Cardiology Flashcards
Define hs-Tnl
High sensitivity Troponin I
- released from cardiac myocytes due to necrosis
Features of STEMI
ST elevation > 1mm in limb leads and 2mm in chest leads
hs-Tnl > 100ng/L
CK > 400
Features of NSTEMI
ECG may show - ST segment depression - T wave inversion - may be normal hs-Tnl > 100ng/L Previously established ECG changes may be present - old MI - LV hypertrophy - AF
Features of unstable angina
ECG may show - ST segment depression - T wave inversion - may be normal hs-Tnl in normal range
Change in troponin levels in ACS
Rise 3-4 hours after myocardial damage and stay elevated for up to 2 weeks
- males > 34ng/L = high likelihood of myocardial necrosis
- females > 16ng/L
Elevations 5 fold have very high predictive value for type 1 MI
Rising and falling levels differentiate acute from chronic cardiomyocyte damage
- ACS = more pronounced change - > 5ng/L
When are hs-Tnl levels taken
On admission and 1 hour later
- only 1 if onset of symptoms 3+ hours previously
False positive elevation of hs-Tnl
Renal failure Large PE Severe congestive cardiac failure Myocarditis Prolonged tachyarrhythmias Aortic dissection Aortic stenosis Hypertrophic cardiomyopathy Takotsubo cardiomyopathy Malignancy Stroke Severe sepsis
ECG changes in STEMI
ST elevation in 2 or more leads from the same zone or presence of LBBB (left bundle branch block)
ST depression confined to leads V1-V4 may have true posterior MI
Leads giving inferior views
II, III and aVF
Leads giving right ventricle and septum view
V1 and V2
Leads giving anterior views
V3 and V4
Leads giving IVS and anterior surface views
V1-V4
Leads giving lateral view
I, aVL, V5, V6
Which extra leads should be used in supspected MI
Posterior - V7-V9
Right ventricular leads
- ST elevation in RV4 highly sensitive for right ventricular infarction
ECG changes in unstable angina and NSTEMI
Transient ST segment depression or elevation
T wave inversion or flattening
T wave pseudo-normalisation
Conditions that can mimic STEMI on ECG
Early repolarisation - up-sloping ST elevation - leads V1 and V2 - commonly younger, athletic pts and Afro-Caribbeans Pericarditis - concave ST elevation - widespread ST changes Brugada syndrome - similar to anterior STEMI Takotsubo cardiomyopathy - can mimic STEMI and NSTEMI
Management of STEMI
Transfer to catheter lab
IV access
Pain relief - morphine and anti-emetic
Oxygenation - if hypoxic aim for sats > 94%
Aspirin - 300mg loading followed by 75mg od for life
Prasugrel - 60mg loading and 10mg daily for 12 months
Primary Percutaneous Coronary Intervention
Full biochemical screen - incl. lipid profile, random glucose and Hb1Ac
Bisoprolol - 1.25mg od
Ramipril - 2.5mg od or Losartan 25mg od
Atorvastain 80mg od
Control diabetes, hypertension and smoking cessation
MOA of prasugrel
Thienopyridine inhibits ADP receptors
Uses of prasugrel
Patients undergoing PPCI for STEMI
- under 75
- weigh more than 60kg
- no prior TIA or stroke
Alternatives to prasugrel
Clopidogrel
- loading 600mg followed by 75mg od for 12 months
- for those who do not fulfil criteria for prasugrel
Ticagrelor
- 180mg loading dose followed by 90mg bd for 12 months
- used for those who cannot have prasugrel or NSTEMI
What is PPCI
Primary Percutaneous Coronary Intervention
- primary therapeutic measure in pts presenting with MI - without thrombolysis
- restoration of normal flow in culprit artery achieved in over 95%
Effects of bisoprolol
Beta-blocker
- reduces HR
- avoid shock or hypotension
Effects of ramipril
ACE inhibitor
- prevents muscle over-damage
Effects of losartan
ARB
Atorvastatin effects
Statin
- reduce LDL-C < 1.8mmol/L or 40% reduction in non-HDL-C
- total cholesterol target < 4.0mmol/L
Control of diabetes in MI
Insulin infusions HbA1c targets - type 1 < 7% - type 2 = 6.5-7.5% Metformin introduced with caution if LV dysfunction suspected post MI
Complications of STEMI
Heart failure - diuretics
Shock - inotropes and balloon pump
Valve damage
Septal defect
Management of NSTEMI/unstable angina
Pain relief - morphine and anti-emetic
Aspirin - 300mg loading and 75mg od
LMWH (Enoxaparin) - 48hrs based on weight and creatinine
