Term
| name the triangle that describes the way an electrocardiogram is set out |
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Definition
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Term
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Definition
to test for clinical abnormalities in the conduction of electrical activity of the heart.
it is non-evasive, external measure of the heart's electrical activity. there are no indication of physical defects caused by an ECG |
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Term
| what does the body act as in an ECG? |
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Definition
a conductor
the currents spread to the surface |
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Term
| a normal ECG consists of a P wave, a QRS complex and a T wave. what do each of these represent? |
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Definition
P wave = depolarisation of atria
QRS = ventricles depolarise
T wave = ventricles repolarise (K+ moving out) |
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Term
| how is atrial depolarisation depicted on an ECG? |
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Definition
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Term
| how is ventricular depolarisation depicte on an ECG? |
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Definition
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Term
| how is ventricular repolarisation depicted on an ECG? |
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Definition
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Term
| on an ECG what does the PQ segment depict? |
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Definition
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Term
| on an ECG what does the QT segment depict? |
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Definition
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Term
| on an ECG ventricular diastole is depicted by which interval? |
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Definition
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Term
| cardiac arrhythmias can result from the abnormal firing of whihc node? |
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Definition
| the abnormal firing of the SA node |
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Term
| what is a fast abnormal heart rate known as? |
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Definition
Tachycardia - fast
sometimes on an ECG tachycardia has an inverted T wave |
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Term
| what is a slow abnormal heart rate also known as? |
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Definition
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Term
| heart block occurs in varying degrees, through the slowed/ diminished conduction through which node? |
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Definition
the AV node.
in slowed AV node conduction we see an increased PQ segment - delay between atrial and ventricula contraction
in no conduction through the AV node there is an absece of the QRS complex and T wave |
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Term
| if there were no conduction through the AV node what would we see or not see on an ECG machine? |
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Definition
| We would see the absence of QRS complex and T wave |
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Term
| what would we see on an ECG if there were slowed conduction through the AV node? |
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Definition
| we would see an increased PQ segment . this is the delay between atrial and ventricular contraction. |
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Term
| what is the loss of co-ordination of synchronised electrical activity of the heart known as? |
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Definition
ventricular fibrillation
this results in death within a few minutes and one must quickly defibrillate the ventricular muscle by passing a large current through the chest |
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Term
| inflammation of the pericardium is known as? |
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Definition
pericarditis
this can be caused by trauma, infections, tumor and results in accumulation of blood/pus/fluid in pericardial space |
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Term
| name symptoms of pericarditis |
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Definition
chest pain, breathing difficulty, fatigue
pericarditis can impair function of the heart by inducing compression of the heart - reducing the end diastolic volume (EDV) |
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Term
inflammation of cardiac valves is also known as.......................................
it slows blood flow from heart chambers |
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Definition
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Term
| what is a leaky mitral (bicuspid) valve also known as? what is the consequence of this condition? |
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Definition
| also known as Mitral Valve Prolapse. results in reduced ejection fraction |
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Term
| name the condition where leaky aortic semilunar valve causes volume overload in Lv. the left ventricle does something to compensate this. what is it? |
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Definition
Aortic regurgitation is the condition whereby the aortic valves are leaky.
this causes volume overload in the left ventricle but it increases its contraction to compensate. |
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Term
| mitral valve prolapse can begin at any age but when do most people notice symptoms? |
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Definition
between ages of 20-30
around 7.6% of women and 2.5% of men have MVP. abnormality of the mitral valve leaflets, or supporting chords, or both - the leaflets prolapse (buckle back) into the left atrium during ventricular systole thus some blood leaks back into the left atrium. associated with symptoms such as chest pain, fatigue, palpitations, dizziness, shortness of breath. |
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Term
| which arteries provide blood to the heart muscles? |
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Definition
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Term
| coronary artery disease CAD results in reduced blood flow to the myocardium. it can cause a blockage of the coronary artery. what is CAD caused by? |
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Definition
caused by thrombosis and embolism
blockage of coronary artery can lead to myocardial infarction also known as a heart attack. this is known as tissue death. |
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Term
| what does myocardial infarction (heart attack) result in? |
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Definition
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Term
| in congestive heart failure a ......... heart leads to reduced ...... circulation due to ...... artery disease, .......... infaction and infection |
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Definition
weak, blood, coronary, myocardial
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Term
| what effect does congestion heart failure have on EDV and pumping pressure to systemic circulation? |
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Definition
pumping pressure to systemic circulation decreases
EDV increases
so heart enlargens
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Term
decrease in pumping pressure and increase in EDV can lead to swelling of legs/ankle due to water retention and congestion of blood in pulmonary circulation known as pulmonary oedema.
