Medicine Marrow Pg No 417-426 (ECG)

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Questions and Answers

Which of the following is NOT part of the right coronary circulation?

Lateral wall MI (correct)

Posterior wall MI

Inferior wall MI

Right ventricular MI

Left dominant coronary circulation is more common than right dominant coronary circulation.

False

What leads correspond to inferior wall myocardial infarction?

II, III, AVF

Most individuals have a ______ dominant coronary circulation.

right Signup and view all the answers

Match the following terms with their corresponding descriptions:

Right Coronary Artery = Supplies the right side and inferior walls of the heart Left Coronary Artery = Supplies the left anterior and lateral walls Posterior Descending Artery = Determines coronary dominance Left Atrium = Located on the posterior surface of the heart Signup and view all the answers

What is the primary mechanism of hibernation in myocardium?

Chronic Signup and view all the answers

Stunning of the myocardium is characterized by chronic ischemic dysfunction.

False Signup and view all the answers

What investigation is preferred to differentiate between ischemia and infarction?

FDG-PET Signup and view all the answers

The target LDL cholesterol level for statin therapy is greater than ______ mg/dL.

190 Signup and view all the answers

Match the following terms with their definitions:

Ischemia = Condition of reduced blood flow Hibernation = Chronic persistent ischemic dysfunction Stunning = Acute transient dysfunction post-reperfusion Statins = Medications to lower LDL cholesterol Signup and view all the answers

What consequence is associated with proximal RCA occlusion?

Sinus bradycardia Signup and view all the answers

Distal RCA occlusion is associated with RVMI.

False Signup and view all the answers

What is the role of the acute marginal artery?

It supplies the right ventricular free wall. Signup and view all the answers

Proximal RCA occlusion can result in _____ arrhythmias.

atrial Signup and view all the answers

Match the following types of RCA occlusions with their effects:

Proximal Right Dominant = RVMI + IWMI Distal Right Dominant = IWMI Proximal Left Dominant = RVMI Distal Left Dominant = No MI Signup and view all the answers

Which of the following T wave characteristics indicates a potentially serious condition?

Tall/peaked T wave Signup and view all the answers

The presence of U waves in an ECG trace is commonly associated with hyperkalemia.

False Signup and view all the answers

What does ST depression in an ECG typically indicate?

Ischaemia or stress on the heart Signup and view all the answers

The ECG analysis shows recordings at ____ minutes to observe ST depression changes.

60, 90, and 120 Signup and view all the answers

Match each type of T wave characteristic to its description:

Normal myocardium = Unaffected T wave Tall/peaked T wave = Can indicate hyperkalemia Deep symmetrically inverted T wave = Often associated with ischaemic conditions U wave = Possible indicator of hypokalemia Signup and view all the answers

What is a necessary criterion for diagnosing a myocardial infarction (MI)?

Reciprocal changes must be present Signup and view all the answers

ST elevation in leads V1 to V3 should be ≥1.5mm in females to be considered significant.

True Signup and view all the answers

What are the ECG morphologies associated with ST elevation?

Convex, Coved, Horizontal/Plateau, Oblique, Concave Signup and view all the answers

A significant ST elevation of ≥2.5mm in leads V1 to V3 indicates myocardial infarction in individuals over ______ years old.

40 Signup and view all the answers

Match the following causes of ST elevation with their descriptions:

Prinzmetal angina = Transient ST elevation Hyperkalemia = Electrolyte imbalance causing elevation LBBB = Bundle branch block leading to ST changes Normal variant = Benign early repolarization pattern Signup and view all the answers

What is a common trigger for symptoms in chronic stable angina?

Physical exertion or stress Signup and view all the answers

Chronic stable angina typically lasts more than 30 minutes.

False Signup and view all the answers

What type of medication is commonly used to relieve symptoms of chronic stable angina?

Nitroglycerine Signup and view all the answers

A positive treadmill test indicates a ST segment deviation of ______ mm.

2 Signup and view all the answers

Match the following conditions with their corresponding categories:

Chronic stable angina = Indicated for exercise stress test Rest symptoms = Contraindication for exercise stress test Aortic stenosis = Contraindication for exercise stress test Asymptomatic with risk factors = Indicated for exercise stress test Signup and view all the answers

Which of the following is indicative of pericarditis?

PR segment depression Signup and view all the answers

Benign early repolarization is characterized by global ST elevation and PR segment depression.