Repeat ECG
Risk assessment of patient with elevated hs-Tnl - grace score
Ticagrelor if risk > 3% (medium) - 180mg loading and 90mg BD
Whilst waiting for inpatient angiography consider anti-anginals - nitrates, ranolazine, CCB
Symptoms of stable angina
Chest discomfort provoked by effort or emotion and relieved by rest
Isolated throat tightness
Arm heaviness
Exertional breathlessness
Features of severe stable angina
Fear
Sweating
Nausea
Risk factors for CAD
Cigarette smoking Hypertension DM Hypercholesterolaemia FH of premature of coronary artery disease Vascular disease
Coronary risk factor profile
Chest discomfort more likely to represent coronary artery disease in an individual with two or more existing risk factors
Causes of angina
Coronary artery disease
Aortic stenosis
Hypertensive heart disease
Hypertrophic cardiomyopathy
History for angina should include
Precipitants of anginal attacks Relieving factors Stability of symptoms Risk factors Occupation Assessment of intensity, length and regularity of exercise Basic dietary assessment Alcohol intake Drug history Family history
Features that make angina unlikely
Pain continuous or very prolonged
Unrelated to activity
Brought on by breathing
Associated symptoms such as dizziness or dysphagia
Features of examination for angina
Weight and height - calculate BMI Blood pressure Presence of murmurs - aortic stenosis Evidence of hyperlipidaemia Evidence of peripheral vascular disease and carotid bruits
Investigations for stable angina
Full blood count and biochemical screen - inclucing glucose/HbA1c
Full lipid profile
Resting 12-lead ECG - rhythm, heart block, previous MI, myocardial hypertrophy and ischaemia
Treatment for CAD
Estimated likelihood of CAD
61-90% - Invasive coronary angiography
30-60% - Functional imaging as 1st line diagnostic intervention - stress MRI, echo, myoview
10-29% - CT calcium scoring
Drug treatment of CAD
75mg aspirin OD
- clopidogrel 75mg OD for those allergic or intolerant
Sublingual GTN
Beta-blockers for symptomatic relief
- Ivabradine 5-7.5mg alternate if HR > 70bpm
Non-dihydropyridine CCB for rate limitation - diltiazem or verapamil
Long-acting nitrates - isosorbide mononitrate
Potassium channel opening drugs - nicorandil
Ranolazine 375mg-750mg - add on
Statin
Non-cardiac causes of chest pain
Costochondritis Gastro-oesophageal PE Pneumonia Pneumothorax Psychogenic/psychosomatic
Stages of hypertension
Stage 1 - clinical BP > 140/90 - ABPM or HBPM average > 135/85 Stage 2 - clinical BP > 160/100 - ABPM or HBPM average > 150/95 Severe hypertension - clincial BP > 180/110
ABPM
Ambulatory Blood Pressure Monitoring
HBPM
Home Blood Pressure Monitoring
Symptoms of hypertension
Nil or headache
Sweating, headache, palpitations, anxiety -> phaeochromocytoma
Muscle weakness and tetany -> hyperaldosteronism
CVS risk
TIA Stroke Diabetes Previous renal disease Smoking Cholesterol NSAID excess Angina CCF Palpitations Syncope Valvular heart disease FH of hypertension, premature coronary disease and polycystic kidney disease
Physical assessment for hypertension
Look for secondary causes
- Cushing’s syndrome
- enlarged kidney (PCK)
- renal bruits
- radio-femoral delay (coarctation)
Investigations for hypertension
Urine albumin:creatinine ratio and haematuria
Blood sample - glucose, electrolytes, creatinine, eGFR, serum total cholesterol and HDL cholesterol
- may suggest secondary cause - low K+, high Na+, hyperaldosteronism
Examine fundi - hypertensive retinopathy
12-lead ECG
Echocardiography - suggestion of LVH, valve disease or LVSD
LVSD
Left Ventricular Systolic Dysfunction
Target blood pressure in hypertension
Low risk = < 140
High risk = < 130/80
Elderly <80 = 140-150 but <140 if tolerated
Elderly >80 = 140-150
Diastolic = <90 except in diabetes where target <85
Non-pharmacological hypertension treatment
Weight reduction if BMI > 25 - each kg lost yields BP reduction of 3/2 mmHg Moderate salt intake - can reduce BP by 8/5 mmHg Minimise alcohol intake Aerobic exercise Smoking cessation - reduce CVS risk
Pharmacological hypertension treatment
1st line