what can pulmonary oedema lead to? what can treat congestive heart failure and how does it do this? |
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Definition
pulmonary oedema can lead to right heart failure
Digitalis can treat congestive heart failure by increasing the force of contraction |
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Term
| Digitalis is a common drug used in heart disease. what does it do and what can it be used for? |
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Definition
Digitalis makes the heart contract harder. It is used when the hearts pumping function has been weakened.
It also slows down some fast heart rhythms known as Tachycardia |
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Term
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Definition
| they are blood-cholesterol lowering agents |
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Term
what do angiotensin converting enzyme (ACE) inhibitors do?
what are they used for? |
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Definition
they stop production of angiotensin (II), a hormone that constricts blood vessels.
used to control high BP and also for people with heart failure where the heart is unable to pump enough blood to supply the body's needs. |
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Term
what do angiotensin (II) receptor antagonists do?
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Definition
| they work on the same system as ACE inhibitors and stop angiotensin (II) from acting on cells |
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Term
| describe the mechanism of action of Digitalis |
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Definition
it is a potent inhibitor of the active sodium potassium pump. This causes intracellular sodium to rise as sodium is diffusing into the cell and the pump which pumps out 3Na for 2K in isnt functioning.
at the Na/Ca ion exchange system, Na is exchanged for Ca thus leeds to accumulation of intracellular Calcium. This leads to increased contractility of the heart muscle via interaction of Ca with troponin
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Term
| from the use of Digitalis when get an accumulation of intracellular calcium that leads to increase heart muscle contractility as a result of the interaction between calcium and which amino acid? |
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Definition
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Term
| Beta blockers are drugs commonly used in heart disease. what do they do? |
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Definition
they slow the heart and make it beat with less contracting force so BP drops.
used for high BP, angina, and to prevent repeat heart attacks
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Term
| what do nitroglycerine and amyl nitrite do? when are they used? |
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Definition
they dilate coronary arteries
used to stop chest pain in angina |
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Term
what do calcium channel blockers do?
when are they used? |
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Definition
they dilate blood vessels and can slow the heart
used for high BP and chest pains |
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Term
| when are thrombolytic agents administered. what effect do they have? |
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Definition
| administered during or immediately after a heart attack to break up a blood clot in a coronary artery and to restore blood flow. |
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Term
| which drug lowers the risk of heart attack in at risk individuals and also keeps arteries open in those who have had a previos heart bypass or other artery opening-procedure |
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Definition
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Term
which receptors do beta blockers bind to?
what do they inhibit the binding of? |
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Definition
| beta blockers bind to B-adrenergic receptors. these are 7TM receptors located in cardiac tissue that inhibit the binding of noradrenaline and adrenaline to these receptors |
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Term
| Beta blockers ..... sympathetic influences that nomrally ...... heart rate and contractility and so they cause a ........ in these activities |
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Definition
reduce, stimulate, decrease
they slow HR
> delay at AV Node
< action potential frequency at SA Node
< contractile force of cardiac muscle
lower BP |
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Term
true or false
some beta blcokers are partial antagonists? |
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Definition
True
they provide some background of sympathetic activity while preventing enhanced sympathetic activity |
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Term
| in relation to nitroglycerine and amyl nitrite what is the active metabolite the prodrug is converted into? |
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Definition
NO (nitric oxide) in vascular smooth muscle
this causes relaxation of smooth muscles and vasodilation of coronary arteries
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