Cardiology — MCQs

Cardiology Indian Medical PG Practice Questions and MCQs

Question 991: QT prolongation is seen in all of the following conditions except?

A. Digitalis toxicity (Correct Answer)
B. Hypokalemia
C. Hypocalcemia
D. Jervell syndrome

Explanation: The correct answer is **Digitalis toxicity**. In clinical practice and for NEET-PG, it is crucial to distinguish between drugs that prolong the QT interval and those that shorten it. **1. Why Digitalis Toxicity is the correct answer:** Digitalis (Digoxin) acts by inhibiting the Na+/K+ ATPase pump. Its characteristic effect on the EKG is **shortening of the QT interval**. Other classic digitalis effects include the "reverse tick" or "scooped-out" ST-segment depression and T-wave inversion. Therefore, it does not cause QT prolongation. **2. Analysis of incorrect options (Conditions that DO prolong QT):** * **Hypokalemia:** Low potassium levels lead to delayed repolarization, which manifests as a prominent U-wave and an apparent prolongation of the QT interval (often called the QU interval). [2, 3] * **Hypocalcemia:** Calcium is responsible for the plateau phase (Phase 2) of the cardiac action potential. Low calcium levels prolong this phase, leading to a lengthened ST segment and a prolonged QT interval. (Note: Hypercalcemia shortens the QT). * **Jervell and Lange-Nielsen Syndrome:** This is a congenital long QT syndrome (LQTS) inherited in an autosomal recessive pattern. It is characterized by a very long QT interval and associated sensorineural deafness. **Clinical Pearls for NEET-PG:** * **Mnemonic for QT Prolongation:** "The **ABCDE** of QT prolongation" – **A**ntiarrhythmics (Class IA, III), **B**iotics (Macrolides, Quinolones), **C**ychotics (Haloperidol), **D**epressants (TCAs), and **E**lectrolytes (Hypo-K, Hypo-Mg, Hypo-Ca). * **Complication:** The most feared complication of a prolonged QT interval is **Torsades de Pointes**, a polymorphic ventricular tachycardia. [1] * **Romano-Ward Syndrome:** Another congenital LQTS, but it is autosomal dominant and lacks deafness.

Question 992: A pacemaker is indicated in which of the following conditions?

A. Acute myocardial infarction with first-degree atrioventricular block
B. Acute myocardial infarction with fascicular block
C. Sick sinus syndrome (Correct Answer)
D. Sick sinus syndrome

Explanation: The primary indication for permanent pacemaker (PPM) implantation is **symptomatic bradycardia** resulting from either Sinus Node Dysfunction (Sick Sinus Syndrome) or high-grade Atrioventricular (AV) conduction disturbances [1]. **Why Sick Sinus Syndrome (SSS) is correct:** SSS is a collection of disorders characterized by the inability of the sinoatrial node to perform its pacemaking function. It often manifests as sinus bradycardia, sinus arrest, or tachycardia-bradycardia syndrome. A pacemaker is indicated in SSS when the bradycardia is **symptomatic** (causing syncope, dizziness, or exercise intolerance) or when essential medications (like beta-blockers) cause profound symptomatic bradycardia [1]. **Why the other options are incorrect:** * **Acute MI with First-degree AV block:** This is generally a benign, transient finding during the acute phase of an MI and does not require a pacemaker unless it progresses to higher degrees of block. * **Acute MI with Fascicular block:** Isolated fascicular blocks (e.g., LAFB or LPFB) or even bifascicular blocks in the setting of an acute MI do not routinely require a permanent pacemaker unless accompanied by symptomatic high-degree AV block (Type II Second-degree or Third-degree block). **High-Yield Clinical Pearls for NEET-PG:** * **Most common indication for PPM:** Sick Sinus Syndrome is the leading cause of permanent pacemaker implantation worldwide. * **Mobitz Type II and 3rd-degree AV block:** These are "class I" indications for a pacemaker, even if the patient is asymptomatic, due to the high risk of sudden cardiac death [1]. * **Reversible causes:** Always rule out reversible causes of bradycardia (hyperkalemia, digoxin toxicity, or hypothyroidism) before considering a permanent pacemaker. * **Tachy-Brady Syndrome:** This is a subset of SSS where the patient requires a pacemaker to prevent bradycardia, which then allows for the safe use of anti-arrhythmic drugs to control the tachycardia [1]. Pacemakers are also essential for patients with chronotropic incompetence who can't increase their heart rate during exercise [2].

