Cardiology Flashcards
on an ecg one large square is how much in time
0.2seconds or 200ms
on an ecg one small square is how long in time
0.04 seconds or 40ms
how many large squares per second in an ecg
5 large squares per second
what is the PR interval and how long should it be
time from the onset of the P wave to the start of the QRS complex
it should normally be 120-200ms
this is 3-5 small squares
draw the ecg axis diagram
normal axis is from what degrees to what degrees
-30 degrees to +90 degrees
left axis deviation will look like what
QRS predominantly negative in VF II and III
QRS predominantly positive in VL and I
right axis deviation will look like what
QRS predominantly negative in I
QRS predominantly positive in III
which leads look at the septum
V3 and V4
what is the transition point
- the v1 lead looks at the heart from the right
- it begins with a small septal r wave as the septum is depolarised left to right initially
- then as the left ventricle depolarises there follows a large downwards S
- the v1 complex is therefore predominantly negative
- the v6 lead looks at the heart from the left
- it begins with a small downwards Q as the septum is initially depolarised left to right
- then there is a large upwards R wave as the left ventricle is depolarised
- the v6 complex is therefore predominantly positive
- the transition point is the point at which the R waves and the S waves are of equal size
- it is usually around v3-v4
what is the significance of the transition point
- it can shift with changing shape of the heart
- with right ventricular hypertrophy the transition point would shift to the left
- this would mean that it would be around v5-v6 rather than v3-v4
- it is as if, seen from the perspective of the feet, the heart has rotated clockwise
what is first degree heart block
it is when the pr interval is longer than 200ms
it’s ‘marked first degree heart block’ if >300ms
what is second degree heart block
- mobitz i (wenckeback)
- progressive lengthening of pr
- followed by a dropped QRS complex
- pr then goes back to being shorter and the cycle continues
- mobitz ii
- PR interval is constant but there is an occasional dropped QRS
- there may be two or three or four P waves for every successful QRS in which case it is given a ratio 2:2 or 3:1 etc
- PR interval is constant but there is an occasional dropped QRS
what is third degree heart block
atrial contraction may be normal but no beats are conducted to the ventricles themselves
ventricular contraction is maintained by ventricular escape rhythms
what does blockage of both bundle branches look like
it has the same effect as a complete block of the his bundle and resembles complete heart block
why does right bundle branch block look like that
- best seen in v1 where there is an RSR pattern
- upwards deflection as septum initially depolarised from left to right
- then s wave as the left ventricle is depolarised as normal
- it takes longer for the right ventricle to be depolarised so there then follows a second R wave as the right ventricle is depolarised after the left
- in v6 there is a wide deep qrs
- initially a q as the septum is depolarised left to right
- then an R wave as the left ventricle is depolarised
- then follows a deep wide s wave as the right ventricle catches up
- right bundle branch block is only significant if the qrs is longer than 120ms
why does left bundle branch block look like that
- if conduction down the left bundle branch fails then the septum is depolarised from right to left
- in V1 this appears as a small q wave
- then the right ventricle is depolarised before the left so there is then an r wave in v1
- subsequent depolarisation of the left ventricle then causes an s wave in v1
- in V6 the initial right to left depolarisation of the septum causes a small r wave
- then follows a small (like a notch) s wave as the right ventricle is depolarised
- then v6 shows another R wave as the left ventricle catches up
- in V1 this appears as a small q wave
in summary how does right bundle branch block appear
best seen in v1
there is an RSR pattern
in summary how does LBBB appear
best seen in v6 where there is a broad qrs with a notched top
the complete picture with a w shape in v1 is often not fully visible
what happens in atrial tachycardia
depolarisation is from an origin in the atria that is different to the sa node
the av node cannot conduct rates fasterr than 200/min so there may be a physiological block
what happens in atrial flutter
