Management of Cardiac Pacemakers and ICDs — MCQs

10 questions

Asynchronous cardioversion is given in:

A patient presents with intense chest pain of 2 hours duration. ECG shows ST depression in leads I and V1 to V4. There is associated T inversion and CPK-MB is elevated. Which of the following should be included in his management?

The most common complication of intrauterine contraceptive devices is:

A 25-year-old female presented to ER unconscious. Her mother tells you about her having recurrent syncopal episodes. Her BP is 80/60 mm Hg and you order an ECG. Treatment is

In which of the following conditions is the implantation of an Automatic Implantable Cardioverter Defibrillator (AICD) indicated?

Which of the following is not used in controlling heart rate intraoperatively?

Drug that does not cause cardiac depression:

The most sensitive and practical technique for detection of myocardial ischemia in the perioperative period is -

Which block is described as regional anesthesia of the arm:-

Q10Medium

Which of the following is NOT a treatment for supraventricular tachycardia with hypotension in a patient under general anesthesia?

Management of Cardiac Pacemakers and ICDs Indian Medical PG Practice Questions and MCQs

Question 1: Asynchronous cardioversion is given in:

A. AF
B. Atrial flutter
C. Ventricular tachycardia
D. Ventricular fibrillation (Correct Answer)

Explanation: ***Ventricular fibrillation*** - **Asynchronous cardioversion** is also known as **defibrillation**, which means it delivers a shock randomly without synchronization to the cardiac cycle [1]. - **Ventricular fibrillation (VF)** is a chaotic rhythm with no discernible QRS complexes, thus synchronization is impossible and immediate defibrillation is life-saving [1], [2]. *AF* - **Atrial fibrillation (AF)** can be treated with **synchronized cardioversion** if it is unstable or persistent and requires rhythm control, as there are still discernible QRS complexes [3]. - Asynchronous cardioversion is generally not recommended for AF due to the risk of inducing **ventricular fibrillation** if the shock falls on the T-wave [2]. *Atrial flutter* - **Atrial flutter** with a rapid ventricular response is typically treated with **synchronized cardioversion** because the organized atrial activity allows for synchronization of the shock with the QRS complex [3]. - This minimizes the risk of delivering a shock during the vulnerable period of the T-wave, which could lead to more dangerous arrhythmias [2]. *Ventricular tachycardia* - **Ventricular tachycardia (VT)**, if stable and with a pulse, is treated with **synchronized cardioversion** to avoid delivering the shock during the vulnerable T-wave [2]. - If **pulseless VT**, it is treated as **ventricular fibrillation** (asynchronous defibrillation) due to the hemodynamic instability and immediate life threat [1].

Question 2: A patient presents with intense chest pain of 2 hours duration. ECG shows ST depression in leads I and V1 to V4. There is associated T inversion and CPK-MB is elevated. Which of the following should be included in his management?

A. IV metoprolol
B. Aspirin
C. Nitroglycerine drip
D. All of the options (Correct Answer)

Explanation: ***All of the options*** - This patient presents with symptoms and ECG findings consistent with an **ST-elevation myocardial infarction (STEMI)** or **non-ST-elevation myocardial infarction (NSTEMI)**, given the ST depression and T-wave inversions with elevated CPK-MB [4]. - All listed medications (aspirin, IV metoprolol, and nitroglycerine drip) are standard and essential components of early management used to stabilize the patient, reduce myocardial oxygen demand, and prevent further cardiac events [1]. *Aspirin* - **Aspirin** is an antiplatelet agent used to inhibit platelet aggregation and prevent further thrombus formation in acute coronary syndromes [2]. - It is critical for immediate administration in suspected myocardial infarction to reduce mortality and recurrent ischemic events. *IV metoprolol* - **IV metoprolol** (a beta-blocker) reduces myocardial oxygen demand by decreasing heart rate, contractility, and blood pressure [3]. - It is indicated in acute coronary syndromes unless contraindicated, as it can limit infarct size and reduce the risk of arrhythmias. *Nitroglycerine drip* - The **nitroglycerine drip** is a vasodilator that reduces preload and dilates coronary arteries, improving myocardial blood flow and relieving ischemic chest pain [2]. - It is particularly useful for persistent chest pain and helps reduce myocardial oxygen demand.

Question 3: The most common complication of intrauterine contraceptive devices is:

A. Bleeding (Correct Answer)
B. Ectopic pregnancy
C. Backache
D. Cervical stenosis

Explanation: ***Bleeding*** - **Irregular bleeding** and **heavier menstrual periods (menorrhagia)** are the most common reasons for IUD discontinuation. - This is particularly true for **non-hormonal copper IUDs**, which can increase menstrual blood loss and dysmenorrhea. *Ectopic pregnancy* - While IUDs significantly reduce the overall risk of pregnancy, if a pregnancy does occur with an IUD in place, there is a **higher relative risk** that it will be **ectopic**. - However, the **absolute number** of ectopic pregnancies is low due to the high effectiveness of IUDs in preventing pregnancy altogether. *Backache* - Backache is **not a common complication** directly attributed to IUD use. - It could be a general discomfort but isn't specifically caused by the device itself or its mechanism of action. *Cervical stenosis* - **Cervical stenosis** is a narrowing of the cervical canal, which is **not typically caused by IUD insertion or presence**. - More commonly, it results from **surgical procedures** on the cervix, infection, or radiation.

