Week 5 Flashcards
Describe the ECG waveform:
- P waves represent atrial depolarisation
- PR interval represents time taken for electrical activity to travel from atria to ventricles
- QRS complex represents depolarisation of the ventricles
- ST segment is an isoelectric line that represents time between depolarisation and re-polarisation of the ventricles (ie contraction)
- T wave represents ventricular re-polarisation
- QT interval is the time it takes ventricles to depolarise and re-polarise
Where are ECG electrodes placed?
6 chest electrodes: - V1 at 4th IC space, right sternal edge - V2 at 4th IC space, left sternal edge - V3 midway between V2 and V4 - V4 at 5th IC space on the midclavicular line - V5 left anterior axillary line, same horizontal level as V4 - V6 left mid-axillary line, same horizontal level as V4,5 Limb electrodes: - LA - RA - LL - RL
Outline the systematic approach to ECG interpretation:
- Before you get traces:
- always ask for clinical context
- check date, time and patient
- assess technical quality (artefact/speed/gain) - Look at the rhythm strip
- check the QRS rate/ECG intervals
- identify P/QRS/T and determine rhythm - Look at the limb leads
- determine the QRS axis - Look across all leads
- P/QRS/T morphology
What is a normal cardiac rhythm?
- Normal QRS rate
- Regular QRS complexes
- Usually narrow QRS
- P waves present
- 1:1 P:QRS relation
How do you recognise abnormal cardiac rhythms?
What is the QRS rate? Are the QRS complexes regular? Is the QRS broad or narrow? Are there P waves What is the P:QRS relation
What does acute MI look like on ECG?
ST elevation in acute coronary occlusion
Reciprocal ST depression
Describe the hierarchy of evidence in cardiology:
Classes of recommendations;
- Class I; evidence and/or general agreement that a given treatment or procedure is beneficial, useful and effective
- Class II; conflicting evidence and/or a divergence of opinion about the usefulness/efficacy of the given procedure
-class IIa; weight of evidence/opinion is in favour of usefulness/efficacy
- class IIb; usefulness/efficacy is less well established by evidence/opinion
- Class III; evidence or general agreement that the given treatment or procedure is not useful/effective, and in some cases may be harmful
Also level of evidence A,B or C
Describe the pathophysiology of HF:
- Failure of the heart to pump blood at a rate sufficient to meet the metabolic requirements of tissues
- Characterised by haemodynamic changes (e.g. systemic vasoconstriction) and neurohumeral activation
- Common causes include coronary artery disease (MI and muscle atrophy), hypertension (compensatory hypertrophy and dilatation of ventricular myocardium), toxins and degenerative valve disease
What are the main types of heart failure?
HF-REF
- younger
- more often male
- coronary aetiology
HF-PEF
- older
- more often female
- hypertensive aetiology
Chronic
- present for a period of time
- may have been acute or may become acute
Acute
- usually admitted to hospital
- worsening of chronic
- new onset ('de novo')Describe the clinical presentation of HF:
Symptoms: - dyspnoea (orthopnoea, PND) & cough - ankle swelling (also legs/abdomen) - fatigue/tiredness Signs: - peripheral oedema (ankles, legs, sacrum, abdomen) - elevated JVP - third heart sound - displaced apex beat (cardiomegaly) - pulmonary oedema (lung crackles) - pleural effusion
What is the New York Heart Association functional classification of HF?
NYHA
Class I: no symptoms and no limitation in ordinary physical activity, e.g. SOB when walking, climbing stairs
Class II: mild symptoms (mild SOB and/or angina) and slight limitation during ordinary activity
Class III: marked limitation in activity due to symptoms even during less-than-ordinary activity (e.g. walking short distances, comfortable only at rest)
Class IV: severe limitations. Experiences symptoms even while at rest- mostly bed-bound patients
What are the main drugs used to treat HF?
- Beta-blocker and ACE inhibitor (renin-angiotensin system blockade)
- Mineralocorticoid receptor antagonist
- Sacubutril/valsartan (angiotensin II receptor antagonist)
- Ivabradine (acts on If ion current in SA node)
- Digoxin (inhibition of Na/K ATPase mainly in myocardium)
- Diuretics to treat oedema
What are some non-pharmacological treatments of HF?
- Implantable defibrillator
- Heart transplantation
- Ventricular assist devices
What are the radiological signs of HF in stage 1?
