Cardiology Flashcards
Name the 4 valves in the heart
Mitral valve/ Bicuspid valve (left atrium -> left ventricle)
Aortic valve (left ventricle, exit)
Tricuspid valve (right atrium -> right ventricle)
Pulmonary semilunar valve (right ventricle, exit)
When is blood supply to the heart at its lowest?
During systole
-heart contracted
-high pressure
Pulmonary circulation provides blood to the…
Lungs (and back to the heart)
Systemic circulation provides blood to the…
Systemic tissues (and back to the heart)
Is pulmonary circulation provided by the left or right ventricle?
Right
Is systemic circulation a low or high pressure system?
High pressure
In normal instances, do cardiomyocytes have an aerobic or anaerobic metabolism?
Why?
Aerobic
Name the 2 types of cells of the myocardium
Contractile
Conducting
Cardiac muscle cells are (2)
Electrically excitable
Capable of contraction/relaxation
Properties of cardiomyocytes (4)
Striated muscle fibres
Intercalated Discs (Gap Junctions)
Under involuntary control
Have branches
Are human cardiomyocytes single nucleated or multi nucleated?
Single nucleated
What is the purpose of gap junctions?
Gap junctions allow cardiomyocytes to communicate electronically
What is the effect of elevated Ca2+ on the cardiomyocyte?
Muscle contracts
Name the 3 regions of the heart that can spontaneously generate an action potential
Sinoatrial node (SA node)
Atrioventricular node (AV node)
Purkinje fibres
In the heart, AP travel from: (6)
- SA node
→ Atria
→ AV node
→ AV bundle (bundle of His)
→ Left and right bundle branches
→ Purkinje fibres
3 distinct waves of the ECG & what they stand for
P wave: atrial contraction
QRS complex: ventricular contraction
T wave: ventricular relaxation
What is Einthoven’s triangle?
A theoretical representation in electrocardiography to explain the relationship between the electrical activity of the heart and the placement of electrodes on the body.
What is the electrode position in Einthoven’s triangle?
Right arm (RA)
Left arm (LA)
Left leg (LL)
What is the lead positioning in Einthoven’s triangle?
Lead I: LA - RA
Lead II: RA - LL
Lead III: LL - LA
Einthoven’s Law
Lead II = Lead I + Lead III
Used to verify the consistency of the ECG readings
Is a depolarisation wave travelling towards the positive electrode is a positive or negative deflection?
Positive deflection
Normals QRS axis is in what range in the electrical QRS axis of the heart?
Between -30 and +90 degrees.
Positive deflection in aVF, positive deflection in lead I
LAD is in what range in the electrical QRS axis of the heart?
Between -90 and -30 degrees.
Negative deflection in aVF, positive deflection in aVL, positive in lead I.
What is systole?
Phase of contraction
What is diastole?
Phase of relaxation
What is stroke volume?
Volume of blood ejected from heart.
End-Diastolic Fraction
Workload placed on ventricles before contraction (preload).
At what stage does blood flow from atria to ventricles?
Atrial pressure > ventricular pressure
AV valves open
Blood flows from atria to ventricles.
At what stage does blood flow from ventricles to arteries?
Ventricular pressure > arterial pressure
Semilunar valves open
Blood ejected from heart
End-Systolic Volume
Blood that remains in heart after blood ejected from ventricles.
Isovolumetric contraction
Left ventricular pressure > atrial pressure
Mitral valve closes
Isovolumetric relaxation
Aortic pressure > ventricular pressure
Aortic valve closes
Frank-Starling Law of the Heart
Contractility is directly proportional to preload. As EDV ^ Contractility ^ SV ^
Total peripheral resistance (TPR)
Fractional resistance to blood flow in arteries.
End diastolic volume (EDV)
Workload placed on ventricles before contraction.
Which of the following is unique to cardiac muscle cells?