Question 993: Automated external defibrillators are used for which cardiac rhythm?

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

Explanation: **Explanation:** Automated External Defibrillators (AEDs) are portable electronic devices designed to treat life-threatening cardiac arrhythmias that lead to sudden cardiac arrest [1]. **Why Ventricular Fibrillation (VF) is Correct:** The primary function of a defibrillator is to deliver a high-energy electrical shock to the heart. This shock simultaneously depolarizes the entire myocardium, momentarily stopping all electrical activity. This "reset" allows the heart’s natural pacemaker (the SA node) to re-establish a functional, organized rhythm. AEDs are specifically programmed to recognize two "shockable" rhythms: 1. **Ventricular Fibrillation (VF):** Disorganized electrical activity with no effective ventricular contraction [2]. 2. **Pulseless Ventricular Tachycardia (pVT):** Rapid, organized ventricular rhythm that fails to produce a pulse [1]. **Why Other Options are Incorrect:** * **Atrial Fibrillation (AF) and Atrial Flutter:** These are supraventricular arrhythmias. While they can be treated with "cardioversion" (synchronized shocks), they are not immediately life-threatening in the context of sudden cardiac arrest [3]. AEDs are designed to ignore these rhythms to prevent unnecessary shocks. * **Supraventricular Tachycardia (SVT):** This is an organized rhythm originating above the ventricles. It requires synchronized cardioversion or pharmacological intervention (e.g., Adenosine), not the unsynchronized high-energy shock provided by an AED. **High-Yield Clinical Pearls for NEET-PG:** * **Non-Shockable Rhythms:** Asystole and Pulseless Electrical Activity (PEA) are **not** shockable [1]. The management for these is high-quality CPR and Epinephrine. * **Time is Tissue:** For every minute defibrillation is delayed, the probability of survival declines by 7–10% [1]. * **Safety:** Always ensure "All Clear" before delivering a shock to prevent accidental provider injury.

Question 994: What does displacement of the cardiac apex towards the left and downwards indicate?

A. Right ventricular hypertrophy
B. Left ventricular hypertrophy (Correct Answer)
C. Right atrial hypertrophy
D. Left atrial hypertrophy

Explanation: ### Explanation The cardiac apex (apex beat) is normally located in the **left 5th intercostal space**, just medial to the midclavicular line. Its position and character are vital clinical indicators of cardiac chamber size and function. **1. Why Left Ventricular Hypertrophy (LVH) is correct:** In LVH, particularly when associated with **ventricular dilatation** (volume overload), the left ventricle expands both laterally and inferiorly [1]. Because the left ventricle forms the anatomical apex of the heart, its enlargement pushes the apex beat **downwards (to the 6th or 7th intercostal space) and laterally (left of the midclavicular line)** [1]. This is often described as a "heaving" or "sustained" apex beat in NEET-PG questions [1]. **2. Why the other options are incorrect:** * **Right Ventricular Hypertrophy (RVH):** RVH typically causes a **left parasternal heave** [1]. While it may displace the apex beat laterally by pushing the LV backward, it does **not** displace it downwards; in some cases of RV dilatation, it may even displace the apex upwards [2]. * **Right Atrial Hypertrophy (RAH):** RAH does not significantly alter the position of the apex beat; it is usually identified on ECG (P-pulmonale) or by a prominent 'a' wave in the JVP. * **Left Atrial Hypertrophy (LAH):** LAH (often seen in mitral stenosis) does not displace the apex. In fact, in pure mitral stenosis with LAH, the apex beat remains in its normal position but may become "tapping" in quality [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Tapping Apex:** Suggests Mitral Stenosis (palpable S1) [1]. * **Heaving/Sustained Apex:** Suggests Pressure Overload (e.g., Aortic Stenosis, Hypertension) [1]. * **Hyperdynamic/Ill-sustained Apex:** Suggests Volume Overload (e.g., Mitral Regurgitation, Aortic Regurgitation) [1]. * **Double Apical Impulse:** Characteristic of Hypertrophic Obstructive Cardiomyopathy (HOCM).