- under 55 - ACEi or ARB
- over 55 or black person or African/Caribbean family - CCB
2nd line
- ACEi/ARB + CCB
3rd line
- ACEi/ARB + CCB + thiazide-like diuretic
Resistant hypertension
- ACEi/ARB + CCB + thiazide-like diuretic + further diuretic or alpha/beta blocker
Define hypertensive crisis
Increase in blood pressure which if sustained over next few hours will lead to irreversible end-organ damage
- encephalopathy
- LV failure
- aortic dissection
- unstable angina
- renal failure
Treatment for hypertensive crisis
Reduce diastolic BP to 110mmHg in 3-12 hours
IV
- sodium nitroprusside
- labetalol
- GTN - 1-10mg/hr
- esmolol
- acts in 60 secs with duration of 10-20 mins
- 0.5-1mg/kg loading dose followed by infusion of
50μ/kg/min-300μ/kg/min
Define hypertensive urgency
Severe blood pressure elevation that will cause damage within days
- diastolic > 130mmHg
- retinal changes apparent
Hypertensive urgency treatment
Reduce BP gradually to diastolic of 100mmHg over 48-72hrs Oral - amlodipine 5-10mg OD (CCB) - diltiazem 120-300mg OD (CCB) - lisinopril 5mg OD (ACEi)
Symptoms of phaeochromocytoma
Episodic headache, sweating and tachycardia
Sustained or paroxysmal hypertension most common
Diagnosis of phaeochromocytoma
24 hour urine collection
- fractionated metanephrines and catecholamines
CT or MRI abdo and pelvis - detect tumours
MIBG scan
Treatment of phaeochromocytoma
Surgery - resection
Whilst waiting surgery
- alpha and beta adrenergic blockade
- phenoxygenzamine 10mg OD/BD - 10-20mg every 2-3 days
Features of Cushing’s syndrome
Increased weight Mood change - depression, lethargy, irritability, psychosis Proximal weakness Gonadal dysfunction - irregular menses, hirsutism, erectile dysfunction Central obesity Moon face Buffalo hump Skin and muscle atrophy Purple abdominal striae Increased BP Increased blood glucose Elevated 24hr urine cortisol - 3x
Diagnosis of Cushing’s syndrome
Low-dose dexamethasone suppreession test
Adrenal CT
Features of primary aldosteronism
Low serum potassium and high/normal sodium
Very low/undetectable plasma renin
High plasma aldosterone
Adrenal CT
Causes of heart failure
Ischaemic heart disease Hypertension Valvular heart disease - rheumatic fever in elderly Atrial fibrilation Chronic lung disease Cardiomyopathy - hypertrophic, dilated right ventricle, post-viral, post-partum Previous cancer chemotherapy drugs HIV
HFREF
Heart Failure with Reduced Ejection Fraction
HFNEF
Heart Failure Normal Ejection Fraction
NFNEF patient profile
Elderly
Overweight
Hypertension
AF
Features of heart failure which contribute to poor prognosis
Severe fluid overload Very high NT-proBNP levels Severe renal impairment Advanced age Mulit-morbidity Frequent admissions
Investigations in heart failure
Renal function - baseline and for diuretic effect
FBC - anaemia as consequence of bone marrow issue
LFT’s - hepatic congestion
TFT’s - thyroid disease
Ferritin and transferrin - possible haemochromatosis in younger patients
NT-proBNP - < 100ng/L rules out acute heart failure
NT-proBNP
Brain Natriuretic Peptide
- secreted by cardiomyocytes in ventricles in response to stretching caused by increased ventricular blood volume
Features of CXR in heart failure
Cardiomegaly Perihilar shadowing/consolidations Alveolar oedema Air bronchograms Increased width of vascular pedicle Could be pleural effusions
Assessment of LV function
Echocardiography - confirm diagnosis
Cardiac MRI - echogardiogram may miss right ventricle
Features of heart failure in echocardiogram
Dilated poorly contracting left ventricle - systolic dysfunction
Stiff, poorly relaxing, small diameter left ventricle - diastolic dysfucntion
Valvular disease
Atrial myxoma
Pericardial disease
Lifestyle modification in heart failure
Smoking cessation
Restriction of alcohol consumption
Salt restriction
Fluid restriction - presence of hyponatraemia
Medication for heart failure
Diuretics
ACEi
ARBs
Angiotensin Receptor-Neprilysin Inhibitor (ARNI)
Beta blockers
Vasodilators - hydralazine and isosorbide mononitrate
Ivabradine - those who cannot tolerate beta blockers
Nitrates
How are diuretics used in heart failure?