A. Only cardiac muscle contains a sarcoplasmic reticulum.
B. Only cardiac muscle has gap junctions.
C. Only cardiac muscle is capable of autorhythmicity
D. Only cardiac muscle has a high concentration of mitochondria.
C
The influx of which ion accounts for the plateau phase of the contractile cardiomyocte action potenial?
A. sodium
B. potassium
C. chloride
D. calcium
D
Which portion of the ECG corresponds to repolarization of the atria?
A. P wave
B. QRS complex
C. T wave
D. none of the above
B
Which component of the heart conduction system would have the slowest rate of autorhythmicity?
A. atrioventricular node
B. atrioventricular bundle
C. bundle branches
D. Purkinjefibres
A
Which of the following induces Ca2+ release from sarcoplasmic reticulum in the cardiomyocyte?
A. Ca2+
B. Na+
C. K+
D. All of the above
A
How many leads are in a 12-lead ECG?
10
On an ECG trace, a depolarisation wave travelling toward a positive electrode results in a?
A. Positive deflection
B. Negative deflection
C. Complex wave deflection
D. None of the above
A
From what limbs is Lead II observed?
A. Right arm to left arm
B. Left arm to left leg
C. Right arm to left leg
D. None of the above
C
List the order of actions in a single heart cycle (5)
- Atrial Contraction
- Isovolumetric contraction
- Ejection
- Isovolumetric relaxation
- Rapid Filling
If the influence of the autonomic nervous system was removed from the heart, what would happen to heart rate?
A. Heart rate would be unchanged
B. Heart rate would increase
C. Heart rate would decrease
D. The heart would fail to contract
B
If the influence of the ANS was removed, the heart rate would increase to around 100 bpm, which is the intrinsic rate of the SA node, since the parasympathetic system’s “braking” effect would be lost. However, the heart would still beat rhythmically because of its internal pacemaking activity.
Which of the below factors are capable of regulating stroke volume?
A. Preload
B. Ventricular contractility
C. Total peripheral resistance (TPR)
D. Afterload
E. All of the above
E, primarily preload, afterload and contractility, higher TPR increases afterload
What is the effect of the SNS in heart rate?
Releases hormones (catecholamines and epinephrine and norepinephrine) to accelerate the heart rate.
What is the effect of the PSNS on heart rate?
The PSNS releases the hormone acetylcholine to slow the heart rate.
List some cardiac abnormalities (pathologies). (8)
- Congenital heart defects (genetic)
- Inflammatory heart diseases
- Ischemic heart disease (low oxygen due to narrowed arties)
- Valvular heart disease (one or more of the valves does not open/close properly)
- Cardiomyopathies (Any disorder that affects the heart muscle - heart loses ability to pump blood well)
- Arrhythmias
- Hypertension
- Heart failure
Non-modifiable risk factors (3)
- Age
- Sex
- Genetics
Modifiable risk factors
- Smoking
- Diet
- Exercise levels
- Stress
What is a beta-blocker?
Block the effects of adrenaline and other stress hormones on the heart.
Reduce heart rate, contractility and lower blood pressure.
What is an Angiotensin-Converting Enzyme (ACE) Inhibitor?
Angiotensin-Converting Enzyme (ACE) Inhibitors block the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor.
Causes vasodilation, reduced blood pressure, and decreased cardiac afterload.
What is a Angiotensin II Receptor Blocker (ARB)?
Angiotensin II Receptor Blockers (ARBs) block the action of angiotensin II at its receptor sites. Results in vasodilation, reduced blood pressure, and decreased cardiac afterload.
What are Calcium Channel blockers?
Calcium Channel Blockers inhibit the entry of calcium into cardiac and smooth muscle cells.
Reduces contractility and dilates coronary/peripheral blood vessels leading to reduced heart rate, blood pressure, and afterload.
What are diuretics?
Diuretics increase the excretion of sodium and water by the kidneys.
Reduces blood volume and cardiac preload resulting in decreased blood pressure.
What is Nitroglycerin?
Nitroglycerin relaxes smooth muscle in blood vessels.
