ECGs Flashcards
What are atrial extrasystoles? [1]
common interruptions of sinus rhythm (SR), which may trigger episodes of AF
A patient has LAD.
You suspect a they might have left ventricular hypertrophy.
What other ECG changes would you expect to see? [1]
Deep S waves in V1 & V2
&
Tall R waves V6
OR
T wave inversion in lateral leads: I, aVL and V5/6
Commonly presents with LAD
When you ID an atrial flutter - how do you make your result more specific? [1]
Report on the AV block (how many atrial contractions c.f QRS)
A 20-year-old male had a recent collapse while playing football with his friends. He was then referred to a cardiologist and diagnosed with hypertrophic obstructive cardiomyopathy. An ECG is done which shows a PR interval of 100ms with a wide QRS complex.
Which of the following conditions is the patient most likely to have?
Atrial flutter
First-degree heart block
Third-degree heart block
Wolff-Parkinson White
Second-degree type 1 heart block
A 20-year-old male had a recent collapse while playing football with his friends. He was then referred to a cardiologist and diagnosed with hypertrophic obstructive cardiomyopathy. An ECG is done which shows a PR interval of 100ms with a wide QRS complex.
Which of the following conditions is the patient most likely to have?
Atrial flutter
First-degree heart block
Third-degree heart block
Wolff-Parkinson White
Second-degree type 1 heart block
The ECG pattern of widespread ST depression and reciprocal ST elevation in aVR simply represents []
The ECG pattern of widespread ST depression and reciprocal ST elevation in aVR simply represents subendocardial ischaemia.
Note: ST depression in II and V4-6, with reciprocal ST elevation in aVR. Changes are significantly more pronounced than our patient with a GI bleed
What is a normal PR interval? [1]
120-200 ms / 2-5 small boxes
What is a normal QRS interval? [1]
< 120secs / 3 boxes
A patient has sinus rhythm, but irregular R-R intervals. The ECG is otherwise normal.
She states she has non-specific chest pain, what is the most likely cause? [1]
Sinus arrythmia
Causes can be:
* Respiratory - where the P-P interval lengthens and shortens with inspiration and expiration.
* Non-respiratory - where the process occurs seemingly for no reason.
* Sometimes seen in association with Complete Heart Block.
Chest pain is most likely MSK
A patient has an ‘RSR’ in V1 and ‘wide and notched S wave in lead 6’
What is the most likely diagnosis? [1]
RBBB
A patient has alternate conducting and non-conducting beats.
What is the most likely diagosis? [1]
2nd Degree Heart Block (Mobitz type 2)
If a patient has 2nd degree heart block and LAD, what does this indicate? [1]
Conduction down the anterior fascile of the left bundle branch is blocked - so most likely LBBB
An ECG has marked T-wave inversion; you think it might be BBB.
Which leads have T wave inversion in LBBB and RBBB?
LBBB
- T-wave inversion in the lateral leads I, aVL and V5-6
RBBB:
- T wave inversion in V1-3
Name 5 differentials for T wave inversion
MI
Left ventricular hypertrophy
BBB
PE - in lead III as part of the SI QIII TIII pattern; right heart strain causes T-wave inversions in the right precordial (V1-3) and inferior (II, III, aVF) leads due to pulmonary HTN
Hypertrophic Cardiomyopathy (HCM)
Describe this T wave [1]
What are the two main differentials? [2]
Biphasic T waves
* Myocardial ischaemia
* Hypokalaemia
How can you differentiate between MI and Hypokalemia based off T waves? [2]
Describe an ECG changes that would indicate aortic stenosis [2]
Marked T wave inversion in
- Due to left ventricular hypertrophy
- T wave inversion in lateral leads I, aVL, V5-6
Could also cause heart block due to disordered myocytes
Bifid P waves in the absence of left ventricular hypertrophy can indicate
Aortic regurgitation
Mitral regurgitation
Aortic stenosis
Mitral stenosis
Bifid P waves (aka **P mitrale) **in the absence of left ventricular hypertrophy can indicate
Aortic regurgitation
Mitral regurgitation
Aortic stenosis
Mitral stenosis
A patient’s ECG recording shows a consistent pattern of two P waves followed by a normal QRS complex and T wave.