Question 995: A 40-year-old male presents with headache and convulsions. His blood pressure is 210/140 mm Hg. Fundus examination reveals papilledema. Which one of the following drug combinations is suitable for this patient?

A. Diazoxide + Triamterene
B. Nitroprusside + Triamterene
C. Nitroprusside + Furosemide (Correct Answer)
D. None of the above

Explanation: ### Explanation **Clinical Diagnosis:** The patient presents with a **Hypertensive Emergency** (BP >180/120 mm Hg with target organ damage). The presence of headache, convulsions (hypertensive encephalopathy), and papilledema (Grade IV hypertensive retinopathy) necessitates immediate, controlled reduction of blood pressure using intravenous agents [1]. **Why Option C is Correct:** * **Sodium Nitroprusside:** It is a potent, rapid-acting balanced vasodilator (arteriolar and venous). It is a gold-standard drug for hypertensive emergencies because its effect is instantaneous and easily titratable [1]. * **Furosemide:** Nitroprusside causes significant sodium and water retention (pseudotolerance) and can increase intracranial pressure. A loop diuretic like Furosemide is added to counteract fluid retention, enhance the hypotensive effect, and manage potential cerebral edema. **Why Other Options are Incorrect:** * **Option A & B (Triamterene):** Triamterene is a weak, potassium-sparing diuretic. It is insufficient for the rapid diuresis required in an acute hypertensive crisis and is typically used for chronic hypertension management. * **Option A (Diazoxide):** While Diazoxide is a potent vasodilator, it often causes reflex tachycardia and significant fluid retention. It has largely been replaced by safer agents like Nitroprusside, Labetalol, or Nicardipine due to its long half-life and lack of titratability. **High-Yield Clinical Pearls for NEET-PG:** * **Goal of Therapy:** Reduce Mean Arterial Pressure (MAP) by no more than **20–25% within the first hour** to prevent cerebral ischemia. * **Drug of Choice (General):** Sodium Nitroprusside or Labetalol [1]. * **Drug of Choice in Aortic Dissection:** Nitroprusside + Esmolol (Beta-blocker must be given first to prevent reflex tachycardia). * **Nitroprusside Toxicity:** Prolonged use can lead to **Cyanide/Thiocyanate toxicity**. The antidote is Sodium Thiosulfate. * **Contraindication:** Avoid Nitroprusside in pregnancy (risk of fetal cyanide poisoning); use Hydralazine or Labetalol instead.

Question 996: What is the most common cause of a mycotic aneurysm?

A. Candida albicans
B. Treponema pallidum
C. Staphylococcus aureus (Correct Answer)
D. Pseudomonas aeruginosa

Explanation: **Explanation:** A **mycotic aneurysm** is a misnomer; it refers to an infected arterial wall leading to a localized dilation, regardless of whether the pathogen is fungal or bacterial. These typically arise from hematogenous seeding (often due to infective endocarditis), direct extension from a nearby infection, or trauma [2]. **1. Why Staphylococcus aureus is correct:** *Staphylococcus aureus* is the **most common** causative organism overall [3]. Its high virulence allows it to easily adhere to and destroy the arterial wall, especially in the setting of intravenous drug use (IVDU) or bacteremia [2], [3]. *Salmonella* species are the second most common cause, particularly in patients with pre-existing atherosclerotic plaques. **2. Analysis of Incorrect Options:** * **Candida albicans:** While "mycotic" implies a fungal origin, true fungal causes are rare. They typically occur in severely immunocompromised patients or as a complication of cardiac surgery. * **Treponema pallidum:** This causes **Syphilitic (Luetic) Aneurysms**, which primarily involve the ascending aorta (obliterative endarteritis of the vasa vorum). It is a chronic inflammatory process, not an acute "mycotic" infection. * **Pseudomonas aeruginosa:** This is a common cause in specific subsets, such as IVDU or post-surgical infections, but it does not surpass the incidence of *S. aureus*. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** The femoral artery (due to IVDU) or the abdominal aorta. * **Most common cause of Syphilitic Aneurysm:** *Treponema pallidum* (affects the ascending aorta). * **Most common cause of Abdominal Aortic Aneurysm (AAA):** Atherosclerosis [1]. * **Classic Presentation:** A painful, pulsatile mass associated with fever and leukocytosis. * **Gold Standard Diagnosis:** CT Angiography.

