Cardiac Arrhythmias — MCQs
Identify the ECG given below?
A 54-year-old man presents after a syncopal episode with no recollection of the event, and bystanders report that he regained consciousness approximately 45 seconds after falling. He has a history of bipolar disorder managed with quetiapine, and recently experienced prostatitis treated with ciprofloxacin. His other medications include lisinopril and hydrochlorothiazide for hypertension, and cyclobenzaprine and a hydrocodone/acetaminophen combination pill for low back pain. On examination, the patient is alert and oriented, with a nonfocal neurological examination and an unremarkable cardiac examination. Electrocardiogram shows nonspecific ST and T wave changes and a prolonged QT interval (QTc of 540 milliseconds). What is the best initial management approach?
Sine wave in ECG is seen in?
Which of the following is true about torsades de pointes?
Preferred drug for the treatment of ventricular tachycardia is
In ACLS, which antiarrhythmic drug can be given following ventricular fibrillation after cardiac arrest other than epinephrine?
25-year-old female presented to emergency with palpitations and dizziness. ECG was done and was diagnosed supraventricular tachycardia. Her blood pressure was 60/40 mm Hg. First line of management for this patient is ?
Which of the following is not a complication of hypokalemia?
A patient presents to you with an irregularly irregular pulse of 120/minutes and a pulse deficit of 20. Which of the following would be the jugular venous pressure (JVP) finding?
In which of the following conditions is the implantation of an Automatic Implantable Cardioverter Defibrillator (AICD) indicated?
Cardiac Arrhythmias Indian Medical PG Practice Questions and MCQs
Question 1: Identify the ECG given below?
- A. Viral myocarditis
- B. Torsades de pointes (Correct Answer)
- C. Cardiac tamponade
- D. Pericarditis
Explanation: ***Torsades de pointes*** - The ECG shows a polymorphic ventricular tachycardia where the **QRS complexes appear to twist around the baseline**, a classic feature of Torsades de pointes. - This condition is often associated with **QT prolongation**, which is evident in some of the strips preceding the tachyarrhythmia. *Viral myocarditis* - While viral myocarditis can lead to various ECG abnormalities, it typically doesn't present with this specific **polymorphic ventricular tachycardia** morphology. - Common ECG findings in myocarditis include non-specific ST-T wave changes, sinus tachycardia, or conduction blocks, rather than the characteristic "twisting" pattern seen here. *Cardiac tamponade* - Cardiac tamponade is characterized by **electrical alternans** (alternating QRS amplitude), low voltage, and sinus tachycardia on ECG. - It does not cause a polymorphic ventricular tachycardia with the appearance of QRS complexes twisting around the baseline. *Pericarditis* - Pericarditis typically presents with **diffuse ST-segment elevation** (often concave up) and PR-segment depression. - It does not manifest as a polymorphic ventricular tachycardia like Torsades de pointes.
Question 2: A 54-year-old man presents after a syncopal episode with no recollection of the event, and bystanders report that he regained consciousness approximately 45 seconds after falling. He has a history of bipolar disorder managed with quetiapine, and recently experienced prostatitis treated with ciprofloxacin. His other medications include lisinopril and hydrochlorothiazide for hypertension, and cyclobenzaprine and a hydrocodone/acetaminophen combination pill for low back pain. On examination, the patient is alert and oriented, with a nonfocal neurological examination and an unremarkable cardiac examination. Electrocardiogram shows nonspecific ST and T wave changes and a prolonged QT interval (QTc of 540 milliseconds). What is the best initial management approach?
