Cardio Flashcards
What is the intrinsic rate of the SA node?
60 - 100 BPM
What is the intrinsic rate of the AV node?
40 - 60 BPM
What is the intrinsic rate of the ventricular cells?
20 - 45 BPM
What is the intrinsic rate of the ventricular cells?
20 - 45 BPM
Describe the impulse conduction pathway
SAN -> AVN -> Bundle of His -> Bundle branches -> Purkinje fibres
One small box on ECG = ?
0.04 seconds
(40 milliseconds)
One large box on ECG = ?
0.20 seconds (horizontally)
0.5 mV (vertical)
Cardiac output (L/min) =
Stroke volume (L) x HR (BP)
Define total peripheral resistance
The total resistance to slow in systemic blood vessels from start of aorta to vena cava
What vessels provide the most resistance?
Arterioles
What is Starling’s Law?
Force of contrition is proportional to end diastolic length of cardiac muscle fibres
i.e. more ventricle fills, harder it contracts
What is S1?
Mitral and tricuspid valve closure
What is S2?
Aortic and pulmonary valve closure
What is S3?
In early diastole during rapid ventricular filling
Normal in children and pregnant women
Associated w/ Mitral Regurg and heart failure
What is S4?
“Gallop” in late diastole
Produced by blood forced into stiff hypertrophic ventricle
Associated w/ LV hypertrophy
Key presentation of peripheral arterial disease
6 Ps
Pain
Pulseless
Pallor
Perishingly cold
Paraesthesia
Paralysis
Symptoms of PAD
Intermittent claudication
Ix PAD
Colour Duplex USS - shows vessels and blood flow within
Ankle Brachial Pressure Index (ABPI) -
highest ankle systolic pressure / highest brachial systolic pressure
Normal = 1 - 1.2
PAD = ≤ 0.9 (below 0.4 is severe - rest pain)
If thinking of intervention,
MRI/CT angiography - identify stenosis and quality of vessels
Tx PAD
Lifestyle changes - to minimise risk of MI and relieve symptoms
e.g. stop smoking, treat HTN, lower cholesterol, improve diet, exercise
Anti-platelet therapy - Clopidogrel (P2Y12-i)
If severe :
percutaneous transluminal angioplasty or surgery
Describe the stages of chronic limb ischaemia
stage 1 - asymptomatic
stage 2 - intermittent claudication
stage 3 - rest pain/nocturnal pain
stage 4 - necrosis/gangrene
Complications of PAD
Acute limb ischaemia
∴ loss of limb
Key presentation of peripheral venous disease (DVT)
Red, swollen, warm limb
Dull achy contact pain
Ix DVT
Wells score - to assess likelihood
If DVT likely - venous ultrasound
If DVT unlikely - D-dimer first
GS : Venous ultrasound
If unavailable, CT scan
Tx DVT
If proximal, ANTI-COAG! for 3 months (unless CI)
DOACs, warfarin, heparin
Apixaban, rivaroxaban
If distal, check local protocol.
In UK, start anticoag unless ↑ risk of bleeding or if DVT < 5cm
What type of patients will need a tailored approach of treatment for DVT?
Pregnant, cancer, renal impairment patients
Complications of DVT
Pulmonary embolism
If a DVT patient present with marked swelling, significant pain and cyanosis, what should you suspect?
Phlegmasia cerulea dolens
IMMEDIATE TREATMENT - life and limb threatening !!!
Which artery? Hip/buttock pain
Aortic or iliac artery
Which artery? Thigh pain
Common femoral artery
Which artery? Upper 2/3rd of calf pain
Superior femoral artery
Which artery? Lower 2/3rd of calf pain
Popliteal artery
Which artery? Foot pain
Tibial or peroneal artery
Other signs/symptoms of PAD
Bruit - ‘Whooshing sounds’ when stethoscope over iliac arteries
Buerger’s test
Absent pulses
Ulcer’s don’t fully heal
Define HTN
Clinical BP - 140/90
At home - 135/85
Causes of 1st degree heart block
LEV’s disease (aka Lenegre’s)
IHD - scar tissue from myocyte death
Myocarditis
Hypokalaemia
AVN blocking drugs e.g. beta blockers, CCBs, Digoxin
Define 1st degree Heart Block
Delayed AV conduction but still makes it to ventricles
Prolonged PR interval > 0.22s
Key presentation of 1st Degree Heart Block
ASYMPTOMATIC!