Question 4: A 25-year-old female presented to ER unconscious. Her mother tells you about her having recurrent syncopal episodes. Her BP is 80/60 mm Hg and you order an ECG. Treatment is

A. Cathether Ablation
B. Adenosine
C. DC shock (Correct Answer)
D. Radiofrequency ablation

Explanation: ***DC shock*** - The ECG shows a **wide complex tachycardia** with alternating morphology in the QRS complex, consistent with **Torsades de Pointes**. - Given the patient's **unconsciousness** and **hypotension (80/60 mmHg)**, she is hemodynamically unstable, making immediate **electrical cardioversion (DC shock)** the treatment of choice irrespective of the cause. *Catheter Ablation* - **Catheter ablation** is an invasive procedure used for definitive treatment of recurrent arrhythmias, often considered in patients who are *hemodynamically stable*. - It is not an acute, emergency treatment for an **unstable patient** in a life-threatening arrhythmia. *Adenosine* - **Adenosine** is primarily used to terminate **supraventricular tachycardias (SVTs)** and can be harmful in wide complex tachycardias, especially if due to ventricular tachycardia or Wolff-Parkinson-White syndrome. - Its use is contraindicated in wide complex tachycardias like Torsades de Pointes, and it would not be effective in an **unstable patient** with Torsades de Pointes. *Radiofrequency ablation* - **Radiofrequency ablation** is a type of catheter ablation, which ablates or destroys abnormal electrical pathways in the heart. - Similar to other ablative therapies, it is a **definitive treatment** for recurrent arrhythmias in *stable patients*, not an emergency measure for an unconscious, hypotensive patient with an acute arrhythmia.

Question 5: 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.

Question 6: Which of the following is not used in controlling heart rate intraoperatively?

A. Verapamil
B. Esmolol
C. Propanolol/Metoprolol
D. Procainamide (Correct Answer)

Explanation: ***Procainamide*** - While an antiarrhythmic, **procainamide** is primarily used for the treatment of various *atrial* and *ventricular arrhythmias* and *Wolff-Parkinson-White syndrome*, not for heart rate control alone. - Its mechanism involves blocking sodium channels and some potassium channels, affecting myocardial excitability and conduction. *Verapamil* - **Verapamil** is a **non-dihydropyridine calcium channel blocker** frequently used intraoperatively to **slow heart rate** by acting on the sinoatrial and atrioventricular nodes. - It is effective in treating *supraventricular tachycardias* (SVT) and controlling ventricular rate in *atrial fibrillation* or *flutter*. *Esmolol* - **Esmolol** is a **short-acting, cardioselective beta-1 adrenergic blocker** that is often administered intraoperatively due to its rapid onset and offset of action. - It is used to quickly **decrease heart rate** and blood pressure, particularly in response to surgical stress or in cases of *supraventricular tachycardia*. *Propranolol/Metoprolol* - **Propranolol** (non-selective) and **Metoprolol** (cardioselective) are **beta-adrenergic blockers** commonly used to **reduce heart rate** and myocardial oxygen demand. - They are effective in managing *tachycardia*, *hypertension*, and preventing *myocardial ischemia* during surgery.

Question 7: Drug that does not cause cardiac depression:

A. Thiopentone
B. Ketamine
C. Propofol
D. Etomidate (Correct Answer)

Explanation: ***Etomidate*** - Etomidate is known for its **cardiovascular stability**, making it a preferred induction agent in patients with **compromised cardiac function**. - It maintains **myocardial contractility** and does not typically cause a significant drop in blood pressure. *Thiopentone* - Thiopentone causes **dose-dependent myocardial depression** and peripheral vasodilation. - This can lead to a significant **decrease in blood pressure** and cardiac output, especially in hypovolemic patients. *Propofol* - Propofol is a potent **vasodilator** and can cause significant **myocardial depression**, leading to hypotension. - Its cardiovascular effects are often more pronounced than those of other induction agents, necessitating careful titration. *Ketamine* - Ketamine causes indirect cardiovascular stimulation (due to **sympathetic nervous system activation**), but direct myocardial depression. - While it often increases heart rate and blood pressure, this is a compensatory mechanism and its direct effect on the myocardium is depressant.

