Cardiology Flashcards
amaurosis fugax treatment
aspirin with dipyridamole
amaurosis fugax and AF treatment
warfarin
Incidence of probe patent foramen ovale
The incidence of PFO in the normal population is approximately 25%, as determined by post mortem examination.
Although particularly common, PFO is often silent through life, but is associated with paradoxical venous thromboembolism, for example, stroke associated with DVT.
Complications of foramen ovale
Paradoxical venous thromboembolism, for example, stroke associated with DVT.
Amaurosis fugax causes
With recurrent TIA, the likely underlying diagnosis is embolism either from the right internal carotid plaque or in association with atrial fibrillation.
Potassium loss causes
Causes of hypokalaemia include excess body loss from the gastrointestinal tract from vomiting, diarrhoea or entero-cutaneous fistulae.
Excess loss can also occur from the renal tract due to
Conn's syndrome Cushing's syndrome Drugs (diuretics) or Renal tubular acidosis. Other causes include decreased oral intake of potassium, alkalosis or insulin excess.
Hypokalaemia will be seen if blood is taken from an arm in which IV fluid is being run.
ECG and hypokalaemia
Characteristic ECG changes associated with hypokalaemia are
S-T segment depression
U- waves
Inverted T waves and
A prolonged P-R interval.
ECG and hyperkalaemia
Changes that may be seen with hyperkalaemia are
Tall, tented T- waves
Wide QRS complexes and
Small P- waves.
Normal ECG findings
T wave inversion in leads I and II also in v 4-6 should be regarded as abnormal.
The timings in the other stems are all within normal limits.
In order for a Q wave to be abnormal it must be at least 0.04 s and be at least 25% of the height of the subsequent R wave.
Regions of the mediastinum
The mediastinum is the space located between the two pleural sacs.
It is divided into superior and inferior mediastinal regions by a horizontal line between the angle of Louis and the T4/5 intervertebral disc.
The inferior mediastinum is divided into the anterior mediastinum, middle mediastinum and posterior mediastinum.
It is the middle mediastinum that contains the heart and roots of the great vessels.
Posterior of heart
The posterior surface of the heart comprises the left atrium receiving the four pulmonary veins
Left border of cardiac shadow
The left border of the cardiac shadow consists of
The aortic arch
The pulmonary trunk
The left auricle and
The left ventricle.
Mitral valve
The mitral valve or bicuspid valve is a flat valve composed of anterior and posterior cusps. It guards the passage of blood from the left atrium to the left ventricle.
The cusps are attached to chordae tendineae which are then attached to papillary muscles that prevent cusp eversion during ventricular systole.
Auscultation
This is the position for auscultation of the aortic valve.
The pulmonary valve is best heard over the left side of the sternum at the second intercostal junction and the tricuspid valve at the lower left quadrant of the body of the sternum.
The mitral valve is auscultated at the fifth intercostal space in the mid-clavicular line and the cardiac apex is palpated in the same position.
Narrow complex tachcardia
This patient has a narrow complex supraventricular tachycardia.
From history and examination she is not haemodynamically compromised and, therefore, initial management would be IV adenosine in the absence of contraindication (for example, asthma) in order to create a transient conduction delay.
This may terminate the tachycardia, or cause a slowing in rate to allow identification of the underlying rhythm, to guide optimal antiarrhythmic therapy.
If the patient had chest pain, hypotension, SBP
Inferior myocardial infarction-artery?
Right coronary artery
This patient has an inferior myocardial infarction which is usually due to occlusion of the right coronary artery and, less commonly, circumflex occlusion may be responsible.
A 74-year-old man presented with acute pain, pallor and absent pulses in his right leg.
Investigations revealed an embolus in his femoral artery.
What is the most likely source of this embolus?
Ulceration of an atheromatous plaque of the abdominal aorta is the most common source of emboli in this situation.
Right ventricular thrombi would embolise to the lung.
The others are possible but less likely causes.
radiograph of the pelvis are several prominent calcified vessels.
This finding is typical for Monckeberg’s calcific medial sclerosis, a benign condition involving muscular arteries of older persons.
bioprosthesis
The bioprosthesis has the advantage of not requiring anticoagulation, but it does not wear well with time, and typically must be replaced within five to 10 years.
All the other responses can occur but are significantly less common causes of late bioprosthetic valve failure.
