Cardiology Practice Questions

Q: Reciprocal ST depression in leads V1-V3 is typically seen in which type of myocardial infarction?

Posterior wall MI. The correct answer is **Posterior wall MI**. This is a classic "mirror image" phenomenon in electrocardiography [1]. Because the standard 12-lead ECG does not have electrodes placed directly on the back, we must look for reciprocal changes in the anterior leads (V1-V3), which are positioned directly opposite the posterior wall [2], [3]. **Why Posterior MI is correct:** In a posterior MI, the injury current travels toward the back (away from V1-V3). This results in **ST depression** (the reciprocal of ST elevation) and **tall R waves** (the reciprocal of deep Q waves) in leads V1, V2, and V3. Think of V1-V3 as looking at the heart from the front; if the back is "elevated," the front appears "depressed." **Analysis of Incorrect Options:** * **Inferior wall MI:** Characterized by ST elevation in leads II, III, and aVF. Reciprocal changes are typically seen in lead aVL [1]. * **Anterior wall MI:** Characterized by ST elevation in leads V1-V4 [1], [2]. * **Lateral wall MI:** Characterized by ST elevation in leads I, aVL, V5, and V6. **NEET-PG High-Yield Pearls:** 1. **Confirmatory Test:** If you suspect a posterior MI based on ST depression in V1-V3, the next step is to perform a **Posterior ECG** using leads **V7, V8, and V9**. ST elevation ≥ 0.5 mm in these leads confirms the diagnosis. 2. **The "Flip Test":** If you flip the ECG paper upside down and look at V1-V3 in a mirror, the ST depression and tall R waves will look like a classic STEMI pattern. 3. **Artery Involved:** Most commonly caused by occlusion of the **Right Coronary Artery (RCA)** or the Left Circumflex Artery (LCx). 4. **Association:** Posterior MI often occurs concurrently with Inferior wall MI. Always check II, III, and aVF.

Q: In the treatment of severe bradycardia, all of the following can be the best modality of treatment except?

Diltiazem. **Explanation:** The goal in treating severe bradycardia is to increase the heart rate and improve cardiac output. **Diltiazem** is a non-dihydropyridine Calcium Channel Blocker (CCB) that acts as a negative chronotrope and negative dromotrope. It inhibits the influx of calcium ions into the sinoatrial (SA) and atrioventricular (AV) nodes, further slowing the heart rate and delaying conduction. Therefore, Diltiazem is **contraindicated** in bradycardia as it would worsen the condition and potentially lead to asystole. **Analysis of other options:** * **Atropine:** This is the **first-line drug** for symptomatic bradycardia. It is a muscarinic antagonist that blocks the vagal (parasympathetic) tone on the SA node, thereby increasing the heart rate. * **Pacing (Transcutaneous or Transvenous):** This is the **most definitive treatment** for severe, unstable bradycardia, especially if it is unresponsive to pharmacotherapy or caused by high-grade AV blocks (e.g., Mobitz II or 3rd-degree block). * **Isoproterenol:** This is a potent non-selective beta-adrenergic agonist ($\beta_1$ and $\beta_2$). By stimulating $\beta_1$ receptors in the heart, it exerts strong positive chronotropic and inotropic effects, making it a useful chemical "bridge" to pacing. **Clinical Pearls for NEET-PG:** * **Drug of choice for Bradycardia:** Atropine (0.5 mg IV, repeated up to 3 mg). * **Atropine Caution:** It may be ineffective or worsen bradycardia in patients with heart transplants (denervated heart) or high-grade AV blocks; pacing is preferred here. * **Diltiazem/Verapamil:** These are used for rate control in **Tachyarrhythmias** (like Atrial Fibrillation or PSVT), not bradycardia. * **Glucagon:** The specific antidote for bradycardia caused by Beta-blocker or CCB overdose.

Q: A patient presents with chest pain. Two days later, cardiac enzyme levels (CK and CK-MB) are within the normal range. Which of the following is true?

Excludes the diagnosis of myocardial infarction.. **Explanation:** The diagnosis of Myocardial Infarction (MI) relies on the detection of a rise and/or fall of cardiac biomarkers [2]. **CK-MB (Creatine Kinase-MB)** is a highly sensitive and specific marker for myocardial necrosis [2]. **1. Why Option A is Correct:** CK-MB begins to rise 4–6 hours after the onset of chest pain, peaks at **18–24 hours**, and typically returns to baseline within **48–72 hours (2–3 days)**. If a patient presents with chest pain and the CK-MB levels are measured two days later and found to be normal, it implies that no significant myocardial necrosis occurred during that window. Therefore, a normal CK-MB level at the 48-hour mark effectively excludes a diagnosis of MI that occurred two days prior. **2. Why Other Options are Incorrect:** * **Option B:** Reperfusion (either via PCI or thrombolysis) actually causes a **"washout phenomenon,"** leading to an earlier and higher peak of CK-MB, not a normal level. * **Option C:** While normal enzymes *can* occur in extracardiac pain, the clinical utility of the test in this context is specifically to rule out MI [3]. * **Option D:** Cardiac surgery typically **elevates** CK-MB due to direct surgical trauma to the myocardium [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Troponins (T and I):** The gold standard for MI. They stay elevated for **7–14 days**, making them better for late diagnosis. * **CK-MB:** The marker of choice for detecting **re-infarction** because it returns to normal quickly (within 3 days). * **Myoglobin:** The earliest marker to rise (1–3 hours) but lacks specificity. * **LDH:** Rises late and stays elevated for up to 2 weeks (historical marker).