Leads to vasodilation of coronary arteries and systemic veins. It also reduces myocardial O2 demand and increases coronary blood flow.
What is the purpose of Antiplatelet Drugs?
Antiplatelet Drugs prevent platelets from aggregating and forming blood clots.
Reduce the risk of arterial thrombosis and myocardial infarction.
What are statins?
Statins lower blood cholesterol levels by inhibiting the enzyme HMG-CoA reductase, which plays a key role in cholesterol synthesis. Reduce the risk of atherosclerosis and cardiovascular events.
What is vasodilation?
Widening of blood vessels due to the relaxation of the blood vessel’s muscular walls
What is another name for Ischaemic Heart Disease (IHD)?
Coronary Artery Disease (CAD)
What causes CAD/IHD?
Narrowing of coronary arteries.
Leads to myocardial ischaemia.
What is associated with CAD/IHD?
- Chest pain (angina)
- Reduced blood flow
- Increased blood pressure
Why does angina happen during CAD/IHD?
Cardiomyocytes are not receiving enough nutrients nor are waste products being removed sufficiently
What is a cardiomyocyte?
The contractile myocytes (cells) of the cardiac muscle.
What is a pacemaker cell?
A specialised cardiomyocyte that sets the rhythm of the heart contractions.
How can IHD/CAD be detected and diagnosed in the early stages?
ECG
What is atherosclerosis?
Build up of cholesterol, fatty acids, and other substances on the artery walls.
Leading cause of CAD
Describe the pathophysiology of atherosclerosis. (3)
Fat infiltrates the arterial wall developing a fatty streak.
- Intracellular accumulation of fat
- Extracellular accumulation of fat
- Fibrotic/calcified layers
- Rupture
Myocardial Infarction can develop if plaque ruptures and blood clot forms
What is difference between cardiac ischaemia vs infarction?
Ischaemia: decreased blood flow
Infarction: blood flow completely cut off
What is the effect of IHD on stroke volume?
Decreased blood pumping efficiency
Reduced due to impaired contractility from coronary blockages
At what location is a catheter entered to implant a stent in the coronary artery?
Wrist or groin
Percutaneous Coronary Intervention (PCI)
Insertion of a stent via the coronary artery to relieve a blockage
Steps:
- dye & xray to visualise & locate
- diagnose
- catheter + stent
In what situations is bypass grafting used?
Severe blockage
Bypass grafting
Involves taking a blood vessel from another part of the body (usually the chest, leg or arm) and attaching it to the coronary artery above and below the narrowed area or blockage
The great saphenous vein—the large vein running up the length of the leg—is often used as a bypass due to its size and the ease of removing a small segment.
Why is a vein used in bypass grafting?
Large diameter
Long
Easilly harvested
Classifications of heart failure (2)
Left vs right
Acute vs chronic
What are cardiomyopathies?
Diseases of the heart that lead to heart failure
What is fibrosis?
Scarring of the heart
What is a desmosome and what is its function?
- intercellular junctions that provide strong adhesion between cells.
- form the adhesive bonds in a network that gives mechanical strength to tissues.
- glue holding cardiomyocytes together
Give an example of a stress test
The Bruce Protocol
What is SADS? When is it most to cause a cardiac event?
- Sudden Arrythmic Death Syndrome
- Congenital heart defect that affects the rhythm of the heart, and causes premature death.
- Primarily happens at sleep or rest
What is a feature of a restrictive cardiomyopathy?
The heart quickly fills with blood
What are the types of white blood cells?
- granulocytes (neutrophils, eosinophils, and basophils)
- monocytes
- lymphocytes (T cells and B cells)
What is a good chemical marker of how much stress the heart is under?
BNP
(Brain Naturletic Peptide)
What do diuretics do to blood volume?
Reduce
What is heart failure?
Heart works but not at the same standard
Hearts failing ability to pump
Is heart failure with preserved ejection fraction (HFpEF) diastolic or systolic heart failure?
