Cardiology Flashcards
Cardiology: What is the definition of syncope?
A transient loss of consciousness due to transient global cerebral hypoperfusion characterized by rapid onset, short duration and complete recovery.
Cardiology: What features would suggest vasovagal syncope?
- Long-history of syncope
- Prolonged standing
- Noxious stimulus
- Nausea and vomiting associated.
- Absence of cardiac disease
- After exertion
- After head tilting / carotid pressure
Cardiology: What features would suggest cardiac syncope?
- Known history of cardiac disease
- Evidence of structural abnormality
- Preceded by chest pain / palpitations
- During exercise
Cardiology: What is the treatment for syncope? (In broad terms)
Treat the underlying condition.
E.g. Ischaemia, drug-induced.
Cardiology: What is the normal PR interval? (In squares and time)
120-200ms
3-5 small squares
Cardiology: What is the normal size of a QRS?
120ms
3 small squares
Cardiology: What is the first-line treatment for symptom relief in chronic stable angina?
Nitrates, e.g. GTN
Cardiology: What is the mechanism of action of nitrates?
Release of NO to activate and increase cyclic-GMP which causes smooth muscle relaxation and subsequent cardiac vasodilation.
Cardiology: What are the side-effects of nitrates?
- Hypotension
- Headache
- Flushing
Cardiology: What are the contraindications of nitrates?
- Hypotension
- Aortic/ Mitral stenosis
- Hypertrophic cardiomyopathy
Cardiology: What is the first-line treatment of chronic stable angina?
Beta-blockers
Cardiology: What is the mechanism of action for beta-blockers in the treatment of chronic stable angina?
- Reduces sympathetic stimulation to the heart, causing a reduction in heart rate and myocardial contraction.
- Reduces cardiac workload to increase exercise tolerance and reduce symptoms.
Cardiology: If a patient is contra-indicated for beta-clockers what is the first-line treatment for the management of chronic stable angina?
- Non-dihydropyridine calcium channel blocker.
* E.g. Verapamil, Diltiazem
Cardiology: What are the side-effects of beta-blockers?
Bronchospasm, bradycardia, cold peripheries, sleep disturbance, sexual dysfunction, fatigue.
Cardiology: What are the contra-indications of beta-blockers?
Asthma Bradycardia Uncontrolled heart failure 2/3rd degree heart block Severe peripheral arterial disease
Cardiology: Which medications may be added for treatment of chronic stable angina if beta-blockers are not provided sufficient relief?
- 2nd Line - Calcium-channel blockers (Amlodipine, Felodipine, Nifedipine)
- Longer-acting nitrates
- Potassium channel activators (Nicorandil)
Cardiology: What is the mechanism of action of calcium channel blockers in the treatment of chronic stable angina?
- Smooth muscle relaxation due to inhibition of influx of calcium ions.
- Relaxation of coronary and peripheral smooth muscle.
Cardiology: Non-dihydropyridine calcium channel blockers (Verapamil, Diltiazem) have an additional mechanism to other calcium channel blockers, what is it?
Slows conduction of AV node so has a rate limiting effect.
Cardiology: What are the side-effects of dihydropyridine calcium channel blockers? (amlodipine, felodipine, nifedipine)
- Flushing
- Dizziness
- Ankle-swelling
- Hypotension
- Headache
Cardiology: What are the contraindications for the use of dihydropyridine calcium channel blockers? (Amlodipine, felodipine, nifedipine)
- Uncontrolled heart failure
- Within one month post-MI
- Severe aortic stenosis
Cardiology: What are the side-effects of non-dihydropyridine calcium channel blockers? (Verapamil, diltiazem)
- Bradycardia
- AV/SA heart-block
- Constipation (Verapamil)
Cardiology: What are the contraindications of non-dihydropyridine calcium channel blockers? (Verapamil, diltiazem)
- Bradycardia
- 2/3 degree heart block
- Verapamil not to be used with beta-blocker
- Heart failure
- Acute porphyria
Cardiology: What is the mechanism of action of nicorandil in the treatment of chronic stable angina?
- NO donor to acticate cyclic-GMP to act as a vasodilator to both venous and arteries.
- Opens K channels resulting in efflux of K and reduction in Ca causing smooth muscle relaxation.
Cardiology: What are the side-effects of nicorandil?
- Headache
- GI irritation
- Hypotension
Cardiology: What is the acronym for the initial management of a suspected ACS?
MONA • Morphine (5-10mg Given by slow I.V, an anti-emetic will also be needed) • Oxygen • Nitrates • Aspirin (300mg stat)
Cardiology: What is the MI-5? (Secondary prevention for an ACS)
- Aspirin
- ACE-I
- Beta-blocker
- Statin
- Clopidogrel
Cardiology: What is the mechanism of action of aspirin?
- Irreversibly inhibits COX-1 and COX-2.
- This inhibits the production of Thromboxane A2.
- Which in turn inhibits platelet aggregation.
Cardiology: What are the side-effects of aspirin?
- GI irritation
* Bronchospasm
Cardiology: What are the contra-indications and interactions of aspirin?
- Active peptic ulceration, hypersensitivity, bleeding disorder.
- Any other drugs that increase the risk of bleeding.
Cardiology: What is the mechanism of action of clopidogrel?
- A prodrug converted to active metabolite by CYP enzymes.
* Irreversibly blocks py12 receptor on platelet surface.
Cardiology: What are the side-effects of clopidogrel?
• GI irritation
Cardiology: What are the contra-indications and interactions of clopidogrel?
- Active bleeding.
- Any other drug which increases bleeding risk, Fluoxetine (reduces antiplatelet effect), Enzyme inducers (carbamazepine, fluconazole, PPIs)
Cardiology: What is the mechanism of action of ACE-I?
