Cardiology Practice Questions

Q: A 65-year-old male presents with sweating and chest pain that began 26 hours ago, with no ongoing ischemic symptoms at the time of presentation, and the following ECG. Which of the following medications is not indicated in managing the patient?

Thrombolytic therapy. ***Thrombolytic therapy*** - **Thrombolytic therapy** is not indicated in this patient given the **26-hour delay** from symptom onset with no ongoing ischemia, as fibrinolytic therapy is generally not recommended beyond **12 hours** and is generally not indicated after **24 hours** because expected benefit is minimal. - The **risk-benefit ratio** becomes unfavorable after this time window, with increased bleeding risk and minimal myocardial salvage potential. *Aspirin* - **Aspirin** remains indicated in STEMI regardless of presentation timing as an **antiplatelet agent**. - It provides ongoing **secondary prevention** benefits and helps prevent further thrombotic events even in delayed presentations. *Clopidogrel* - **Clopidogrel** (or another P2Y12 inhibitor) is indicated as dual antiplatelet therapy alongside aspirin in ACS patients, including those with delayed presentation. - It reduces the risk of further thrombotic events and is a standard component of medical management in STEMI. *High-dose statin* - **High-dose statin therapy** is recommended immediately in all ACS patients, including those with delayed presentation. - Statins provide **plaque stabilization** and **anti-inflammatory effects** that are beneficial regardless of symptom onset timing.

Q: Identify the ECG given in the figure below.

Normal sinus rhythm. ***Normal sinus rhythm*** - The ECG shows regular **P waves** followed by **QRS complexes**, with a consistent PR interval and a heart rate between 60-100 beats per minute, which are all characteristics of a normal sinus rhythm. - The QRS complexes are narrow, indicating normal ventricular depolarization, and the T waves are appropriately configured. *Paroxysmal supraventricular tachycardia* - This rhythm would typically show a **very rapid heart rate** (150-250 bpm) with narrow QRS complexes and often obscured or absent P waves. - The rate in this ECG is clearly within the normal range, and P waves are distinctly visible before each QRS. *Atrial fibrillation* - Atrial fibrillation is characterized by an **irregularly irregular rhythm**, absence of distinct P waves, and an erratic baseline due to chaotic atrial activity. - This ECG clearly shows a regular rhythm with discernible P waves. *Ventricular fibrillation* - Ventricular fibrillation is a life-threatening arrhythmia characterized by completely **chaotic and irregular electrical activity** in the ventricles, resulting in no identifiable P waves, QRS complexes, or T waves. - The ECG in the image shows clearly defined, organized waveforms, making ventricular fibrillation incorrect.

Q: A 25-year-old woman presents with complaints of recurrent episodes of sudden onset palpitations. What does her ECG tracing show?

Paroxysmal Supraventricular Tachycardia (PSVT). ***Paroxysmal Supraventricular Tachycardia (PSVT)*** - The ECG shows a **narrow QRS complex tachycardia** with a regular rhythm and a heart rate around 150 bpm, consistent with PSVT. - The sudden onset and termination of symptoms described by the patient are characteristic features of **re-entrant tachycardias**, such as AVNRT or AVRT, which fall under the umbrella of PSVT.

Q: A 42-year-old male with poorly controlled diabetes presents with stuttering chest pain occurring at rest, representing a new and crescendo pattern, for up to 15 minutes at a time over 24 hours. Serial cardiac troponin measurements remain within normal limits. He is pain-free at the time of this ECG. ECG shows:

Unstable angina. ***Unstable angina*** - The patient presents with **new-onset chest pain** that occurs at rest and is prolonged (up to 15 minutes) and "stuttering" over 24 hours in a crescendo pattern, which is characteristic of unstable angina. - The ECG shows **ST segment changes and T-wave abnormalities** consistent with **myocardial ischemia**, even though the patient is currently pain-free. *Stable angina* - Characterized by **predictable chest pain** that is relieved by rest or nitroglycerin and occurs with exertion. - The patient's pain is prolonged, occurring at rest, and is new/worsening in a crescendo pattern, which is inconsistent with typical stable angina. *Silent ischemia* - Refers to myocardial ischemia that occurs **without symptoms of chest pain**, often seen in patients with diabetes due to neuropathy. - While the patient has diabetes, he is actively presenting with chest pain, ruling out silent ischemia as the primary current diagnosis. *Aortic dissection* - Typically presents with **sudden onset, severe, tearing chest pain** that often radiates to the back or neck. - The overall clinical presentation — stuttering chest pain at rest, new crescendo pattern, normal troponins, and ECG ischemic changes — favors acute coronary syndrome (ACS) over aortic dissection.

Q: Which of the following finding is shown in the chest leads?

