Heart Flashcards
heart block causes heart beat to be (2)
slow and irregular
heart block is a type of
arrhythmia
chest trauma can initiate arrhythmias =
heart contusion
right bundle branch block often shows which symptoms?
no symptoms
in right bundle branch block ,activation of which chamber of the heart is delayed?
right ventricle
right bundle branch block has what affect on QRS complex
prolongs QRS complex
left bundle branch block is often due to
problems with heart (e.g. high BP)
interventricular septum is normally activated by
left bundle branch
if conduction in left bundle branch is slowed, interventricular septum is activated by
right bundle branch
in right bundle branch block, what shape is seen in V1?
M
in right bundle branch block, what shape is seen in V6?
W
In left bundle branch block, what shape is seen in V1?
W
In left bundle branch block, what shape is seen in V6?
M
Mnemonic that can be used to remember ECG appearances of left and right bundle branch blocks?
WiLLiaM MaRRoW
referred pain: heart dermatomes =
body wall and upper limb (T1-T5)
……. men die of CHD
1/5
…… women die of CHD
1/7
CHD is ……….. cause of death and premature death in UK
most common
CHD causes ……….. deaths in UK per year
94 000
myocardial infarction defintion
damage to heart muscle due to interruption in regional coronary circulation
myocardial infarction often caused by
clot/ fatty deposit
non-function area of heart after MI =
infarct
ischaemia definition
reduced blood delivery to organ, sufficient to compromise function
infarction definition
reduced blood delivery to organ, sufficient to lead to its death
types of MI
STEMI, NSTEMI
STEMI =
coronary artery completely blocked. large amount of muscle damage
NSTEMI =
tests positive for troponin I/T (unlike angina). Partial/ temporary blockage
coronary artery spasm =
artery tightens, comes and goes, no plaque
demand ischaemia =
heart requires more oxygen than available e.g. infarction, anaemia
symptoms of MI (8)
chest pain (tightness), pain travelling from chest to other parts of body, shortness of breath, feeling/being sick, anxiety, coughing, wheezing, light headedness
Mi can be missed in …….. as mistakes for symptoms of …..
diabetics; neuropathy
diagnosis of MI using (2)
ECG, blood tests
treatment of MI (10)
antiplatelets, heparin, pain relief, clot busting meds, beta blocker, insulin, oxygen, ACE inhibitor, statin, coronary artery bypass
angina pectoris =
pain from heart usually caused by coronary artery narrowing and reduced blood blow
stable angina =
symptoms stereotypic. lower risk of infarct, improves with meds
unstable angina =
pain at rest, increased attack severity, high risk of infarct, pain over 15 mins
classic/ exertional angina pectoris =
provoked by physical exertion. pain fades quickly with rest
nocturnal angina =
at night, may wake patient. provoked by vivid dreams. vasospasm, critical coronary artery disease
decubitis angina =
lying down. impaired left ventricle function as result of severe coronary artery disease
variant (Prinzmetal’s) angina =
without provocation, at rest. result of coronary artery spasm. more common in women. ST elevation. Arrhythmias during ischaemic episode
cardiac syndrome X =
history angina, positive exercise test and angiogram normal. coronary arteries seem normal. most common in women. highly symptomatic. difficult to treat.
unstable angina =
recent onset, worsening. at rest
symptoms of angina (4)
pain in arm, jaw, neck, stomach; pain eases with rest; breathlessness on exertion; pain, ache, discomfort, tightness across front of chest on exertion
exacerbating factors of angina (4)
physical exercise, high emotion, cold temperatures, eating large meal
risk factors of angina (8)
smoking, high BP, overweight, high cholesterol, inactivity, diet, salt, alcohol
medication for angina (8)
glyceryl trinitrate, statin, aspirin, beta blocker, ACE inhibitor, calcium-channel blocker, nitrate medicines, potassium channel activators
2 types of cardiac centres in medulla oblongata
cardioacceleratory and cardioinhibitory centres
vasomotor centres in medulla oblongata have which 2 populations of neurons
large group = widespread vasoconstriction; small group = skeletal muscle and brain vasodilation
vasomotor centre controls activity of …… motor neurons
sympathetic
vasoconstriction neurons of vasomotor centre have what type of neurotransmitter?
