Cardiology Practice Questions

Q: Comment on the diagnosis?

Myocardial infarction. ***Myocardial infarction*** - **ST elevation** in multiple leads with **pathological Q waves** are classic ECG findings indicating **acute myocardial infarction** with full-thickness myocardial damage. - **Reciprocal changes** in opposite leads further support the diagnosis of **STEMI** with localized coronary artery occlusion. *Prinzmetal angina* - Characterized by **transient ST elevation** during vasospastic episodes that **resolves completely** between attacks. - **No pathological Q waves** develop as there is no permanent myocardial damage or necrosis. *Pulmonary embolism* - ECG typically shows **S1Q3T3 pattern** with **right heart strain** features like right axis deviation. - May show **T wave inversions in V1-V4** and **incomplete RBBB**, not the ST elevation pattern seen here. *Hyperkalemia* - ECG shows **peaked T waves**, **widened QRS complexes**, and **flattened P waves** in severe cases. - Advanced hyperkalemia may progress to a **sine wave pattern**, completely different from the acute coronary syndrome changes.

Q: J waves are typically seen in which of the following conditions?

Hypothermia. Explanation: J waves, also known as Osborn waves, are positive deflections occurring at the junction between the QRS complex and the ST segment (the J-point). 1. Why Hypothermia is Correct: Hypothermia is the classic cause of J waves. They typically appear when the core body temperature drops below 32°C (90°F). The physiological basis involves a temperature-sensitive gradient between the epicardium and endocardium during early ventricular repolarization, leading to a prominent notch at the J-point. The size of the J wave often correlates with the severity of the hypothermia. 2. Why Incorrect Options are Wrong: * Hyperthermia: Does not cause J waves; it is more commonly associated with sinus tachycardia or nonspecific ST-T changes [1]. * Hypokalemia: Characterized by U waves, flattened T waves, and ST-segment depression. * Hyperkalemia: Classically presents with tall, peaked "tented" T waves, widened QRS complexes, and loss of P waves [1]. 3. NEET-PG High-Yield Pearls: * Other causes of J waves: Hypercalcemia, Brugada syndrome, and early repolarization syndrome (normal variant). * ECG Triad of Hypothermia: 1. Sinus bradycardia (most common arrhythmia). 2. J waves (Osborn waves). 3. Prolonged PR, QRS, and QT intervals. * Artifact Alert: Shivering in hypothermic patients can cause a baseline artifact on ECG that mimics atrial flutter. * Management: Treatment focuses on active/passive rewarming rather than anti-arrhythmics, as J waves resolve with normalization of temperature.

Q: What is considered a wide QRS duration?

Greater than 0.12 seconds. ### Explanation The QRS complex represents **ventricular depolarization**. In a healthy heart, electrical impulses travel rapidly through the specialized His-Purkinje system, ensuring synchronous ventricular contraction. **1. Why 0.12 seconds is correct:** A normal QRS duration is typically between **0.06 and 0.10 seconds** (1.5 to 2.5 small squares). A duration of **≥ 0.12 seconds** (3 small squares) is the standard diagnostic threshold for a **"Wide QRS."** This delay indicates that ventricular depolarization is occurring slowly, usually because the impulse is traveling through the working myocardium rather than the rapid conduction system [1]. **2. Why the other options are incorrect:** * **Options A and B (0.8 and 0.9 seconds):** These values are physiologically impossible for a single QRS complex. A duration of 0.8 seconds would mean a single heartbeat takes nearly a full second just to depolarize the ventricles, which is incompatible with life. These options likely confuse *seconds* with *milliseconds* (e.g., 80ms or 90ms), which fall within the normal range. * **Option D:** Since A and B are incorrect, "All the above" is invalid. **Clinical Pearls for NEET-PG:** * **Differential Diagnosis of Wide QRS:** 1. **Bundle Branch Blocks (RBBB/LBBB):** The most common cause. 2. **Ventricular Ectopy:** Premature Ventricular Contractions (PVCs) or Ventricular Tachycardia (VT) [2]. 3. **Pre-excitation:** Wolff-Parkinson-White (WPW) syndrome (due to the Delta wave) [1]. 4. **Metabolic/Toxic:** Hyperkalemia (classic "sine wave" appearance) or Sodium Channel Blocker toxicity (e.g., TCA overdose) [3]. 5. **Pacemaker-induced** rhythms. * **High-Yield Tip:** In the setting of tachycardia, a wide QRS should be considered **Ventricular Tachycardia** until proven otherwise [2].