What is the cause for this abnormal wave pattern? [2]
Bifid P waves: left atrial hypertrophy
- Mitral stenosis
- Mitral regurg
Describe the ECG changes you would expect in a person with hypothermia [4]
- Bradycardia (< 60bpm) and not tachycardia
- J waves
- Prolonged PR, QT and QRS intervals
- Shivering artefacts
- VT, VF or asystole
Which ECG variants are considered normal in an athlete? [4]
- sinus bradycardia
- junctional rhythm
- first degree heart block
- Mobitz type 1 (Wenckebach phenomenon)
How do posterior MIs present on an ECG? [3]
Tall, broad R waves (>30ms)
- ST DEPRESSION in V1, V2, V3 - most important
Upright T waves.
Dominant R wave (R/S ratio > 1) in V2.
What effect does hypercalcemia have on an ECG? [1]
shortened QT interval on ECG
How do you manage a type A aortic dissection? [1]
IV BB and surgery
The patient’s blood pressure must be controlled within 100 -120 mmHg (systolic) whilst awaiting surgical intervention, therefore IV labetalol must be given.
A patient has acute HF.
Under what circumstances would you prescribe norepinephrine? [1]
If hypotensive / in cardiogenic shock and have an insufficient response to inotropes and there is evidence of end-organ hypoperfusion
How do you differentiate between a posterior and anterior MI on an ECG?
Anterior MI
- ST-segment elevation in the precordial leads V1-V4
Posterior MI
- tall R waves V1-3 PosteRioR contains 2 tall Rs
- Horizontal ST depression in V1-3
Posterior MI is usually caused due to which which arteries? [2]
Left circumflex;
RCA
How do you confirm a posterior MI? [1]
Posterior infarction is confirmed by ST elevation and Q waves in posterior leads (V7-9)
(In general) How do you differentiate between SVT and VT on an ECG? [1]
SVT: Narrow QRS
VT:Wide QRS
Describe what is meant by Wellen’s syndrome [2]
What does Wellen’s syndrome suggest? [1]
What is important to note about the presentation of Wellen’s syndrome?
Wellens Syndrome is a clinical syndrome characterised by biphasic or deeply inverted T waves in V2-3, plus a history of recent chest pain now resolved.
It is highly specific for critical stenosis of the left anterior descending artery (LAD)
ECG pattern present in pain-free state is part of the diagnostic criteria
Wellen’s syndrome suggests stenosis of which coronary artery
RCA
LCA
Circumflex artery
LAD
Wellen’s syndrome suggests stenosis of which coronary artery
RCA
LCA
Circumflex artery
LAD
‘V2 & V3 T wave inversion on an ECG + a pain free state’
This suggests which pathology? [1]
Wellen’s syndrome - suggests stenosis in LAD
*
Kartagener’s syndrome is associated with which cardiac condition? [1]
How does this present on an ECG? [3]
Kartagener’s syndrome - linked to dextrocardia
Dextrocardia is associated with an inverted P wave in lead I, right axis deviation, and loss of R wave progression
How can you determine on an ECG if a person is suffering from Mobitz type II or 3rd Degree Heart block? [1]
In third degree HB:
Since the P and QRS waves are completely unrelated this means the atria and ventricles each pace themselves:
* the p-p interval will always be the same
* the R-R interval will always be the same
i think complete AV block is most easily confused with Mobitz Type II - however Mobitz II:
* R-R interval will not be the same since there will be a dropped QRS complex somewhere!
Which one of the following ECG changes is associated with Wolff-Parkinson White syndrome?
Long QT
P wave inversion
‘J’ waves
Hyperacute T waves
Short PR interval
Which one of the following ECG changes is associated with Wolff-Parkinson White syndrome?
Long QT
P wave inversion
‘J’ waves
Hyperacute T waves
Short PR interval
Describe the different Long QT syndromes [3]
hereditary long QT syndrome (LQTS):
* Long QT syndrome (LQTS) is an inherited condition associated with delayed repolarization of the ventricles
* The most common variants of LQTS (LQT1 & LQT2) are caused by defects in the alpha subunit of the slow elayed rectifier potassium channel.