noradrenaline and adrenaline (adrenergic neurons)
vasodilation neurons of vasomotor centre have what type of neurotransmitter?
nitrogen oxide
most common vasodilator synapses are ….. and trigger the endothelial release of …. which causes local vasodilation
cholinergic, NO
other vasodilator synapses have …. as neurotransmitter which has intermediate and direct effect on vascular …. …. cells
NO; smooth muscle
3 locations of baroreceptors
walls of carotid sinuses, aortic sinuses, walls of right atrium
baroreceptors in aortic sinuses are in walls of ….. aorta and trigger the ….. reflex
ascending; aortic
baroreceptors in walls of right atrium trigger …. reflex
atrial
baroreceptors in aortic sinuses monitor BP at beginning of …..
systemic circuit
baroreceptors in walls of right atrium monitor BP at end of …..
systemic circuit
effects on heart result from release of …. from sympathetic neurons innervating …, …. and …..
noradrenaline; SAN, AVN and myocardium
smoking causes immediate and long term …… in BP
increase
smoking causes immediate and long term …. in HR due to …… which causes increase in adrenaline and HbCO2
increase; nicotine
smoking causes …. in cardiac output and coronary blood flow
decrease
smoking reduces the amount of oxygen delivered to tissues due to binding of …. to Hb
CO
smoking ….. blood clotting process
stimulates
increased blood cholesterol in smoking is due to …… which interferes with the transport of HDLs by modifying site in ……
acrolein; apoA-1
current smokers have …. fibrinogen levels
high
smoking causes increase in levels of proinflammatory ….. and leukocytes as well as an increase in cell adhesion molecules and platelet …….
cytokines; dysfunction
two types of natriuretic peptide
ANP (atrial natriuretic peptide) BNP (brain natriuretic peptide)
ANP produced by
myocytes of right atrium
BNP produced by
myocytes of ventricles
ANP produced in response to
excessive stretching in diastole
BNP produced in response to
stress
Natriuretic peptides reduce blood volume and BP by which 5 methods:
reduce thirst; increase kidney sodium ion excretion; stimulate peripheral vasodilation; promote water loss and increase urine production; block release of ADH, aldosterone, adrenaline and noradrenaline
……. and …… from adrenal medullae stimulate cardiac output and …..
adrenaline and noradrenaline; peripheral vasoconstriction
ADH is release from the ……… pituitary in response to decreased blood volume, increase in osmotic conc. or secondary to circulating angiotensin II
posterior
ADH stimulates conservation of water in
kidneys (collecting duct)
erythropoietin is released by ….. when BP falls or …. is low
kidneys; oxygen
erythropoietin stimulates ….. and stimulates production and maturation of erythrocytes
vasoconstriction
…………… cells release renin in response to fall in renal BP
juxtaglomerular
renin converts ………… to ………….
angiotensinogen to angiotensin I
ACE converts ………. to …….
angiotensin I to angiotensin II
4 functions of angiotensin II
stimulates thirst; stimulates cardiac output and constriction of arterioles; stimulates ADH secretion; stimulates renal aldosterone production and therefore sodium ion retention and potassium ion loss
chemoreceptors respond to changes in …., …. and …. in blood and ….
carbon dioxide, oxygen and pH; cerebrospinal fluid
chemoreceptors have sensory neurons in (2)
carotid and aortic bodies
sympathetic activation stimulates …. and ….. centres
cardioacceleratory and vasomotor centres
parasympathetic activation stimulates …. centre
cardioinhibitory centre
chemoreceptors for CBS fluid prioritise blood flow to brain to ensure …. delivery there
oxygen
endocardium =
thin, internal layer - covers valves. squamous epithelium over thin areolar tissue. no adipose
myocardium =
thick, helical middle layer. cardiac muscle
epicardium =
mesothelium formed by visceral layer of serous pericardium. simple squamous epithelium overlying thin areolar tissue. some areas have thick layers of adipose
systole =
ventricular contraction
diastole =
ventricular filling
5 properties of cardiac muscle
striates, short, thick, branches, 1 centrally placed nucleus surrounded by glycogen
sarcoplasmic reticulum of cardiac muscle is …. developed than skeletal as it lacks …. although it’s T tubules are …. than in skeletal muscle
less; terminal cisternae; larger
cardiac myocytes have large ….