Diastolic HF
Is heart failure with reduced ejection fraction (HFrEF) diastolic or systolic heart failure?
Systolic HF
Is Troponin T found inside cardiomyocytes or in the blood?
Inside cardiomyocytes
If it’s in the blood -> damage!
What is the physical damage to the heart in heart failure? And what is the result of this?
- Stiff and thick chambers
- Heart can’t fill
or
- Stretched and thin chambers
- Heart can’t pump
What is considered a normal EF in a health heart?
50 - 70%
(With each heartbeat, 50% to 70% of the blood in your left ventricle gets pumped out to your body)
Is <40% EF preserved or reduced ejection fraction?
Reduced
List 3 common causes of HFrEF and HFpEF?
- CAD & MI
- Hypertension
- Cardiomyopathy * Arrhythmia
- BMI (Obesity)
- Age
- Smoking
- Damage to heart valves
Is HFrEF more common in males or females?
Males
Is HFpEF more common in males or females?
Females
What happens to collagen deposits in HFpEF?
Increases
HF Symptoms
- breathlessness (after activity or at rest)
- tired most of the time/exercise exhausting
- palpitations
- feeling lightheaded/fainting
- swollen ankles and legs
How can HF be diagnosed? (5)
- Blood tests (Troponin T, BNP)
- ECG
- Echocardiogram (EF assessment)
- Breathing test (Spirometry, Peak flow)
- Imaging (CT, MRI, X-Ray, Angiogram)
What is the optimal treatment for HFpEF?
Treat hypertension & other causes
What is the difference between HFpEF and HFrEF? (3)
HFpEF:
- stiff + thick chambers -> heart can’t fill (cardiomyocytes thicker)
- diastolic
- ageing & hypertension
-females
HFrEF:
- stretched and thin chambers -> heart can’t pump (cardiomyocytes fail to pump)
- systolic
- males
What is involved in Cardiac Resynchronization Therapy (CRT)?
ICD will monitor HR & detect irregularities - Emit tiny electrical pulses correct HR = resynchronizing HR
What is Cardiac Resynchronization Therapy (CRT)?
- Pacemaker with implantable cardioverter defibrillator (ICD) - 3 wires; RA, RV, LV
What is the benefit of Cardiac Resynchronization Therapy (CRT)?
Improves symptoms in moderate to severe HF patients & those with RV/LV asynchrony by resynchronising HR
What is a cardiomyopathy?
group of diseases relating to cardiac muscle
In what way can a heart be physically diseased in a cardiomyopathy? (3)
- weakened
- enlarged
- stiffened
List 3 cardiomyopathies
- LV hypertrophy (LVH)
- Dilated cardiomyopathy (DCM)
- Restrictive cardiomyopathy
- LV non-compaction
- Takotsubo
- Desmoplakin
What is the most common cause of LVH?
Hypertension and aortic valve stenosis
What is aortic valve stenosis?
Aortic valve is narrowed and doesn’t open fully
What is the first sign of LVH?
Heart failure - symptoms begin to develop as heart starts failing to pump blood effectively
How would LVH be diagnosed?
- Imaging (MRI & echo)
- ECG (need something else also)
What is dilated cardiomyopathy (DCM)? (3)
Disease that causes the ventricles to thin and stretch, resulting in
- increased ventricular volume
- weakened pump efficiency (reduced EF)
Is dilated cardiomyopathy (DCM) more common in men or women?
Men
What happens to the cardiomyocytes during dilated cardiomyopathy? (5)
- Lengthening of myocytes (impaired contraction)
- Myocardial scarring and fibrosis
- Myocytes hypertrophy
- Cellular injury (myofibrillar degeneration)
- Loss of parallel alignment
What is the rarest form of cardiomyopathy?
Restrictive cardiomyopathy
Acute vs chronic? + examples
Acute: severe & sudden onset e.g. broken bone, asmtha attack
Chronic: long-developing condition e.g. osteoporosis, asmtha
Which leads look at the Inferior view of the heart?