- Long QT1 - usually associated with exertional syncope, often swimming
- Long QT2 - often associated with syncope occurring following emotional stress, exercise or auditory stimuli
- Long QT3 - events often occur at night or at rest
- sudden cardiac death
Describe the causes of a prolonged QTc interval that’s not from any obvious cause, such as drugs or electrolyte derangement? [3]
hereditary long QT syndrome (LQTS):
* Long QT syndrome (LQTS) is an inherited condition associated with delayed repolarization of the ventricles
* The most common variants of LQTS (LQT1 & LQT2) are caused by defects in the alpha subunit of the slow delayed rectifier potassium channel.
Long QT syndrome arises from a defect in the alpha subunit in which channel
- Gain-of-function of K+ channels
- Gain-of-function of Na+ channels
- Loss-of-function of Ca2+ channels
- Loss-of-function of K+ channels
- Loss-of-function of Na+ channels
Long QT syndrome arises from a defect in the alpha subunit in which channel
- Gain-of-function of K+ channels
- Gain-of-function of Na+ channels
- Loss-of-function of Ca2+ channels
- Loss-of-function of K+ channels
- Loss-of-function of Na+ channels
K+ leaves during repolarisation hence loss of function would prolong the QT segment
Explain the differences in QT in hypo- and hypercalcaemia [2]
Hypocalcaemia: prolongs QT
Hypercalcaemia: shortens QT
- QT is start of depol. to repol (systole)
- platau phase in cardiac cycle is controlled by Ca2+ movement into cytoplasm
- More Ca2+ means more movement and more systole = shorter QT
A previous ECG taken four months ago was completely normal. What is the most likely diagnosis?
Sick sinus syndrome
Stokes-Adams attack with associated complete heart block
Myocardial infarction with new left bundle branch block
Second-degree atrioventricular block (Mobitz II)
Second-degree atrioventricular block (Mobitz I / Wenckebach)
Stokes-Adams attack with associated complete heart block
Explain which ECG changes are expected in primary ciliary dyskinesia [2]
Embryonically this can cause dysfunction with the developmental axis of the foetus - and may lead to situs inversus
. Patients with situs inversus have their heart on the right, and this can lead to a right axis and not left axis deviation
A 55 year old female presents with chest pain. He has an ECG performed as part of her preliminary investigations which shows left axis deviation.
Which of the following may lead to the appearance of this ECG? [1]
Explain your answer [1]
After an inferior myocardial infarction, the inferior wall loses an extensive amount of tissue and becomes electrically inactive. Because of the loss of electrical activity in this area, the heart depolarises away from the inferior leads - hence leading to left axis deviation
The normal PR interval is []-[] seconds?
How many small squares is this? [1]
120-200ms
3-5 squares
A prolonged QT interval (more than 480ms) is a risk factor for what? [1]
VT
‘V2 & V3 T wave inversion on an ECG + a pain free state’
This suggests which pathology? [1]
Wellen’s syndrome - suggests stenosis in LAD
You suspect someone is suffering from digoxin toxicity. What would this look like on an ECG? [1]
What question would you ask them about their symptoms that might suggest this? [1]
Down-sloping ST segments = digoxin toxicty (reverse tick)
Loss of appetite is first symptom - followed by nausea and vomiting
Describe the main findings on this ECG
Inferior Q waves (II, III, aVF) with T-wave inversion due to previous MI
You suspect a person is suffering from an SVT. How do you determine if this is an AVNRT? [1]
There wont be any P waves present
A patient has rhabdomyolysis. How might you expect their ECG to change? [1]
may result in hyperkalemia - tall tented T wave
A trans-thoracic echocardiogram is performed which shows a 5mm vegetation on a tricuspid valve leaflet. A blood culture has also returned positive for Staph aureus. He is admitted and commenced on IV antibiotics.
The day following his admission, his ECG shows the following:
Which of the following complications is likely to have manifested?
Perivavlular or aortic root abscesses are a potential complication of infective endocarditis.
A 25-year-old female is found to have a left hemiparesis following a deep vein thrombosis. An ECG shows RBBB with right axis deviation. What is the most likely underlying diagnosis?
Ventricular septal defect
Patent ductus arteriosus
Coarctation of the aorta
Ostium secundum atrial septal defect
Tetralogy of Fallot
A 25-year-old female is found to have a left hemiparesis following a deep vein thrombosis. An ECG shows RBBB with right axis deviation. What is the most likely underlying diagnosis?
The ostium secundum in this patient has allowed passage of an embolus from the right-sided circulation to the left causing a stroke
