Cardiology 1 Flashcards
What is a channelopathy?
A genetic disorder in which the electrical activity of the heart is abnormal, but the heart is structurally normal.
When do symptoms first appear in channelopathies?
30-40 years
What is the cause of Brugada syndrome, a type of channelopathy?
Cardiac sodium channelopathy (SCN5A gene)
Autosomal dominant inheritance but can be a new mutation.
How does Brugada syndrome cause arrhythmias?
Abnormally slow conduction in the heart - decreased flow of Na+ ions changes the AP, slowing conduction.
“Short circuits” form, causing wavebreak and causing re-entry (U-turns).
What are the symptoms of channelopathies?
May be asymptomatic Syncope Sudden cardiac death Palpitations Chest pain Breathlessness or dizziness
How is syncope caused by a channelopathy?
Brief arrhythmias revert to a normal rhythm spontaneously OR vasovagal syncope.
In Brugada syndrome, when do arrhythmias occur?
At rest
Following a heavy meal
Fever/alcohol
When vagus nerve is activated
How is Brugada syndrome diagnosed?
Genetic testing
ECG with or without flecainide (provocation test):
Brugada sign: coved ST segment elevation >2mm in >1 of V1-V3 followed by a negative T wave
What must Brugada sign be associated with to diagnose channelopathies?
One of:
- Documented VF or polymorphic VT
- FH of SCD<45 years
- FH of similar ECG
- Syncope
Which arrhythmias may be caused by a Brugada syndrome?
Ventricular fibrillation
Polymorphic ventricular tachycardia
AV nodal re-entrant tachycardia
Sinus node dysfunction
As part of the treatment of Brugada syndrome, what triggers must be avoided?
Fever Alcohol and drugs Dehydration Tricyclics, anaesthetics, sodium channel blockers (flecainide) CCBs
What is the main treatment of Brugada Syndrome?
Implantable cardiac defibrillator
If not appropriate - quinidine
What is a normal QT interval?
<440ms (two large squares)
What are the risks of prolonged QT syndrome?
Delayed repolarization of the heart following a heart beat increases the risk of toursades des pointes episodes
What are the congenital causes of LQTS?
Cardiac ion channel mutation:
Jervell and Lange Nielson syndrome
Romano-Ward syndrome
What are the acquired causes of LQTS?
Low Ca/K/Mg Drugs: amiodarone, TCAs, SSRIs MI 3rd degree heart block Fasting and bradycardia
What are the subtypes of LQTS?
Potassium channel: risk of SCD when patient is startled or awoken suddenly
Sodium channel: risk of SCD when patient is sleeping
What are the symptoms of LQTS?
Syncope and palpitations as a result of polymorphic VT
Nausea, pallor, dyspnoea, chest pain
What is seen on the ECG in LQTS?
QTc>440m/s
Toursades des points
Degeneration into sustained VT or VF
What is the treatment of congenital LQTS?
Propanolol (unless bradycardic)
Pacing
ICD
Why is propranolol contra-indicated in acquired LQTS?
Bradycardia can precipitate toursades.
What is the treatment of toursades des pointes?
IV magnesium sulphate
Temporary atrial pacing to increase HR and reduce QT
Correct predisposing factor e.g. QT prolonging drug
IV isoprenaline
Define cardiomyopathy.
Myocardial disorder in which the heart muscle in structurally and functionally abnormal without coronary artery disease, hypertension, valvular, or congenital heart diseases.
How can cardiomyopathies present?
Heart failure
Arrhythmias
SCD
Thromboembolism
What is the most common form of cardiomyopathy?
Dilated cardiomyopathy
What is the hallmark of dilated cardiomyopathy?
Left or both ventricles are dilated with impaired systolic function
What are the causes of dilated cardiomyopathy?
Idiopathic
Familial
Alcoholic
What is hypertrophic cardiomyopathy?
Left or right sided hypertrophy leading to LV outflow obstruction
What is affected in restrictive cardiomyopathy?
Diastolic filling
What is the pathophysiology of arrhythmogenic right ventricular cardiomyopathy?
Fatty and fibrous replacement of ventricular myocardium
Prolonged isometric training may result in athlete’s heart which may have features of…
Hypertrophic cardiomyopathy
What is seen on CXR in cardiomyopathy?
Cardiomegaly
What is seen on ECG in cardiomyopathy?
T wave inversion
ST changes
LVHT
What investigation differentiates between the different types of cardiomyopathy?
Transthoracic echo
What are the aims of treatment in cardiomyopathy?
Symptomatic
Treat heart failure
Prevent thromboembolism
What is the treatment of cardiomyopathies?
BB
Verapamil
ICD
Cardiac Tx
What are the indications for amiodarone in cardiomyopathy?