if there atrial rate is >250/minute then there is no baseline between p waves
what happens in junctional/nodal tachycardia
the depolarisation originates from the area around the av node
therefore the atria and the ventricles are depolarised at the same time
therefore p wave will be very close to the QRS complex or may be lost within it
what happens in wolff parkinson white syndrome
- some people have an accessory bundle connecting the atria and the ventricles
- there is no AV node delaying contraction
- this provides pre-excitation to the ventricles
- therefore there is a short PR interval and the QRS has a wide slurred upstroke called a delta wave
- the second part of the QRS is normal as the excitation from the his bundle catches up
- the his bundle and the accessory bundle can together form a re-entry circuit that causes tachycardias
what are the 6 questions to ask yourself when identifying abnormal ecg rhythms
- is the abnormality occasional or sustained
- are there p waves
- what is the P:QRS ratio
- are the ventricles contracting regularly or irregularly
- is the QRS a normal shape
- what is the ventricular rate
identify the rhythms
what are the two important abnormalities in form of the p wave
- peaked p wave
- right atrial hypertrophy
- pulmonary hypertension
- tricuspid valve stenosis
- broad and bifid p wave
- left atrial hypertrophy
- usually due to mitral stenosis
- left atrial hypertrophy
what are the 4 characteristics of a normal QRS
- duration no longer than 120ms (3 little squares)
- in a right ventricular lead the (V1) the S is greater than the R
- in a left ventricular lead (V6) the R is less than 25mm
- left ventricular leads show a Q wave due to septal depolarisation which is initially left to right but these are less than 1mm across and 2mm deep
what are the ECG findings of PE
- in many cases there is a normal ecg
- sinus tachycardia is the most common finding
- but there may be findings of acute cor pulmonale
- S1Q3T3
- large S wave in lead 1
- pathological Q wave in lead 3
- inverted T wave in lead 3
- S1Q3T3
what are the ecg findings of right ventricular hypertrophy
- peaked p waves (as it normally accompanies right atrial hypertrophy)
- right axis deviation
- tall r waves in v1
- maybe right bundle branch block
- inverted T waves which are normal in v1 spread across to v2 and v3
- transition point shifts to the left with a deep s wave persisting in v6
in which leads are q waves normal
in the left ventricular leads
when are q waves abnormal
when they are greater than 1 small square in width (40ms) and 2mm in depth
what does a q wave of more than 1 small square in width (40ms) and 2mm in depth signify
MI
can be old or new as once q waves appear they rarely go
why are q waves from MI
- because ventricles depolarise from inside to outside
- therefore an area that’s not depolarising will record as a cavity potential
- therefore a lead looking at that area will record a q wave
- this will therefore be the case for anterior, lateral and anterolateral MIs
- not posterior MIs as there’s no leads looking at the back typically
how does a posterior MI look on ECG
- there may or may not be ST elevation
- left ventricular depolarisation no longer overshadows right ventricular in V1
- therefore V1 shows a tall R wave
- this is similar to as in right ventricular hypertrophy but doesn’t have the other features of rvh
st elevation is due to
MI or pericarditis
pericarditis it will be in all of the leads whereas in MI it’s usually localised
horizontal depression of the ST segment means
ischaemia rather than infarction
downward sloping ST segments are due to treatment with digoxin
T waves are normally inverted in which leads
- VR
- V1
- sometimes in III
- sometimes in V2
- in V3 in some black people
what is the effect of digoxin in the ecg
af
downward sloping st
inverted t waves
what’s the process of stemi ecg changes
- the first abnormality seen in st elevation
- then Q waves appear and the T wave becomes inverted
- the st segment then returns to baseline
nstemi ecg changes
not full thickness so no Q wave and no ST elevation
but there will still be t wave inversion
main ecg finding of left ventricular hypertrophy
- there may be left axis deviation
- but the main thing is that there will be inverted t waves in the lateral leads
- I, II, aVL, v5 and v6
why can t wave inversion be seen in bundle branch block
because abnormal depolarisation can lead to abnormal repolarisation
what are the 4 situations you can see t wave inversion in?