II, III, aVF
Which leads look at the Lateral view of the heart?
I, aVL, V5, V6
Which leads look at the Anterior view of the heart?
V3, V4
Which leads look at the Septal view of the heart?
V1, V2
Why would a 24-hr BP monitor be used? Give 3 example cases
- borderline hypertension
- suspected white coat hypertension
- hypertension in pregnant or elderly
- to investigate possible postural hypotension
- to investigate possible drug-induced hypotension
- BP evaluation in patients with the suspected or confirmed autonomic dysfunction.
What is white coat hypertension?
HIgh BP reading in doctor’s office, normal at home
What is postural hypertension?
a type of high blood pressure that occurs when someone goes from lying down to standing
What is postural hypotension?
dizziness / lightheadedness after standing or sitting down
At what mmHg is a patient considered to be at hypertension? (Systolic)
> 140 mmHg
At what mmHg is a patient considered to be at hypertension? (Diastolic)
> 90 mmHg
What is considered a high daytime ambulatory BP?
135/85
What is considered a high nighttime BP?
120/75
What is considered a high pulse pressure?
50 mmHg
What is considered a morning hypertension?
140/90
What level (%) systolic BP drop would you expect to see in the nighttime monitoring session?
> 10%
What can be used for a 24-hr BP monitor? Can this used for longer than 24 hrs?
Holter monitor
Can be used for up to 1 week
After a 24-hr Holter monitor, what is the next most common time for a patient to use a Holter monitor? (2)
48 or 72 hrs
Why would a Holter monitor be used? (5)
- investigate palpitations
- investigate unexplained case of syncopy or transient episode of cerebral ischemia
- high incidence of serious cardiac arrythmias
- evaluate effect of new cardiac medication
- investigate possible malfunction of new cardiac device
What leads of 12-lead ECG are used in Holter monitor?
Lead I, II, & III
List 7 types of heart disease.
- CAD
- HF
- Aneurysm
- Valvular disease
- Cardiac Arrhythmia
- Cardiomyopathy
- Pericarditis
Explain how an aneurysm can be fatal.
- An aneurysm is an abnormal bulge or ballooning in the wall of a blood vessel.
- An aneurysm can burst - ruptue
- Ruptured aneurysm -> internal bleeeding -> death!
What is pericarditis?
An inflamed pericardium
What happens to the myocardium during a cardiomyopathy?
Thickening
What is wrong with the heart when a patient present’s with a cardiac arrhythmia?
Disorganised electrical signals
Angina, heart attack, and stroke are associated with which type of heart disease?
CVD
What is often the first sign of CVD?
Heart attack or stroke
What is another term for an echo?
Cardiac Ultrasound
What happens during an exercise stress test?
- If obstruction present in coronary arteries, increasing blood flow drives up need for oxygen causing supply/demand imbalance
- Myocardium becomes ischemic
- Heart functions abnormality which manifests in the ECG and the patient
- Test is stopped if patient becomes symptomatic, or reaches their max HR, or ischemic ECG changes noticed
How many leads are used in an exercise stress test?
10 (same as 12-lead ECG, but hand and leg electrodes are placed on upper chest and hips)
In what cases may bpm be converted to ms?
When talking about tachycardias in the CRM clinic and EP lab
60,000/bpm = ms
What accounts for the duration of the P-R interval?
This slow conduction through the AV node allows for the atria to fill the ventricles before ventricular contraction commences.
Explain why a broad QRS complex may happen.
QRS is broad is because it is not going through the His-Purkinje conduction system, cell to cell depolarization takes longer.
Explain R-wave progression through a 12-lead ECG
R wave progression refers to the changing morphology of the QRS complex representing ventricular depolarization moving through the 12-Lead ECG.
As move from V1-V6 – QRS becomes more positive.
The RV has thinner wall than LV : V1 and V2 over RV but V4-V5 over LV
In what leads are Q wave pathologies seen?
Leads V1-3
What happens in the electrically opposite leads when ST elevation happens?