Q: What is the most common infection in patients with prosthetic valves?

Staphylococcus. The most common cause of Prosthetic Valve Endocarditis (PVE) is **Staphylococcus**. The etiology is further divided based on the timing of the infection post-surgery: 1. **Early PVE ( 1 year post-surgery):** The microbiology begins to resemble native valve endocarditis, where **Staphylococcus aureus** and Viridans group Streptococci are the most frequent isolates [2]. Since both early and late phases are dominated by different species of the same genus, **Staphylococcus** is the overall correct answer. **Analysis of Incorrect Options:** * **Pneumococcus (Streptococcus pneumoniae):** While a cause of native valve endocarditis (historically part of Osler’s triad), it is an uncommon cause of prosthetic valve infections [2]. * **Pseudomonas:** This is a Gram-negative organism occasionally seen in intravenous drug users (IVDU) or healthcare-associated infections, but it is not the most common overall. * **Enterococci:** These are the third most common cause of PVE (after Staphylococci and Streptococci), often associated with urinary tract manipulations or gastrointestinal procedures [2]. **Clinical Pearls for NEET-PG:** * **Most common overall cause of Endocarditis (Native Valve):** *Staphylococcus aureus* (previously Viridans Streptococci) [2]. * **Most common cause in IV drug users:** *Staphylococcus aureus* (often involving the Tricuspid valve) [2]. * **Culture-negative Endocarditis:** Most commonly due to prior antibiotic use or fastidious organisms like the **HACEK** group or *Coxiella burnetii*. * **Streptococcus bovis (S. gallolyticus):** If found in endocarditis, always screen the patient for **Colorectal Carcinoma** [2].

Q: What is the treatment of choice for congestive heart failure with hypertension?

ACE inhibitors. **Explanation:** **ACE inhibitors (ACEIs)** are the treatment of choice for patients with coexisting congestive heart failure (CHF) and hypertension [1]. The underlying medical concept is their ability to provide **balanced vasodilation** (reducing both preload and afterload) and, more importantly, to inhibit the **Renin-Angiotensin-Aldosterone System (RAAS)** [2]. By blocking Angiotensin II, ACEIs prevent cardiac remodeling and fibrosis, which are key drivers of heart failure progression [2]. They are one of the few drug classes proven to **reduce mortality** in CHF [1]. **Why other options are incorrect:** * **Alpha-blockers:** These are not first-line for CHF. While they lower blood pressure, they can cause reflex tachycardia and fluid retention, potentially worsening heart failure symptoms. * **Calcium Channel Blockers (CCBs):** Non-dihydropyridines (Verapamil/Diltiazem) are contraindicated in CHF due to their negative inotropic effects. While Amlodipine is safe, it does not provide the mortality benefits seen with ACEIs. * **Nitrates:** These are primarily venodilators (reducing preload) [3]. While useful in acute heart failure or in combination with Hydralazine (especially in specific populations), they are not the primary first-line monotherapy for managing chronic CHF with hypertension [3]. **High-Yield Clinical Pearls for NEET-PG:** * **First-line triad for HFrEF:** ACEIs (or ARBs/ARNIs), Beta-blockers, and Aldosterone antagonists [1]. * **Side Effects:** Watch for **dry cough** (due to bradykinin accumulation) and **angioedema**. If a cough develops, switch the patient to an ARB (Losartan). * **Contraindications:** ACEIs are strictly contraindicated in **pregnancy** (teratogenic) and **bilateral renal artery stenosis**.

Q: A patient develops sudden palpitation with a heart rate of 150 beats per minute, which is regular. What could be the cause?