no treatment required
Describe 2 places where electrical energy can be blocked
- AVN or Bundle of His = AV block
- Lower conduction system = BBB
Causes of 2nd Mobitz Type 1 heart block
AV node blocking drugs e.g. BB, CCB, Digoxin
Inf. MI
Define 2nd Mobitz Type 1 Heart Block
Atrial impulses fail to reach the ventricles
Progressive PR interval prolongation until beat is ‘dropped’ and P wave fails to conduct
PR wave then returns to normal
Key presentation of 2nd Mobitz Type 1 heart block
Light-headedness, dizziness, syncope
Causes of 2nd Mobitz Type 2 heart block
Block at intra-nodal level
Ant. MI
Mitral valve surgery
SLE, Lyme disease
Rheumatic fever
Key presentation of 2nd Mobitz Type 2 heart block
Dyspnoea, postural hypotension, chest pain, syncope
Describe 2nd Mobitz Type 2 heart block
PR interval is CONSTANT (NO PROLONGATION)
QRS intervals widened and dropped
State the causes of 3rd degree Heart Block
Structural heart disease
IHD e.g. acute MI
HTN
Endocarditis, Lyme disease
Describe 3rd degree heart block
COMPLETE dissociation between atria and ventricles i.e. P waves completely independent of QRS complex
What is a Narrow-complex escape rhythm?
QRS complex less than 0.12 seconds
Implies block originates in Bundle of His ∴ region of block lies more proximally in AV node
Tx 3rd degree heart block
IV atropine
Permanent pacemaker insertion
Tx 2nd degree heart block
If severe enough, permanent pacemaker insertion
What is Broad-complex escape rhythm?
QRS > 0.12 s
Block indicated to be Below His, more distal in His-Purkinje system
What can often occur with Broad-complex escape rhythm B?
Dizziness, Blackouts
Causes of Right Bundle Branch Block
PE
IHD
Atrial-ventricular septal defect
Causes of Left Bundle Branch Block
IHD
Aortic valve disease
Describe Right Bundle Branch Block
Right bundle no longer condutcs
∴ ventricles don’t receive impulses at same time, spread from left to right instead
∴ late activation of RV
How is a RBBB seen on an ECG?
Deep S wave in leads 1 and V6
Tall late R wave in lead V1
RF for PE
Age
DVT
Surgery within last 2 months
Bed rest > 5 days
Previous venous thromboembolic events
FHx
Why is there a difference in treatment between proximal and distal DVTs?
Proximal has a chance of PE, stroke etc
Bigger risk
Describe Virchow’s triad
- Vessel injury
- Venous stasis
- Activation of clotting system
Ix PE
ABCDE assessment
PERC rule if doesn’t meet PERC (PE rule-out criteria), use Wells score
D-dimer
GS : CT pulmonary angiography
Tx PE
Anticoag= - rivaroxaban, LMWH
Start O2 if sats < 90%
Thrombolysis - if massive clot
Key presentation of PE
If small - asymptomatic
If large - pleuritic pain + other symptoms
If massive - sudden death
Dyspnoea (↑ RR)
Syncope
Dizziness
Leg pain - DVT
Complications of PE
Respiratory alkalosis (due to ↑ RR)
Infarction
What can be heard in RBBB?
Wide physiological splitting of S2
What can be heard in LBBB?
Reverse splitting of S2
Cause of Infective Endocarditis
BACTERIA
Staph. aureus - most common
IVDU, diabetes + surgery
Infects damaged + healthy valves
Strep. viridans - most common in LICs
Dental problems!
Attacks previously damaged valves, low virulence
Staph. epidermis
Prosthetic materials e.g. prosthetic valves
Psuedomonas aeruginosa
Describe the pathophysiology of IE
Damaged endocardium allows bacteria to thrive.
