Aortic stenosis, atrial fibrillation, cerebral infarction

Question 1

What is aortic stenosis?

Answer 1

Aortic stenosis is one of the most common and most serious valve disease problems. Aortic stenosis is a narrowing of the aortic valve opening. Aortic stenosis restricts the blood flow from the left ventricle to the aorta and may also affect the pressure in the left atrium.

Question 2

What are the structural abnormalities of aortic stenosis?

Answer 2

From birth (congenital) the valve may have two cusps (bicuspid) rather than the usual three cusps (tricuspid)

Valve becomes calcified (deposition of calcium causing stiffening) and narrowed (stenosed) – gradually over many years

Normally- Aortic valve at outflow to left ventricle and origin of ascending aorta

Question 3

What are the physiological abnormalities of aortic stenosis?

Answer 3

The left ventricle has to generate more force (pressure) to eject blood through the narrowed aortic valve – and becomes more muscular (hypertrophied)

This situation is an example of “pressure overload”.

Normally- Opens to allow blood to exit the left ventricle, closes to prevent blood from passing backwards from aorta to left ventricle (regurgitation).

Question 4

What are prior events of aortic stenosis?

Answer 4

Patients are most frequently male over the age of 65yr

Aortic stenosis can cause no symptoms for many years

Question 5

What are experienced symptoms of aortic stenosis?

Answer 5

Angina type chest pain – worse with exercise improved by rest

Breathlessness with exercise

Light-headedness or collapse (syncope) with exercise

Question 6

What are the clinical signs of aortic stenosis?

Sound? Pulse pressure? How does the heart beat?

Answer 6

Harsh and loud “ejection systolic” heart murmur heard loudest in the top right side of the chest (the aortic area)

Reduced pulse pressure (difference between systolic blood pressure and diastolic blood pressure – normally 120/70 mmHg = 50mmHg changed to 110/90 mmHg = 20 mmHg)

Forceful apex beat (felt on left side of chest in mid-clavicular line, 5th intercostal space)

Question 7

What are the abnormal test results from aortic stenosis?

Answer 7

• ECG (electrocardiogram) shows evidence of more muscular left ventricle – QRS is increased in size
• Echocardiogram (ultrasound scan of the heart) shows a narrowed aortic valve – and a more muscular (hypertrophied) left ventricle

Question 8

What are the medical/ surgical interventions with aortic stenosis?

What pressure difference do doctors keep patients under observation?

What happens to ventricles to consider surgery?

How can the aortic valve be replaced?

What are valves made of?

Answer 8

• If the pressure difference between the left ventricle and the aorta remains below 60 mmHg – then the patient is kept under observation
• If the left ventricle starts to dilate – or symptoms are present - then surgery is considered irrespective of the echocardiogram scan results
• The aortic valve can be replaced by open chest surgery – or using a percutaneous (through skin and via femoral artery) approach
• Surgical valves are either made of metal and plastic (prosthetic) or are pig valves (tissue valves)

Question 9

What is the primary and secondary prevention for aortic stenosis?

Answer 9

• Patients with metallic artificial aortic (and other) valves require life-long anticoagulant treatment with warfarin
• Patients with tissue valves do not require warfarin

Question 10

What is artrial fibrillation?

Answer 10

Atrial fibrillation is a heart condition that causes an irregular and often abnormally fast heart rate.

Question 11

What are the structural abnormalities of atrial fibrillation?

Answer 11

• Dilated atria

- Fibrosis (scarring) of the atrial muscle

Question 12

What are the physiological abnormalities of atrial fibrillation?

Answer 12

Pacemaker of the heart (sinus node) overwhelmed by disorganized atrial electrical discharge – often originating at pulmonary vein insertion.

Normally:

• Pacemaker activity of the heart
• Conduction of electrical depolarization through the atrium
• Stimulation of electrical activity in ventricles

Question 13

What prior events would you have to atrial fibrillation?

Answer 13

• Hypertension (High blood pressure)
• Primary heart diseases (including coronary artery disease)
• Lung diseases (such as pneumonia, lung cancer, pulmonary embolism)
• Excessive alcohol consumption (binge drinking or chronic excess)
• Hyperthyroidism (overactive thyroid gland)
• Heart failure (all causes e.g. valve disease)

Question 14

What symptoms would you have for arterial fibrillation?

Answer 14

• Palpitations (awareness of heart beat as fast, irregular or both)
• Tired and / or breathless with exercise
• Sometimes chest tightness (angina) or ankle swelling (oedema)

Question 15

What are the clinical signs of atrial fibrillation?