Loop diuretics most effective for symptomatic treatment
Furosemide 40-500mg OD
- IV when severe fluid overload
- large doses in renal impairment
- prolonged infusions give better effects - 250mg over 7 hrs
Bumetanide
- better oral absorption
Thiazides added on
- bendroflumethiazide 2.5mg OD
- metolazone 2.5-5mg OD
If hypokalaemia persists spironolactone 25mg OD
Uses of ACEis in heart failure
Improve
- symptoms and signs in all stages
- exercise tolerance
- slow disease progression
- survival
Use of ARBs in heart failure
Valsartan and Candesartan
Use of ARNIs in heart failure
Sacubitril with Valsartan
Symptomatic chronic heart failure with reduced ejection fraction with stable dose of ACEis and ARBs
Use of beta blockers in heart failure
Safe if systolic BP > 100mmHg with resting HR > 60bpm and no postural drop
Carvedilol - 3.125mg BD - 25mg BD
Bisoprolol - 1.25mg OD - 10 mg OD
Uses of vasodilators in heart failure
Hydralazine and isosorbide mononitrate
Beneficial effect on survival
- pts of African or Caribbean origin - cannot take ACEi/ARBs
- pts with resistant CCF
Use of Ivadbradine in heart failure
Those who cannot tolerate beta-blockers or those who HR>75 despite beta-blockers
In sinus rhythm
No impact on blood pressure
Effect of nitrates in heart failure
Reduce
- preload
- pulmonary oedema
- ventricular size
Uses of nitrates in heart failure
Acute heart failure
- underlying ischaemia
- hypertension
- regurgitant aortic and mitral valve disease
Chronic heart failure
- relief of orthopnoea and exertional dyspnoea
Contraindications of nitrates in heart failure
Aortic and mitral stenosis
HOCM
Pericardial constriction
HOCM
Hypertrophic Obstructive CardioMyopathy
ECG of LBBB
Broad QRS duration
- depolarisation is delayed from septum to lateral wall -> mechanical reduction
LBBB
Left Bundle Branch Block
Uses of complex implantable devices in LBBB
Cardiac Resynchronisation Pacemaker (CRT)
- double pace spikes before QRS
ICD
Implantable Cardiac Defibrillators
Uses of ICDs
Do not improve symptoms
Prevent sudden cardiac death associated with heart failure
- detect and cardiovert VT/VF
Symptoms of Aortic Stenosis
Decrease in exercise tolerance or dyspnoea on exertion
Angina
Heart failure
Syncope
Causes of aortic stenosis
Age related
Congenital bicuspid valve
Chronic kidney disease
Previous rheumatic fever
Features of aortic stenosis murmur
Aortic area - 2nd intercostal space right side
Ejection systolic radiating to carotid/neck
Severity of AS
Mild - mean gradient <25mmHg - peak gradient <36mmHg - AoV area > 1.2cm2 Moderate - mean gradient 25-39mmHg - peak gradient 36-64mmHg - AoV area 1.0-1.2cm2 Severe - mean gradient >40mmHg - peak gradient >65mmHg - AoV area < 1.0cm2
Indications for surgery for AS
Symptoms causes by AS Asymptomatic severe AS with - left systolic dysfunction - abnormal exercise test - time of other cardiac surgery
What should be used in older patients with many co-morbidities in symptomatic AS
Transcatheter aortic valve implantation (TAVI)
- implanted by femoral artery
Symptoms of AR
Asymptomatic - many years
Exertional dyspneoa and reduced exercise tolerance - increased volume load on LV -> LV dilation -> heart failure
Causes of AR
Idiopathic dilation of aorta - pulling valve leaflets apart
Congenital abnormalities of aortic valve - bicuspid
Calcific degeneration
Rheumatic disease
Infective endocarditis
Marfan syndrome
Describe AR murmur
Left sternal edge
Early diastolic blowing murmur
- associated with collapsing pulse
Treatment for patients with severe AR
ACEi - afterload reduction
- slows rate of LV dilation
Assessment of AR
Echocardiography
- quantification of severity of disease