Massive LVHT
Family history SCD
Unexplained syncope
VT
What is infective endocarditis?
Infection of the endocardium, cardiac valves, intrathoracic vessels and prostheses.
What are the effects of infective endocarditis?
Valvular insufficiency
Systemic emboli
What are the two factors required for development of infective endocarditis?
Bacteraemia
Abnormal cardiac endothelium
Name three risk factors that cause bacteraemia and therefore infective endocarditis.
Poor dental hygiene - s.viridans
IV drug use - s.aureus
Cardiac surgery - s.epidermis
Name some causes of abnormal cardiac endothelium.
Valvular disease including replacement
Structural heart disease
Hypertrophic CMY
What are the most common organisms in infective endocarditis?
S.aureus
S.viridans
What are the symptoms of infective endocarditis?
Fever
New/changing murmur
CCF
Pleuritic or back pain
Name some immunological phenomena of infective endocarditis.
Splinter haemorrhages
Roth’s spots
Glomerulonephritis
Embolic stroke
Name 6 signs of infective endocarditis.
Petechiae Splinter and subungal haemorrhages Osler's nodes Roth's spots Janeway lesions Splenomegaly
What are the appropriate investigations for infective endocarditis?
3 sets of blood cultures prior to starting treatment
ECG, CXR, TTE
What is the diagnostic criteria for infective endocarditis?
Modified Duke criteria
Major: +ve culture, evidence of endocardial involvement
Minor: predisposition, fever, vascular/immunological phenomena, echo findings
What is the choice empirical antibiotic for infective endocarditis whilst awaiting blood culture results?
Amoxicillin and gentamycin
What is the typical cause of pericarditis?
80% postviral or idiopathic
What is the function of the pericardium?
Protects cardiac efficiency by limiting dilation, maintaining ventricular compliance.
Aids atrial filling and is a barrier against infection
Reduces external friction
Name three other causes of pericarditis.
SLE
Sarcoidosis
Primary/metastatic neoplasms
Describe the pain of pericarditis.
Sharp pain in the substernal/precordial region, which can radiate to the neck or shoulders.
Inspiration, swallowing, coughing, and lying flat exacerbates pain; sitting up or leaning forward relieves pain.
What are the other symptoms of pericarditis?
Fever
Chills
Non-productive cough
Signs include tachycardia, tachypnoea.
What is the pathognomonic sign of pericarditis?
Pericardial friction rub heard best in the midline and lower left parasternal edge, louder in inspiration
Why does dyspnoea develop in pericarditis?
Cardiac tamponade
What are the main ECG changes seen in pericarditis?
Saddle shaped ST elevation
T wave elevation which flattens and inverts as time goes by
PR segment depression
What is seen on CXR in pericarditis?
Enlarged flask shaped cardiac silhouette
What other investigations should be done in suspected pericarditis?
Echo
Blood cultures
Bloods for WCC, ESR, CRP, urea, cardiac enzymes, RF etc
What is the treatment of pericarditis?
Rest and avoid physical activity
Naproxen 250mg 6-8hourly
Colchicine
What is Beck’s triad of cardiac tamponade?
Hypotension, elevated systemic venous pressure, muffled heart sounds.
Define hyperkalaemia.
Plasma potassium >5.5mmol/L
Severe>6.5mmol/L
Give four causes of hyperkalaemia.
AKI/CKD
Tumour lysis syndrome
DKA
Spironalactone
The symptoms of hyperkalaemia are non specific; what are the signs?
Bradycardia from heart block
Tachypnoea from respiratory muscle weakness
Flaccid paralysis
Depressed or absent tendon reflexes
What is seen on ECG in hyperkalaemia?
Peaked T waves, wide QRS complex, prolonged PR interval, reduced P wave
What is the cardiac protection aspect of hyperkalaemia treatment?
10ml 10% calcium gluconate
How is hyperkalaemia managed after cardiac protection?
Insulin-glucose infusion, then nebulised salbutamol if necessary
Calcium resonium
Define hypokalaemia.
Serum K<3.5mmol/L
Severe<2.5mmol/L
Give four causes of hypokalaemia.
Persistent vomiting
Burns
Respiratory or metabolic alkalosis
Diuretic use
what are the symptoms of hypokalaemia?
Generalised weakness and then paralysis
Constipation
Respiratory failure and ileus
Paraesthesiae and tetany
What is seen on ECG in hypokalaemia?
Flat T waves, ST depression, prominent U waves
What other investigations are important in hypokalaemia?
U&Es, ABG, urinalysis for K, Na, and osmolality
What is the oral ambulatory treatment of mild hypokalaemia in primary care?
Perform an ECG
Treat any underlying cause
Dietary supplementation 40-120mmol/day
What is the treatment of severe hypokalaemia?
