INCORRECT EXAMPREP Q'S - CARDIOVASCULAR Flashcards
What is the normal duration of a PR interval? (in seconds)
0.12-0.2
What is the first heard sound?
occurs at the beginning of ventricular systole, caused by the closure of mitral & tricuspid valves
Why does the first heart sound have a lower pitch & a longer duration than the second heart sound?
the mitral & tricuspid valves close more gradually than the pulmonary & aortic valves
What vessels have individual smooth muscle cells rather than a continuous tunica media?
metarterioles
Where does the mitral valve lie?
Lies posterior to the sternum at the level of the 4th left CC
If the flux of glucose is observed to be directly proportional to the trans-membrane concentration gradient, what is the likely method of movement?
simple diffusion
How do cells in the SAN discharge?
Spontaneously
What may increased rate of conduction of the SAN result in?
Supraventricular tachycardia
To which receptor does NA bind in order to mediate vasoconstriction?
alpha 1
What do gap junctions allow in cardiac muscle cells?
impulses to travel from one cardiac fibre to another
Which organ receives approx 9% of the cardiac output ? i.e. 430ml/min
Skin
What tissue forms the most superficial layer of the heart?
visceral pericardium
The IVC is formed by the union of the common iliac veins at what vertebral level?
L5
During exercise what happens to the arterioles in the muscles? What does this result in?
they dilate due to local mechanisms (fall in oxygen & increase in CO2 & other metabolites)
it greatly reduces the TPR
What represents the depolarisation of the IV septum from left to right on an ECG?
The Q wave
What is the main characteristic of the excitation contraction coupling process in cardiac muscle that differentiates it from that seen in skeletal muscle?
the AP can last several hundred milliseconds
What do vasa vasorum consist of?
small blood vessels which provide nutrients for the outer regions of the vessel wall
What 5 things does the sympathetic NS do to the CVS?
decreases capacitance increases CO increases SV increases venous return vasocontriction
Do cardiac muscle fibres branch regularly or irregularly?
irregularly
What proportion of Ca ions enter cardiac muscle cells via L type channels in order to induce CICR?
10%
Starling’s law of the heart states that the energy released during contraction depends on the initial fibre length. The amount of stretch of the heart muscle depends on the EDV, which is affected by WHAT?
- The inherent compliance of the muscle
- heart muscle becomes stiffer & less compliant with age & becomes more difficult for the heart to stretch - The Preload or EDP
- the filling pressure of the heart (determined by pressure in great veins)
What does the starling curve show?
That SV increases with EDP until the muscle is overstretched & then the SV begins to fall
What on an ECG represents the depolarisation of the area of the heart near the base?
S wave
Why is the S wave tall?
becasue of the large muscle mass & rapidity of depoarisation
What vessel is an indirect branch of the abdominal aorta?
inferior gluteal as it arises from the internal iliac artery
What is the origin of sympathetic nerves that innervate the nodal tissue & heart muscle?
T1-5
What is the 1st branch of the external carotid artery?
superior thyroid artery
From which artery do the coronary arteries branch from?
ascending aorta
What is NOT a baroreceptor on the carotid sinus?
Aortic nerve
What substance has a high MW & => a low permeability?
albumin
What on an ECG varies with heart rate?
The QT interval
What is the normal duration of the QRS interval? (in seconds)
0.06-0.10 s
into which vein does the great saphenous vein drain?
femoral
What is the normal sodium concentration found in the blood plasma?
140nM
What occurs in the isovolumetric contraction phase?
Ventricular volume DOESNT change
- contraction of ventricles commences immediately after QRS & increase in pressure of ventricles causes AV valves to close.
- first part of systole occurs without change in vol of ventricles as semilunar valves still shut (=> high pressure in Ao & PT) this is isovolumetric contraction
Which part of the heart is supplied by the circumflex artery?
lateral, posterior & inferior segments of the LV
Where does the inferior thyroid drain into?
brachiocephalic vein
Describe what an ECG would look like for ventricular fibrillation.
The ventricular muscle fibres are contracting independently => no QRS identified
ventricular movement is rapid & irregular
What is AF due to?
multiple circulating re-entrant excitation in the atria
Resulting in an irregular & fast atrial rate
=> AVN discharges at irregular (but slower) rate & P waves cannot usually be detected on ECG
What are 3 examples of pathological causes for AF?
myocardial ischaemia
stenosis of mitral valve
thyrotoxicosis
What condition is likely to result in lower plasma levels of free drug?
dehydration
What is a feature of moderate hypertension?
retinal vein changes
What is generally a cause of diastolic but not systolic heart failure?
infiltrative disease
Dyspnoea, angina & syncope are the characteristic symptoms of which valvular disorder?
Aortic stenosis
What is an indication for the use of intermittent IV infusion?
Drug has concentration-dependent effects
A blockage to which artery would be referred to as an inferior infarction?
Right coronary artery
What type of shock is caused by systemic bacterial infection (septicaemia)?
vasodilatory
What is a potential complication of essential (primary systemic) hypertension?
Ischaemic heart disease as pt is at risk of developing atherosclerosis
- also have increased risk for intracerebral haemorrhage, aortic dissection & subarachnoid haemorrhage
What is the action of a class IV drug in the Vaughan Williams classification?
Reduces conduction predominantly in the AVN
According to the NHS Tayside cardiac rehabilitation programme, how long in duration should the conditioning phase be?
20 mins
What are most ischaemic symptoms of the heart caused by?
Atherosclerosis either via stenosis of the coronary artery or atherosclerosis with superimposed thrombi
What type of drug is given to reduce plasma lipids?
statins
Infarcts involving the inferior & posterior wall of the LV result from occlusion of which coronary vessel?
RCA
What is the main mechanism of action of ACE inhibitors?
Reduction in peripheral resistance
A GP sees a 49 year old female pt with moderate hypertension & wants to start her on anti-hypertensive treatment. What drug (&type of drug) would be an appropriate starting point in her treatment?
Lisinopril
ACE inhibitor
What can be seen on an ECG within 24-48hrs of acute, complete obstruction of the right coronary artery?
ST elevation in II, III & aVL
Which artery has the highest incidence of atherosclerosis?
abdominal aorta
What is sinus tachycardia defined as?
Having a HR of greater than 100 beats/min
What type of drug is Loasartan?
An ARB
- note it does not produce a dry cough
What are cardiac thrills?
Vibrations synchronous with certain phases of the cardiac cycle
What does complete heart block look like on an ECG?
P waves are disocciated from QRS-T complexes as ventricles spontaneously establish their own signal (usually originating in AVN or AV bundle
The appearance of tall, tented T waves on the ECG is characteristic of which condition?
Hyperkalaemia
What drug is a potassium-sparing diuretic which can help prevent diuretic-induced hypokalaemia?
Spironolactone
- it acts competively on aldosterone receptors in the distal convoluted tubes inhibiting its antidiuretic effect by inhibiting the Na retaining & K secreting actions of aldosterone
=> ‘sparing’ potassium
What is the principal mechanism by which sublingual GTN terminates angina episodes in pts with advanced atherosclerotic coronary vessel disease?
Decreased preload (& decreased myocardial demand)
- due to venous capacitance vessel dilation
Which condition features narrowing of the pulmonary trunk & an over-riding aorta?
Fallot’s tetralogy