Reciprocal ST depressionin the electrically opposite leads
What does STEMI stand for and what does it represent?
ST Elevation Myocardial Infarction
heart attack that is more serious and has a greater risk of serious complications and death
What form of ST elevation is commonly seen in young patients, but has no long term problems?
Benign Early Repolarization
Also has tall T waves in precordial leads
Where is V4 placed in the 12-lead ECG?
5th intercostal space, mid-clavicular line
List 3 examples of cardiovascular disease
- Ischemic heart disease
- Myocardial infarction
- Heart failure
- Arrhythmias
- Coronary artery disease
- Angina
- Stroke / cerebrovascular accident
- Hypertension
Describe how symptoms associated with CAD differ between men and women.
Men:
- Chest pain: burning, fullness, pressure, squeezing/crushing
- Pain can also radiate to the neck, jaw, shoulder, arms or back
- Other symptoms of angina: dizziness, fatigue, nausea, shortness of breath, sweating
Women:
- Chest pain - stabbing pain instead of chest pressure
- Discomfort in the neck, jaw, teeth or back (not shoulders or arms)
- Shortness of breath
- Abdominal pain
Malnutrition: Marasmus
Total calorie defeciency leading to adipose and muscle tissue lost, gradually
Malnutrition: Kwashiorkor
Consequence of relative or absolute protein deficiency, prevalent in people with a very limited diet
Why is low BMI a risk factor for CVD?
Give 4 reasons.
- electrolyte and water imbalance
- hypokalaemia
- hypophospaemia
- Aging? But more prominent in <40 years
- May have increased proportion of visceral fat or metabolic abnormalities
- Poor nutritional status (deficiencies in vitamins and minerals)
- Lower muscle mass may reduce capacity for exercise and cardio-respiratory fitness
- Sarcopenia (loss of muscle mass and strength) leading to inflammation, metabolic dysregulation and/or insulin resistance
Dyslipidemia
Abnormal levels of lipids in bloodstream
- High tri-glycerides
- Low HDL cholesterol
- Metabolic Syndrome
Hyperglycemia
High Blood Sugar (glucose levels)
List investigations that may be carried out to determine cardiac disease. (6)
- BP Measurement
- ECG
- Cardiac Mapping (electrogram)
- Auscultation (stethoscope)
- Phonocardiography (graphical recording of heart sounds and murmurs)
- Haemodynamics
What determines the reliability of a cardiac measurement?
- accuracy
- precision/resolution
- reproducibility
Calibration
process of comparing a reading from an instrument to another instrument that has been calibrated to a reference set of standards/parameters.
Quality Control
monitor the accuracy and precision of laboratory assays before releasing patient results
When ST segment depression is observed, what ion has been release from cardiomyocytes?
potassium
An ST depression may be the result of ischemia in the sub endocardium. Explain the process by which this happens resulting in the ST depression. (4 steps)
Rapid efflux of potassium from cardiac myocytes which sets up a diastolic injury current.
Hypoxic conditions: diminished intracellular concentrations of ATP.
Losing ATP leads to decreased activity of ATP-dependent transport systems, including the Na+/K+ ATPase pump that normally transports K+ into the cell and Na+ out of the cell.
When ventricular depolarisation occurs, there is no current flow from the injured cells.
Symptoms of Inflammation (4)
- heat
- pain
- swelling
- redness
Echocardiogram
Ultrasound of the heart
What is the frequency range of ultrasound?
20 kHz to 20 MHz
Velocity of US in blood
1540 m/s
What 2 US modalities are used for Echo?
And how is the image created in each type?
M-mode and 2D-mode
2D: border, plotted against time
M: shape, swept scan plane
Name the three types of Doppler
continuous wave
colour flow wave
pulsed wave
What is the process that causes the frequency of backscattered echoes from moving blood to be different
to that from the transmitted frequency?
Doppler shift / Doppler frequency
Explain how each type of Doppler wave works for US.
