Cardiology Practice Questions

Q: All of the following may occur due to hypokalemia, except?

Prolonged QRS Interval. Hypokalemia (Serum $K^+ < 3.5$ mEq/L) causes characteristic ECG changes primarily by delaying ventricular repolarization and increasing myocardial excitability. **Why "Prolonged QRS Interval" is the correct answer:** In hypokalemia, the QRS complex typically remains **normal in duration**, though it may show a slight increase in amplitude. Significant QRS widening is a hallmark of **Hyperkalemia** (due to slowed intraventricular conduction), not hypokalemia [1]. Therefore, this is the "except" option. **Analysis of other options:** * **Prolonged PR Interval:** Hypokalemia slows conduction through the AV node, which can lead to a prolonged PR interval and, in severe cases, AV blocks [1]. * **Prolonged QT Interval (Pseudo-prolongation):** This is a classic NEET-PG trap. Hypokalemia causes **T-wave flattening** and the appearance of prominent **U-waves**. As the T and U waves fuse, it creates the illusion of a prolonged QT interval, often referred to as a **prolonged QU interval**. * **Ventricular Asystole:** Severe hypokalemia increases the risk of life-threatening arrhythmias, including Ventricular Tachycardia, Torsades de Pointes, and eventually ventricular fibrillation or asystole. **High-Yield Clinical Pearls for NEET-PG:** 1. **Sequence of ECG changes in Hypokalemia:** T-wave flattening/inversion → ST-segment depression → Prominent U-waves (best seen in V2-V4) → Apparent QT prolongation (QU interval). 2. **Digoxin Toxicity:** Hypokalemia potentiates the effects of Digoxin, increasing the risk of arrhythmias even at "normal" therapeutic levels. 3. **Hyperkalemia Mnemonic:** "Tall T, Wide QRS, Flat P" (Tall peaked T-waves are the earliest sign) [1].

Q: Which medication should be administered to a patient with congestive heart failure and a left ventricular ejection fraction (LVEF) less than 40%?

ACE inhibitor + beta-blocker. ### Explanation **Core Concept: Mortality Benefit in HFrEF** In patients with Heart Failure with reduced Ejection Fraction (HFrEF, LVEF <40%), the primary goal of pharmacological therapy is to block the maladaptive neurohormonal activation (Renin-Angiotensin-Aldosterone System and Sympathetic Nervous System) that leads to cardiac remodeling [1]. **ACE inhibitors (ACEIs)** and **Beta-blockers** are the foundational "disease-modifying" agents proven to reduce mortality and hospitalization in these patients [1], [2]. **Analysis of Options:** * **Option A (Correct):** ACEIs reduce afterload and prevent remodeling, while Beta-blockers (specifically Carvedilol, Metoprolol succinate, or Bisoprolol) prevent catecholamine-induced cardiotoxicity [2]. Together, they form the cornerstone of Guideline-Directed Medical Therapy (GDMT). * **Option B:** Furosemide (a loop diuretic) is excellent for symptomatic relief of congestion (edema/dyspnea) but has **no proven mortality benefit** [1]. * **Option C:** Non-dihydropyridine Calcium Channel Blockers (Verapamil/Diltiazem) are generally **avoided** in HFrEF due to their negative inotropic effects, which can worsen heart failure [3]. * **Option D:** Combining an ACEI and an ARB is generally avoided due to the increased risk of adverse effects like hyperkalemia and renal dysfunction without significant added survival benefit. **NEET-PG High-Yield Pearls:** 1. **The "Big Four" of HFrEF:** Current guidelines recommend a quadruple therapy to reduce mortality: **ARNI** (Sacubitril/Valsartan) or ACEI/ARB + **Beta-blocker** + **MRA** (Spironolactone) + **SGLT2 Inhibitor** (Dapagliflozin). 2. **Beta-blocker Initiation:** Never start a beta-blocker during an *acute* decompensation; the patient must be stable and "dry" (euvolemic). 3. **Contraindication:** ACEIs are strictly contraindicated in pregnancy and bilateral renal artery stenosis.

Q: The murmur of hypertrophic obstructive cardiomyopathy is decreased in which of the following positions or maneuvers?