Creates a prothrombotic millieu
∴ colonisation of thrombus
∴ ↑ Platelet and fibrin deposition
∴ mature infected vegetation
Why does damaged endocardium allow bacteria to thrive?
Increased platelet and fibrin deposition
They adhere to underlying collagen surface
Key presentation of IE
Fever, headache, malaise, confusion, night sweats
(non-specific ∴ easily missed)
Other signs/symptoms of IE
FROM JANE
Fever
Roth spots
Osler nodes
Murmur - usually aortic regurg
Janeway lesions
Anaemia
Nail-bed haemorrhages
Emboli
–
Sepsis of unknown origin
Clubbing
Anorexia
Weight loss
Fatigue
Glomerulonephritis
Haematuria
What valves are usually affected with congenital or acquired defects in IE?
Left heart valves
More common to be left (mitral and aortic)
What valves are usually affected with IVDU cause of IE?
Right heart valves
Which bacteria causes IE to progress rapidly?
Staph. Aureus
NEW HEART MURMUR + FEVER =
SUSPECT INFECTIVE ENDOCARDITIS
Initial Ix IE
Duke’s criteria
Blood cultures - 3 sets over 24 hours OR 3 x persistently positive (i.e. 3 cultures 12 hours apart) FROM DIFFERENT SITES.
BEFORE Abx (but don’t delay Tx if sepsis or similar)
also bloods show - ↑ CRP, ↑ ESR, normochromic and normocytic anaemia
CXR - cardiomegaly
ECG long PR interval
GS Ix IE
2 options :
TTE (transthoracic echo) - less discomfort, low sensitivity, negative TTE doesn’t rule out IE
TOE (transoesophageal) - signif more discomfort, much more sensitive and better at diagnosing!!
Describe Duke’s criteria
2 major criteria
o Bugs grown from blood cultures
o Evidence of endocarditis on echo, or new valve leak
5 Minor criteria
o Predisposing factors
o Fever
o Vascular phenomena
o Immune phenomena
o Equivocal blood cultures
Definite IE: 2 major / 1 major + 3 minor / 5 minor
What are some vascular phenomena of IE?
Janeway lesions, major arterial emboli
What are some immunologic phenomena?
Roth spots, Osler nodes, Glomerulonephritis, Rh factor
Tx IE
MDT approach
Abx ASAP - organism needs to be identified (and check for prosthetic valve) for specific antibiotic
Prolonged course! (6 weeks)
2 weeks IV, then oral
Treat comps if any
What GS treatment should be chosen if a patient has a prosthetic valve?
TOE
DDx IE
SLE
Antiphospholipid syndrome
Reactive arthritis
Meningitis
IE complications
Arrhythmia
Heart failure
Heart block
Embolisation
Stroke rehab
Abscess drainage
What Abx would you use to treat Staphylococcus in IE?
Vancomycin and Rifampicin (if MRSA)
What Abx would you use for anything other than Staphylococcus in IE?
Penicillin - benzylpenicillin and gentamycin (doesn’t work by itself bc can’t get through bacterial cell wall)
When might surgery be required in IE?
If infection cannot be cured by Abx i.e. returns after treatment
What does surgery for IE comprise of?
Removal infected devices or removing large vegetations before they embolise
Epidemiology of Acute pericarditis
M > F
Adults > children
Define acute pericarditis
Acute inflammation of pericardium with or without effusion
Causes of acute pericarditis
Viral - *Coxsackie virus B, echovirus, adenovirus, EBV
Bacterial - Mycobacterium tuberculosis
Fungal (rare) - Histoplasma spp. (immunocomp Pxs)
Non-infectious causes -
Autoimmune e.g. RA
Neoplastic e.g. tumours
Metabolic e.g. uraemia
Dressler’s
Key presentation of Acute pericarditis
Chest pain - severe, sharp, pleuritic
Rapid onset
Might radiate to arm (trapezius ridge)
Relieved by sitting forward, exacerbated by lying down and inspiration
Other signs/symptoms of Acute Pericarditis
Beck’s triad
Pericardial rub
Signs of effusion
Sinus tachycardia
Dyspnoea
Cough
Systemic disturbance - skin rash, joint pain
Ix Acute Pericarditis
GS : ECG
Saddle shapped ST elevation - diagnostic
Diffuse ST segment elevation
PR depression
Other :
CXR - cardiomegaly in case of effusion
Echo - confirms effusion
FBC - for troponin, CK etc
D-dimer to rule out PE (but can be raised in both so consult senior if needed)
Why is it important to rule out PE?