mitochondria
cardiocytes joined by
intercalated discs
2 types of mechanical junctions
fascia adherens, desmosomes
interdigitating folds =
plasma membrane at end of cell (folded and interlock)
fascia adherens = most extensive. broad bands of …. and …. form transmembrane proteins interrupted by ….
actin, myosin, desmosomes
desmosomes =
weld-like junctions between cells
desmosomes prevent cardiocytes from
pulling apart during contraction
electrical junctions =
intercalated discs contain gap junctions which form channels to allow ion flow from different cell cytoplasms > stimulate neighbours
order of heart conductive system (5)
SAN > signals spread through atria > AVN > bundle of His > Purkinje fibres
Parasympathetic stimulation > occupation of … ….. …. ….. > negatively coupled with ….. …. > reduce cAMP formation > inhibit and slow calcium ion current
M2 muscarinic acetylcholine receptors; adenylate cyclase
parasympathetic stimulation also opens ….. channels creating a …… current
potassium ion; hyperpolarising current
sympathetic stimulation > … …. stimulation > enhanced … flux in myocyte > strengthened force of contraction
beta1 adrenergic; calcium ion
binding of ….. to myocyte … …. receptor stimulates membrane bound … …. > enhances production of cAMP > activates intracellular protein kinases > ……. cellular proteins
catecholamines; beta1 adrenergic receptor; adenylate kinases; phosphorylate
return of calcium ion from cytosol to sarcoplasmic reticulum regulated by
phospholamban
beta1 adrenergic activation of protein kinase phosphorylates phospholamban > greater uptake of calcium ions by ……… > myocyte ……….
sarcoplasmic reticulum; relaxation
increased cAMP activity > phosphorylation of ………. > inhibits actin-myosin interaction
troponin I
sinus rhythm =
normal heart beat triggered by SAN
ectopic focus =
any region of spontaneous firing other than SAN.
nodal rhythm =
slower HR produced by AVN if SAN not working properly
4 phases of cardiac cycle
ventricular filling, isovolumetric contraction, ventricular ejection, isovolumetric relaxation
3 phases of ventricular filling
rapid ventricular filling, diastasis (slower filling), atrial systole
P wave of ECG =
end of diastasis
isovolumetric contraction =
atria repolarise and remain in diastole for rest of cycle. ventricles depolarise,
QRS complex of ECG =
ventricles depolarise and begin to contract
S1 can be heard as beginning of
isovolumetric contraction
ventricular ejection =
ventricular pressure exceeds atrial pressure and valves forced open. rapid ejection followed by reduced ejection
T wave of ECG =
late in ventricular ejection stage
in ventricular ejection, not all blood ejected. (~54% is) what is left is
end systolic volume
isovolumetric relaxation =
early ventricular diastole. T wave ends - ventricles begin to expand
S2 can be heard as
blood rebounds from closed semi lunar valves (end of isovolumetric relaxation)
SAN cells do not have stable resting potential - starts at -60mV and drifts upwards > gradual depolarisation = …. …. from slow influx of … and outflow …
pacemaker potential; sodium ions; potassium ions
SAN - when pacemaker potential reaches threshold potential of …… > volatage-gated fast ………….. open > influx …. ….. > 0mV > outflow …. > repolarisation
+40mV; calcium-sodium channels; sodium ions, calcium ions; potassium ions
SAN firing excites atrial cardiocytes > atria contract > AVN ………. contraction which allows ventricular filling before …..
