Cardiovascular System

Question 1

The most common ECG finding of hypercalcemia is a ___ __ _________

Answer 1

short QT interval

Question 2

Long QT syndrome (LQTS) is an inherited condition associated with _________________________________________

Answer 2

delayed repolarization of the ventricles.

Question 3

LQTS can lead to ______________________

Answer 3

ventricular tachycardia/torsade de pointes and can therefore cause collapse/sudden death.

Question 4

What are the most common variants of LQTS and what are they caused by?

Answer 4

LQT1 and LQT2
caused by defects in the alpha subunit of the slow delayed rectifier potassium channel

Question 5

A normal corrected QT interval is less than ____ ms in males and ___ ms in females.

Answer 5

430 ; 450

Question 6

Congenital causes of LQTS

Answer 6

Jervell-Lange-Nielsen syndrome (includes deafness and is due to an abnormal potassium channel)

Romano-Ward syndrome (no deafness)

Question 7

Drugs that can cause LQTS

Answer 7

amiodarone, sotalol, class 1a antiarrhythmic drugs

tricyclic antidepressants, selective serotonin reuptake inhibitors (especially citalopram)

methadone

chloroquine

terfenadine (a non-sedating antihistamine and classic cause of prolonged QT in a patient, especially if also taking P450 enzyme inhibitor, e.g. Patient with a cold takes terfenadine and erythromycin at the same time)

erythromycin

haloperidol

ondanestron

Question 8

Diseases/conditions that cause LQTS

Answer 8

electrolyte: hypocalcaemia, hypokalaemia, hypomagnesaemia
acute myocardial infarction
myocarditis
hypothermia
subarachnoid haemorrhage

Question 9

Long QT1

Answer 9

usually associated with exertional syncope, often swimming

Question 10

Long QT2

Answer 10

often associated with syncope occurring following emotional stress, exercise or auditory stimuli

Question 11

Long QT3

Answer 11

events often occur at night or at rest
sudden cardiac death

Question 12

Management of LQTS

Answer 12

avoid drugs which prolong the QT interval and other precipitants if appropriate (e.g. Strenuous exercise)

beta-blockers (note sotalol may exacerbate long QT syndrome)

implantable cardioverter defibrillators in high risk cases

Question 13

What are the 4 factors affecting stroke volume?

Answer 13

Cardiac size, contractility, preload and afterload are the 4 factors affecting stroke volume

Question 14

Stroke volume (SV)

Answer 14

SV is the amount of blood pumped by the left ventricle in one contraction.

Question 15

Cardiac output

Answer 15

This is the total volume of blood the heart pumps per minute and is calculated as cardiac output = SV x heart rate.

Question 16

Ejection fraction

Answer 16

This is the percentage of blood ejected from the left ventricle during systole, calculated as ejection fraction = SV / end-diastolic volume x 100.

Question 17

End-systolic volume (ESV)

Answer 17

ESV refers to the volume of blood remaining in the ventricle after systole. It is related to stroke volume through the formula SV = end-diastolic volume − end-systolic volume.

Question 18

Total peripheral resistance (TPR)

Answer 18

TPR is the resistance to blood flow in the systemic circulation and is calculated as TPR = mean arterial pressure / cardiac output

Question 19

B-type natriuretic peptide is released in response to _________

Answer 19

ventricular strain

[Ventricular strain occurs when there is increased pressure or volume load on the ventricles, often seen in conditions like heart failure. This strain leads to the stretching of the ventricular walls, triggering the release of BNP.]

Question 20

Endothelin is a peptide that is released locally by endothelial cells and contributes to arteriolar ___________

Answer 20

constriction.

Question 22

Vasoconstrictor mediators

Answer 22

Endothelin

noradrenaline from the sympathetic nervous system

circulating catecholamines

angiotensin-2

Question 23

Endothelin acts on ____receptors in order to cause constriction but can also cause dilation of arterioles by acting on ____ receptors.