ischaemia
ventricular hypertrophy
bundle branch block
digoxin treatment
what does low sodium do to the ecg
it doesn’t change the ecg at all
low k+ causes what ecg changes
T wave flattening
hump on the end of the T wave called the U wave
high potassium does what to the ecg
peaked t waves with disappearance of the ST segment
QRS may be widened
low calcium does what to the ecg
long qt
high calcium does what to the ecg
short qt
what investigations for angina
ECG
FBC
lipid profile
HbA1c
LFTs (before statins)
U&E (before ACEIs)
TFTs
CT Coronary angiography
management of angina
- 1st line:
- lifestyle advice
- secondary prevention:
- antiplatelet
- aspirin OR clopidogrel
- OR aspirin AND clopidogrel
- statin
- atorvastatin 10mg PO OD
- antiplatelet
- if symptomatic:
- sublingual GTN spray +/-
- beta blocker (metoprolol) +/-
- calcium channel blocker (nifedipine) +/-
- long acting nitrate (isosorbide mononitrate PO)
explain PCI
Percutaneous Coronary Intervention (PCI) with coronary angioplasty (dilating the blood vessel with a balloon and/or inserting a stent) is offered to patients with “proximal or extensive disease” on CT coronary angiography. This involves putting a catheter into the patient’s brachial or femoral artery, feeding that up to the coronary arteries under xray guidance and injecting contrast so that the coronary arteries and any areas of stenosis are highlighted on the xray images. This can then be treated with balloon dilatation followed by insertion of a stent.
explain cabg
Coronary Artery Bypass Graft (CABG) surgery may be offered to patients with severe stenosis. This involves opening the chest along the sternum (causing a midline sternotomy scar), taking a graft vein from the patient’s leg (usually the great saphenous vein) and sewing it on to the affected coronary artery to bypass the stenosis. The recovery is slower and the complication rate is higher than PCI.
the right coronary artery supplies the
- Right atrium
- Right ventricle
- Inferior aspect of left ventricle
- Posterior septal area
the circumflex artery supplies the
- Left atrium
- Posterior aspect of left ventricle
the left anterior descending artery supplies the
- Anterior aspect of left ventricle
- Anterior aspect of septum
different sub-devisions of acs
- if there’s st elevation or new LBBB it’s a stemi
- it’s nstemi if no st elivation but trops are high OR there’s other ecg changes such as
- st depression
- t wave inversion
- pathological q waves
- if trops normal and there’s no pathological changes on ecg then it’s unstable angina or another cause such as MSK
anterolateral infarct is likely which artery and would show in which leads
left coronary artery
aVL, V3-6, I
anterior infarct is likely which artery and would show in which leads
LAD
V1-4
lateral infarct is likely which artery and would show in which leads
I, aVL, V5-6
inferior infarct is likely which artery and would show in which leads?
right coronary artery
II, III and aVF
alternative causes of raised troponins
- Chronic renal failure
- Sepsis
- Myocarditis
- Aortic dissection
- Pulmonary embolism
what are serial troponins
baseline and 6 or 12 hours after onset of symptoms
explain thrombolysis
Thrombolysis involves injecting a fibrinolytic medication (they break down fibrin) that rapidly dissolves clots. There is a significant risk of bleeding which can make it dangerous. Some examples of thrombolytic agents are streptokinase, alteplase and tenecteplase.
ideal treatment for STEMI
Patients with STEMI presenting within 12 hours of onset should be discussed urgently with local cardiac centre for either:
- Primary PCI (if available within 2 hours of presentation)
- Thrombolysis (if PCI not available within 2 hours)
The local cardiac centre will advise about further management (such as further loading with aspirin and ticagrelor).
acute nstemi treatment
- BATMAN
B – Beta-blockers unless contraindicated
A – Aspirin 300mg stat dose
T – Ticagrelor 180mg stat dose (clopidogrel 300mg is an alternative if higher bleeding risk)
M – Morphine titrated to control pain
A – Anticoagulant: Fondaparinux (unless high bleeding risk)
N – Nitrates (e.g. GTN) to relieve coronary artery spasm
Give oxygen only if their oxygen saturations are dropping (i.e. <95%).
scoring system for NSTEMI mortality and what it means for treatment
GRACE Score
- <5% Low Risk
- 5-10% Medium Risk
- >10% High Risk
If they are medium or high risk they are considered for early PCI (within 4 days of admission) to treat underlying coronary artery disease.
what’s included in the grace score
Age
Heart rate/pulse
Systolic BP
Creatinine
Cardiac arrest at admission
CHF
Pulmonary edema
Cardiogenic shock
what is dressler’s syndrome?