- Redistribution of pulmonary vessels; upper zone vessels are greater than equivalent lower zone vessels
- Cardiomegaly, measured from midline to each widest side of heart
What are the radiological signs in stage 2 HF?
- Interstitial oedema
- sub-pleural pulmonary oedema
- fluid can accumulate in the loose CT beneath the visceral pleura
- seen as a sharply defined band of increased density
- sub-pleural pulmonary oedema
- Kerley lines
- B lines
- septal lines
- seen at the bases perpendicular to the pleural surface
- if transient or rapidly developing, almost diagnostic of interstitial pulmonary oedema
- Peribronchial cuffing
- normally walls of bronchi are invisible
- when fluid collects in peribronchial interstitial space the bronchial walls become visible
- Hazy contours of vessels
- vessels not only enlarge but lose their defined margin due to surrounding oedema
- Thickened interlobar fissures
What are the radiological signs in stage 2 HF?
- Interstitial oedema
- sub-pleural pulmonary oedema
- fluid can accumulate in the loose CT beneath the visceral pleura
- seen as a sharply defined band of increased density
- sub-pleural pulmonary oedema
- Kerley lines
- B lines
- septal lines
- seen at the bases perpendicular to the pleural surface
- if transient or rapidly developing, almost diagnostic of interstitial pulmonary oedema
- Peribronchial cuffing
- normally walls of bronchi are invisible
- when fluid collects in peribronchial interstitial space the bronchial walls become visible
- Hazy contours of vessels
- vessels not only enlarge but lose their defined margin due to surrounding oedema
- Thickened interlobar fissures
What are the radiological signs in stage 3 HF?
- Alveolar oedema
- represents spill of fluid from interstitium into alveolar spaces resulting in airspace opacity
- bilateral usually
- if unilateral, predisposition for right lung
- Bat’s wing or butterfly distribution
- rapid change
- Pleural effusions
- transudates and exudates
What are the radiological signs in stage 3 HF?
- Alveolar oedema
- represents spill of fluid from interstitium into alveolar spaces resulting in airspace opacity
- bilateral usually
- if unilateral, predisposition for right lung
- Bat’s wing or butterfly distribution
- rapid change
- Pleural effusions
- transudates and exudates
- Consolidation
- Air bronchogram
- Cottonwool appearance
- Pleural effusions
What abnormalities affect heart valves?
Valve leaflets: calcification, thickening, degeneration, infection, prolapse
Apparatus/annulus: annular dilatation, annular calcification, apparatus tethering/thickening/rupture, regional wall motion abnormality
What is the difference between stenosis and regurgitation?
Stenosis= pressure overload Regurgitation= volume overload
What is the pathogenesis of aortic stenosis?
- Causes: thickening, calcification, rheumatic valve disease, congenital
- Increased LV cavity pressure
- Pressure overload- LV hypertrophy
- Symptoms: SOB, presyncope, syncope, chest pain, reduced exercise capacity
What is the pathogenesis of aortic regurgitation?
- Causes: degeneration, rheumatic valve disease, aortic root dilatation, systemic disease (Marfan’s syndrome, Ehlers Danlos syndrome, Anklyosing Spondylitis, SLE), endocarditis
- Volume overload with LV dilatation
- Symptoms: SOB, reduced exercise capacity
What is the pathogenesis of mitral stenosis?
- Causes: rheumatic valve disease, pressure overload, dilated LA, atrial fibrillation, pulmonary hypertension, secondary right heart dilatation
- Symptoms: SOB, palpation, chest pain, haemoptysis, right heart failure symptoms
What is the pathogenesis of mitral regurgitation?
- Causes: multifactorial (leaflets, annulus, apparatus), volume overload (LA/LV), LV and LA dilatation, pulmonary hypertension, secondary right heart dilatation, AF
- Symptoms: SOB, palpitation, right heart failure symptoms
How are common valvular lesions investigated?
- History
- Examination
- Blood pressure
- ECG
- Exercise tolerance test
- CPET
- Stress echo
- Echo, CT, MRI
- Left heart catheterisation/right heart catheterisation
What is bicuspid aortic valve?
- 1-2% prevalence
- Prone to premature dysfunction
- Associated with aortic abnormalities
- Genetic component (~10%)
How are common valvular lesions treated?
- Medication
- Intervention
- surgical
- valve repair
- valve replacement (mechanical vs tissue valve)
- procedural
- TAVI
- Mitraclip
- Valvuloplasty
- surgical
