Cardiology Practice Questions

Q: Corrected QT (QTc) is calculated by dividing QT/x. What is the value of x as per given ECG.

0.82. ***0.82*** - The standard **Bazett's formula** for corrected QT interval is: **QTc = QT / √RR**, where QTc is the corrected QT, QT is the measured QT interval, and the denominator **x = √RR** (square root of the RR interval in seconds). - From the ECG, the **RR interval** (segment 4) spans approximately **17 small squares**. Each small square = 0.04 seconds, so **RR = 17 × 0.04 = 0.68 seconds**. - Therefore, **x = √RR = √0.68 ≈ 0.82**. *Incorrect — 0.77* - This corresponds to √0.60, which would result from an RR interval of only 15 small squares (0.60s). This is an incorrect reading of the RR interval from this ECG. *Incorrect — 0.88* - This corresponds to √0.77, implying an RR interval of ~0.77s. This overestimates the RR interval seen in the ECG. *Incorrect — 0.71* - This corresponds to √0.50, implying a shorter RR interval of ~0.50s (a faster heart rate than shown). This does not match the ECG tracing provided.

Q: A 40-year-old man was admitted to the hospital emergency with sudden onset of the symptoms and signs of severe left ventricular failure. Calculate the atrial rate of the patient:

300 / min. ***300 / min*** - The ECG shows a **sawtooth pattern** of atrial activity, which is characteristic of **atrial flutter**. - To calculate the atrial rate, observe the number of flutter waves in a particular interval. In lead II (long rhythm strip), there is one **flutter wave every large box** (0.2 seconds), indicating a rate of 300 beats/min (60 seconds / 0.2 seconds = 300). *100 / min* - This rate might represent the **ventricular rate** in some cases of atrial flutter, especially with 3:1 conduction. However, it does not represent the rapid atrial activity. - The P waves (or flutter waves) are clearly much faster than 100/min. *150 / min* - This rate could represent the **ventricular rate** if there was 2:1 AV block in atrial flutter. - However, the atrial activity itself is much faster than 150/min. *200 / min* - While a rapid rate, 200/min is not consistent with the typical flutter wave rate of 300/min seen in the ECG. - The flutter waves are clearly occurring at a faster interval than would correspond to 200 beats/min.

Q: The following ECG finding is seen in all except:

Hypercalcemia. ***Hypercalcemia*** - The ECG shows a **J wave (Osborn wave)**, which is a common finding in **hypothermia**. - **Hypercalcemia** is associated with a shortened QT interval and has no direct association with J waves. *Hypocalcemia* - **Hypocalcemia** typically causes a **prolonged QT interval** on an ECG. - While it affects cardiac electrophysiology, it does not cause J waves. *Subarachnoid hemorrhage (SAH)* - **SAH** can lead to various ECG changes, including **QT prolongation**, T wave inversions, or ST segment changes. - However, the classic J wave seen in the image is not a characteristic finding of SAH. *Hypothermia* - **Hypothermia** is a well-known cause of the **J wave (Osborn wave)**, which is visible as a positive deflection at the QRS-ST junction. - Other ECG findings in hypothermia include bradycardia, prolonged PR, QRS, and QT intervals.

Q: This ECG was recorded from a 65 -year-old man who had crescendo pattern episodes of chest pain. His current episode has been persisting at rest for 2.5 hours. Plasma troponin level was normal. Diagnosis is?

