Master ECG Interpretation Quiz: Test Your Skills

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Questions and Answers

What is the formula for calculating heart rate on an ECG?

Heart rate (bpm) = 300 / R-R interval in big squares

What is the normal range for heart rate on an ECG?

Normal heart rate on an ECG is 60-100 bpm

What is the formula for calculating corrected QT interval (QTc) on an ECG?

Corrected QTc interval = QT interval / √RR interval

What is the normal range for corrected QT interval (QTc) on an ECG?

Normal corrected QTc interval on an ECG is 380-420 ms (0.38-0.42 sec) Signup and view all the answers

What does the presence of normal P waves in lead III on an ECG suggest?

The presence of normal P waves in lead III on an ECG can suggest pulmonary embolism (PE) Signup and view all the answers

What are the possible causes of prolonged QT interval?

Vote Trigger Prolonged QT Interval can be caused by Acute Myocardial Ischaemia, Myocarditis, Bradycardia, Head Injury, Hypothermia, U&E Imbalance (K+ Ca2+ Mg2+ ), Congenital factors, and certain drugs (Quinidine, Antihistamines, Macrolides, Amiodarone, Phenothiazines). Signup and view all the answers

What does the ST segment represent on an ECG?

The ST segment represents the time from the end of ventricular depolarisation to the start of ventricular repolarisation. It is usually isoelectric. Signup and view all the answers

What are the criteria for abnormal ST segment?

An abnormal ST segment is characterized by elevation greater than 2mm in two adjacent chest leads or elevation greater than 1mm in two adjacent limb leads. It is indicative of infarction. Depression of the ST segment indicates ischemia. Signup and view all the answers

What is the normal pattern of T wave inversion in an ECG?

In a normal ECG, the T wave is normally inverted in VR and V1, and in V2 in young individuals. Abnormal T wave inversion is observed if it is inverted in leads I, II, and V4-V6, which could indicate ischemia or infarction. Signup and view all the answers

What are the effects of Digoxin on T waves?

Digoxin can cause T wave inversion on an ECG. Signup and view all the answers

What is the process called when the bilaminar disc is turned into a tri-laminar disc?

Gastrulation Signup and view all the answers

What is the name of the cavity in the blastocyst?

Blastocele (blastocyst cavity) Signup and view all the answers

What are the three parts of the mesoderm?

Paraxial mesoderm, intermediate mesoderm, and lateral plate mesoderm Signup and view all the answers

What is the name of the structure that grows from the primitive pit and induces changes in the overlying ectoderm?

Notochord Signup and view all the answers

What are the three shunts or bypasses in foetal circulation?

The three shunts or bypasses in foetal circulation are: 1) Bypass of the hepatic circulation via ductus venosus, 2) Bypass of the pulmonary circulation via the foramen ovale, and 3) Bypass of the pulmonary circulation via the ductus arteriosus. Signup and view all the answers

What is the purpose of the umbilical vein in foetal circulation?

The umbilical vein carries oxygen- and nutrient-rich blood from the placenta to the foetus. Signup and view all the answers

What happens to the shunts or bypasses in foetal circulation after birth?

The shunts or bypasses in foetal circulation must be obliterated at birth when the pulmonary circulation comes on stream. The ductus venosus becomes the ligamentum venosum, the foramen ovale closes and becomes the fossa ovalis, and the ductus arteriosus closes and becomes the ligamentum arteriosum. Signup and view all the answers

Explain in detail how blood circulates through the foetal heart

Blood enters the foetal heart through the inferior vena cava and is directed to the right atrium. From the right atrium, it passes through the foramen ovale to the left atrium, bypassing the lungs. In the left atrium, the oxygenated blood mixes with a small amount of deoxygenated blood returning from the lungs. The mixed blood then flows into the left ventricle, which pumps it out through the aorta to supply oxygen and nutrients to the body. Signup and view all the answers