Question 997: All of the following are features seen in cardiac tamponade, EXCEPT:

A. Raised JVP
B. Pericardial effusion
C. Rapid y descent (Correct Answer)
D. Pulsus paradoxus

Explanation: In cardiac tamponade, the heart is compressed by fluid within the pericardial space, leading to an equalization of diastolic pressures in all four cardiac chambers [1]. ### Why "Rapid y descent" is the correct answer: The **'y' descent** in the Jugular Venous Pulse (JVP) represents the opening of the tricuspid valve and the rapid filling of the right ventricle from the right atrium. In cardiac tamponade, the high intrapericardial pressure is transmitted to the heart throughout the cardiac cycle. This prevents rapid ventricular filling during early diastole. Consequently, the **'y' descent is either absent or blunted**. *Note: A "rapid/prominent y descent" is a hallmark of Constrictive Pericarditis (Friedreich’s sign), not tamponade.* [2] ### Explanation of other options: * **A. Raised JVP:** This is a classic finding (part of Beck’s Triad) due to the heart's inability to accommodate venous return because of external compression. * **B. Pericardial effusion:** Tamponade is a clinical diagnosis resulting from the accumulation of fluid (effusion) that increases intrapericardial pressure [1]. * **D. Pulsus paradoxus:** Defined as an inspiratory drop in systolic BP >10 mmHg. It occurs due to exaggerated ventricular interdependence (the septum shifts toward the left ventricle during inspiration). ### High-Yield Clinical Pearls for NEET-PG: * **Beck’s Triad:** Hypotension, Raised JVP, and Muffled Heart Sounds. * **JVP Pattern:** In Tamponade, you see a **prominent 'x' descent** but an **absent/blunted 'y' descent**. * **ECG Findings:** Low voltage complexes and **Electrical Alternans** (swinging heart) [1]. * **Treatment:** Immediate ultrasound-guided pericardiocentesis [1].

Question 998: What is the recommended number of drugs and diuretics for managing resistant hypertension when the goal is not achieved?

A. Four drugs plus diuretics
B. Two drugs plus diuretics
C. Three drugs plus diuretics (Correct Answer)
D. Five drugs plus diuretics

Explanation: **Explanation:** **Resistant Hypertension (RH)** is defined as blood pressure that remains above goal despite the concurrent use of **three antihypertensive drug classes**, commonly including a Long-acting Calcium Channel Blocker (CCB), an ACE inhibitor or ARB, and a **Diuretic** [1]. All drugs must be administered at maximum tolerated doses. 1. **Why Option C is Correct:** According to the AHA/ACC and ESC guidelines, the standard definition of resistant hypertension involves a three-drug regimen. If the target BP is not achieved with these three agents (which must include a diuretic), the next step in management is the addition of a **fourth drug**, typically a Mineralocorticoid Receptor Antagonist (MRA) like Spironolactone [1]. Therefore, the condition itself is defined by the failure of **three drugs plus a diuretic** (or the requirement of four or more drugs to achieve control) [1]. 2. **Why Other Options are Incorrect:** * **Option B (Two drugs):** This is considered "uncontrolled hypertension" but does not meet the criteria for "resistant," as many patients require a triple-drug combination for initial control. * **Options A & D (Four/Five drugs):** These represent the *treatment* phase of resistant hypertension. If a patient requires four or more drugs to reach their goal, they are categorized as having "controlled resistant hypertension." **High-Yield Clinical Pearls for NEET-PG:** * **Pseudo-resistance:** Always rule out "White coat hypertension" or non-compliance before diagnosing RH [1]. * **Drug of Choice (4th line):** **Spironolactone** is the most effective add-on drug for resistant hypertension (PATHWAY-2 trial). * **Commonest Secondary Cause:** Primary Aldosteronism and Obstructive Sleep Adea (OSA) are frequently implicated in resistant cases. * **Chlorthalidone/Indapamide:** These are preferred over Hydrochlorothiazide in RH due to their longer half-life and superior potency.