NSTEMI/UA. ***NSTEMI/UA*** - The patient presents with **chest pain at rest** and **dynamic ST changes** (ST depression in V1-V3, ST elevation in aVR not meeting STEMI criteria) with an initial **normal troponin level**. This clinical picture, especially the **crescendo pattern** of chest pain, is highly suggestive of **unstable angina (UA)** or **NSTEMI** if troponin later becomes elevated. - The ECG shows significant **ST depression in precordial leads (V1-V3)** and **ST elevation in aVR**, which is a sign of potentially extensive ischemia, often associated with a proximal left anterior descending (LAD) or multivessel disease. The initial normal troponin keeps the diagnosis at UA or NSTEMI until further serial troponin measurement. *Chronic stable angina* - This condition is characterized by **predictable chest pain** that occurs with physical exertion or stress and is relieved by rest or nitroglycerin. - The patient's description of **crescendo pattern episodes** and pain persisting **at rest** indicates a departure from chronic stable angina, suggesting an acute coronary syndrome. *STEMI* - **STEMI (ST-segment Elevation Myocardial Infarction)** requires significant **ST elevation** in at least two contiguous leads (typically ≥2 mm in V1-V3 or ≥1 mm in other leads) or new LBBB. - While there is **ST elevation in aVR**, it does not meet the criteria for STEMI in other leads, and the prominent **ST depressions** point more towards NSTEMI/UA. *Acute chest syndrome* - **Acute chest syndrome (ACS)** is a serious complication primarily seen in patients with **sickle cell disease**, characterized by fever, chest pain, and pulmonary infiltrates. - The patient's age (65 years old) and lack of any mention of sickle cell disease make this diagnosis highly unlikely in this context.

Q: This ECG was recorded from a 60 -year-old woman with hypertension. Which is correct about the ECG shown?

Left ventricular hypertrophy. ***Left ventricular hypertrophy*** - The ECG shows significantly **increased R wave amplitude** in lead V5 (approximately 25 small boxes or 25mm) and V6 (approximately 20 small boxes), along with deep S waves in V1 (approximately 15 small boxes), satisfying various voltage criteria for LVH, such as the **Sokolow-Lyon index** (SV1 + RV5 or RV6 ≥ 35mm). - The elevated T waves in V5 and V6, along with the depressed ST segment in V5, are also consistent with **repolarization abnormalities** often seen in LVH. *Left axis deviation* - The QRS complex is predominantly positive in lead I and negative in lead aVF, indicating a normal axis, not left axis deviation. - For left axis deviation, the QRS complex should be **negative in lead II and aVF**, which is not the case here. *Atrial fibrillation* - The ECG shows clear, regular P waves followed by QRS complexes, indicating a **regular rhythm with discernible P waves**, inconsistent with atrial fibrillation which is characterized by an irregularly irregular rhythm and absence of P waves. - The **RR intervals are regular**, ruling out the chaotic rhythm of atrial fibrillation. *Aortic dissection* - Aortic dissection is a clinical diagnosis and while it can cause ECG changes due to myocardial ischemia or infarction (if coronary arteries are involved), there are **no specific ECG changes** that diagnose aortic dissection directly. - The ECG findings here directly point to **cardiac structural changes** (LVH) rather than an acute vascular emergency like aortic dissection.

Q: This ECG is of a 23 -year-old medical student who complained of an irregular heartbeat. Other than an irregular pulse, his heart was clinically normal. What does the ECG show?

Ventricular extrasystole. ***Ventricular extrasystole*** - The ECG shows occasional **premature, wide QRS complexes** not preceded by a P wave, originating from the ventricles. These are classic signs of ventricular extrasystoles (also known as premature ventricular contractions or PVCs). - The **irregular heartbeat** complained of by the patient is consistent with the presence of these extra beats, which disrupt the normal rhythm. *Sinus tachycardia* - Sinus tachycardia is characterized by a **regular heart rhythm** with a **heart rate above 100 bpm**, originating from the sinus node. - This ECG clearly shows an **irregular rhythm** and wide QRS complexes, which are not features of sinus tachycardia. *PSVT* - Paroxysmal supraventricular tachycardia (PSVT) typically presents as a **fast, regular rhythm** with **narrow QRS complexes** and a sudden onset and termination. - The ECG in question exhibits **wide QRS complexes** and an **irregular rhythm**, making PSVT an unlikely diagnosis. *Complete heart block* - Complete heart block is characterized by a **dissociation between atrial and ventricular activity**, where P waves and QRS complexes occur independently. - While the rhythm is irregular in complete heart block, the presence of **normal QRS complexes interspersed with wide, premature beats** is not consistent with the fixed AV dissociation seen in complete heart block.