PO potassium bicarbonate in lower risk patients
IV KCL in normal saline 10mmol/hour or less, until ECG abnormalities resolve
Define hypocalcaemia.
Serum corrected calcium<2.1mmol/L
What are the causes of hypocalcaemia?
Hypoparathyroidism Secondary hypoparathyroidism Tumour lysis syndrome Osteoblastic metastases Acute pancreatitis
How does hypocalcaemia present?
Paraesthesia of the fingers, toes, and mouth
Tetany, muscle cramps, and carpopedal spasm
What are the main signs of hypocalcaemia?
Chvostek’s sign
Trousseau’s sign
Laryngospasm
Seizures
What is seen on ECG in hypocalcaemia?
Arrhythmias and prolonged QT interval
What blood tests are important in hypocalcaemia?
U&Es: exclude CKD
Amylase: exclude pancreatitis
CK: exclude rhabdomyolysis
Serum PTH, Mg, PO4, vit D
What is the treatment of acute hypocalcaemia (symptomatic, or calcium <1.9mmol/L)?
Slow 10ml IV 10% calcium gluconate
Correct Mg prior if low
Define hypercalcaemia?
Serum calcium>2.5mmol/L
What are the most common causes of hypercalcaemia?
Primary hyperparathyroidism
Ectopic PTH
Granulomatous conditions e.g. TB or sarcoid
What are the main symptoms of hypercalcaemia?
Polyuria and polydipsia Dyspepsia Depression Constipation Muscle weakness Nausea and anorexia Abdo pain and pancreatitis Coma Cardiac arrhythmias and shortened QT interval
Which investigations are required in hypercalcaemia?
PTH
X-Ray
USS parathyroid
U&Es, LFTs for ALP
What is the treatment of acute hypercalcaemia?
0.9% saline
IV pamidronate or IV zolendronic acid
Furosemide if fluid overload
What is the treatment of symptomatic PTH-mediated hypercalcaemia?
Reduce dietary calcium
Partial parathyroidectomy
What are the types of PE?
Thrombosis
Fat following long bone fracture
Amniotic fluid
Air
What is Virchow’s triad?
Hypercoagulability
Reduced mobility
Blood vessel abnormalities
Other than surgery, thrombotic disorders, and heart disease, give fourother risk factors for a PE.
Malignancy
Late pregnancy/puerperium
Myeloproliferative disorders
COCP/HRT
How does a PE present?
Dyspnoea
Pleuritic/retrosternal chest pain
Cough and haemoptysis
Collapse/sudden death
What are the signs of PE?
Tachypnoea, tachycardia, pyrexia, hypotension
Hypoxia
Raised JVP
Gallop rhythm, split S2, TR murmur
How is PE diagnosed?
CTPA and raised D-Dimer
Two level PE Well’s score
What is Hampton’s hump?
Wedge shaped area of pulmonary infarction seen on CXR
What is seen on ABG in PE?
Reduced PaO2
Reduced PaCO2 due to hyperventilation or acidosis
What is the management of PE?
ABCDE approach
100% oxygen, IV access
If haemodynamically unstable: IV alteplase
If not, then LMWH or fondaparinux
What is the further management of patients who have had PE?
Warfarin or rivaroxaban 3 months and then assess risks and benefits of continuing
What is the management of recurrent PE on anticoagulation?
Inferior vena cava filter
What are the contraindications to LMWH or fondaparinux and what is the alternative?
eGFR<30ml
Bleeding risk
Unfractionated heparin
What is aortic dissection?
Disruption of the medial layer of the wall of the aorta provoked by intramural bleeding, resulting in separation of the aortic wall layers and subsequent formation of a true lumen and a false lumen
Give five causes of aortic dissection.
Hypertension Marfan's syndrome or EDS Direct blunt chest trauma Cocaine and amphetamines Familial thoracic aortic aneurysm type 1 and 2
What are the two classification systems for aortic dissection?
Stanford and Debakey
What is the main symptom of aortic dissection?
Migratory tearing/sharp chest pain
What can aortic dissection lead to?
Cardiac tamponade Haemothorax Sudden death Multiorgan failure Cardiac failure from gross AR
How is suspected aortic dissection investigated?
Distinguish from MI as thrombolysis will worsen the dissection
ECG normal or non specific ST changes
Echo
How is aortic dissection managed?
IV access, analgesia, ICU
IV BB to reduce the force of ventricular contraction
Blood products
Stents or grafts
What is seen on ECG in pulmonary embolism?
Sinus tachycardia
What is seen on ECG in hypothermia?
J waves
What is the treatment of acquired LQTS?
Correct predisposing factor
IV MgSO4
IV isoprenaline accelerates AV conduction and decreases QT interval
How is streptococcal infection diagnosed?
High anti-streptolysin O titre