Cardiology Practice Questions

Q: In which of the following types of cardiac arrest is DC counter shock the only definitive treatment?

Ventricular fibrillation. ### Explanation In cardiac arrest management, rhythms are categorized into **Shockable** and **Non-shockable** rhythms. **1. Why Ventricular Fibrillation (VF) is correct:** Ventricular Fibrillation is a "shockable" rhythm characterized by chaotic, disorganized electrical activity that prevents coordinated ventricular contraction [1]. The underlying medical concept is **defibrillation**: the DC counter shock delivers a high-energy current that simultaneously depolarizes the entire myocardium [2]. This "resets" the heart, allowing the natural pacemaker (SA node) to regain control and re-establish a perfusing rhythm [3]. Without this electrical reset, VF is almost always fatal. [2] **2. Why other options are incorrect:** * **Asystole (Option A):** This is a "non-shockable" rhythm representing the total absence of electrical activity ("flatline") [1]. Shocking an empty electrical system is ineffective and can cause further myocardial damage. Treatment focuses on high-quality CPR and Epinephrine. * **Electromechanical Dissociation / PEA (Option B):** Pulseless Electrical Activity (PEA) occurs when the ECG shows a rhythm (organized electrical activity), but there is no mechanical contraction or pulse. Since the electrical system is already "organized," a shock will not help. Treatment involves identifying reversible causes (the 5 H’s and 5 T’s). **Clinical Pearls for NEET-PG:** * **Shockable Rhythms:** Ventricular Fibrillation (VF) and Pulseless Ventricular Tachycardia (pVT) [1]. * **Non-Shockable Rhythms:** Asystole and PEA [1]. * **Energy Levels:** For Biphasic defibrillators, the standard initial dose is **120–200 Joules**; for Monophasic, it is **360 Joules**. * **Time is Tissue:** For every minute defibrillation is delayed in VF, the chance of survival drops by 7–10% [1].

Q: Which of the following diseases can be associated with a short QT interval on ECG?

Multiple myeloma. The correct answer is **Multiple Myeloma**. The underlying medical concept linking Multiple Myeloma to a short QT interval is **Hypercalcemia**. 1. **Why Multiple Myeloma is correct:** Multiple myeloma is a plasma cell dyscrasia characterized by extensive osteolytic bone lesions [1]. These lesions release calcium into the bloodstream, leading to hypercalcemia. On an ECG, hypercalcemia causes a shortening of the ST segment, which results in a **shortened QT interval**. This occurs because high extracellular calcium levels accelerate phase 2 (plateau phase) of the cardiac action potential, leading to faster repolarization. 2. **Why the other options are incorrect:** * **Chronic Myeloid Leukemia (CML), Chronic Lymphocytic Leukemia (CLL), and Hodgkin’s Disease:** While these are hematological malignancies, they are not classically associated with the profound, bone-resorption-driven hypercalcemia seen in Multiple Myeloma. While any advanced malignancy can cause hypercalcemia of malignancy (usually via PTHrP), Multiple Myeloma is the "textbook" association for this electrolyte abnormality in the context of ECG changes. **High-Yield Facts for NEET-PG:** * **Short QT Interval Causes:** Hypercalcemia, Hyperkalemia [2], Digoxin toxicity, and Congenital Short QT Syndrome. * **Long QT Interval Causes:** Hypocalcemia, Hypokalemia [2], Hypomagnesemia, and drugs (Class IA and III antiarrhythmics, Macrolides, TCAs). * **Formula:** The QT interval must be corrected for heart rate using **Bazett’s Formula** ($QTc = QT / \sqrt{RR}$). * **Clinical Pearl:** In hypercalcemia, the "shortening" specifically involves the ST segment; the T-wave duration usually remains normal.

Q: Which of the following is NOT TRUE regarding ECG changes in hyperkalemia?