- occurs about 2-3 weeks after an MI
- it’s an autoimmune pericarditis
how does dressler’s syndrome present?
pleuritic chest pain, low grade fever and a pericardial rub on auscultation. It can cause a pericardial effusion and rarely a pericardial tamponade
how do you diagnose dressler’s syndrome?
diagnosis can be made with an ECG (global ST elevation and T wave inversion), echocardiogram (pericardial effusion) and raised inflammatory markers (CRP and ESR).
management of dressler’s syndrome
NSAIDs (aspirin / ibuprofen) and in more severe cases steroids (prednisolone). They may need pericardiocentesis to remove fluid from around the heart.
triggers for acute left ventricular failure
- Iatrogenic (e.g. too much fluids in an elderly patient with poor LV function)
- Sepsis
- MI
- Arrhythmias
what is the function of BNP
To relax the smooth muscle in blood vessels. This reduces the systemic vascular resistance making it easier for the heart to pump blood through the system.
BNP also acts on the kidneys as a diuretic to promote the excretion of more water in the urine. This reduces the circulating volume helping to improve the function of the heart.
non heart failure causes of a raised BNP
- Tachycardia
- Sepsis
- Pulmonary embolism
- Renal impairment
- COPD
it is very sensitive not specific
work up for acute LVF
- ECG (to look for ischaemia and arrhythmias)
- Arterial Blood Gas (ABG)
- Chest Xray
- Bloods (routine bloods for infection, kidney function, BNP and consider troponin if suspecting MI)
presentation of acute left ventricular failure
- Shortness of breath
- Cough (frothy white/pink sputum)
- Reduced oxygen saturations
- 3rd Heart Sound
- Bilateral basal crackles (sounding “wet”) on auscultation
- Hypotension in severe cases (cardiogenic shock)
There may also be signs and symptoms related to underlying cause, for example:
- Chest pain in ACS
- Fever in sepsis
- Palpitations in arrhythmias
what is a normal ejection fraction
anything above 50%
normal pulmonary artery pressure at rest
18 to 25 mmHg
heart failure chest x ray findings
- dilated upper airway vessels (upper lobe diversion)
- cardiomegaly (cardiothoracic ratio of >0.5)
- kerly B lines
- bilateral pleural effusions
management of acute left ventricular failure
- Pour SOD
- Pour away (stop) IV fluids
- Sit the patient upright
- Oxygen
- Diuretics (e.g. 40mg IV furosemide)
why does PND happen at night
- fluid over larger area as laid down
- respiratory centre is less responsive during sleep: resp effort doesn’t increase in response to hypoxia
- less adrenaline during sleep so myocardium is more relaxed and cardiac output is worse
what are the different types of heart failure
- heart failure with reduced ejection fraction
- LVEF <40%
- heart failure with mid range ejection fraction
- LVEF 40%-49%
- raised BNP
- and at least one other criterion
- relevant structural heart disease (e.g., left ventricular hypertrophy [LVH] or left atrial enlargement),
- diastolic dysfunction
- heart failure with preserved ejection fraction
- LVEF >50%
- raised BNP
- and at least one other criterion
- relevant structural heart disease
- diastolic dysfunction
NHYA heart failure classification
Class I: Mild. No limitation of physical activity. Ordinary physical activity does not cause undue fatigue, palpitations, or dyspnoea.
Class II: Mild. Slight limitation of physical activity. Comfortable at rest, but ordinary physical activity results in fatigue, palpitations, or dyspnoea.
Class III: Moderate. Marked limitation of physical activity. Comfortable at rest, but gentle activity causes fatigue, palpitations, or dyspnoea.