- assessment of rest of heart
Indiciations for surgery in AR
Symptomatic severe AR
Asymptomatic severe AR with evidence of early LV dysfunction
- EF <50%
- LV end-systolic diameter > 5cm
- LV end-diastolic diameter > 7cm
Asymptomatic AR of any severity with aortic root dilation > 5.5cm
Symptoms of MR
Mostly asymptomatic
Causes of MR
Mitral valve prolapse - Marfan's syndrome - pectus excavatum Rheumatic heart disease IHD Infective endocarditis Drugs Collagen vascular disease
Describe MR murmur
Pan-systolic blowing murmur
- mitral area - 5th ICS mid-clavicular line
- radiates to axilla
Assessment of MR
Echocardiography
- assess LV function and size
- severity of blood coming through valve
Surgical treatment of MR
Replacement
Repair
- reduced operative mortality
Indications for surgical intervention in severe MR
Symptomatic MR
Asymptomatic with mild-moderate LV dysfunction
- EF 30-60%
- LVESD 4.5-5.5cm
LVESD
Left Ventricular End-Systolic Diameters
Medical treatment of MR
Diuretics ACEI in functional or ischaemic MR If LV systolic dysfunction - ACEi - beta-blockers - CRT
Predisposing conditions for infective endocarditis
Mitral valve prolapse Presence of prosthetic material - valves - patches Rheumatic heart disease Degenerative and bicuspid aortic valve disease Congenital heart disease
Common causative organisms of infective endocarditis
Streptococci viridans
Staphylococcus aures - IV drug users
Coagulase-negative staphylococci (S.epidermis) - 1 yr post prosthetic heart vavlue implantion
Enterococcal endocarditis - GU or lower GI tract
Causes of mortality in infective endocarditis
Heart failure
CNS emboli
Uncontrolled infection
Features of IE
Unexplained fever
Bacteraemia
Systemic illness
New murmur
Routine investigations for IE
FBC ESR and CRP U&Es LFTs Urine dipstick analysis and MSU for MS&C CXR ECG
Key diagnostic investigations for IE
Blood cultures
- min 3 from different sites over several hours
- if pt stable delay antibiotics to allow for comprehensive sampling
Echocardiogram
- transoesophageal echocardiography (TOE)
Diagnostic criteria for IE
2 major
1 major and 3 minor
5 minor
Major diagnostic criteria for IE
Positive blood cultures - typical organism from 2 - persistent positive blood cultures taken > 12 hrs apart - > 3 positive blood cultures taken over more than one hour Endocardial involvement Positive echo findings - vegetation - abscess New valvular regurgitation Dehiscence of prosthesis
Minor diagnostic criteria for IE
Predisposing valvular or cardiac abnormality IV drug user Pyrexia > 38 Embolic phenomenon Vasculitic phenomenon Blood cultures suggestive - organism grown but not achieving major criteria Suggestive echo findings
Management of IE
Antibiotic therapy
- tunnelled central venous line for prolonged courses
Surgery
Antibiotic therapy for management of IE
Streptococci
- benzylpenicillin IV plus low-dose gentamicin (80mg BD)
- vancomycin if penicillin-allergic
Enterococci
- amoxicillin IV plus low-dose gentamicin (80mg BD)
- vancomycin if penicillin-allergic
Staphylococci
- flucloxacillin plus gentamicin
- benzylpenicillin if penicillin-sensitive
- vancomycin if penicillin-allergic
How to monitor response to therapy in IE
Echocardiogram weekly - assess vegetation size - look for complications - valve destruction, intracardiac abscesses ECG twice weekly - detect conduction disturbances - indicate development of aortic root abscess in aortic valve infection Blood tests twice weekly - ESR - CRP - FBC - U&Es
Indications for surgery in IE
Moderate to severe cardiac failure due to valve compromise
Valve dehiscence
Uncontrolled infection despite appropriate antimicrobial therapy