Bc if patient treated with anti-coag, can develop CARDIAC TAMPONADE!!
bc bleeding into pericardial space
Tx Acute Pericarditis
NSAIDs, Aspirin
Colchicine - for 3 weeks, limited by nausea and diarrhoea but reduces recurrence
What is commonly associated with acute pericarditis?
Pneumonia
DDx Pericarditis
MI
Angina
Pleuritic pain
Pulmonary infarction
Pneumonia, GI reflux, peritonitis, aortic dissection
What is seen on an ECG with hypothermia?
J waves
What is commonly associated with Aortic Regurg?
Wide pulse pressure
Collapsing pulse
Early-diastolic
Best heard over left sternal edge in 4th intercostal space
Best hear when patient sits forward
- Du Musset’s sign
Corrigan’s sign
Muller’s sign
Quincke’s sign
Describe Aortic Regurg
Leakage of blood into LV from aorta during diastole
Due to ineffective coaptation of aortic cusps
Causes of Aortic Regurg
IE - acute
Rheumatic fever - chronic
Congenital bicuspid aortic valve - chronic
Aortic root dilation
Key presentation of Aortic Regurg
May be asymptomatic for many years before
Exertional dyspnoea
Palpitations
Angina
Other signs/symptoms of Aortic Regurg
Orthopnea
Syncope
Paroxysmal nocturnal dyspnea
Ix Aortic Regurg
ECG - shows LVH, rules out MI
CXR - cardiomegaly, aortic root enlargement
GS : Echo - TTE
TOE better but more invasive, use if suspect aortic dissection
Tx Aortic Regurg
IE prophylaxis
Vasodilators - ACEi e.g. ramipril
Monitor progression
Surgery if symptoms increase - before LV dysfunction
When would you prescribe vasodilators to treat a patient with aortic regurgitation?
If patient is symptomatic or has HTN
Otherwise, isn’t effective
Define Aortic Stenosis
Narrowing of aortic valve resulting in obstruction to LV stroke volume
Key presentation of aortic stenosis
SAD
Syncope, Angina, Dyspnoea
Who commonly has Aortic Stenosis?
Elderly
Describe some key characteristics of Aortic Stenosis
Ejection systolic murmur
Crescendo-decrescendo
Soft/absent S2
Prominent S4
Slow rising carotid pulse
Decreased pulse amplitude
How would you manage Dressler’s syndrome?
High dose aspirin
What is adenosine?
Bronchoconstrictor
When is adenosine contraindicated?
2nd and 3rd degree heart block
Decompensated heart failure
Causes of aortic stenosis
Primarily bc of ageing - calcified aortic valve
Congenital bicuspid aortic valve (more common in men) - more prone to calcification
Rheumatic heart disease (v rare now)
3 types of Aortic Stenosis
- Supravalvular
- Valvular
- Subvalvular
When does calcification happen?
As you get older
What is the normal area of the aortic valve?
3-4 cm2
When do symptoms of Aortic Stenosis occur?
1/4 normal area
(i.e. ~1cm2)
In Aortic Stenosis, what is the relationship between loudness of the murmur and severity?
Loudness does NOT indicate severity
Elderly person w/ chest pain, exertional dyspnoea or syncope =
Aortic Stenosis!!