Supine position. **Explanation:** The murmur of **Hypertrophic Obstructive Cardiomyopathy (HOCM)** is a harsh systolic ejection murmur [1] caused by dynamic left ventricular outflow tract (LVOT) obstruction. The intensity of this murmur depends on the **Left Ventricular (LV) volume**: * **Decreased LV Volume** (less blood) → Increases obstruction → **Louder murmur.** * **Increased LV Volume** (more blood) → Decreases obstruction → **Softer murmur.** **1. Why Supine Position is Correct:** When a patient moves from a standing to a **supine position**, there is an increase in venous return to the heart (increased preload). This increases the LV end-diastolic volume, which pushes the hypertrophied septum away from the mitral valve, widening the outflow tract and **decreasing the murmur intensity.** **2. Why the Other Options are Incorrect:** * **Standing Position:** Decreases venous return (preload), leading to a smaller LV cavity and an **increase** in murmur intensity. * **Valsalva Maneuver (Strain phase):** Increases intrathoracic pressure, which decreases venous return to the heart. This reduces LV volume and **increases** the murmur. * **Amyl Nitrite Inhalation:** This is a potent vasodilator that decreases systemic vascular resistance (afterload). Lower afterload facilitates faster ejection and smaller LV volume, thereby **increasing** the murmur. **Clinical Pearls for NEET-PG:** * **The "Rule of Two":** HOCM and Mitral Valve Prolapse (MVP) are the only two murmurs that get **louder** with standing and Valsalva. All other murmurs generally get softer. * **Handgrip Exercise:** Increases afterload, which pushes the septum away and **decreases** the HOCM murmur (unlike most other systolic murmurs). * **Squatting:** Increases both preload and afterload, significantly **decreasing** the HOCM murmur.

Q: Which of the following is true about the pain of pericarditis?

Pain increases during inspiration. The correct answer is **C. Pain increases during inspiration.** ### **Explanation of the Correct Answer** The pain of acute pericarditis is typically **pleuritic** in nature. This occurs because the inflamed parietal pericardium is in close contact with the adjacent pleura. During inspiration, the lungs expand and the diaphragm moves downward, causing the inflamed layers to rub against each other or the pleura. This friction triggers sharp, stabbing pain [2]. Additionally, the phrenic nerve (which supplies the pericardium) can be irritated, often leading to pain radiation to the trapezius ridge [2]. ### **Analysis of Incorrect Options** * **A & B (Positional Changes):** Pericarditic pain is characteristically **positional**. It **decreases** (improves) when the patient leans forward (tripod position) because this pulls the heart away from the adjacent pleura and reduces tension on the pericardium. Conversely, the pain **increases** (worsens) in the **supine position** due to gravity-induced pressure on the parietal pericardium [2]. * **D (Eating):** Pain related to eating is more characteristic of gastrointestinal issues (like GERD or peptic ulcers). While swallowing (odynophagia) can occasionally aggravate pericarditis due to the esophagus's proximity to the posterior heart, it is not a classic diagnostic feature like pleuritic pain. ### **High-Yield Clinical Pearls for NEET-PG** * **ECG Findings:** Look for **diffuse ST-segment elevation** (concave upwards/saddle-shaped) and **PR-segment depression** (the most specific early sign) [1]. * **Physical Exam:** The pathognomonic sign is a **Pericardial Friction Rub**, best heard with the diaphragm at the left lower sternal border while the patient leans forward. * **Treatment:** First-line therapy includes **NSAIDs (High dose)** plus **Colchicine** (to prevent recurrence) [1]. Steroids are reserved for refractory cases or specific etiologies.

Q: What is the most common cause of native valve endocarditis?