slows down; contraction
Signals travel through AV bundle and Purkinje fibres > depolarisation of …… ….. in near unison > signals reach …. ….. first > take up slack in …. … > opens valves (mitral and tricuspid) before blood surges against them
ventricular myocardium; papillary muscle; chordae tendinae
cardiocytes have stable resting potential of
-90mV
cardiocytes normally only depolarise when stimulated > voltage gated …. channels open > influx of sodium ions > depolarisation to ……… …… > additional …. gates open > ……. feedback loop > +30mV > sodium ion channels close
sodium ion; threshold potential; sodium ion; positive
as action potential spreads throughout heart, …. influx into cells > bind to ……… > calcium ions from sarcoplasmic reticulum to cytosol > second wave of calcium ions bind to ….. > contraction
calcium ion; sarcoplasmic reticulum; troponin
depolarisation of heart is prolonged causing ……. of action potential (more prolonged in ……) > at end of plateau ….. channels close, …. channels open > potassium ions …. cell and calcium ions are transported back into …..
plateau; ventricles; calcium; potassium; leave; sarcoplasmic reticulum
propioceptors =
muscles and joints - change in physical activity
3 hormones that increase heart rate
adrenaline, noradrenaline, thyroid hormone
end diastolic volume
blood volume of ventricles at end of diastole
end diastolic volume is affected by
filling time and venous return - Starling’s law
venous return directly affects
nodal cells
venous return has indirect effect on HR via
atrial reflex
Increased venous return > stretching … cells > more rapid depolarisation > Increased HR
SAN
end systolic volume
ventricular blood volume at the end of systole
factors affects end systolic volume =
preload, overload, contractility of ventricle
preload =
degree of ventricular stretching in diastole
preload affects ability of myocytes to produce
tension
as sarcomere length increases past resting length forced produced during systole
increases
as sarcomeres approach optimal lengths > more ….. and …. contraction
efficient and forceful
contractility =
amount of force produced during contraction at given preload
positive inotropic action
factors that increase contractility
negative inotropic action
factors that decrease contractility
positive inotropic factors stimulate ….. entry into cell
calcium ion
negative inotropic factors block calcium ion movement/ depress cardiac muscle ….
contraction
parasympathetic stimulation (vagus) > negative inotropic effect > release of …. > hyperpolarisation and inhibition
acetylcholine
sympathetic stimulation > positive inotropic effect > release of ……. by postganglionic fibres of cardiac nerves and secretion of …… and ….. from adrenal medulla > stimulate alpha and beta receptors in cardiac muscle plasma membranes
noradrenaline; adrenaline and noradrenaline
4 things that have positive inotropic effects
adrenaline, noradrenaline, glucagon, thyroid hormones
how do stretch receptors work
stretch detected > greater number of actin-myosin cross links > increased calcium ion uptake > increased rate of contraction
afterload =
amount of tension contracting ventricle must produce to open atrioventricular valve
as afterload increases, stroke volume ….
increases
any factor restricting blood flow through atrial system …… afterload
increases
frank starling law
greater the stretch of heart muscle during filling, the greater the force of contraction and the greater the quantity of blood pumped into the aorta
basal crepetations/ lower lung crackles
explosive opening of small airways
basal crepetations are more common during
inspiration
if basal crepetations don’t clear after cough, could be sign of (2)
pulmonary oedema / fluid in alveoli
basal crepetations heard over which lobe of lung
inferior
echocardiogram =
ultrasound scan of heart
echocardiogram helps define …. of heart failure
aetiology
echocardiogram provides information of ejection fraction of left ventricle. what is normal value
~60%
heart failure patients with preserved left ventricle function have ejection fraction of..
more than 45%
heart failure patients with left ventricular systolic dysfunction have ejection fraction of…
less than 45%
7 causes of mitral valve regurgitation
degenerative, rheumatic heart disease, mitral valve prolapse, hypertrophic cardiomyopathy, MI, congenital heart problems, endocarditis
most common cause of mitral valve regurgitation
degenerative (tissues connecting valve to wall become weak and stretched over time)
rheumatic heart disease sometimes follows
infection with streptococcus > antibodies attack body, particularly mitral valve. developing countries
3 features of atrial fibrillation
HR fast, irregular (arrhythmia), irregular force of heart beat
in atrial fibrillation SAN overridden by other signals from
atrial cardiac muscle
Fibrillate =
rapid partial contraction > only some impulses to ventricles
Atrial fibrillation process: high BP > stretch receptors > increased ….. uptake > increased rate of contraction > fibrillation
calcium ion
3 types of atrial fibrillation
paroxysmal, persistent, permanent
paroxysmal atrial fibrillation
recurring and sudden episodes. stops without treatment within 7 days
persistent atrial fibrillation
longer than 7 days. needs treatment
permanent atrial fibrillation
long term. heart beat not normal. treated. heart rate still irregular. most common.
