New Series of Interactive Cardiology MCQs 21: ECG - All About Cardiovascular System and Disorders

Q1

In a patient presenting with central chest pain, the ECG reveals upsloping ST-segment depression at the J-point in the precordial leads (V1-V6) that continues into tall, prominent, and symmetrical T waves. What is this ECG pattern called, and what does it signify?

Q2

When applying the Brugada Algorithm to differentiate Ventricular Tachycardia (VT) from Supraventricular Tachycardia (SVT) with aberrancy, what is the VERY FIRST criteria assessed, which immediately confirms a diagnosis of VT if met?

Q3

A patient with an established Left Bundle Branch Block (LBBB) presents with acute chest pain. According to the original Sgarbossa Criteria, which specific ECG finding is the most specific (weighted at 5 points) for diagnosing a superimposed acute myocardial infarction?

Q4

In diagnosing a true posterior myocardial infarction using a standard 12-lead ECG, what is the classic reciprocal pattern seen in the anterior precordial leads (V1-V3)?

Q5

A 22-year-old athlete undergoes an ECG which shows a slightly shortened PR interval and a slurred upstroke of the QRS complex (delta wave). The patient has a history of paroxysmal rapid palpitations. During an episode of Atrial Fibrillation, what is the classic, highly dangerous ECG presentation of this syndrome?

Q6

Which of the following ECG findings is considered the most specific electrocardiographic marker for acute Right Ventricular (RV) Infarction in the setting of an acute Inferior STEMI?

Q7

A patient taking therapeutic doses of Digoxin for rate control of Atrial Fibrillation has a routine ECG performed. Which of the following is the classic expected ECG finding of the ‘Digitalis Effect’ (NOT toxicity)?

Q8

In evaluating a patient for Left Ventricular Hypertrophy (LVH) on a 12-lead ECG, the Cornell Voltage Criteria are considered highly accurate and account for gender differences. What specific measurements comprise the Cornell criteria?

Q9

A patient with a history of syncope while swimming is evaluated. Their ECG shows a prolonged QT interval with broad-based T waves. Genetic testing confirms Long QT Syndrome Type 1 (LQT1). Which specific ion channel mutation is responsible for this condition?

Q10

During an acute episode of central chest pain, a patient’s ECG shows ST-segment elevation >= 1 mm in lead aVR that is greater than the ST elevation in lead V1, accompanied by widespread horizontal ST-segment depression in multiple other leads (I, II, V4-V6). What is the most critical anatomical diagnosis?

Q11

A patient develops a regular narrow-complex tachycardia at 150 bpm. You suspect Typical Atrial Flutter with 2:1 block. If ‘typical’ (counterclockwise) flutter is present, what is the expected morphology of the flutter waves in the inferior leads (II, III, aVF) and lead V1?

Q12

In patients presenting with Acute Pulmonary Embolism, the classic ‘S1Q3T3’ pattern is famous but relatively insensitive. Which ECG finding actually has the highest correlation with Right Ventricular Dysfunction (RV strain) and adverse outcomes in acute PE?

Q13

When examining an ECG to differentiate acute Pericarditis from Benign Early Repolarization (BER), which specific feature strongly favors a diagnosis of Pericarditis?

Q14

A patient with a history of recurrent syncope presents with an ECG showing a Left Bundle Branch Block (LBBB) morphology and Left Axis Deviation. This pattern represents a block of two of the three main fascicles of the ventricular conduction system. What defines a ‘Trifascicular Block’ on an ECG?

Q15

During ECG interpretation, you observe a rhythm with a 2:1 atrioventricular (AV) conduction ratio (two P waves for every QRS). How can you best differentiate if this is a Mobitz Type I (Wenckebach) variant at the AV node versus a dangerous Mobitz Type II block below the AV node?

Q16

An ECG demonstrates severe Left Axis Deviation (-60 degrees), a qR complex in leads I and aVL, and rS complexes in leads II, III, and aVF, with a normal QRS duration. This pattern is the hallmark of which conduction system defect?

Q17

The ‘Epsilon wave’ is a subtle notch or ‘blip’ found between the end of the QRS complex and the onset of the ST segment, best seen in leads V1-V3. It represents delayed activation of which cardiac structure, and is a major diagnostic criterion for what disease?

Q18

A patient presenting with acute dyspnea has an ECG showing a tachycardia where the QRS amplitude distinctly alternates between being tall and short on every other beat, while the P-R interval remains constant. What is the anatomical mechanism behind this finding?

Q19

The ‘P-mitrale’ pattern (broad, notched P waves in lead II > 120 ms, and a deep negative terminal P wave in V1) indicates Left Atrial Enlargement. Why does V1 display a biphasic P wave with a deep negative terminal component?

Q20

A patient on hemodialysis presents with profound muscle weakness. The ECG demonstrates extremely peaked, symmetrical T waves with a narrow base, a flattened/absent P wave, and widening of the QRS complex. This pattern of severe Hyperkalemia represents sequential paralysis of the cardiac action potential. Why is the P wave lost before the QRS widens?

Q21

During routine ECG interpretation, you note prominent U waves (a positive deflection following the T wave) in leads V2 and V3. While positive U waves can be a normal variant or a sign of hypokalemia, what does a deeply INVERTED U wave in the precordial leads signify?

Q22

A 45-year-old patient with a history of palpitations has a non-diagnostic ‘saddleback’ (Type 2) Brugada pattern on their baseline ECG. What specific class of medications is infused in the EP lab to unmask the diagnostic Type 1 coved Brugada pattern?