False Signup and view all the answers

What is another name for Takotsubo cardiomyopathy?

Broken heart syndrome Signup and view all the answers

The presence of an Osborne wave is associated with ______.

hypothermia Signup and view all the answers

Match the following ECG features with their corresponding conditions:

Global ST elevation = Pericarditis Notching of J point = Benign early repolarization Osborne wave = Hypothermia Catecholamine induced cardiac failure = Takotsubo Cardiomyopathy Signup and view all the answers

Which of the following is a correct indication for myocardial perfusion scintigraphy (MPS)?

Patients with resting symptoms Signup and view all the answers

Intravascular ultrasound is the gold standard for ejection fraction measurement.

False Signup and view all the answers

Which radionuclide is commonly used in myocardial perfusion scintigraphy?

Tc99 or Thallium Signup and view all the answers

The primary treatment to decrease heart rate and blood pressure after myocardial infarction is ______.

β-blockers Signup and view all the answers

Match the following drugs with their primary action:

Nitrates = Increase heart rate, decrease blood pressure β-blockers = Decrease heart rate, decrease blood pressure Calcium Channel Blockers = Decrease heart rate Ranolazine = No effect on blood pressure or heart rate Signup and view all the answers

Which statements accurately describe Prinzmetal Angina features? (Select all that apply)

Angiography shows normal results. Signup and view all the answers

Diastolic current in injury indicates current flow towards ischemia.

False Signup and view all the answers

What are the names of the three glycoprotein IIb-IIIa inhibitors used for periprocedural stenting?

Abciximab, Eptifibatide, Tirofiban Signup and view all the answers

The Kingmaker segment is also known as the __________.

ST segment Signup and view all the answers

Match the current types with their characteristics:

Systolic current = ST elevation Diastolic current = ST depression Subepicardial injury = Current flows towards injured myocardium Subendocardial ischemia = Current flows away from ischemia Signup and view all the answers

What does ST depression in an ECG typically indicate?

Possible ischemia Signup and view all the answers

De Winter T Waves are considered a normal finding in an ECG.

False Signup and view all the answers

What condition does the presence of Left Bundle Branch Block indicate in an ECG?

It indicates a block in the electrical conduction system, affecting how electrical impulses travel through the heart. Signup and view all the answers

Horizontal ST Depression is associated with __________.

ischemia Signup and view all the answers

Match the ECG findings with their implications:

Left Ventricular Hypertrophy = Increased heart muscle mass Acute antero-septal infarction = Heart attack in the front septal wall Pseudoinfarction = Pattern mimicking a heart attack Brugada syndrome = Heart rhythm problem Signup and view all the answers

Which of the following is a potential diagnosis associated with ECG findings?

Brugada syndrome Signup and view all the answers

Evolving to MI implies a progression towards a myocardial infarction.

True Signup and view all the answers

What is the significance of 'scoop' in an ECG analysis?

It may indicate the presence of digoxin, a medication often used for heart conditions. Signup and view all the answers

Study Notes

Coronary Circulation

Right coronary circulation supplies the inferior, posterior, and right ventricular walls of the heart.
Left coronary circulation supplies the anterior, septal, and lateral walls of the heart.

Surfaces of the Heart

Anterior sternocostal surface is primarily composed of the right ventricle.
Inferior diaphragmatic surface is comprised of both the right and left ventricles.
Posterior surface is primarily the left atrium.

Coronary Dominance

Dominance is determined by the artery supplying the posterior interventricular sulcus (posterior descending artery).
Right dominant: 85% of the population.
Left dominant: 15% of the population.

Right Coronary Artery

Origin: Right AV sulcus.
Branches: SA nodal branch, atrial branches, acute marginal artery, branch to AV node, terminal branches.
Proximal RCA occlusion: Can cause sinus bradycardia, atrial arrhythmias, and right ventricular MI.
Distal RCA occlusion: Can cause right ventricular MI depending on the relationship to the acute marginal artery.

Left Coronary Artery

Origin: Left AV sulcus
Branches: Left anterior descending artery (LAD)...

Acute Coronary Syndrome (ACS)

ACS is a spectrum of conditions involving a sudden blockage of coronary arteries, including unstable angina, non-ST-elevation MI, and ST-elevation MI.