Ix Aortic Stenosis
ECG - LV hypertrophy
LV strain pattern - depressed ST, T wave inversion (in LV leads)
CXR - LV hypertrophy, calcified aortic valve
GS : Echo - TTE
LV size + functions, doppler derived gradient and valve area
DDx Aortic Stenosis
Mitral Regurg
Tx Aortic Stenosis
Surgical aortic valve replacement
OR transcutaneous aortic valve implantation (TAVI)
Define Mitral Regurg
Backflow of blood from LV to LA during systole
Causes of Mitral Regurg
Abnormalities of valve, chordae etc
Myxomatous degeneration
Ischaemic mitral valve
Rheumatic heart disease
IE
Papillary muscle dysfunction
DCM
RF Mitral Regurg
Females
Lower BMI
Advanced age
Renal dysfunction
Prior MI
Describe the characteristics of Mitral Regurgitation
Pansystolic murmur at apex, radiates to axilla
Soft S1
Austin flint murmur at apex
Systolic ejection murmur
Diastolic blowing murmur at L sternal border
Ix Mitral Regurg
ECG - may show LAH, LVH, AF. NOT diagnostic
CXR - LA enlargement, central pulmonary artery enlargement
GS : Echo - LA and LV size and function
Valve structure assessment
TOE is very helpful
Key presentation of Mitral Regurg
Exertional dyspnoea, fatigue, lethargy, palpitations, symptoms of heart failure
Tx Mitral Regurg
IE prophylaxis
Vasodilators - ACEi (hydralazine or ramipril)
HR control for AF - BB (atenolol), CCB, digoxin
Anti-coag for AF/flutter e.g. rivaroxaban
Diuretics for fluid overload - Furosemide
Monitoring for Mitral Regurg
Do a follow-up echo
Mild - 2-3 years
Mod - 1-2 years
Severe - 6-12 months
Indications for surgery in Mitral Regurg
ANY symptoms at rest OR exercise
If asymptomatic, if ejection fraction < 60%
OR if new onset AF
Define Mitral Stenosis
Obstruction of LV inflow, prevents proper filling during diastole
How many cusps in mitral valve?
2 cusps
Normal mitral valve area
4-6 cm2
Symptoms of Mitral Stenosis occur when
Mitral valve area < 2 cm2
Cause of Mitral Stenosis
Rheumatic heart disease
obvs bc of rheumatic fever
∴ Untreated Strep infection is a RF !
Epidemiology of Mitral Stenosis
M > F
Key presentation of Mitral Stenosis
Symptoms present years/decades after rheumatic fever
Progressive dyspnoea
Other signs/symptoms of Mitral Stenosis
Haemoptysis
Oedema
Malar flush
Palpitations
R HF
Describe the characteristics of Mitral Stenosis
Diastolic murmur, heard when Px lying on left side in held exp
Longer murmur = more severe !!!
Loud S1
Most prominent at apex
Ix Mitral Stenosis
ECG - AF, LAV
CXR - LAV, Pulmonary oedema, calcified mitral valve (maybe)
GS : Echo
Assesses mitral valve mobility, gradient and mitral valve area
Tx Mitral Stenosis
Rate control - BB, digoxin
Diuretics - furosemide
Percutaneous mitral balloon valvotomy (less invasive) or surgical mitral valve replacement
Why does medical therapy not prevent progression of Mitral Stenosis?
Because it is a mechanical problem
Define heart failure
Inability of the heart to deliver blood and ∴ O2 that is required of the metabolising tissue of the body
Syndrome, not a disease
Prognosis of heart failure
25-50% of patients die within 5 years of diagnosis
RF of heart failure
65 +
African descent
M > F
Obesity
Prior MI
Cause of Prinzmetal’s Angina
Coronary artery spasm
Key presentation of Stable Angine
Chest pain/discomfort that :
- Heavy, central, tight and radiates to arms, jaw and neck
- Coincides with exertion/stress
- Relieved by rest/GTN spray
Key presentation of Pericardial Effusion
Obscured apex beat, heart sounds are soft
Pleuritic pain
Other signs/symptoms of Pericardial Effusion
Kussmaul’s sign - elevated JVP, rises w insp
Tachycardia
Hypotension
Chest discomfort
Cardiomegaly
Pulsus paradoxus
What is pulsus paradoxus?
> 10mmHg decrease on inspiration
Complication of Pericardial Effusion
CARDIAC TAMPONADE
Ix Pericardial Effusion
CXR - large globular heart
ECG - low voltage QRS
GS : Echo
echo-free space around heart
What is Beck’s triad?
Hypotension
Elevated JVP
Quiet heart sounds
How would you treat cardiac tamponade?
Emergency pericardiocentesis