Relapse after optimal medical therapy
Threatened or actual systemic emboli
Coxiella burnetii or fungal infections
Paravalvar infection - aortic root abscess
Sinus of valsalva aneurysm
Valve obstruction
How to calculate rate in an ECG
Standard 12 lead ECG rhythm strip = 10 seconds
- number of QRS complexes * 6 = HR per min
Normal heart rate
60-100 bpm
Bradycardia
< 60 bpm
- absolute < 40bpm or HR inappropriately slow for haemodynamic state of patient
Tachycardia
> 120 bpm
Stages of reading an ECG
Rate Rhythm Axis Intervals ST/T wave changes
How to work out if ECG rhythm is regular?
Mark out several consecutive R-R intervals on piece of paper and move along rhythm strip to check is subsequent intervals are the same
Types of heart rhythm
Normal
Irregular
- regularly irregular
- irregularly irregular
Define cardiac axis
Overall direction of electrical spread within the heart
Normal cardiac axis
11 o’clock to 5 o’clock
- spread of depolarisation to leads I, II and III - positive deflection
- most negative deflection in aVR
Causes of right axis deviation (RAD)
Right ventricular hypertrophy - extra heart muscle causes stronger signal to be generated by the RHS of the heart Pulmonary conditions - strain the heart Normal finding in very tall individuals
Features of RAD
1-7 o’clock depolarisation
- deflection in lead I becomes negative
- deflection in lead aVF/III to be more positive
Causes of left axis deviation (LAD)
Conduction defections
- not increased mass of LV
Features of LAD
Depolarisation to left
- deflection in lead III becomes negative
- only significant if lead II becomes negative
P wave features of ECG
P-waves present
Each p-wave followed by a QRS complex
Normal shape, duration and direction
What to consider if no p waves on ECG
Atrial flutter - sawtooth baseline
AF - choatic baseline
No atrial activity - flatline
Normal P-R interval
120-200 ms
- 3-5 small squares
What does a prolonged PR interval indicate
AV block
Features of first degree heart block
Fixed prolonged PR interval (>200ms)
Occurs between SA node and AV node - in atrium
Features of second degree heart block Mobitz type 1
PR interval slowing increasing then dropped QRS complex
Occurs in the AV node
Features of second degree heart block Mobitz type 2
Fixed PR interval then dropped QRS complex
Occurs after the AV node in bundle of His or Purkinje fibre
Features of third degree heart block
P waves and QRS complexes completely unrelated
Occurs anywhere after AV node - complete conduction blockage
Causes of shortened PR interval
Normal - smaller atria or closer location of SA node
Accessory pathway
- delta wave = Wolff Parkinson White Syndrome
Aspects of QRS complex to observe in ECG
Width
Height
Morphology
Normal width of QRS complex
< 0.12 seconds
Causes of broad QRS complex
Abnormal depolarisation sequence
- ventricular ectopic
- bundle branch block
Normal height of QRS complex
< 5mm in limb leads or < 10mm in the chest leads
Causes of tall QRS complex
Imply ventricular hypertrophy
- can be due to body habitus - tall slim people
Delta waves
Slurred upstroke of QRS complex
- early activation of ventricles
- featured in Wolff-Parkinson-White syndrome
Pathological Q waves
> 25% of the size of the R wave that follows it or > 2mm in height and > 40ms in width
Single not cause for concern
- in entire territory for evidence of previous MI
R wave progression
In lead V1 R wave should be small
- becomes larger throughout precordial leads
- R wave larger than S wave in lead V3 or V4
- S wave gets smaller
Causes of poor R wave progression
Previous MI
Larger people due to lead position
Define J point
Where S wave joins ST segment