Hibernation vs. Stunning of Myocardium

Hibernation: Chronic ischemia, persistent ischemic dysfunction, diagnosable via FDG-PET or MRI.
Stunning: Acute ischemia, transient post-reperfusion segmental dysfunction.

Management of ACS - Pharmacological Intervention

First-line drugs:
- Nitrates: Increase heart rate and lower blood pressure; Tolerance can be a limitation.
- Beta-blockers: Decrease heart rate and lower blood pressure, prolong life post MI.
- Calcium channel blockers: Decrease heart rate and lower blood pressure.

Stenting

Drug-eluting stents: Coating of drugs (tacrolimus/paclitaxel) for prolonged drug release.
Bare metal stents: Not as effective as drug eluting stents.

Prinzmetal Angina

Characterised by rest angina rapidly relieved by nitrates.
Transient ST elevation.
Normal coronary angiography.
Beta-blockers are avoided in this condition due to vasospastic angina.

Kingmaker Segment

Also known as the ST segment.
Starts at the end of the J point and ends at the onset of the T wave.

ECG Analysis

ECG waveform descriptions: RR interval, P wave duration, PR segment, QRS duration, ST segment duration, QT interval, U interval.
Waveform types: Non-concave (convex shaped), Concave (saddle shaped).

ST Elevation MI (STEMI)

ECG morphologies: Convex, Coved, Horizontal/Plateau, Oblique, Concave.
Sequence of changes in STEMI:
- Hyperacute T wave
- Hyperacute T waves with ST Elevation
- Development of pathologic Q waves, decreased amplitude of the R waves, and further ST and T wave changes

Other Causes of ST Elevation

Prinzmetal angina
Hyperkalemia
Left Bundle Branch Block

Normal Variant/Benign Early Repolarization

Can be mistaken for ST elevation.
Often seen in patients with left ventricular aneurysm.

ECG Interpretations

Left Ventricular Hypertrophy: Indicated by ECG findings.
Left Bundle Branch Block: Another finding from the ECG.
ST Depression: Showing possible ischemia, various types of ST depression are noted, with probable ischemia being the primary interpretation.
De Winter T Waves: Identified as a type of T wave abnormality.
Evolves to MI: Implies progression towards a myocardial infarction (heart attack).

Other ECG Findings

Pericarditis
Pseudoinfarction
Acute Antero-Septal Infarction
Brugada Syndrome
Horizontal ST Depression
Sloping ST
Scoop

Myocardial Perfusion Scintigraphy (MPS)

Done with Tc99m or Thallium.
Useful in patients with resting symptoms or abnormal baseline ECG.
Helps differentiate between ischemia and infarction, localize ischemia, assess revascularization completeness.

Miscellaneous Points

FDG PET: Distinguishes between stunned and scarred myocardium.
Electron beam CT: Quantifies cardiac calcification.
MRI: IOC for myocardial fibrosis/ejection fraction, gold standard for ejection fraction.
Intravascular USG: IOC for ostial left main lesion/coronary dissection.

Investigations

Exercise stress test/Treadmill test:
- Indications: Chronic stable angina, asymptomatic patients with risk factors.
- Contraindications: Rest symptoms, aortic stenosis, hypertrophic cardiomyopathy (HOCM).

Bruce Protocol

Positive treadmill test: Indicates 2 mm horizontal or down sloping ST segment depression.

Benign Early Repolarization

ST elevation
Notching of J point (hook effect).
Differential diagnosis: Pericarditis.
No PR segment depression.

Pericarditis

Clinical Features: History of acute illness
Global ST elevation.
Concave upward ST segment.
PR segment depression.
No reciprocal changes.

Post-DC Cardioversion

Related to electrical shock therapy.

Hypothermia

Characterized by Osborne wave.

Takotsubo Cardiomyopathy

AKA Broken heart syndrome.
Catecholamine induced cardiac failure.
Most common in middle-aged females.

Chronic Stable Angina

Presentation: Middle-aged to elderly patient with risk factors.
Symptoms: Chest tightness/squeezing/burning.
Location: Behind/left of mediastinum.
Radiation: Any dermatome from C4 - T.
Duration: 30 minutes suggest ACS.
Treatment: Excellent response to sublingual or oral NTG.

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Description

This quiz covers essential aspects of coronary circulation, including the right and left coronary arteries and their supply areas. It also explores the surfaces of the heart and the concept of coronary dominance in the population. Test your knowledge on these critical cardiovascular topics.