Q: Severity of mitral regurgitation can be assessed by which of the following findings?

Presence of left ventricular S3 gallop. In Mitral Regurgitation (MR), the severity is determined by the volume of blood leaking back into the left atrium, which subsequently leads to volume overload of the Left Ventricle (LV). [1] ### **Why Option C is Correct** The **presence of a low-pitched S3 gallop** is the most reliable clinical indicator of **severe MR**. It occurs during the rapid filling phase of diastole. In severe MR, the massive volume of blood that leaked into the atrium during systole rushes back into the ventricle during diastole. [1] This sudden impact of a large volume of blood against a dilated, compliant LV wall creates the S3 sound. It signifies hemodynamically significant volume overload. ### **Why Other Options are Incorrect** * **A & B (Intensity and Duration):** The loudness (grade) of a pansystolic murmur correlates poorly with the severity of MR. A very loud murmur can be heard in mild MR if the orifice is small (high velocity), while a "silent" or soft murmur can occur in severe acute MR due to rapid equalization of pressures. * **D (Loud S1):** In chronic MR, the S1 is typically **soft or absent** because the mitral leaflets fail to appose properly or are structurally damaged. A loud S1 is a hallmark of Mitral Stenosis, not MR. ### **High-Yield Clinical Pearls for NEET-PG** * **Indicators of Severe MR:** 1. Presence of **S3 gallop**. [1] 2. **Mid-diastolic flow rumble** (due to increased flow across the mitral valve). [2] 3. **Early closure of A2** (leading to wide splitting of S2). 4. **Leftward displacement** of the apex beat (indicates LV enlargement). * **Murmur Character:** A classic pansystolic murmur radiating to the axilla. [1] If the posterior leaflet is involved, the murmur may radiate to the base of the heart/aorta.

Q: A 15-year-old boy presented in an unconscious state with diagnosed atrial fibrillation on ECG. He had similar episodes of syncope in the past. Lab studies revealed normal potassium and calcium levels, and normal CK-MB levels. The patient died of cardiac arrest. Previous ECGs showed undue abnormalities, and there was a history of sudden cardiac death in the family. What is the most likely genetic defect in this patient?

SCN5A. The clinical presentation of a young patient with recurrent syncope, atrial fibrillation (AF), and a family history of sudden cardiac death (SCD) strongly suggests an inherited primary arrhythmia syndrome. In pediatric and adolescent populations, the most common genetic link to familial atrial fibrillation and associated SCD is a mutation in the **SCN5A** gene. **1. Why SCN5A is correct:** The **SCN5A** gene encodes the **alpha subunit of the cardiac sodium channel (Nav1.5)**. Mutations in this gene are "pleiotropic," meaning they can cause various phenotypes, including: * **Brugada Syndrome:** Characterized by ST-segment elevation in V1-V3 and high risk of SCD. * **Long QT Syndrome Type 3 (LQT3):** Leading to torsades de pointes [1]. * **Familial Atrial Fibrillation:** SCN5A mutations are the most common genetic cause of lone AF in young patients. The combination of AF and SCD risk in a 15-year-old points directly to a sodium channelopathy. **2. Why other options are incorrect:** * **KCN5A:** While potassium channel genes (like KCNQ1 or KCNH2) are involved in Long QT syndrome, "KCN5A" is not a standard nomenclature for a major cardiac channel gene associated with this specific clinical triad. * **CCN5A & PCN5A:** These are distractors. They do not represent recognized cardiac ion channel genes associated with familial arrhythmia or sudden cardiac death. **Clinical Pearls for NEET-PG:** * **Brugada Syndrome:** Look for "Pseudo-right bundle branch block" and ST-elevation in V1-V3. It is a common cause of SCD in young males of Southeast Asian descent. * **Lone AF:** AF occurring in patients <60 years old without structural heart disease or hypertension [2]. * **SCN5A Summary:** Loss-of-function leads to Brugada/Conduction disease; Gain-of-function leads to LQT3.