Question 8: The most sensitive and practical technique for detection of myocardial ischemia in the perioperative period is -

A. Direct measurement of end diastolic pressure
B. Radio labeled lactate determination
C. Magnetic Resonance Spectroscopy
D. Regional wall motion abnormality detected with the help of 2D transoesophageal echocardiography (Correct Answer)

Explanation: ***Regional wall motion abnormality detected with the help of 2D transesophageal echocardiography*** - **Transesophageal echocardiography (TEE)** provides high-resolution images of the heart, allowing for the sensitive detection of **regional wall motion abnormalities (RWMA)**, an early and practical indicator of myocardial ischemia in the perioperative setting. - The development of new or worsening RWMA is often the **first sign of ischemia**, preceding ECG changes or hemodynamic alterations, making it a highly sensitive and clinically useful tool. *Direct measurement of end-diastolic pressure* - While an elevated **end-diastolic pressure** can indicate ventricular dysfunction, it is an **indirect sign** and not specific enough for early myocardial ischemia detection. - This measurement often requires invasive monitoring, which is less practical for routine detection compared to TEE. *Radio-labeled lactate determination* - **Lactate production** can increase in ischemic tissue, but its detection is a **biochemical marker** that typically lags behind the onset of ischemia. - This technique is generally **research-oriented** and not a practical, bedside method for rapid perioperative ischemia detection. *Magnetic Resonance Spectroscopy* - **Magnetic Resonance Spectroscopy (MRS)** can provide detailed metabolic information about tissue, including changes related to ischemia. - However, it is a **complex, time-consuming, and expensive imaging modality** that is not practical for routine, real-time perioperative monitoring of myocardial ischemia.

Question 9: Which block is described as regional anesthesia of the arm:-

A. Interscalene block
B. Infraclavicular block
C. Axillary block
D. Supraclavicular brachial plexus block (Correct Answer)

Explanation: ***Supraclavicular brachial plexus block*** - The **supraclavicular block** targets the **trunks of the brachial plexus** as they exit the scalene muscles, providing comprehensive anesthesia to the entire upper limb, including the shoulder, arm, forearm, and hand. - This block is particularly effective for procedures involving the arm due to its proximal location within the brachial plexus, covering multiple nerve distributions. *Interscalene block* - An **interscalene block** primarily targets the **roots or trunks of the brachial plexus** and is typically used for shoulder and upper arm surgery, but may spare the ulnar nerve. - While it anesthetizes the arm, it is primarily chosen for more proximal procedures and may not provide complete distal arm anesthesia compared to the supraclavicular approach. *Infraclavicular block* - An **infraclavicular block** targets the **cords of the brachial plexus** and is suitable for procedures involving the elbow, forearm, and hand, providing good coverage for these areas. - While it does anesthetize the distal arm, it is more distal than the supraclavicular block and may not provide full coverage for the entire upper arm and shoulder. *Axillary block* - An **axillary block** targets the **terminal branches of the brachial plexus** in the axilla, mainly anesthetizing the forearm and hand. - This block is often used for procedures distal to the elbow and provides less comprehensive coverage for the entire upper arm and shoulder compared to more proximal blocks.

Question 10: Which of the following is NOT a treatment for supraventricular tachycardia with hypotension in a patient under general anesthesia?

A. Carotid sinus massage
B. Adenosine 3-12 mg IV
C. Direct current cardioversion
D. Verapamil 5 mg IV (Correct Answer)

Explanation: ### Explanation The management of intraoperative supraventricular tachycardia (SVT) depends primarily on the patient's **hemodynamic stability**. **1. Why Verapamil is the Correct Answer (The "NOT" treatment):** In a patient with SVT and **hypotension** (hemodynamic instability), calcium channel blockers like Verapamil are **contraindicated**. Verapamil has potent negative inotropic and vasodilator properties. Administering it to a hypotensive patient can cause a further drop in systemic vascular resistance and myocardial contractility, potentially leading to cardiovascular collapse or cardiac arrest. **2. Analysis of Other Options:** * **Direct Current (DC) Cardioversion (Option C):** This is the **treatment of choice** for any tachyarrhythmia causing hemodynamic instability (hypotension, altered mentation, or pulmonary edema) under general anesthesia. Synchronized cardioversion (starting at 50-100J) provides immediate rhythm correction. * **Adenosine (Option B):** If the patient is unstable but IV access is immediately available, Adenosine (6mg, then 12mg) can be attempted as it has an ultra-short half-life and may terminate the reentry circuit without prolonged hemodynamic depression. * **Carotid Sinus Massage (Option A):** This is a non-invasive vagal maneuver that can be attempted quickly to increase vagal tone and slow AV node conduction while preparing for cardioversion. **Clinical Pearls for NEET-PG:** * **Unstable Tachycardia:** Always choose **Synchronized DC Cardioversion**. * **Stable SVT:** First-line is Vagal maneuvers, followed by Adenosine (Drug of Choice). * **Verapamil Warning:** Never give Verapamil in wide-complex tachycardias of unknown origin or in patients with WPW syndrome + Atrial Fibrillation, as it can lead to ventricular fibrillation. * **Amiodarone:** Preferred for stable ventricular tachycardia or refractory SVT.

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