Q: Which is correct about the ECG shown below?

Atrial flutter 4:1 conduction. ***Atrial flutter 4:1 conduction*** - The ECG shows regular **sawtooth flutter waves** in leads II, III, and aVF, characteristic of atrial flutter. - There are four flutter waves for every QRS complex, indicating a **4:1 conduction ratio** from the atria to the ventricles. *P pulmonale* - **P pulmonale** is characterized by tall, peaked P waves (amplitude >2.5 mm) in leads II, III, or aVF, indicative of **right atrial enlargement**. - While there are P-like waves, they are **sawtooth patterns** consistent with flutter waves, not normal P waves with increased amplitude. *Electrical alternans* - **Electrical alternans** is a beat-to-beat variation in the **QRS complex amplitude** or axis, typically associated with large pericardial effusions. - The ECG shows consistent QRS complex morphology and amplitude, ruling out electrical alternans. *Atrial flutter 1:1 conduction* - In **atrial flutter with 1:1 conduction**, the ventricular rate would be extremely fast (around 300 bpm), often leading to **hemodynamic instability**. - The ventricular rate in this ECG is slower (approximately 75 bpm), inconsistent with 1:1 conduction.

Q: A 25-year-old girl presents with history of recurrent syncopal attacks. Holter device was put and the recording is shown below. Which is correct about the recording?

PSVT. ***PSVT*** - The ECG shows a **narrow QRS complex tachycardia with a regular rhythm** and a heart rate around 150 bpm, which is characteristic of Paroxysmal Supraventricular Tachycardia (PSVT). - In PSVT, **P waves are often hidden within the QRS complex** or T wave, or appear shortly after the QRS, as can be inferred from the rapid rate and regular narrow complex. *P pulmonale* - **P pulmonale** is characterized by tall, peaked P waves (> 2.5 mm in height in inferior leads) and is indicative of **right atrial enlargement**. - The ECG does not show such P wave morphology; instead, the rapid rate makes P waves difficult to discern. *P mitrale* - **P mitrale** is characterized by wide, notched P waves (> 0.12 s in duration) and is indicative of **left atrial enlargement**. - This ECG pattern is inconsistent with P mitrale, as the P waves are either obscured or not widened/notched. *Electromechanical dissociation* - **Electromechanical dissociation (EMD)**, also known as pulseless electrical activity (PEA), occurs when there is organized electrical activity on the ECG but **no palpable pulse**. - EMD typically presents with a slow, wide QRS complex rhythm or a normal-looking rhythm without a mechanical response, which is not what is seen here; this ECG shows a fast, regular rhythm.

Q: A 30-year-old male was brought to the ER after a car crash. On admission, pulse is weak with BP=80 / 60 mm Hg. ECG is shown below. Right heart catheter is placed. Which is the most consistent value with patient's diagnosis?

16 | 34 / 16 | 16. ***16 | 34 / 16 | 16*** - The ECG shows low voltage QRS complexes and electrical alternans (alternating amplitude of P, QRS, and T waves), which are classic signs of **cardiac tamponade** due to fluid accumulation compromising cardiac filling. - In cardiac tamponade, there is an equalization of diastolic pressures in all four heart chambers, specifically the **right atrial (RA) pressure**, **right ventricular (RV) end-diastolic pressure**, and **pulmonary artery wedge pressure (PAWP)**, reflecting the extrinsic compression on the heart. *16 | 100 / 30 | 28* - This set of numbers (RA | RV | PAWP) shows a **significantly elevated RV systolic pressure (100 mmHg)**, which is indicative of **severe pulmonary hypertension** or right ventricular outflow tract obstruction, neither of which are consistent with tamponade. - While PAWP (28 mmHg) is elevated, the disparity between RV systolic pressure and RA pressure (16 mmHg) does not suggest the pressure equalization typical of tamponade. *16 | 45 / 22 | 20* - This data indicates an elevated RV systolic pressure (45 mmHg) and elevated RV end-diastolic pressure (22 mmHg), suggesting **right ventricular dysfunction** or pulmonary hypertension. - However, the PAWP (20 mmHg) is not significantly elevated to the point of equalizing with the RV end-diastolic pressure or RA pressure, which would signify cardiac tamponade. *16 | 75 / 30 | 11* - This option presents an **elevated RV systolic pressure (75 mmHg)** and an elevated RV end-diastolic pressure (30 mmHg), suggesting significant **right ventricular pressure overload**, likely due to severe pulmonary hypertension or a massive pulmonary embolism. - The **PAWP (11 mmHg)** is relatively low compared to the right-sided pressures, which rules out cardiac tamponade and suggests a problem primarily affecting the right heart and pulmonary circulation.