Staphylococcus aureus. **Explanation:** The epidemiology of Infective Endocarditis (IE) has shifted significantly in recent decades. **Staphylococcus aureus** is now the most common cause of native valve endocarditis (NVE) worldwide, particularly in developed nations. This shift is attributed to the rise in healthcare-associated infections, intravenous drug use (IVDU), and the increased use of invasive procedures. *S. aureus* is highly virulent, capable of infecting healthy valves, and often leads to rapid valvular destruction and systemic embolization. **Analysis of Options:** * **Streptococcus (Option C):** Historically, *Streptococcus viridans* was the leading cause of NVE. While it remains a major cause (especially in patients with pre-existing valvular disease or poor dental hygiene), it has been surpassed by *S. aureus* in overall frequency. * **Coagulase-negative staphylococci (CoNS) (Option B):** These (e.g., *S. epidermidis*) are the most common cause of **Prosthetic Valve Endocarditis (PVE)**, particularly within the first year of surgery, but are less common in native valves. * **Enterococcus (Option D):** These are the third most common cause of IE, typically associated with older men undergoing genitourinary or gastrointestinal procedures. **High-Yield Clinical Pearls for NEET-PG:** * **IV Drug Users:** *S. aureus* is the most common cause, frequently involving the **Tricuspid valve**. * **Subacute IE:** Most commonly caused by *Streptococcus viridans*. * **Culture-Negative IE:** Most common cause is prior antibiotic therapy; otherwise, consider the **HACEK** group or *Coxiella burnetii*. * **Streptococcus bovis (S. gallolyticus):** If isolated, always perform a **colonoscopy** to rule out colorectal malignancy.

Q: What are the ECG changes of hypomagnesemia?

Increased QT interval. **Explanation:** Hypomagnesemia often coexists with other electrolyte imbalances (hypokalemia and hypocalcemia) and shares similar ECG features. The hallmark of hypomagnesemia is **prolongation of the QT interval**. This occurs because magnesium acts as a natural calcium channel blocker and cofactor for the Na+/K+-ATPase pump; its deficiency leads to delayed ventricular repolarization, thereby increasing the QT interval. This is clinically significant as it predisposes patients to **Torsades de Pointes**, a life-threatening polymorphic ventricular tachycardia [1]. **Analysis of Options:** * **A. Decreased QT interval:** This is incorrect. Shortening of the QT interval is typically seen in **hypercalcemia** and hypermagnesemia (though rare). * **B. Increased QT interval (Correct):** As explained, magnesium deficiency delays repolarization, lengthening the QT interval [1]. * **C. Greatly increased PT interval:** This is incorrect. The PT (Prothrombin Time) is a coagulation parameter, not an ECG finding. If referring to the **PR interval**, hypomagnesemia actually causes PR prolongation, but QT prolongation is the more classic association. * **D. Tall T waves:** This is incorrect. Tall, peaked T waves are the classic sign of **hyperkalemia**. In hypomagnesemia, T waves are more likely to be flattened or inverted. **High-Yield NEET-PG Pearls:** 1. **The "Magnesium-Potassium" Link:** Refractory hypokalemia cannot be corrected until hypomagnesemia is treated first. 2. **ECG Summary:** Look for prolonged QT, PR prolongation, ST-segment depression, and T-wave flattening/inversion. 3. **Drug of Choice:** Intravenous Magnesium Sulfate is the treatment of choice for Torsades de Pointes, even if serum magnesium levels are normal [1].

Q: Which of the following conditions is most likely to cause these ECG changes?

Hypokalemia. ***Hypokalemia*** - **Hypokalemia** causes characteristic ECG changes including **prominent U waves**, **flattened or inverted T waves**, and **ST segment depression** with prolonged **QU interval**. - These changes occur due to altered **cardiac repolarization** and increased risk of **ventricular arrhythmias**, particularly **torsades de pointes**. *Hyponatremia* - **Hyponatremia** primarily affects the **central nervous system** causing confusion, seizures, and cerebral edema. - It does not produce specific **ECG changes** and cardiac manifestations are rare unless severe. *Hypernatremia* - **Hypernatremia** mainly causes **neurological symptoms** like altered mental status, hyperreflexia, and seizures. - It has **no characteristic ECG findings** and primarily affects cellular dehydration rather than cardiac conduction. *Hyperkalemia* - **Hyperkalemia** causes distinctly different ECG changes including **peaked T waves**, **widened QRS complexes**, and **flattened P waves**. - Severe cases show **sine wave pattern** and can lead to **asystole**, contrasting with hypokalemia's U wave prominence.

Q: Which of the following can NOT be used to treat peripheral arterial disease?