- A. Admit for permanent implantable cardioverter-defibrillator (ICD)
- B. Admit and begin amiodarone infusion
- C. Refer for genetic counseling
- D. Admit the patient for telemetry and evaluate for reversible causes of QT prolongation (Correct Answer)
Explanation: ***Admit the patient for telemetry and evaluate for reversible causes of QT prolongation*** * The patient experienced a **syncopal episode** with a **prolonged QT interval (QTc of 540 ms)**, which significantly increases the risk of **Torsade de Pointes (TdP)** and sudden cardiac death [1]. * **Telemetry monitoring** is crucial to detect arrhythmias, and identifying and removing **QT-prolonging medications** (quetiapine, ciprofloxacin, hydrocodone) and correcting **electrolyte imbalances** are essential initial steps [1]. *Admit for permanent implantable cardioverter-defibrillator (ICD)* * While an ICD is used for prevention of sudden cardiac death in high-risk patients, it's generally considered after **reversible causes of QT prolongation** have been addressed and the patient remains at high risk or has recurrent **life-threatening arrhythmias**. * Implanting an ICD without first attempting to manage the modifiable risk factors like certain medications or electrolyte imbalances would be premature. *Admit and begin amiodarone infusion* * **Amiodarone** is an **antiarrhythmic drug** that itself can **prolong the QT interval**, which would exacerbate the patient's existing risk for TdP. * This medication would be contraindicated in the presence of an already prolonged QT interval due to the increased risk of potentially fatal arrhythmias. *Refer for genetic counseling* * While **congenital long QT syndrome** can cause profound QT prolongation, **acquired causes** (medications, electrolyte abnormalities) are far more common, especially given the patient's extensive medication list. * Genetic counseling may be considered if reversible causes are ruled out or if there's a strong family history, but it is not the immediate best management for an acute syncopal episode with acquired QT prolongation.
Question 3: Sine wave in ECG is seen in?
- A. Hypokalemia
- B. Hypercalcemia
- C. Hypocalcemia
- D. Hyperkalemia (Correct Answer)
Explanation: ### Hyperkalemia - A **sine wave pattern** on ECG is a severe and late manifestation of **hyperkalemia**, indicating significant cardiac electrical instability [1]. - It results from the fusion of the widened QRS complexes with the tall, peaked T waves, leading to a smooth, almost sinusoidal waveform [1]. *Hypokalemia* - ECG features of hypokalemia typically include **ST depression**, **T wave flattening** or inversion, prominent U waves, and a prolonged QU interval [1]. - It does not cause a sine wave pattern. *Hypercalcemia* - Hypercalcemia primarily causes a **shortening of the QT interval** and may also lead to ST elevation. - It does not produce a sine wave configuration. *Hypocalcemia* - Hypocalcemia characteristically leads to **prolongation of the QT interval** due to lengthening of the ST segment. - A sine wave pattern is not associated with hypocalcemia.
Question 4: Which of the following is true about torsades de pointes?
- A. Presence of polymorphic QRS complexes
- B. It is a type of supraventricular tachycardia
- C. QRS complexes appear to rotate around the isoelectric baseline of ECG
- D. Presence of prolonged QT interval on ECG (Correct Answer)
Explanation: ***Presence of prolonged QT interval on ECG*** - Torsades de pointes is a polymorphic ventricular tachycardia associated with a **prolonged QT interval**, which often precedes the arrhythmia [1]. - A prolonged QT interval indicates a delayed repolarization of the ventricles, creating a vulnerable period for the development of aberrant electrical activity [2]. *Presence of polymorphic QRS complexes* - While torsades de pointes does exhibit **polymorphic QRS complexes**, this is a characteristic *feature* of the arrhythmia itself, not the primary predisposing factor or defining characteristic that initiates it [1]. - The key underlying condition leading to torsades is the **QT prolongation**. *It is a type of supraventricular tachycardia* - Torsades de pointes is a **ventricular tachycardia**, meaning it originates in the ventricles, not above them in the atria or AV node (supraventricular) [1]. - Its origin below the Bundle of His differentiates it from supraventricular arrhythmias. *QRS complexes appear to rotate around the isoelectric baseline of ECG* - This description accurately depicts the characteristic **"twisting of the points"** morphology of torsades de pointes, but it is a *description of the ECG appearance* during the arrhythmia itself, not the fundamental predisposing factor [1]. - The rotation is a consequence of the changing amplitudes and axes of the polymorphic QRS complexes [1].