Q: Wellen's syndrome suggests which of the following cardiac conditions?

Unstable angina. **Wellen’s Syndrome** is a clinical-electrocardiographic pattern highly specific for critical stenosis of the **proximal Left Anterior Descending (LAD) artery**. It is considered a pre-infarction stage of **Unstable Angina (UA)**. The underlying pathophysiology involves a sudden occlusion of the LAD followed by spontaneous reperfusion, leading to characteristic T-wave changes. Because the artery is critically narrowed but not permanently occluded, it falls under the spectrum of Acute Coronary Syndrome (specifically UA) [1], carrying a high risk of progressing to an extensive anterior wall myocardial infarction (STEMI) if not managed with urgent coronary intervention. **Analysis of Options:** * **Option A (Stable Angina):** This involves predictable chest pain on exertion due to fixed atherosclerotic plaques [2]. Wellen’s syndrome represents an acute, unstable situation with high risk of imminent infarction. * **Option C (Ludwig’s Angina):** This is a non-cardiac condition. It is a rapidly spreading cellulitis of the submandibular space, usually of odontogenic origin. * **Option D (Prinzmetal Angina):** Also known as variant angina, this is caused by coronary artery vasospasm rather than critical fixed stenosis. It typically presents with transient ST-segment elevation during pain, not the specific T-wave patterns of Wellen’s. **High-Yield Clinical Pearls for NEET-PG:** * **ECG Criteria:** Occurs during a **pain-free interval**. Look for biphasic T-waves (Type A) or deep, symmetrical T-wave inversions (Type B) in leads V2–V3. * **Cardiac Enzymes:** Usually normal or only minimally elevated. * **Management Warning:** Stress tests (Treadmill Test) are **contraindicated** as they can trigger a fatal MI. The definitive treatment is Cardiac Catheterization.

Question 1

Prophylactic antibiotic coverage before dental extraction is indicated for all the following conditions except:

Accepted Answer

Coronary artery bypass graft surgery

Answer

Kidney damage on hemodialysis

Answer

Prosthetic aortic valve

Answer

Rheumatic heart disease

Question 2

Reciprocal ST depression in leads V1-V3 is typically seen in which type of myocardial infarction?

Accepted Answer

Posterior wall MI

Answer

Inferior wall MI

Answer

Anterior wall MI

Answer

Lateral wall MI

Question 3

In the treatment of severe bradycardia, all of the following can be the best modality of treatment except?

Accepted Answer

Diltiazem

Answer

Atropine

Answer

Pacing

Answer

Isoproterenol

Question 4

A patient presents with chest pain. Two days later, cardiac enzyme levels (CK and CK-MB) are within the normal range. Which of the following is true?

Accepted Answer

Excludes the diagnosis of myocardial infarction.

Answer

Indicates reperfusion after myocardial infarction.

Answer

Suggests an extracardiac source of pain.

Answer

Is related to recent cardiac surgery.

Question 5

Severity of mitral regurgitation can be assessed by which of the following findings?

Accepted Answer

Presence of left ventricular S3 gallop

Answer

Intensity of murmur

Answer

Duration of murmur

Answer

Loud S1

Question 6

A 15-year-old boy presented in an unconscious state with diagnosed atrial fibrillation on ECG. He had similar episodes of syncope in the past. Lab studies revealed normal potassium and calcium levels, and normal CK-MB levels. The patient died of cardiac arrest. Previous ECGs showed undue abnormalities, and there was a history of sudden cardiac death in the family. What is the most likely genetic defect in this patient?

Accepted Answer

SCN5A

Answer

KCN5A

Answer

CCN5A

Answer

PCN5A

Question 7

What is the least common cause of endocarditis?

Accepted Answer

Atrial Septal Defect (ASD)

Answer

Patent Ductus Arteriosus (PDA)

Answer

Tetralogy of Fallot (TOF)

Answer

Ventricular Septal Defect (VSD)

Question 8

Wellen's syndrome suggests which of the following cardiac conditions?

Accepted Answer

Unstable angina

Answer

Stable angina

Answer

Ludwig's angina

Answer

Prinzmetal angina

Question 9

A patient with mitral regurgitation and atrial fibrillation presents with syncope. On examination, the patient has a heart rate of 55. What is the most probable cause?

Accepted Answer

Digitalis toxicity

Answer

Incomplete heart block

Answer

Stroke

Answer

Subarachnoid hemorrhage

Question 10

What is the treatment of choice in patients with congestive heart failure with ejection fraction < 40% and normal fluid levels achieved?

Accepted Answer

ACE inhibitors + Beta blockers

Answer

ACE inhibitors + Diuretics

Answer

ACE inhibitors + ARBs

Answer

ACE inhibitors + CCBs

Cardiology — MCQs

Cardiology — MCQs

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