Answer 23

ET(A) ; ET(B)

Question 24

Mediators of arteriolar dilation

Answer 24

The parasympathetic nervous system, nitric oxide and prostacyclin

Question 25

Possible ECG signs in patients with pulmonary embolism are:

Answer 25

Sinus tachycardia (the most common) Signs of right heart strain T wave inversion in the anterior leads S1Q3T3 the classic ECG changes seen in PE are a large S wave in lead I, a large Q wave in lead III and an inverted T wave in lead III - 'S1Q3T3'. However, this change is seen in no more than 20% of patients right bundle branch block and right axis deviation are also associated with PE sinus tachycardia may also be seen

Question 26

PE common triad of Sx

Answer 26

few patients (around 10%) present with the textbook triad of pleuritic chest pain, dyspnoea and haemoptysis. The relative frequency of common clinical signs is shown below: Tachypnea (respiratory rate >20/min) - 96% Crackles - 58% Tachycardia (heart rate >100/min) - 44% Fever (temperature >37.8°C) - 43%

Question 27

Atheroma formation:

Answer 27

initial endothelial dysfunction is triggered by a number of factors such as smoking, hypertension and hyperglycaemia this results in a number of changes to the endothelium including pro-inflammatory, pro-oxidant, proliferative and reduced nitric oxide bioavailability fatty infiltration of the subendothelial space by low-density lipoprotein (LDL) particles monocytes migrate from the blood and differentiate into macrophages. These macrophages then phagocytose oxidized LDL, slowly turning into large 'foam cells'. As these macrophages die the result can further propagate the inflammatory process. smooth muscle proliferation and migration from the tunica media into the intima results in formation of a fibrous capsule covering the fatty plaque.

Question 28

There are many causes of infective endocarditis, ________ is now the commonest cause in the developed world and is particularly likely if the patient is an intravenous drug user

Answer 28

S. aureus

Question 29

______________ is the commonest cause of IE in patients from developing countries with an absence of other specific risk factors.

Answer 29

Streptococcus viridans

Question 30

____________ is a more likely causative organism of infective endocarditis if the patient has prosthetic valves

Answer 30

S. epidermidis

Question 31

_________ is a causative organism for IE that can be found in patients who have colorectal cancer

Answer 31

S. bovis

Question 32

_______ is an unusual cause of infective endocarditis and is typically only found in immunocompromised patients.

Answer 32

Candida albicans

Question 33

ECG features of hypokalaemia

Answer 33

U waves small or absent T waves (occasionally inversion) prolong PR interval ST depression long QT

Question 34

The fastest conduction velocities in the heart are in the ________

Answer 34

Purkinje fibres

Question 35

S4 is caused by______________

Answer 35

the atria contracting forcefully in an effort to overcome an abnormally stiff ventricle

Question 36

S3 occurs __________and is caused by ____________________

Answer 36

earlier in diastole ; rapid movement of blood into the ventricle.

Question 37

S1

Answer 37

closure of mitral and tricuspid valves soft if long PR or mitral regurgitation loud in mitral stenosis

Question 38

S2

Answer 38

closure of aortic and pulmonary valves soft in aortic stenosis splitting during inspiration is normal

Question 39

S3

Answer 39

caused by diastolic filling of the ventricle considered normal if < 30 years old (may persist in women up to 50 years old) heard in left ventricular failure (e.g. dilated cardiomyopathy), constrictive pericarditis (called a pericardial knock) and mitral regurgitation

Question 40

S4

Answer 40

may be heard in aortic stenosis, HOCM, hypertension caused by atrial contraction against a stiff ventricle therefore coincides with the P wave on ECG in HOCM a double apical impulse may be felt as a result of a palpable S4

Question 41

_______kalaemia can lead to long QT syndrome

Answer 41

Hypo

Question 42

Patients with heart failure with reduced LVEF should be given a _________ and an___________ as first-line treatment

Answer 42

beta blocker ; ACE inhibitor