Peaked P-wave. In hyperkalemia, the sequence of ECG changes follows a predictable pattern based on increasing serum potassium levels [1]. **Explanation of the Correct Answer:** **Option A (Peaked P-wave)** is the correct answer because it is **NOT** seen in hyperkalemia. In fact, as potassium levels rise, the P-wave becomes **flattened** and eventually disappears (atrial standstill) due to the paralysis of the atrial myocardium [1]. Peaked P-waves (P-pulmonale) are instead characteristic of right atrial enlargement. **Explanation of Incorrect Options:** * **Option B (Peaked T-wave):** This is the earliest sign of hyperkalemia (typically $K^+ > 5.5$ mEq/L). These are "tall, tented" T-waves with a narrow base, best seen in precordial leads [1]. * **Option D (Broad QRS complex):** As potassium levels exceed 6.5 mEq/L, intraventricular conduction slows, leading to a widening of the QRS complex [1]. This can eventually merge with the T-wave. * **Option C (Sinusoidal shape complex):** This is a late, pre-terminal finding (typically $K^+ > 8.0$ mEq/L). The widened QRS merges with the T-wave to form a "sine wave" pattern, indicating imminent ventricular fibrillation or asystole [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Sequence of Changes:** Tall T-waves $→$ PR prolongation → Loss of P-wave → Wide QRS → Sine wave → VF/Asystole. * **Treatment Priority:** If ECG changes are present, the first step is **Calcium Gluconate** (10 ml of 10%) to stabilize the cardiac membrane, though it does not lower serum potassium. * **Pseudohyperkalemia:** Always rule out hemolysis during blood collection if ECG is normal despite high lab values.

Q: Blood pressure is difficult to measure in a patient with which of the following conditions?

Atrial fibrillation. The correct answer is Atrial Fibrillation (AF). In Atrial Fibrillation, the heart rhythm is "irregularly irregular" due to disorganized electrical activity in the atria. This leads to varying ventricular filling times (variable diastole) and inconsistent stroke volumes from beat to beat [1]. Consequently, the systolic blood pressure fluctuates significantly with every pulse. When using a sphygmomanometer, the Korotkoff sounds appear and disappear at different pressure levels, making it technically difficult to pinpoint a single, accurate systolic or diastolic value. In clinical practice, an average of multiple readings is often required. Analysis of Incorrect Options: * Mitral Stenosis (A): While it may lead to a low pulse pressure or trigger AF as a complication, the rhythm itself remains regular unless AF develops. BP measurement is generally straightforward. * Aortic Stenosis (B): This condition typically presents with a "pulsus parvus et tardus" (small and slow rise pulse) and a narrow pulse pressure, but the rhythm remains regular, allowing for consistent BP measurement [2]. * Complete Heart Block (C): Although the heart rate is slow (bradycardia), the ventricular rhythm is usually regular (driven by a stable escape rhythm). This results in a consistent, often wide pulse pressure that is easy to measure. High-Yield Clinical Pearls for NEET-PG: * Pulse Deficit: In AF, the difference between the apical heart rate and the radial pulse rate is called the pulse deficit (usually >10 bpm), occurring because some beats have insufficient stroke volume to open the aortic valve or reach the periphery. * Auscultatory Gap: This is a period of silence between systolic and diastolic pressures often seen in hypertensive patients; it can lead to underestimation of systolic BP. * Gold Standard: For patients with highly irregular rhythms like AF, invasive intra-arterial blood pressure monitoring remains the most accurate method.

Q: What is the most common symptom of orthostatic hypotension?