Digoxin. ***Digoxin*** - The ECG shows a characteristic **downward sloping ST segment depression** with a "sagging" or "scooped" appearance, often referred to as a **"Salvador Dali mustache"** appearance, which is typical of digoxin effect on the ECG. - This pattern is due to the drug's effect on **myocardial repolarization**, specifically shortening the QT interval and inducing these ST changes, even in the absence of toxicity. *Myocardial ischemia* - Myocardial ischemia typically manifests as **ST segment depression** that is **horizontal** or **downsloping** but usually not with the characteristic "scooped" appearance seen with digoxin. - T-wave inversions may also be present, which are not the primary finding here. *Myocardial injury* - Myocardial injury is defined by **elevated cardiac troponin** (biomarker-based definition) and may occur with or without ECG abnormalities; it is not diagnosed by ST morphology alone. - The characteristic **"scooped" ST segment depression** seen in this ECG favors a **digoxin effect** rather than myocardial injury. *Digoxin toxicity* - While this ECG shows a digoxin effect, **digoxin toxicity** usually presents with **arrhythmias** (e.g., ventricular premature beats, bradycardia, AV blocks) in addition to altered ST-T wave morphology. - The ECG alone, showing only repolarization changes characteristic of digoxin, does not confirm toxicity without clinical correlation or evidence of arrhythmias.

Q: Corrected QT (QTc) is calculated using Bazett's formula as QTc = QT/x, where x is the denominator. The ECG is recorded at a paper speed of 25 mm/s. What is the value of x as per given ECG.

1.22. ***1.22*** - 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 **37 small squares**. Each small square = 0.04 seconds, so **RR = 37 × 0.04 = 1.48 seconds**. - Therefore, **x = √RR = √1.48 ≈ 1.22**. *Incorrect — 1.10* - This corresponds to √1.21, which would result from an RR interval of approximately 30 small squares (1.21s). This underestimates the RR interval seen in the ECG. *Incorrect — 1.35* - This corresponds to √1.82, implying an RR interval of ~1.82s. This overestimates the RR interval seen in the ECG. *Incorrect — 0.98* - This corresponds to √0.96, implying a shorter RR interval of ~0.96s (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:

Hypocalcemia. ***Hypocalcemia*** - The ECG shows a **J wave (Osborn wave)**, which is a common finding in **hypothermia**. - **Hypocalcemia** typically causes a **prolonged QT interval** on an ECG and is not a recognized cause of J waves. *Hypercalcemia* - **Severe hypercalcemia** can produce J waves, in addition to its association with a shortened QT interval. *Subarachnoid hemorrhage (SAH)* - **SAH** and other acute neurologic injuries can produce J waves, along with other ECG changes such as **QT prolongation**, T wave inversions, or ST segment changes. *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.

Question 1

A 52-year-old male diabetic patient presents with palpitations to the AIIMS emergency. He is hemodynamically stable with no hypotension, ischemic chest discomfort, altered mental status, or acute heart failure. Urgent ECG was performed showing a regular narrow-complex tachycardia at approximately 150 bpm with visible flutter waves, consistent with atrial flutter with 2:1 conduction. What is the immediate next step in the management?

Accepted Answer

Rate control with a beta-blocker or calcium channel blocker

Answer

Primary PCI

Answer

Adenosine

Answer

Amiodarone

Answer

Electrical cardioversion

Question 2

A 65-year-old male presents with sweating and chest pain that began 26 hours ago, with no ongoing ischemic symptoms at the time of presentation, and the following ECG. Which of the following medications is not indicated in managing the patient?

Accepted Answer

Thrombolytic therapy

Answer

Aspirin

Answer

Clopidogrel

Answer

High-dose statin

Question 3

Identify the ECG given in the figure below.

Accepted Answer

Normal sinus rhythm

Answer

Paroxysmal supraventricular tachycardia

Answer

Atrial fibrillation

Answer

Ventricular fibrillation

Question 4

A 25-year-old woman presents with complaints of recurrent episodes of sudden onset palpitations. What does her ECG tracing show?

Accepted Answer

Paroxysmal Supraventricular Tachycardia (PSVT)

Answer

Ventricular Tachycardia

Answer

Atrial Fibrillation

Answer

Atrial Flutter

Question 5

A 42-year-old male with poorly controlled diabetes presents with stuttering chest pain occurring at rest, representing a new and crescendo pattern, for up to 15 minutes at a time over 24 hours. Serial cardiac troponin measurements remain within normal limits. He is pain-free at the time of this ECG. ECG shows:

Accepted Answer

Unstable angina

Answer

Stable angina

Answer

Silent ischemia

Answer

Aortic dissection

Question 6

Which of the following finding is shown in the chest leads?

Accepted Answer

Digoxin

Answer

Myocardial ischemia

Answer

Myocardial injury

Answer

Digoxin toxicity

Question 7

Corrected QT (QTc) is calculated using Bazett's formula as QTc = QT/x, where x is the denominator. The ECG is recorded at a paper speed of 25 mm/s. What is the value of x as per given ECG.

Accepted Answer

1.22

Answer

1.10

Answer

1.35

Answer

0.98

Question 8

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 9

The following ECG finding is seen in all except:

Accepted Answer

Hypocalcemia

Answer

Hypothermia

Answer

SAH

Answer

Hypercalcemia

Question 10

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

Cardiology — MCQs

Cardiology — MCQs

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