Explain in general terms the circulation of blood in the foetus and placenta

In the foetus, oxygenated blood is supplied by the placenta through the umbilical vein. This blood enters the foetal circulation and is directed to the liver, where a portion is diverted to the hepatic circulation. The majority of the blood bypasses the liver through the ductus venosus and enters the inferior vena cava. It then mixes with deoxygenated blood returning from the lower body and enters the right atrium. The blood then follows the pathway described in the previous question to circulate through the foetal heart. Deoxygenated blood from the foetus is carried back to the placenta through the umbilical arteries, where it is replenished with oxygen and nutrients. Signup and view all the answers

Explain the functions of the foramen ovale, ductus arteriosus and ductus venosus

The foramen ovale is a hole between the right and left atria of the foetal heart. It allows oxygenated blood from the placenta to bypass the non-functioning foetal lungs and enter the left atrium directly. The ductus arteriosus is a blood vessel that connects the pulmonary artery to the descending aorta in the foetus. It allows a portion of the blood pumped by the right ventricle to bypass the non-functioning foetal lungs and flow directly into the systemic circulation. The ductus venosus is a blood vessel that connects the umbilical vein to the inferior vena cava in the foetus. It allows the majority of the oxygenated blood from the placenta to bypass the liver and enter the systemic circulation. Signup and view all the answers

What genetic mutations are associated with Down syndrome?

DSCAM and COL6A2 Signup and view all the answers

What gene is associated with 22q11.2 deletion syndrome?

TBX1 Signup and view all the answers

What is the mode of inheritance for Long QT syndrome?

Channelopathy Signup and view all the answers

What is the significance of identifying a mutation in Long QT syndrome?

Determining risk for life-threatening cardiac events Signup and view all the answers

What gene mutation is associated with Familial Hypercholesterolemia?

Unknown Signup and view all the answers

What are the Simon Broome criteria for diagnosing familial hypercholesterolemia?

Definite FH: Cholesterol >6.7mM (LDL>4mM) in children under 16 OR >7.5mM (LDL>4.9mM) in adults PLUS either Tendon xanthoma in patient or 1st/2nd degree relative. Possible FH: Family history of myocardial infarction. Signup and view all the answers

What are the possible genetic mutations associated with familial hypercholesterolemia?

There are approximately 1000 different mutations associated with familial hypercholesterolemia. Some of these mutations can result in the synthesis, transport, binding, internalization, or recycling of LDL being impaired. Examples include mutations in ApoB (Arg3500Gln), LDL receptor associated protein (null mutations), and PCSK9 (Asp374Tyr). Signup and view all the answers

What is cascade testing in the context of familial hypercholesterolemia?

Cascade testing is a type of genetic testing that involves screening the relatives of an individual with a known genetic mutation for familial hypercholesterolemia. This helps identify other family members who may also be at risk and allows for early intervention and treatment. Signup and view all the answers

What is the difference between autosomal dominant and autosomal recessive inheritance in familial hypercholesterolemia?

Familial hypercholesterolemia can be inherited in an autosomal dominant or autosomal recessive manner. Autosomal dominant inheritance means that only one copy of the mutated gene is needed to cause the condition, while autosomal recessive inheritance requires two copies of the mutated gene. Signup and view all the answers

What is the role of inlclisirin in treating familial hypercholesterolemia?

Inclisirin is a medication that harnesses a natural process in the body to lower LDL cholesterol levels. It inhibits the PCSK9 protein, which normally degrades LDL receptors. By inhibiting PCSK9, more LDL receptors are available to remove LDL cholesterol from the bloodstream, resulting in lower cholesterol levels. Signup and view all the answers

Study Notes

ECG Interpretation

Identity and Standardisation: Confirm patient's name, age, and ECG date. Ensure 1cm = 1mV and paper speed of 25mm/sec.

Rate

Calculate heart rate by dividing 300 by the number of big squares per R-R interval.
Normal heart rate: 60-100 bpm.
Bradycardia: <60 bpm.

Rhythm

Normal P waves present (2 mm).
P waves may be absent in lead III, indicating Pulmonary Embolism (PE).
P waves present after acute Myocardial Infarction (MI).

P-R Interval

Measure from the start of the P wave to the start of the QRS complex.
Normal P-R interval: 120-200 ms.