Q23

When interpreting the QT interval, the Bazett formula (QTc = QT / √RR) is the most widely used correction method. However, what is its primary mathematical limitation in clinical practice?

Q24

An ECG demonstrates severe Right Axis Deviation (+120 degrees), an rS complex in lead I, and a qR complex in leads II, III, and aVF, with a normal QRS duration. This pattern is the hallmark of which specific conduction block?

Q25

A young patient with a morphologically normal heart presents to the ER on a Monday morning with palpitations following a weekend of heavy binge drinking. The ECG reveals an irregularly irregular narrow-complex rhythm lacking P waves. What is the clinical eponym for this specific presentation?

Interactive Cardiology MCQs #21

In a patient presenting with central chest pain, the ECG reveals upsloping ST-segment depression at the J-point in the precordial leads (V1-V6) that continues into tall, prominent, and symmetrical T waves. What is this ECG pattern called, and what does it signify?

When applying the Brugada Algorithm to differentiate Ventricular Tachycardia (VT) from Supraventricular Tachycardia (SVT) with aberrancy, what is the VERY FIRST criteria assessed, which immediately confirms a diagnosis of VT if met?

A patient with an established Left Bundle Branch Block (LBBB) presents with acute chest pain. According to the original Sgarbossa Criteria, which specific ECG finding is the most specific (weighted at 5 points) for diagnosing a superimposed acute myocardial infarction?

In diagnosing a true posterior myocardial infarction using a standard 12-lead ECG, what is the classic reciprocal pattern seen in the anterior precordial leads (V1-V3)?

Which of the following ECG findings is considered the most specific electrocardiographic marker for acute Right Ventricular (RV) Infarction in the setting of an acute Inferior STEMI?

A patient taking therapeutic doses of Digoxin for rate control of Atrial Fibrillation has a routine ECG performed. Which of the following is the classic expected ECG finding of the ‘Digitalis Effect’ (NOT toxicity)?

In evaluating a patient for Left Ventricular Hypertrophy (LVH) on a 12-lead ECG, the Cornell Voltage Criteria are considered highly accurate and account for gender differences. What specific measurements comprise the Cornell criteria?

A patient with a history of syncope while swimming is evaluated. Their ECG shows a prolonged QT interval with broad-based T waves. Genetic testing confirms Long QT Syndrome Type 1 (LQT1). Which specific ion channel mutation is responsible for this condition?

A patient develops a regular narrow-complex tachycardia at 150 bpm. You suspect Typical Atrial Flutter with 2:1 block. If ‘typical’ (counterclockwise) flutter is present, what is the expected morphology of the flutter waves in the inferior leads (II, III, aVF) and lead V1?

In patients presenting with Acute Pulmonary Embolism, the classic ‘S1Q3T3’ pattern is famous but relatively insensitive. Which ECG finding actually has the highest correlation with Right Ventricular Dysfunction (RV strain) and adverse outcomes in acute PE?

When examining an ECG to differentiate acute Pericarditis from Benign Early Repolarization (BER), which specific feature strongly favors a diagnosis of Pericarditis?

During ECG interpretation, you observe a rhythm with a 2:1 atrioventricular (AV) conduction ratio (two P waves for every QRS). How can you best differentiate if this is a Mobitz Type I (Wenckebach) variant at the AV node versus a dangerous Mobitz Type II block below the AV node?

An ECG demonstrates severe Left Axis Deviation (-60 degrees), a qR complex in leads I and aVL, and rS complexes in leads II, III, and aVF, with a normal QRS duration. This pattern is the hallmark of which conduction system defect?

The ‘Epsilon wave’ is a subtle notch or ‘blip’ found between the end of the QRS complex and the onset of the ST segment, best seen in leads V1-V3. It represents delayed activation of which cardiac structure, and is a major diagnostic criterion for what disease?

A patient presenting with acute dyspnea has an ECG showing a tachycardia where the QRS amplitude distinctly alternates between being tall and short on every other beat, while the P-R interval remains constant. What is the anatomical mechanism behind this finding?

The ‘P-mitrale’ pattern (broad, notched P waves in lead II > 120 ms, and a deep negative terminal P wave in V1) indicates Left Atrial Enlargement. Why does V1 display a biphasic P wave with a deep negative terminal component?

During routine ECG interpretation, you note prominent U waves (a positive deflection following the T wave) in leads V2 and V3. While positive U waves can be a normal variant or a sign of hypokalemia, what does a deeply INVERTED U wave in the precordial leads signify?

A 45-year-old patient with a history of palpitations has a non-diagnostic ‘saddleback’ (Type 2) Brugada pattern on their baseline ECG. What specific class of medications is infused in the EP lab to unmask the diagnostic Type 1 coved Brugada pattern?

When interpreting the QT interval, the Bazett formula (QTc = QT / √RR) is the most widely used correction method. However, what is its primary mathematical limitation in clinical practice?

An ECG demonstrates severe Right Axis Deviation (+120 degrees), an rS complex in lead I, and a qR complex in leads II, III, and aVF, with a normal QRS duration. This pattern is the hallmark of which specific conduction block?

A young patient with a morphologically normal heart presents to the ER on a Monday morning with palpitations following a weekend of heavy binge drinking. The ECG reveals an irregularly irregular narrow-complex rhythm lacking P waves. What is the clinical eponym for this specific presentation?