Sildenafil. **Explanation:** Peripheral Arterial Disease (PAD) is characterized by atherosclerotic narrowing of the peripheral arteries, leading to claudication and limb ischemia [1]. The management focuses on risk factor modification, exercise, and improving blood flow. **Why Sildenafil is the Correct Answer:** Sildenafil is a **Phosphodiesterase-5 (PDE-5) inhibitor** primarily used for erectile dysfunction and pulmonary arterial hypertension. While it causes vasodilation, it has **no proven clinical efficacy** in improving walking distance or reducing symptoms in patients with PAD. Therefore, it is not a standard of care for this condition. **Analysis of Other Options:** * **Cilostazol:** A **Phosphodiesterase-3 (PDE-3) inhibitor** with antiplatelet and vasodilatory properties. It is the **first-line pharmacological treatment** for symptomatic claudication as it significantly increases pain-free walking distance. * **Pentoxifylline:** A xanthine derivative that acts as a **rheologic modifier**. It reduces blood viscosity and improves erythrocyte flexibility, allowing better flow through stenosed vessels. It is a second-line agent compared to Cilostazol. * **Percutaneous Angioplasty:** This is a standard **revascularization procedure** used for patients with lifestyle-limiting claudication or critical limb ischemia who do not respond to medical therapy [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Investigation for PAD:** Digital Subtraction Angiography (DSA). * **Best Initial Test:** Ankle-Brachial Index (ABI). An ABI **< 0.9** is diagnostic of PAD [1]. * **Cilostazol Contraindication:** It is strictly contraindicated in patients with **Heart Failure** of any severity (due to increased mortality associated with PDE-3 inhibitors). * **Smoking Cessation:** This is the most important modifiable risk factor to prevent disease progression.

Question 1

All of the following may occur due to hypokalemia, except?

Accepted Answer

Prolonged QRS Interval

Answer

Prolonged PR Interval

Answer

Prolonged QT Interval

Answer

Ventricular asystole

Question 2

Which medication should be administered to a patient with congestive heart failure and a left ventricular ejection fraction (LVEF) less than 40%?

Accepted Answer

ACE inhibitor + beta-blocker

Answer

ACE inhibitor + furosemide

Answer

ACE inhibitor + calcium channel blocker

Answer

ACE inhibitor + angiotensin II receptor blocker

Question 3

A 69-year-old man complains of chest tightness and shortness of breath after lifting boxes 3 hours ago. He perceives that his heart is skipping beats. His medical history is significant for hypertension and cigarette smoking. On examination, his heart rate is 50 beats/min and regular, and his lungs are clear to auscultation. An electrocardiogram shows bradycardia with an increased PR interval and ST-segment elevation in multiple leads including the anterior leads, V1 and V2. What anatomical structures are most likely affected?

Accepted Answer

Right coronary artery + Left anterior descending artery

Answer

Left main coronary artery

Answer

Left anterior descending artery

Answer

Right coronary artery + Left circumflex artery

Question 4

The murmur of hypertrophic obstructive cardiomyopathy is decreased in which of the following positions or maneuvers?

Accepted Answer

Supine position

Answer

Standing position

Answer

Valsalva maneuver

Answer

Amyl nitrite inhalation

Question 5

Which of the following is true about the pain of pericarditis?

Accepted Answer

Pain increases during inspiration

Answer

Pain increases on leaning forward

Answer

Pain decreases in supine position

Answer

Pain increases on eating

Question 6

What is the most common cause of native valve endocarditis?

Accepted Answer

Staphylococcus aureus

Answer

Coagulase-negative staphylococcus

Answer

Streptococcus

Answer

Enterococcus

Question 7

What are the ECG changes of hypomagnesemia?

Accepted Answer

Increased QT interval

Answer

Decreased QT interval

Answer

Greatly increased PT interval

Answer

Tall T waves

Question 8

A 72-year-old male presents with intermittent symptoms of dyspnea on exertion, palpitations, and occasional blood-streaked cough. Cardiac auscultation reveals a faint, low-pitched diastolic rumbling murmur heard best at the apex. What is the most probable underlying cause of the patient's symptoms?

Accepted Answer

Rheumatic fever during youth

Answer

Long-standing hypertension

Answer

Silent myocardial infarction within the past year

Answer

Congenital cardiac anomaly

Question 9

Which of the following conditions is most likely to cause these ECG changes?

Accepted Answer

Hypokalemia

Answer

Hyponatremia

Answer

Hypernatremia

Answer

Hyperkalemia

Question 10

Which of the following can NOT be used to treat peripheral arterial disease?

Accepted Answer

Sildenafil

Answer

Pentoxifylline

Answer

Cilostazol

Answer

Percutaneous angioplasty

Cardiology — MCQs

Cardiology — MCQs

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