Features of benign early repolarisation
Elevated J point - ST segment following raised
- under 50s
- widespread ST elevation in multiple territories
- T waves raised
- does not change over time
QTc
Corrected QT interval
Normal QTc
400-440ms or 2 large squares
Features of ST elevation
Greater than 1mm (1 small square) in 2 or more contiguous leads or >2mm in 2 or more chest leads
Causes of ST elevation
Acute full thickness myocardial infarction - STEMI
Features of ST depression
> 0.5mm in > 2 contiguous leads
Causes of ST depression
Myocardial ischaemia
What do T waves represent
Repolarisation of ventricles
Features of tall T waves
> 5mm in limb leads and > 10mm in chest leads
Causes of tall T waves
Hyperkalaemia - tall tented T waves
Hyperacute STEMI
Features of inverted T waves
Normal on V1 and III
Causes of inverted T waves
Ischaemia Bundle branch blocks - V4-6 in LBBB - V1-3 in RBBB PE Left ventricular hypertrophy - lateral leads Hypertrophic cardiomyopathy - widespread General illness
Causes of biphasic T waves
Ischaemia
Hypokalaemia
Causes of flattened T waves
Ischaemia
Electrolyte imbalance
Featues of U waves
> 0.5mm deflection after T wave
- best seen in V2 or V3
Causes of U waves
Become larger the slower the bradycardia Electrolyte imbalance Hypothermia Antiarrhythmic therapy - digoxin - procainamide - amiodarone
Causes of sinus bradycardia
Medications Hypothyroidism Hypothermia Sleep apnoea Rheumatic fever Viral myocarditis Pericarditis
Treatment of second degree AV block Mobitz type II
Permanent pacing
Causes of third degree AV block
Anti-arrhythmic drugs
- digoxin
Following inferior STEMI
Severe hyperkalaemia
Treatment of third degree AV block
Atropine - 600μg - 3mg
- haemodynamically stable patient
Isoprenaline - 5 μg/min
Urgent pacing
Natural history of AF
Brief paroxysms of increasing duration
Persistent and permanent AF
Associated complications of AF
Haemodynamic instability due to tachyarrhythmia or bradyarrhythmia
Acute coronary syndrome
Congestive cardiac failure
Cardioembolic stroke
Symptoms of AF
Breathlessness Palpitations Syncope/dizziness Chest discomfort Stroke/TIA
Management of AF
Anticoagulation - prevent stroke - apixiban, rivaroxaban and edoxaban - inhibit factor Xa - dabigatran - inhibit thrombin Rate control - beta-blocker - rate-limiting calcium-channel blocker - diltiazem or verapamil - digoxin Rhythm control - amiodarone - electrical cardioversion
Types of supraventricular tachycardia
AV nodal re-entry tachycardia (AVNRT)
Atrio-ventricular re-entry tachycardia (AVRT)
Treatment of supraventricular tachycardia
Transient blocking AV nodal conduction Vagal manoeuvres - haemodynamically stable patients - Valsalva manoeuvre - carotid massage IV adenosine - 6 mg stat followed by 12mg if unsuccessful then further 12mg Verapamil - 5-10mg stat - contraindicated beta-blockers or LV dysfunction Synchronised cardioversion - following sedation - starting at 150J - pts who are hypotensive, pulmonary oedema, chest pain with ischaemia IV flecainide - avoided in pts with MI - past or present
Describe Valsalva maneouvre
Forceful attempted exhalation against closed airway
- blowing into syringe to move the plunger
Describe carotid massage
Massage carotid sinus for several seconds on non-dominant cerebral hemisphere side
- auscultate for bruits before attempting manoeuvre
- wait 10 seconds before trying other side
Treatment of ventricular tachycardia
Cardioversion
- haemodynamically compromised
- synchronised 150-200 J shock with a biphasic defibrillator
Beta-blockers
Amiodarone - 300mg IV stat then 900 mg over 24 hrs
Lidocaine - 50-100mg over 3-5 mins
- alternative