Aortic valve anatomy
it is a tricuspid valve
The right ventricle lies anterior to the left ventricle
The left atrium is the most posterior chamber of the heart, the right atrium is just anterior and to the right of the left atrium.
The left atrial appendage is not readily seen on transthoracic echocardiography and requires transoesophageal echocardiography.
A 66-year-old male presents with left sided hemiparesis that resolves within six hours. Examination is normal with a blood pressure of 126/78 mmHg. Investigations reveal a cholesterol of 6.3 mmol/L, sinus rhythm on the ECG and 75% stenosis of the right and 25% stenosis of the left internal carotid artery (ICA).
Carotid endarterectomy
The first case has a transient ischaemic attack (TIA) with 75% occlusion of the ICA. This would merit carotid endarterectomy.
A 75-year-old male presents with left monocular visual loss which resolves over the next day. On examination he has an irregular pulse, a blood pressure of 144/88 mmHg. Investigations show a cholesterol of 7 mmol/L, ECG shows atrial fibrillation and carotid Dopplers reveal bilateral stenosis of the internal carotids of approximately 50%.
The second case also has a TIA within the anterior territory and has atrial fibrillation with modest ICA occlusion that would not warrant carotid endarterectomy. The most appropriate treatment would be warfarin as this would reduce risk far more than any other intervention.
A 72-year-old female presents with right sided monocular blindness which resolves within two hours. Examination is normal, with a blood pressure of 132/80 mmHg. Her cholesterol is 5.2 mmol/L, ECG shows sinus rhythm and Dopplers reveal that she has stenosis of the right internal carotid artery of 40%.
The third case has a TIA in the anterior cerebral territory but has 40% stenosis of the carotid artery. The Royal College of Phycisians have published National Clinical Guidelines for Stroke that recommend Carotid endarterectomy for carotid stenosis 50-99% by NASCET criteria, for patients with TIA. The most appropriate initial treatment would therefore be antiplatelet therapy, and a statin would also be indicated.
The National Stroke Guidelines suggest patients with suspected TIA who are at high risk of stroke (eg an ABCD2 score of 4 or above) should receive: aspirin or clopidogrel (each as a 300 mg loading dose and 75 mg thereafter) and a statin, eg simvastatin 40 mg started immediately after specialist assessment and investigation within 24 hours of onset of symptoms.
A 62-year-old male presents with bilateral exertional cramping calf pain which tends to occur after approximately 250 metres of walking on the flat and is relieved by rest. He is a smoker of 10 cigarettes per day and is otherwise well.
On examination his pulse is 80 beats per minute regular and his blood pressure is 145/90 mmHg. He has weak foot pulses with bilateral bruits over the femoral arteries.
A 58-year-old hypertensive male attends as he is concerned regarding his health. He has a strong family history of ischaemic heart disease (IHD), his father having died of an MI at the age of 54 and his brother having recently undergone coronary bypass surgery. He also informs you of an aspirin allergy.
On examination, he has a pulse of 88 bpm regular and is noted to have a blood pressure of 148/88 mmHg. Nil else is noted.
Aspirin
Clopidogrel
Both patients require anti-platelet therapy.
In the case of the 58-year-old male he has hypertension and a strong family history of IHD.
Based on the British Hypertensive Society guidelines he merits antiplatelet therapy (his BP needs to be below 150/90 mmHg and target organ damage, diabetes mellitis or 10 year risk of cardiovascular disease [CVD] of 20% to ensure benefits outweight potential risks).
The most appropriate starter would be aspirin but this is relatively contraindicated based on his allergy and so clopidogrel would be a suitable agent. Clopidogrel is as effective as aspirin in the prevention of vascular morbidity/mortality and works through inhibition of platelet aggregation through adenosine diphosphate (ADP) receptor blockade.
In the case of the 62-year-old he too would merit treatment with aspirin for his peripheral vascular disease.
A 52-year-old male presents with a three week history of fevers, deteriorating breathlessness and fatigue. Two years ago he underwent prosthetic valve replacement for a calcified bicuspid aortic valve.
On examination he has a temperature of 37.7°C and four nail-fold infarcts. Vegetations are demonstrated through transoesophageal echocardiography.
Which of the following is the most likely causative organism?
Generally there are two identifiable modes of prosthetic valve endocarditis.
The first occurs in the first year after surgery affecting 0.7-3% of cases and is often due to Staphylococci.
Late endocarditis observed after two years post-surgery is found in 0.5-1% of cases and is typically due to Strep. viridans.