lone atrial fibrillation
no apparent cause
Electrocardiogram (ECG) records …
electrical activity of heart
In ECG electrodes are attached to (3)
arms, legs, chest
Exercise ECG used to detect
narrowing of coronary arteries > angina
Ambulatory ECG used to detect
heart rhythms
P-R interval is time taken for excitation to spread through ….. (usually 0.12-0.2s)
ventricles
Lead to right ankle is
neutral (completes circuit)
Right arm lead known as
aVr
Left arm lead known as
AVl
Left leg lead known as
aVf
Lead I = info between
aVr and aVl
Lead II = info between
aVr and aVf
Lead III = info between
aVl and aVf
aVl looks at ….. side of heart
left
aVf looks at …. of heart
inferior
V2, V3, V4 are …. leads which look at …. of heart
anterior; front
V5, V6 are …. leads that look at …. side of heart
lateral; left
P wave =
atrial depolarisation
flat line between P wave an Q wave is when impulse spreads through
bundle of His
Q wave =
depolarisation in septum (from left > right)
R wave is when impulse spreads through
main portion of ventricular walls
R wave is large because there is more muscle > more cells > more …. required
voltage
S wave =
depolarisation of Purkinje fibres
ST segment =
flat line
If ST segment is not flat, it is an indicator of
myocardial ischaemia/ necrosis
T wave =
ventricular repolarisation
Heart failure as defined by NICE (2003)
complex syndrome resulting from structural/ functional cardiac disorder impairing pump function of heart
Heart failure accounts for 900 000 - ……… deaths in UK per year
1 000 000
Mortality rate of heart failure at 1 year`
20-30%
Heart failure accounts for ……% hospital admissions
5-10%
5 physiological changes that lead to heart failure
failure of pump, obstruction to flow, regurgitation of flow, disorders of cardiac conduction, disruption of continuity of circulatory system
Heart failure is when adaptive mechanisms to overcome physiological changes ….
fail
2 symptoms of heart failure
breathlessness, loss of energy
7 signs of heart failure
pulmonary oedema, pleural effusion, S3 ‘gallop’, raised JVP, pitting oedema, ascites, tachycardia
10 causes of heart failure
ischaemic, heart failure, infective, dilated cardiomyopathy, diabetes, valvular, genetic, tachycardia induced, toxins/drugs, endocrine
5 treatments for heart failure with impaired systolic function
diuretics, ACE inhibitors, beta blockers, aldosterone receptor agonists, CRT/ICD devices
2 treatments for heart failure with preserved left ventricular function
diuretics, treating comorbidities
left sides heart failure =
failure of left ventricle
right sides heart failure =
failure of right ventricle
8 signs of left sided heart failure
exercise intolerance, dizziness/confusion, wheezing, heart murmurs, gallop rhythm, cyanosis > hypoxemia, pulmonary oedema > crackles at lung base, increased breathing rate& work of breathing
8 signs of right sided heart failure
ascites, pitted peripheral oedema, hepatomegaly, parasternal heave, nocturia, excess fluid accumulation in body, jaundice, impaired liver function
3 signs of biventricular heart failure
reduced breath sounds, pleural effusion (particularly of left side), dullness of lung fields to finger percussion
TROPONIN T TEST: 3 forms
C, T, I
TROPONIN T TEST: cardiac troponin has which 2 forms
I and T
TROPONIN T TEST: cardiac troponin levels are usually
so low cannot be meaured
TROPONIN T TEST: troponin is found with ….. on thin ….. filamin
tropomyosin; actin
TROPONIN T TEST: troponin …. attached to ….., troponin C binds calcium and troponin I …… myosin binding site on ….
T; tropomyosin; inhibits; actin
TROPONIN T TEST: monoclonal antibody tests to cardiac specific troponin > identifies myocyte ….
necrosis