Question 1

Corrected QT (QTc) is calculated by dividing QT/x. What is the value of x as per given ECG.

Accepted Answer

0.82

Answer

0.77

Answer

0.88

Answer

0.71

Question 2

A 40-year-old man was admitted to the hospital emergency with sudden onset of the symptoms and signs of severe left ventricular failure. Calculate the atrial rate of the patient:

Accepted Answer

300 / min

Answer

100 / min

Answer

150 / min

Answer

200 / min

Question 3

The following ECG finding is seen in all except:

Accepted Answer

Hypercalcemia

Answer

Hypocalcemia

Answer

SAH

Answer

Hypothermia

Question 4

This ECG was recorded from a 65 -year-old man who had crescendo pattern episodes of chest pain. His current episode has been persisting at rest for 2.5 hours. Plasma troponin level was normal. Diagnosis is?

Accepted Answer

NSTEMI/UA

Answer

Chronic stable angina

Answer

STEMI

Answer

Acute chest syndrome

Question 5

This ECG was recorded from a 60 -year-old woman with hypertension. Which is correct about the ECG shown?

Accepted Answer

Left ventricular hypertrophy

Answer

Left axis deviation

Answer

Atrial fibrillation

Answer

Aortic dissection

Question 6

This ECG is of a 23 -year-old medical student who complained of an irregular heartbeat. Other than an irregular pulse, his heart was clinically normal. What does the ECG show?

Accepted Answer

Ventricular extrasystole

Answer

Sinus tachycardia

Answer

PSVT

Answer

Complete heart block

Question 7

In a patient with the given clinical sign which of the following ECG will be seen?

Accepted Answer

Transient ST-segment elevation with prominent peaked T-waves (Prinzmetal's vasospastic angina pattern)

Answer

Normal sinus rhythm with normal P-waves, QRS complexes, and T-waves

Answer

Widened QRS complex with ST-segment elevation bowed upward (left bundle branch block pattern)

Answer

Rapid, chaotic rhythm with no discernible P-waves (ventricular fibrillation)

Question 8

Which is correct about the ECG shown below?

Accepted Answer

Atrial flutter 4:1 conduction

Answer

P pulmonale

Answer

Electrical alternans

Answer

Atrial flutter 1:1 conduction

Question 9

A 25-year-old girl presents with history of recurrent syncopal attacks. Holter device was put and the recording is shown below. Which is correct about the recording?

Accepted Answer

PSVT

Answer

P pulmonale

Answer

P mitrale

Answer

Electromechanical dissociation

Question 10

A 30-year-old male was brought to the ER after a car crash. On admission, pulse is weak with BP=80 / 60 mm Hg. ECG is shown below. Right heart catheter is placed. Which is the most consistent value with patient's diagnosis?

Accepted Answer

16 | 34 / 16 | 16

Answer

16 | 100 / 30 | 28

Answer

16 | 45 / 22 | 20

Answer

16 | 75 / 30 | 11

Cardiology — MCQs

Cardiology — MCQs

On this page

Practice by Chapter

Want unlimited practice?