Class IV: Unable to carry out any physical activity without discomfort. Symptoms of cardiac insufficiency at rest. If any physical activity is undertaken, discomfort is increased.
when to refer chronic heart failure
- refer those with NT-proBNP above 2000 to a specialist for an echo within two weeks
- if between 400-2000 then they need an echo within 6 weeks
management of acute heart failure with reduced ejection fraction
- Furosemide titrated according to symptoms
- prescribe both an ace inhibitor and a B blocker but one at a time
- if fluid overload an ace inhibitor first
- if cant tolerate then an ARB
- if angina then a B blocker first
- if fluid overload an ace inhibitor first
- aldosterone antagonist if not controlled with above
- spironolactone or eplerenone
- also
- yearly flu and pneumococcal vaccine
- exercise rehab group for heart failure
- treat cause if known e.g. surgical treatment of valve problems
what is cor pulmonale
right sided heart failure caused by respiratory disease
what are the cause of cor pulmonale
- COPD is the most common cause
- Pulmonary Embolism
- Interstitial Lung Disease
- Cystic Fibrosis
- Primary Pulmonary Hypertension
why might you get pulsatile hepatomegaly
in right sided heart failure with tricuspid regurgitation
above what threshold do you diagnose hypertension
blood pressure above 140/90 in clinic or 135/85 with ambulatory or home readings.
what is the difference between primary (essential) and secondary hypertension? what is more common?
primary (essential hypertension) is 95% of all hypertension and means there is not a known cause
secondary hypertension has a known cause
causes of secondary hypertension
- Consider in patients aged under 40
- Remember with the mnemonic ROPE
- R – Renal disease. This is the most common cause of secondary hypertension. If the blood pressure is very high or does not respond to treatment consider renal artery stenosis.
- O – Obesity
- P – Pregnancy induced hypertension / pre-eclampsia
- E – Endocrine. Most endocrine conditions can cause hypertension
main endocrine consideration for secondary hypertension
hyperaldosteronism (“Conns syndrome”) as this may represent 2.5% of new hypertension. A simple test for this is a renin:aldosterone ratio blood test.
patients with type two diabetes should have hypertension screenings how frequently?
every year
how frequently should the general population be screened for high blood pressure?
every five years
what investigations should all patients with new diagnoses of hypertension get
- Urine albumin:creatinine ratio for proteinuria and dipstick for microscopic haematuria to assess for kidney damage
- Bloods for HbA1c, renal function and lipids
- Fundus examination for hypertensive retinopathy
- ECG for cardiac abnormalities
what are the different stages of hypertension
do the flow diagram for hypertension treatment
blood pressure targets in people under 80
Clinic BP: <140/90 mmHg
ABPM/HBPM: <135/85 mmHg
blood pressure targets in people over 80
Clinic BP: <150/90 mmHg
ABPM/HBPM: <145/85 mmHg
what is the third heart sound
it’s the chordae tendonae twanging open like guitar string
can be normal in people aged 15-40
can indicate heart failure in people over 40
what are the 4 valve areas on the chest
- Pulmonary: 2nd I.C.S left sternal border
- Aortic: 2nd I.C.S right sternal border
- Tricuspid: 5th I.C.S left sternal border
- Mitral: 5th I.C.S mid clavicular line (apex area)
what are the special manoeuvres for listening to certain murmurs
- Patient on their left hand side (mitral stenosis)
- Patient sat up, learning forward and holding exhalation (aortic regurgitation)
mitral stenosis is caused by
- Rheumatic Heart Disease
- Infective Endocarditis
what kind of murmur is mitral stenosis
mid-diastolic, low pitched “rumbling” murmur due to a low velocity of blood flow. There will be a loud S1 due to thick valves requiring a large systolic force to shut, then shutting suddenly
describe the sound of mitral regurgitation
pan-systolic, high pitched “whistling” murmur due to high velocity blood flow through the leaky valve. The murmur radiates to left axilla. You may hear a third heart sound.