CW: requires transmission of a continuous train of ultrasound waves, with simultaneous reception of the returning backscattered echo’s.
CFW: blood flow
PW: blood location and speed
How does aliasing occur in measurement and what is the detrimental effect of it?
Less samples taken
Sine wave ends up looking like line graph
Effect: loss of info, inaccuracy in results, less info available for diagnosis
Nyquest Sampling Theorem
To reconstruct a continuous analog signal from its sampled version accurately, the sampling rate must be at least twice the highest frequency present in the signal
sps >= 2Fmax
What is an advantage of using doppler wave US over other types of US?
Doppler shows blood flow
What determines flow in a vessel? (3)
Diameter, length, viscosity of blood
Name the 4 standard echo windows.
Parasternal Window - Long and Short Axis
Apical Window
Subcostal Window
Suprasternal window
What is pulse repetition frequency (PRF)?
The cycle of alternating transmission and reception of pulses in a pulsed Dopper wave
What is cardiac catheterization?
a procedure used to diagnose and treat certain cardiovascular conditions.
During cardiac catheterization, a long thin tube called a catheter is inserted in an artery or vein in your groin, neck or arm and threaded through your blood vessels to your heart
List 3 properties of an ideal catheter.
Cathteters should be:
- As short as possible (minimize energy loss)
- As rigid as possible (aids transmission of signal)
- Long enough to go from access point to the heart
- Flexible
- Narrow as possible to prevent vascular damage
What is the purpose and process of catheters?
Reliably measure and transmit intracardiac pressures to an external transducer through a fluid column contained in the lumen.
What is the most common access point for catheterisation?
Radial access
Femoral access is preferred in what type of procedure?
coronary artery bypass graft surgery (CABG)
List 3 benefits of radial access in catherterisation.
- Lower complication rate
- Patients can sit up after
- Superficial course at wrist
- Hemostasis achieved easier (TR band)
- Prone to spasm – radial cocktail
- Variable anatomy - tortuosity
How is heart access granted for Right Heart Cath Studies? (3)
- Brachial vein (more common)
- Internal jugular vein
- Femoral vein
Stochastic Effect
Non-threshold biologic effect of radiation that occurs by chance to a population of persons whose probability is proportional to the dose and whose severity is independent of the dose
Deterministic Effect
Dose dependent direct health effect of radiation with dose threshold - patient and medical team
What is the R on T phenomenon? And what is a consequence of this phenomenon?
Superimposition of an ectopic R wave on T wave
Likely to initiate ventricular arrhythmia
Name the 3 parts of Beck’s Triad
Hypertension
Jugular Venous Distention
Muffled Heart Sounds
On an ECG what is the J point? And what does it represent?
Point in the ECG where the QRS complex joins the ST segment
It represents the approximate end of depolarization and the beginning of repolarization
What are persistent Q waves on an ECG a marker for?
Persistent Q waves post MI are a marker of permanent myocardial necrosis
What is MINOCA?
Myocardial infarction with nonobstructive coronary arteries (MINOCA): acute myocardial infarction (MI) with angiographically non obstructive coronary artery disease or stenosis ≤ 50%.
What does elevated cardiac Troponin (cTn) values reflect?
injury to myocardial cells
How does a posterior extension of an inferior or lateral infarct affect the myocardium and heart? (1,2)
Much larger area of myocardial damage
An increased risk of left ventricular dysfunction and death.
Why is a posterior MI often missed on an ECG?
- same pathology as other MIs
- BUT no ST elevation
Missed because:
- no lead looks at posterior area of heart, but V1-V3 are electrically opposite.
Pericarditis
Pericarditis is the inflammation of the pericardium (the fibrous sac surrounding the heart)
Pericardial Effusion
Accumulation of excess fluid in pericardium
Cardiac Tamponade
Cardiac tamponade is a medical emergency that takes place when abnormal amounts of fluid accumulate in the pericardial sac compressing the heart and leading to a decrease in cardiac output and shock