Paroxysmal supraventricular tachycardia (PSVT). ### Explanation **1. Why PSVT is the Correct Answer:** The clinical hallmark of **Paroxysmal Supraventricular Tachycardia (PSVT)** is a sudden onset and termination of palpitations [1]. In PSVT (most commonly AVNRT), the heart rate typically ranges between **140–220 bpm** and is characteristically **regular** [1]. The "sudden" nature described in the question points toward a re-entrant mechanism rather than a gradual physiological response, which involves two pathways with different conducting properties [2]. **2. Analysis of Incorrect Options:** * **Sinus Tachycardia:** While regular, it usually has a gradual onset and offset (not sudden). It is typically a physiological response to stress, fever, or exercise, and rarely exceeds 150 bpm in a resting adult. * **Ventricular Tachycardia (VT):** Although regular, VT usually presents in patients with structural heart disease or prior MI [3]. While it can cause palpitations, PSVT is a more common cause of a regular rate of exactly 150 bpm in a stable, "sudden onset" scenario unless hemodynamic instability is mentioned. * **Atrial Flutter with Block:** Atrial flutter typically has an atrial rate of 300 bpm. With a 2:1 conduction block, the ventricular rate is exactly **150 bpm**. However, the "sudden" paroxysmal onset in a general clinical vignette most classically refers to PSVT. **3. NEET-PG High-Yield Pearls:** * **Vagal Maneuvers:** The first-line treatment for stable PSVT (Carotid sinus massage or Valsalva). * **Drug of Choice:** **Adenosine** (6mg IV rapid bolus) is the DOC for terminating acute PSVT. * **ECG Findings:** Narrow QRS complex, regular rhythm, and P-waves often buried within or following the QRS complex [1]. * **Definitive Treatment:** Radiofrequency ablation of the slow pathway.

Question 1

Which of the following conditions are typically associated with a continuous murmur?

Accepted Answer

Patent ductus arteriosus with reversal of shunt

Answer

Aortic stenosis combined with aortic regurgitation

Answer

Systemic arteriovenous fistula

Answer

Aortopulmonary window

Question 2

Comment on the diagnosis?

Accepted Answer

Myocardial infarction

Answer

Prinzmetal angina

Answer

Pulmonary embolism

Answer

Hyperkalemia

Question 3

J waves are typically seen in which of the following conditions?

Accepted Answer

Hypothermia

Answer

Hyperthermia

Answer

Hypokalemia

Answer

Hyperkalemia

Question 4

Regarding Wolf-Parkinson-White (WPW) syndrome, which of the following statements is incorrect?

Accepted Answer

Type a is seen in association with Ebstein's anomaly.

Answer

There is a risk of ventricular tachycardia.

Answer

Presentation may be with hydrops fetalis.

Answer

Flecainide reduces the recurrence risk of tachycardias.

Question 5

What is considered a wide QRS duration?

Accepted Answer

Greater than 0.12 seconds

Answer

Greater than 0.8 seconds

Answer

Greater than 0.9 seconds

Answer

All the above

Question 6

A 68-year-old man presents with progressive shortness of breath. He had a metallic heart valve replacement 13 years ago for severe aortic stenosis. Which of the following clinical findings is most indicative of a failing aortic valve replacement?

Accepted Answer

Early diastolic murmur heard at the left sternal edge

Answer

Clicking sound to S2

Answer

New onset atrial fibrillation

Answer

Ejection systolic murmur heard in the aortic region

Question 7

What is the most common infection in patients with prosthetic valves?

Accepted Answer

Staphylococcus

Answer

Pneumococcus

Answer

Pseudomonas

Answer

Enterococci

Question 8

Which of the following is associated with atherosclerosis?

Accepted Answer

Chlamydia pneumoniae

Answer

Chlamydia trachomatis

Answer

Chlamydia psittaci

Answer

Chlamydia gingivalis

Question 9

What is the treatment of choice for congestive heart failure with hypertension?

Accepted Answer

ACE inhibitors

Answer

Alpha-blockers

Answer

Calcium channel blockers

Answer

Nitrates

Question 10

A patient develops sudden palpitation with a heart rate of 150 beats per minute, which is regular. What could be the cause?

Accepted Answer

Paroxysmal supraventricular tachycardia (PSVT)

Answer

Sinus tachycardia

Answer

Ventricular tachycardia

Answer

Atrial flutter with block

Cardiology — MCQs

Cardiology — MCQs

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