Lightheadedness. **Explanation:** **Orthostatic Hypotension (OH)** is defined as a sustained reduction in systolic blood pressure of at least **20 mmHg** or diastolic blood pressure of at least **10 mmHg** within 3 minutes of standing [1]. The correct answer is **Lightheadedness** because it is the direct clinical manifestation of transient **cerebral hypoperfusion**. When a person stands, gravity causes 500–1000 mL of blood to pool in the lower extremities. In OH, the compensatory sympathetic response fails, leading to a drop in cardiac output and a temporary decrease in blood flow to the brain, most commonly perceived as lightheadedness or "faintness" [2]. **Analysis of Incorrect Options:** * **A. Vertigo:** This is a sensation of spinning or motion. It usually indicates vestibular dysfunction (inner ear or brainstem) rather than global cerebral hypoperfusion [2]. * **C. Palpitations:** While a compensatory tachycardia (Postural Orthostatic Tachycardia Syndrome - POTS) may cause palpitations, it is a secondary sign rather than the primary symptomatic complaint of OH. * **D. Blurred vision:** This occurs due to ischemia of the retina or occipital lobe, but it typically follows lightheadedness as the severity of hypotension increases. **High-Yield Clinical Pearls for NEET-PG:** * **The "Coat-Hanger" Headache:** A unique symptom of OH involving pain in the neck and shoulders due to ischemia of the trapezius and neck muscles. * **Diagnosis:** Always measure BP in both supine (after 5 mins rest) and standing (at 1 and 3 mins) positions [1]. * **Common Causes:** Dehydration (most common), drugs (alpha-blockers, diuretics), and autonomic failure (Diabetes Mellitus, Parkinson’s disease, Multiple System Atrophy). * **Management:** First-line treatment is non-pharmacological (increased salt/fluid, compression stockings). Pharmacotherapy includes **Fludrocortisone** (volume expansion) or **Midodrine** (alpha-1 agonist) [1].

Question 1

In which of the following types of cardiac arrest is DC counter shock the only definitive treatment?

Accepted Answer

Ventricular fibrillation

Answer

Asystole

Answer

Electromechanical dissociation

Answer

All of the above

Question 2

Which of the following diseases can be associated with a short QT interval on ECG?

Accepted Answer

Multiple myeloma

Answer

Chronic myeloid leukemia

Answer

Chronic lymphocytic leukemia

Answer

Hodgkin's disease

Question 3

Which of the following is NOT TRUE regarding ECG changes in hyperkalemia?

Accepted Answer

Peaked P-wave

Answer

Peaked T-wave

Answer

Sinusoidal shape complex

Answer

Broad QRS complex

Question 4

Blood pressure is difficult to measure in a patient with which of the following conditions?

Accepted Answer

Atrial fibrillation

Answer

Mitral stenosis

Answer

Aortic stenosis

Answer

Complete heart block

Question 5

A patient with heart failure developed ventricular arrhythmia. What is/are the appropriate treatment(s)?

Accepted Answer

Flecainide

Answer

Encainide

Answer

Intracardiac Defibrillation

Answer

Beta-blockers

Question 6

Which of the following is NOT a cause of myocarditis?

Accepted Answer

Mycobacterium tuberculosis

Answer

Trichiasis

Answer

Corynebacterium diptheriae

Answer

Systemic Lupus Erythematosus (SLE)

Question 7

A 50-year-old patient presents with features of poor perfusion following myocardial infarction. On examination, the heart rate is 40/min with a blood pressure of 60 mmHg systolic. Atropine was given twice over 5 minutes, but the patient's condition is not improving. What is the next best step?

Accepted Answer

Transcutaneous pacing

Answer

Transvenous pacing

Answer

Implantable cardioverter-defibrillator

Answer

Repeat atropine

Question 8

What is the most common symptom of orthostatic hypotension?

Accepted Answer

Lightheadedness

Answer

Vertigo

Answer

Palpitations

Answer

Blurred vision

Question 9

Pulses paradoxus can be seen in which of the following clinical states?

Accepted Answer

Acute myocardial infarction

Answer

Pericardial tamponade

Answer

Acute severe asthma

Answer

COPD

Question 10

In congestive cardiac failure (CCF), which of the following is typically observed?

Accepted Answer

Oliguria

Answer

Polyuria

Answer

Oliguria during the day and polyuria during the night

Answer

Anuria

Cardiology — MCQs

Cardiology — MCQs

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