Heart

Question 1

What is an ECG?

Answer 1

An electrocardiogram. A visual representation of the ‘electrical activity’ of the heart. Can assess abnormalities in rhythm, conduction and repolarisation.

Question 2

What does ST segment depression suggest?

Answer 2

Often a sign of myocardial ischemia of which coronary insufficiency is a major cause.

Question 3

What is PTCA angioplasty?

Answer 3

Percutaneous transluminal coronary angioplasty. A minimally invasive procedure to open up clocked coronary arteries. Goes up through femoral artery and uses a balloon to open the arteries up. Can place in a stent-latticed metal scaffold- within the artery to keep it open.

Question 4

What is haemoptysis?

Answer 4

Act of coughing up blood or blood stained mucus.

Question 5

What is Angina Pectoris?

Answer 5

Chest pain due to myocardial ischaemia. Causes a build up of metabolites which activate sensory nerves. Not a disease itself. 3 types: stable, unstable and variant.

Question 6

What is ischaemia due to?

Answer 6

Increased myocardial oxygen demand which is not met.

Question 7

Give details on unstable angina.

Answer 7

Attacks are unpredictable. Coronary artery occlusion due to platelet adhesion to ruptured atherosclerotic plaque.

Question 8

What is ‘coronary steal’?

Answer 8

When the coronary arteries are dilated, this sends more blood to already well perfused areas, but where dilatation cannot occur less blood is delivered because of the fall in input pressure. Termed ‘the reverse Robin Hood effect.’ However, may be useful to dilate coronary arteries in variant angina. Can be a problem with dipyridamole, SNP and adenosine.

Question 9

What does Ivabradine do?

Answer 9

Recently introduced to treat all forms of angina. Blocks Na+ current that contributes to SA node depolarisation towards threshold. Leads to a decrease in heart rate but not force and so decrease myocardial oxygen demand.

Question 10

What is after-load?

Answer 10

Force against which the left ventricle contracts. Can be decreased by dilating arteries.

Question 11

What is pre-load?

Answer 11

Diastolic pressure that distends the relaxed left ventricle. Can be decreased by dilating veins.

Question 12

What is the Bainbridge (atrial) reflex?

Answer 12

A sympathetic reflex initiated by increased blood in the atria which causes stimulation of the SA node.

Question 13

What is GTN?

Answer 13

Glyceryl trinitrate. A vasodilator used in the treatment of angina. Taken as a sub-lingual tablet or spray. Not orally active as it is destroyed by first pass metabolism. Rapid onset but short action.

Question 14

What is amyl nitrate?

Answer 14

A vasodilator used in the treatment of angina. Vials opened and inhaled. Has become a drug of abuse (poppers). Rapid onset but short action.

Question 15

What is Isosorbide mononitrate?

Answer 15

A vasodilator used in angina that is taken orally. Slower in onset and more prolonged duration than GTN. Used for sustained prophylaxis in all forms of angina.

Question 16

What is Nifedipine?

Answer 16

Allosteric modulator of L-type voltage operated calcium channels- binds at allosteric site and reduces channel opening. Nifedipine causes coronary steal in 10% of patients.

Question 17

What is pheochromocytoma?

Answer 17

A rare, cathecolamine- secreting tumour that may precipitate life- threatening hypertension.

Question 18

What is haemostasis?

Answer 18

It functions to limit blood loss (haemorrhage) following vascular damage, yet without compromising the fluidity of blood. Interactions between coagulation factors. blood platelets and the vascular wall are important here.

Question 19

What is thrombosis?

Answer 19

Occlusion of a blood vessel (venous or arterial) by an intravascular blood clot or platelet clump.

Question 20

What is the mechanism of action of hemophilia A?

Answer 20

Deficiency of factor VIII. Located on chromosome X, so males only. Treatment is by replacement of deficient factor.

Question 21

What is the mechanism of action of hemophilia B?

Answer 21

Deficiency of factor IX. Located on chromsome X, so males only. Treatment is by replacement of deficient factor.

Question 22

What is the mechanism of action of hemophilia C?

Answer 22

Deficiency of factor XI.

Question 23

What is the mechanism of action of Von Willebrand disease?

Answer 23

Most common blood clotting disorder. Deficiency of von Willebrand factor which binds to and stabilises factor VIII and binds platelets to collagen.

Question 24

What are platelets?

Answer 24

Cell fragments (no nucleus) produced from megakaryocytes in the bone marrow. If you have a deficiency of platelets you are in danger of a haemorrhage.

Question 25

What is the fibrinolytic system?

Answer 25

The physiological repair system for removing blood involves the generation of the enzyme plasmin which digests fibrin.

Question 26

How do statins work?

Answer 26

They are competitive inhibitors of the rate-limiting step in cholesterol biosynthesis. Lowering intracellular cholesterol stimulates upregulation of LDL receptor and increases the uptake of non-HDL particles from the systemic circulation. Most effective at night as this is when most cholesterol biosynthesis occurs.

Question 27

What are elastic arteries?

Answer 27

They conduct high pressure blood flow out of the heart eg. pulmonary artery, aorta, common carotid artery. Characterised by numerous bundles of elastic fibres (elastic laminae) in the tunica media. This enables the walls to resist pressure and recoil to maintain arterial pressure during diastole.

Question 28

What is the internal elastic lamina (IEL)?

Answer 28

Found in muscular arteries. Forms a clear boundary between the tunica intima and tunica media.

Question 29

What is the external elastic lamina (EEL)?

Answer 29

Found in muscular arteries. Forms a clear boundary between the tunica media and tunica adventitia.

Question 30

What is the left venous angle?

Answer 30

The junction of the internal jugular and subclavian veins.

Question 31

Ventricular septal defects are the most common congenital cardiac malformation. What are the consequences of this?

Answer 31

Ventricular septal defects allow left to right shunting of blood. Can result in pulmonary hypertension and hypertrophy of the right ventricle.

Question 32

Approximately 1 in 4 people have a probe patent foramen ovale. Why is this clinically significant?

Answer 32

Usually asmptomatic, higher pressure in LA pushes septum primum against septum secundum and mechanically shuts valve. However, if there is higher pressure in RA eg. pulmonary hypertension this can push flimsy septum primum open and allow blood to shunt from right to left.

Question 33

Define 'heart failure'

Answer 33

A syndrome in which patients have typical symptoms and signs resulting from an abnormality of cardiac structure and function. Cardinal symptoms and signs of HF: breathlessness, fatigue and ankle swelling.

Question 34

Why is the the prevalence of heart failure increasing?

Answer 34

- Increasing prevalence of risk factors. - Improved post-MI survival. - An ageing population.

Question 35

What is an ICD?

Answer 35

Implantable cardioverter defibrillator.