Question 999: Which of the following is not seen in Mitral Valve Prolapse (MVP)?

A. Transient ischemic attack
B. Infective endocarditis
C. Premature ventricular contractions
D. Defect in type IV collagen (Correct Answer)

Explanation: Mitral Valve Prolapse (MVP), also known as Barlow’s syndrome, is characterized by the displacement of an abnormally thickened mitral valve leaflet into the left atrium during systole. [1] **1. Why Option D is the Correct Answer:** The underlying pathology in MVP is **myxomatous degeneration** of the valve leaflets. This is associated with a defect in **Type I and Type III collagen**, not Type IV. Type IV collagen is primarily found in basement membranes (e.g., Alport syndrome). In MVP, there is an accumulation of dermatan sulfate and a fragmentation of collagen fibers within the *stratum spongiosa* of the valve, leading to its characteristic "floppy" nature. **2. Analysis of Incorrect Options:** * **A. Transient Ischemic Attack (TIA):** MVP is a recognized risk factor for systemic embolization. Fibrin-platelet microemboli can form on the damaged surface of the prolapsing leaflets, leading to TIAs or strokes. * **B. Infective Endocarditis (IE):** The structural abnormality and resultant mitral regurgitation create turbulent blood flow, which predisposes the valve to bacterial seeding. * **C. Premature Ventricular Contractions (PVCs):** Arrhythmias are common in MVP. Patients often present with palpitations due to PVCs or paroxysmal supraventricular tachycardias, likely due to the stretching of papillary muscles. **Clinical Pearls for NEET-PG:** * **Auscultation:** Characterized by a **Mid-systolic click** followed by a **Late systolic murmur**. [1] * **Dynamic Auscultation:** Maneuvers that decrease preload (Standing, Valsalva) make the click/murmur occur **earlier** and louder. * **Associations:** Strongly associated with connective tissue disorders like **Marfan syndrome** and **Ehlers-Danlos syndrome**. * **Most Common Cause:** MVP is the most common cause of isolated mitral regurgitation in developed countries.

Question 1000: What is the most common cause of aortic dissection?

A. Syphilis
B. Hypertension (Correct Answer)
C. Marfan syndrome
D. Cystic medial necrosis

Explanation: ### Explanation **Correct Answer: B. Hypertension** **Why Hypertension is the Correct Answer:** Hypertension is the **most common overall risk factor** for aortic dissection, present in 70–80% of all cases [1]. Chronic high blood pressure leads to mechanical stress on the aortic wall, causing intimal thickening, fibrosis, and degeneration of the vasa vasorum. This results in **hyaline arteriosclerosis** and weakening of the media, which predisposes the aorta to an intimal tear [1]. While it is the leading cause in older patients, it remains the most frequent cause statistically across the general population. **Analysis of Incorrect Options:** * **C. Marfan Syndrome:** This is the most common cause of aortic dissection in **younger patients** (typically <40 years) due to a mutation in the FBN1 gene [1]. While high-yield, it is less common than hypertension in the general population. * **D. Cystic Medial Necrosis:** This is the characteristic **histopathological finding** associated with aortic dissection (especially in Marfan syndrome), involving the loss of smooth muscle cells and elastic tissue. It is a *pathological process* rather than the primary *clinical cause*. * **A. Syphilis:** Tertiary syphilis typically causes **obliterative endarteritis** of the vasa vasorum, leading to **Aortic Aneurysms** (specifically of the ascending aorta) rather than dissection. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site of tear:** Just distal to the left subclavian artery (Stanford Type B) or the ascending aorta (Stanford Type A) [1]. * **Classic Presentation:** Sudden onset "tearing" or "ripping" chest pain radiating to the back [1]. * **Chest X-ray:** Look for **mediastinal widening** (most common finding). * **Gold Standard Investigation:** CT Angiography (stable patients) [2] or Transesophageal Echocardiogram (unstable patients) [2]. * **Management:** Beta-blockers (e.g., Labetalol) are the first-line medical treatment to reduce heart rate and "shear stress" (dP/dt).

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