QRS Complex

Measure duration and amplitude.
Normal QRS duration: <120 ms.

QT Interval

Measure from the start of the QRS complex to the end of the T wave.
Corrected QT interval (QTc) = QT/√RR.
Normal QTc: 380-420 ms.

ST Segment

Time from the end of ventricular depolarization to the start of ventricular repolarization.
Usually isoelectric.
Check for elevation (>2mm) or depression.

T Wave

Normally inverted in leads VR and V1, and in V2 in young individuals.
Abnormal if inverted in leads I, II, and V4-V6, indicating Ischaemia or Infarction.

Axis

Sum of all ventricular forces during ventricular depolarization.
Normal axis: between -30° and +90°.
Left Axis Deviation: -30° to -90°, indicating Left Ventricular Hypertrophy (LVH) or MI.
Right Axis Deviation: +90° to +180°, indicating Right Ventricular Hypertrophy (RVH), PE, or MI.

Other Abnormal Components

Myocardial Infarction (MI): changes evolve through 3 stages: T wave peaking, ST segment elevation, and appearance of new Q waves.
Pulmonary Embolism (PE): large S wave in lead I, deep Q wave in lead III, and inverted T wave in lead III.
Metabolic Abnormalities:
- Hyperkalaemia: tall, tented T wave, widened QRS.
- Hypokalaemia: small T waves, prominent U waves.
- Hypercalcaemia: short QT interval.
- Hypocalcaemia: long QT interval, small T waves.

Foetal Circulation

Foetal Heart: modified by three shunts to avoid the lungs and liver: foramen ovale, ductus arteriosus, and ductus venosus.
Placenta: O2 and nutrients diffuse from mother to foetus, while CO2 and waste are removed.
Umbilical Cord: surrounded by the foetal membrane, amnion, and contains two umbilical arteries and one umbilical vein.
Umbilical Vein to Ductus Venosus: oxygen- and nutrient-rich blood from the placenta bypasses the liver and drains into the inferior vena cava.
Foramen Ovale: most of the blood from the inferior vena cava passes from the right atrium into the left atrium.
Ductus Arteriosus: blood from the pulmonary trunk bypasses the lungs and flows into the aorta.

Post-Natal Circulation

Shunts Obliterated at Birth: foramen ovale, ductus arteriosus, and ductus venosus.
Changes in Circulation: increased systemic vascular resistance, increased aortic pressure, and decreased pulmonary vascular resistance.
Closure of Foramen Ovale: becomes structurally closed by 4 months, forming the fossa ovalis and falx septi.
Patent Foramen Ovale: consequence of non-closure, may cause paradoxical emboli.
Patent Ductus Arteriosus: consequence of non-closure, may cause left-to-right shunt and pulmonary hypertension.

Embryology

Morula to Blastocyst: fluid accumulation in intracellular spaces, forming a cavity called blastocele.
Blastocyst: inner cell mass differentiates to form primary germ layers (endoderm and ectoderm).
Gastrulation: process of turning the bilaminar disc into a trilaminar disc, forming endoderm, mesoderm, and ectoderm.

Genetics in Cardiology

Down Syndrome: common defects include atrioventricular septal defect, ventricular septal defect, and patent ductus arteriosus.
22q11.2 Deletion Syndrome: cardiac abnormalities, abnormal facies, thymic aplasia, cleft palate, and hypothyroidism.
TBX-1 Transcription Factor: dose-dependent phenotype, associated with 22q11.2 deletion syndrome.
Long QT Syndrome: caused by mutations in genes encoding cardiac ion channels, leading to delayed repolarization.
Familial Hypercholesterolemia: high concentration of serum LDL cholesterol, caused by mutations in LDL receptor-related genes.

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Test your knowledge of ECG interpretation with this quiz from the University of St. Andrews School of Medicine. Learn about the methodical approach to analyzing ECGs, including identifying standardization, measuring rates, assessing rhythms, and interpreting various components. Join the quiz at vevox.app or search Vevox in the app store. ID: XXX-XXX-XXX.

ECG Interpretation Quiz