Question 5: Preferred drug for the treatment of ventricular tachycardia is
- A. Digoxin
- B. Propranolol
- C. Diltiazem
- D. Lignocaine (Correct Answer)
Explanation: ***Lignocaine*** *(Historical Answer for FMGE-2019)* - **Lignocaine** (also known as **lidocaine**) is a **Class IB antiarrhythmic** drug that was historically the preferred treatment for **ventricular tachycardia (VT)**, especially in patients with **ischemic heart disease**. - It works by **blocking sodium channels** in the heart, specifically targeting depolarized or partially depolarized cells, which helps to stabilize the ventricular rhythm. - **⚠️ IMPORTANT UPDATE:** Current guidelines (AHA/ACC 2015 onwards) now recommend **amiodarone as the first-line antiarrhythmic** for hemodynamically stable VT, with lignocaine as a **second-line alternative**. This question reflects the teaching prevalent at the time of FMGE-2019. *Digoxin* - **Digoxin** is a **cardiac glycoside** primarily used for **atrial fibrillation** with rapid ventricular response and **heart failure**. - It is **not the preferred drug** for ventricular tachycardia and can even precipitate arrhythmias in some cases. *Propranolol* - **Propranolol** is a **beta-blocker** (Class II antiarrhythmic) typically used to treat **supraventricular tachycardias**, **hypertension**, and **angina**. - While beta-blockers can have some role in preventing recurrent VT, they are **not the first-line treatment** for acute VT. *Diltiazem* - **Diltiazem** is a **calcium channel blocker** (Class IV antiarrhythmic) primarily used for **supraventricular tachycardias** and to control ventricular rate in **atrial fibrillation**. - It is **not effective** for ventricular tachycardia and may worsen the condition in some cases.
Question 6: In ACLS, which antiarrhythmic drug can be given following ventricular fibrillation after cardiac arrest other than epinephrine?
- A. Amiodarone (Correct Answer)
- B. Dopamine
- C. Adenosine
- D. Atropine
Explanation: ***Amiodarone*** - **Amiodarone** is a Class III antiarrhythmic agent recommended in ACLS for **refractory ventricular fibrillation (VF)** or pulseless ventricular tachycardia (pVT) after initial defibrillation and epinephrine. - It works by blocking potassium channels, prolonging repolarization, and increasing the **refractory period** in the heart. *Dopamine* - **Dopamine** is a **vasopressor** used to improve **hemodynamics** in patients with symptomatic hypotension, not primarily as an antiarrhythmic for VF. - Its effects include increasing heart rate, myocardial contractility, and blood pressure. *Adenosine* - **Adenosine** is a drug of choice for **supraventricular tachycardia (SVT)** to interrupt reentry pathways in the AV node. - It is not indicated for ventricular fibrillation, as it would be ineffective in this rhythm. *Atropine* - **Atropine** is an **anticholinergic agent** used to treat **symptomatic bradycardia** by increasing heart rate. - It has no role in the management of ventricular fibrillation.
Question 7: 25-year-old female presented to emergency with palpitations and dizziness. ECG was done and was diagnosed supraventricular tachycardia. Her blood pressure was 60/40 mm Hg. First line of management for this patient is ?
- A. Adenosine 12 mg IV
- B. Cardioversion (Correct Answer)
- C. Vagal manoeuvre
- D. Adenosine 6 mg IV
Explanation: ***Cardioversion*** - This patient presents with **supraventricular tachycardia (SVT)** and is **hemodynamically unstable** (blood pressure 60/40 mmHg), indicating the need for immediate intervention. - **Synchronized cardioversion** is the gold standard for unstable SVT as it rapidly restores sinus rhythm, preventing further deterioration. *Adenosine 12 mg IV* - While adenosine is a common treatment for stable SVT, the patient's **severe hypotension** makes it inappropriate as a first-line therapy. - Administering adenosine to an unstable patient could further worsen hypotension and lead to cardiac arrest. *Vagal manoeuvre* - **Vagal maneuvers** (e.g., Valsalva, carotid sinus massage) are effective first-line treatments for **stable SVT**. - However, they are **insufficient** for an unstable patient with profound hypotension, where rapid rhythm conversion is critical. *Adenosine 6 mg IV* - This is the **initial dose of adenosine** for stable SVT, but it is contraindicated in this hemodynamically unstable patient. - As with the 12 mg dose, adenosine can cause transient **heart block** and **hypotension**, which would be dangerous in an already hypotensive individual.
Question 8: Which of the following is not a complication of hypokalemia?