Answer 15

-Pulse is irregular (irregularly irregular i.e. random strength and rate)
-Signs of underlying cause ( e.g. high blood pressure; lung disease; valve
murmur heard with stethoscope; weight loss with over active thyroid)

Question 16

What are the medical/surgical interventions of atrial fibrillation?

How is HR slowed down?
How is heart rhythm controlled?

What surgery can be done to pulmonary veins?

Answer 16

• Rate control – seeks to slow down the heart rate to prevent symptom of palpitations and to improve efficiency of heart beat
• This is achieved with drugs (e.g. beta blockers, calcium channel blockers, digoxin)
• Rhythm control – seeks to convert the heart rhythm back to normal, regular sinus (pacemaker) rhythm
• This may be achieved with drugs (e.g. amiodarone) or by an electrical shock treatment called DC (direct current) cardioversion
• The pulmonary veins can be electrically isolated / insulated – from the left atrium by surgery or catheter (tube placed in heart from arm or leg) ablation (use of an energy pulse to make atrial cells unable to conduct electricity)

Question 17

What are the primary and secondary prevention?

Answer 17

• Early and effective treatment of diseases that cause atrial fibrillation (e.g. high blood pressure, lung diseases)
• Avoidance of excess alcohol and stimulants such as nicotine, caffeine

-Prevent the formation of blood clots in the atrium by treatment with direct
oral anticoagulant or warfarin

Question 18

What is cerebral infarction?

Answer 18

A cerebral infarction is an area of necrotic tissue in the brain resulting from a blockage or narrowing in the arteries supplying blood and oxygen to the brain.

Question 19

What are the structural abnormalities of cerebral infarction?

Answer 19

• Disease of the wall of the arteries going to or within the brain (e.g. atherosclerosis caused by cholesterol and inflammatory cells)
• Dilated atria of the heart (with atrial fibrillation) that allows blood clots to form

Question 20

What are the physiological abnormalities of cerebral infarction?

Answer 20

-Ischaemia (reduced blood / oxygen supply) of brain tissue
-Necrosis (death of cells) of brain tissue
-Raised intracranial (within the skull) pressure due to brain swelling (oedema) which
can further damage nerve cells

Question 21

What are the prior events for cerebral infarction?

Answer 21

-Smoking, high blood pressure, high cholesterol, diabetes (cardiovascular risk factors)
-Atrial fibrillation
-Possible warning TIAs (transient ischaemic attack – that is a reversible “mini stroke”
that does no obvious lasting damage – caused often by very small blood clots that temporarily block an artery)

Question 22

What are the experienced symptoms of cerebral infarction?

Answer 22

Localised abnormalities of nervous system which may include the following:

• Weakness of the arm and / or leg – usually on one side of the body
• Slurring of speech (dysarthria)
• Drooping of corner of mouth
• Difficulty swallowing (dysphagia)
• Inability to find the right words to speak (expressive dysphasia)
• Inability to understand the words of others (expressive dysphasia)

Question 23

What are the clinical signs of cerebral infarction?

Answer 23

All of the above which can be experienced by patient (symptom) but also detected by clinical examination by a doctor (sign) or other person

• Possible evidence of atrial fibrillation (irregular pulse)
• Possible high blood pressure (hypertension)
• Possible bruit (noise of turbulent blood flow caused by atherosclerosis with
  narrowing) heard over a carotid artery in the neck

Question 24

What are abnormal test results of having cerebral infarction?

Answer 24

• Brain CT (computerized tomography) or MRI (magnetic resonance imaging) shows changes of brain ischaemia (reduced blood flow) swelling and infarction (necrosis or death of brain cells)
• Ultrasound of carotid artery may show evidence of narrowing (atherosclerosis plaque caused by cholesterol)
• Echocardiogram (ultrasound scan) of the heart may show evidence of a blood clot in the atrial appendage
• ECG (electrocardiogram) may show evidence of atrial fibrillation (irregular heart beat with absent “P waves”)

Question 25

What are the medical/ surgical interventions for cerebral infarction?

Answer 25

Thrombolytic drugs (dissolve blood clot from within the artery and restoring blood flow) may be given

Question 26

What are the primary and secondary prevention for cerebral infarction?

Answer 26

• Treating patients with atrial fibrillation with direct oral anticoagulant or warfarin
• Treating patients with carotid atherosclerosis with antiplatelet drugs (e.g. aspirin)
• Management (lowering) of high blood pressure