is a cardiac catheterisation ?
A test to determine if there’s coronary heart disease and to determine its location.
What are the secondary symptoms of right sided heart failure ?
Oliguria, nausea and weight gain.
What is acute heart failure ?
Rapid or gradual symptoms of heart failure leading to unplanned hospital admission. Leading cause of hospitalisation over 65 years old.
What instruments/methods do you use to diagnose acute heart failure ?
Electrocardiogram, pulse oximetry, echocardiography, labs, chest x-ray, lung ultrasound.
Natriuretic peptide testing
With what result of a natriuretic peptide testing is acute heart failure confirmed ?
BNP ≥ 100 pg/mL
NT proBNP ≥ 300 pg/mL
MR proANP ≥ 120 pg/mL
- mid regional pro atrial natriuretic peptide
What is the role of natriuretic peptide in HF?
They play important cardioprotective roles. During HF, due to strains caused by high ventricular filling pressure and increased exposure of neurohormones, the ventricles will be stimulated to secrete ANP and BNP.
What are the types of natriuretic peptides ?
Atrial natriuretic peptide (ANP) secreted in the atrium and brain natriuretic peptide (BNP secreted in the ventricles :
- antagonist effect to angiotensin => diuretics actions, vasodilatation and inhibition of aldosterone
C-type natriuretic peptide (CNP) is expressed in the vasculature, CNS and bone.
- regulate vascular tone and BP
What is the most common form of acute HF?
Acute decompensated heart failure : sudden or gradual onset of signs of HF requiring medical attention.
Findings : pulmonary and systemic congestion due to increased left and right heart filling pressure
What is physiologic shock ?
Life threatening clinical state characterised by body wide deficiency of blood supply causing oxygen depreciations, buildup of waste products and eventual organ failure.
What are the first signs of shock ?
Low BP, weak pulse, rapid heartbeat.
What are the different kinds of shock ?
Hypovolemic shock : severe reduction of the circulating volume of blood, leads to oxygen being unable to be transported.
Cardiogenic shock : severe heart dysfunction, where damage to the heart leads to hypoperfusion.
Obstructive shock : obstruction of blood flow in a major circulatory vessel
Distributive shock : loss of the blood vessel tone leading to decrease in BP
What are the causes and symptoms of hypovolemic shock ?
Caused by :
- External or internal blood loss = hypovolemic hemorrhagic shock
- Ectopic pregnancy
- fluid loss : excessive vomiting, urination or burns
- serious dehydratation
Symptoms : high HR, vasoconstriction, cyanosis, dizziness, confusion, fainting.
What are the causes of Cardiogenic shock ?
Most common : left ventricular failure
Acute ischemia, papillary muscle rupture ventricular septal rupture, cardiomyopathy, acute myocarditis, cardiac tamponade, myocardial infarction, arrhythmia, valvular disease.
What are the symptoms of Cardiogenic shock?
Wet and cold skin, dyspnea.
Low BP, low CO, high HR ( in most case but because the heart is the problem bradycardia is also possible)
What are the causes of obstructive shock?
Pneumothorax, hemothorax, cardiac tamponade, pulmonary embolism.
What are the type of distributive shock ?
Sepsis : blood poisoning caused by infections. The pathogens lead to serious damage to the tissues and organs while the immune system results in vasodilatation and fluid leakage.
Anaphylactic shock : body mistakes a harmless substance as harmful
Neurogenic shock : damage to CNS due mostly to spinal cord injury. The sympathetic tone is lost and blood vessels dilates.
What are symptoms of distributive shock ?
Low BP, varying CO, high blood lactate.
Brain damage
Lack of blood flow to the kidney.
Cold, sweaty or bluish warm skin.