- A. Quadriparesis
- B. Cerebral edema (Correct Answer)
- C. Ventricular Tachycardia
- D. Diabetes insipidus
Explanation: ***Cerebral edema*** - **Cerebral edema** is typically associated with **hyponatremia** (low sodium levels), which causes hypotonicity in the extracellular fluid leading to water shifting into brain cells. - Hypokalemia primarily impacts neuromuscular and cardiac function and does not directly cause brain swelling due to fluid shifts. *Quadriparesis* - **Severe hypokalemia** can lead to **muscle weakness**, which can progress to flaccid paralysis affecting all four limbs (quadriparesis). - This occurs due to alterations in the **resting membrane potential** of muscle cells, making them less excitable. *Ventricular Tachycardia* - Hypokalemia can cause **cardiac arrhythmias**, including **ventricular tachycardia** and **fibrillation**, by prolonging repolarization and increasing myocardial excitability. - It can also lead to characteristic electrocardiogram (ECG) changes such as **flattened T waves**, **ST segment depression**, and prominent **U waves**. *Diabetes insipidus* - **Nephrogenic diabetes insipidus** can be a complication of chronic hypokalemia, where the kidneys become resistant to the effects of **antidiuretic hormone (ADH)**. - This results in the inability to concentrate urine, leading to **polyuria** (excessive urination) and **polydipsia** (excessive thirst).
Question 9: A patient presents to you with an irregularly irregular pulse of 120/minutes and a pulse deficit of 20. Which of the following would be the jugular venous pressure (JVP) finding?
- A. Normal JVP
- B. Absent a wave (Correct Answer)
- C. Cannon a wave
- D. Raised JVP with normal waveform
Explanation: ***Absent a wave*** - An **irregularly irregular pulse** with a **pulse deficit** strongly suggests **atrial fibrillation (AF)**. - In AF, the atria quiver chaotically instead of contracting effectively, leading to the **absence of a coordinated atrial contraction** and thus an **absent 'a' wave** in the JVP. *Normal JVP* - A normal JVP would show a regular **'a' wave** corresponding to normal atrial contraction. - This is inconsistent with the **irregularly irregular pulse** and **pulse deficit** seen in the patient, which points to a significant atrial arrhythmia. *Cannon a wave* - A **cannon 'a' wave** results from the right atrium contracting against a closed tricuspid valve, leading to a large, prominent wave in the JVP. - This is typically seen in conditions like **complete heart block** or **ventricular tachycardia with AV dissociation**, not atrial fibrillation. *Raised JVP with normal waveform* - A raised JVP with a normal waveform indicates increased right atrial pressure but preserves the normal sequence of atrial contraction and relaxation. - This could be due to conditions like **right heart failure** or **volume overload**, but would still show the presence of an 'a' wave, which is absent in atrial fibrillation.
Question 10: In which of the following conditions is the implantation of an Automatic Implantable Cardioverter Defibrillator (AICD) indicated?
- A. None of the options
- B. Ventricular tachycardia with structural heart disease (Correct Answer)
- C. Syncope due to arrhythmias
- D. Brugada syndrome
Explanation: ***Ventricular tachycardia with structural heart disease*** - An **AICD** is strongly indicated for patients with **sustained ventricular tachycardia (VT)** in the presence of **structural heart disease** due to the high risk of sudden cardiac death [1]. - In these cases, the AICD can deliver **therapy (antitachycardia pacing or defibrillation)** to terminate life-threatening arrhythmias [1]. *Syncope due to arrhythmias* - While syncope due to arrhythmias can be serious, an **AICD** is not always the first or only treatment and its indication depends on the specific arrhythmia and underlying cause. - Other treatments like **ablation**, **antiarrhythmic medications**, or a **pacemaker** might be more appropriate depending on the type of arrhythmia (e.g., bradycardia). *None of the options* - This option is incorrect because **ventricular tachycardia with structural heart disease** is a clear and well-established indication for AICD implantation [1]. - AICDs are a cornerstone in the secondary prevention of sudden cardiac death in high-risk patients. *Brugada syndrome* - While **Brugada syndrome** carries a risk of sudden cardiac death, AICD implantation is typically reserved for patients who have experienced **symptomatic arrhythmias** (e.g., syncope, aborted sudden cardiac death) or have certain high-risk features, not for all asymptomatic cases. - Risk stratification in Brugada syndrome is complex, and an AICD is not universally indicated for every diagnosed individual.
Want unlimited practice?
Get full access to all questions, explanations, and performance tracking.
Start For Free