- Reduces formation of Angiotensin II from angiotensin I.
* Results in reduced vasoconstriction and reduced formation of Aldosterone (Which promotes sodium and water retention)
Cardiology: What are the side-effects of ACE-I?
- Cough
- Hyperkalaemia
- Renal impairment
- Hypotension
- Angioedema
- Hepatic impairment
Cardiology: What are the contra-indications and interactions of ACE-I?
- Use with caution in renal impairment. Bilateral renal artery stenosis, severe aortic stenosis.
- Diuretics, nephrotoxic drugs.
Cardiology: What is the mechanism of action of ARBs (sartans)?
• Direct antagonist of Angiotensin II - blocks the vasoconstriction and aldosterone release.
Cardiology: What are the side-effects of ARBs?
- Hypotension
- Angioedema
- Renal impairment
- Hyperkalaemia
Cardiology: What are the contra-indications and interactions of ARBs?
- Cautions - renal artery stenosis, renal impairment.
* Diuretics, use with ACE-I only under specialist supervision.
Cardiology: What is the definition of hypoxia?
• A lack of oxygen resulting in a decrease in aerobic oxidative respiration resulting in cell injury.
Cardiology: What is the definition of ischaemia?
A lack of blood supply to a tissue or drainage away from a tissue due to stenosis or obstruction of a vessel. This results in a loss of oxygen and a build up of toxic metabolites. Tissue injury is quicker from ischaemia than hypoxia.
Cardiology: What is the definition of infarction?
Irreversible damage to a tissue due to ischaemia and hypoxia.
Cardiology: What are the mechanisms of cell injury?
- Decreased ATP production
- Membrane damage
- Increased intracellular calcium
- Increased oxygen derived free radicals
Cardiology: Give some differentials for chronic stable angina.
- Reflux oesophagittis
- PE
- Pneumothorax
- Aortic Dissection
- Costochondral pain
- Pleuritis
- Varicella zoster
Cardiology: What are the three indications for coronary bypass surgery (According to AHA)
- 3 vessel disease
- 2 vessel disease with LV impairment
- LMS
Cardiology: What are the four life-threatening causes of chest pain that you should never miss?
- MI
- PE
- Tension pneumothorax
- Dissecting thoracic aneurysm
Cardiology: What are the three main causes of aortic stenosis?
- Calcific degeneration
- Bicuspid valve
- Rheumatic
Cardiology: What are the complications of aortic stenosis? (Cardiac)
Pressure build up in the left ventricle leading to left ventricular hypertrophy, LV dilation and LV failure.
Cardiology: What pulse do you get with aortic stenosis?
Slow-rising
Cardiology: What is the classification of severe aortic stenosis, in terms of mean gradient mmHg, Jet velocity and valve area.
- Mean gradient >40mmHg
- Jet velocity m/s >4.0
- Valve area cm2
Cardiology: In which four situations is AVR recommended for aortic stenosis?
- Symptomatic severe AS.
- Severe AS undergoing CABG
- Severe AS undergoing surgery on aorta or other heart valves.
- Severe AS and LV systolic dysfunction.
Cardiology: What are the two structures that allow blood to bypass the lungs in the fetal circulation?
- Ductus arteriosus
* Foramen Ovale
Cardiology: What changes occur in the fetal lungs following birth?
- Birth causes the infant to take first breaths.
- Lungs fill with air and alveolar fluid is cleared.
- Pulmonary capillaries absorb oxygen from the air, pulmonary arterioles dilate causing pulmonary vascular resistance to fall dramatically.
- Blood flows into the pulmonary vascular system.
Cardiology: What causes the ductus arteriosus to close following birth?
- Due to decreased pulmonary vascular resistance, the pressure in the pulmonary artery falls.
- This causes blood to flow from the aorta through the Ductus arteriosus into the pulmonary artery.
- The ductus closes in response to oxygen by the contraction of smooth muscle.
Cardiology: How does the foramen ovale close following birth?
- Due to increased blood flow returning from the lungs, the pressure in the left atrium increases.
- As blood flow returning from placaenta is decreased, the pressure in the right atrium decreases.
- Both these changes close the foramen ovale by pressing the septum primum against the septum secundum.
Cardiology: What structures do the ductus arteriosus, ductus venosus, umbilical arteries and umbilical vein become?
- Ductus arteriosus - ligamentum arteriosum
- Ductus venosus - ligamentum venosum
- Umbilical arteries - Medial umbilical ligaments
- Umbilical vein - ligamentum teres
Cardiology: What are the symptoms of persistent pulmonary hypertension of the newborn?
- Right to left shunting across PDA and PFO
- Cyanosis
- Acidosis
- Lower limb sats
Cardiology: What is the treatment for pulmonary hypertension of the newborn?
- Oxygen, ventilation, nitric oxide.
* Extracorporeal membrane oxygenation.
Cardiology: What is Starling’s law of the heart?
The ability of the heart to change its force of contraction and therefore stroke volume in response to changes in venous return.
Cardiology: The presence of a bicuspid aortic valve is associated with which conditions?
- Aortic root dilation
- Heyde’s syndrome
- Coarctation
- Williams syndrome
- PDA
- Turner’s syndrome
Cardiology: What are the symptoms of aortic stenosis?
SAD - Syncope - Exertional - Angina - Dyspnoea (May be asymptomatic in earlier stages)
Cardiology: What are the initial investigations for suspected aortic stenosis?
- FBC - ensure not anaemic
- Renal function
- ECG (Heart block, LBBB)
- CXR (coarctation, heart failure, aneurysm.)
- Echocardiogram
Cardiology: What are the four types of mechanical heart valves?
- Ball and cage
- Tilting disk
- Bi-leaflet
- Tri-leaflet