Cardiology Practice Questions

Q: Which of the following represents the earliest ECG changes in a patient with Hypokalemia?

Flattening of T wave. **Explanation:** In hypokalemia, the resting membrane potential of cardiac myocytes becomes more negative, leading to delayed repolarization. The ECG changes follow a progressive, sequential pattern as serum potassium levels drop [1]. **Why "Flattening of T wave" is correct:** The **earliest** recognizable ECG change in hypokalemia is the **decrease in T-wave amplitude (flattening)**. As potassium levels fall below 3.0 mEq/L, the T-wave becomes progressively lower in voltage. This occurs before the prominent appearance of U waves or ST-segment depression. **Analysis of Incorrect Options:** * **C. Development of U wave:** While highly characteristic of hypokalemia, prominent U waves typically appear *after* the T-wave has started to flatten. The U wave is best seen in precordial leads (V2-V4). * **D. Fusion of TU waves:** This occurs in more severe hypokalemia. As the T-wave flattens and the U-wave grows, they eventually merge, often leading to a "pseudo-prolonged QT interval" (actually a QU interval). * **A. Pseudo-P-Pulmonale:** This refers to an increase in P-wave amplitude and duration. While it can occur in hypokalemia, it is a later finding compared to T-wave changes [1]. **High-Yield NEET-PG Pearls:** * **Sequence of Changes:** T-wave flattening → ST depression → Prominent U waves → TU fusion (QU prolongation). * **The "QU" Interval:** In hypokalemia, the QT interval appears prolonged, but it is actually the **QU interval** due to T and U wave fusion. * **Arrhythmias:** Hypokalemia predisposes patients to Digoxin toxicity and can trigger *Torsades de Pointes* due to the prolonged repolarization phase [1]. * **Differential:** Remember that **Hyperkalemia** presents with the opposite early change: Tall, peaked "tented" T-waves [1].

Q: A 58-year-old man with no prior cardiac history presents with retrosternal chest pain starting at rest and lasting 30 minutes. The pain radiates to the left arm and is associated with diaphoresis and dyspnea. His blood pressure is 150/90 mm Hg, pulse 100/min, the heart sounds are normal, and the lungs are clear to auscultation. Which of the following is the next most appropriate investigation?

Electrocardiogram (ECG). ### Explanation **1. Why the Correct Answer (D) is Right:** The patient presents with classic symptoms of **Acute Coronary Syndrome (ACS)**: retrosternal chest pain at rest, radiation to the left arm, diaphoresis, and dyspnea [1], [5]. In any patient with suspected ACS, the **Electrocardiogram (ECG)** is the most critical initial investigation. According to AHA/ESC guidelines, an ECG should be performed and interpreted within **10 minutes** of presentation. It is the primary tool used to triage patients into ST-Elevation Myocardial Infarction (STEMI) or Non-ST Elevation ACS (NSTE-ACS), which dictates immediate management (e.g., urgent reperfusion vs. stabilization) [2], [4]. **2. Why the Other Options are Wrong:** * **Cardiac Troponin (C):** While essential for diagnosing NSTEMI, troponins take 3–6 hours to rise significantly [3]. Waiting for lab results delays the diagnosis of a STEMI, which can be identified immediately on an ECG. * **Chest X-ray (B):** CXR is useful to rule out differential diagnoses like pneumonia or pneumothorax, but it is not the priority when an MI is suspected. It should be performed after the ECG. * **CT Scan - Chest (A):** This is indicated if aortic dissection or pulmonary embolism is strongly suspected. However, given the classic presentation of ACS, an ECG must always come first to rule out cardiac ischemia. **3. High-Yield Clinical Pearls for NEET-PG:** * **Door-to-ECG time:** Goal is <10 minutes. * **Gold Standard for STEMI:** Primary Percutaneous Coronary Intervention (PCI) within 90 minutes of medical contact. * **Silent MI:** Common in elderly, females, and diabetics; often presents with "anginal equivalents" like dyspnea or epigastric pain [5]. * **ECG Evolution:** Hyperacute T-waves → ST elevation → Q waves → T-wave inversion [4].

Q: A patient of myocardial infarction dies within the first few hours of infarction due to which of the following complications?

Cardiac failure. The correct answer is **Cardiac Failure**. **1. Why Cardiac Failure is correct:** In the immediate aftermath of an acute myocardial infarction (MI), the sudden loss of a significant portion of the ventricular myocardium leads to impaired systolic and diastolic function. This results in **acute left ventricular failure** and cardiogenic shock [1]. According to standard medical literature (including Harrison’s Principles of Internal Medicine), while arrhythmias are common, **cardiac failure remains the most common cause of death in patients who reach the hospital** and the leading cause of in-hospital mortality following an MI [3]. **2. Why the other options are incorrect:** * **Ventricular Fibrillation (VF):** This is the most common cause of **pre-hospital** death (sudden cardiac death) within the first hour of an MI [2]. However, in a clinical or hospital setting, cardiac failure is statistically the leading cause of mortality. * **Atrial Fibrillation:** While common post-MI due to atrial ischemia or stretch [4], it is rarely a direct cause of death; it primarily complicates the clinical course by causing hemodynamic instability. * **Cardiac Tamponade:** This typically occurs due to **ventricular free wall rupture**, which is a mechanical complication that usually manifests **3 to 7 days** after the infarction, not within the first few hours [1]. **Clinical Pearls for NEET-PG:** * **Most common cause of death (Overall/Pre-hospital):** Ventricular Fibrillation [2]. * **Most common cause of death (In-hospital):** Cardiac Failure/Cardiogenic Shock [3]. * **Most common arrhythmia in MI:** Ventricular Premature Complexes (VPCs). * **Timeframe for Myocardial Rupture:** 3–7 days (due to macrophage-mediated wall weakening) [1].

Question 1

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 2

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 3

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 4

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

Question 5

Which organism most commonly leads to infective endocarditis?

Accepted Answer

Staphylococcus aureus

Answer

Klebsiella

Answer

Streptococcus pneumoniae

Answer

Neisseria meningitidis

Question 6

A 65-year-old man with a long history of hypertension presents to the emergency department with tearing chest pain that radiates to the back. An electrocardiogram is normal, as are cardiac enzymes. A chest radiograph demonstrates widening of the mediastinum. What is the most likely diagnosis?

Accepted Answer

Dissecting aneurysm

Answer

Arteriovenous fistula

Answer

Atherosclerotic aneurysm

Answer

Syphilitic aneurysm

Question 7

A continuous murmur is found in all, except?

Accepted Answer

Mitral stenosis with mitral regurgitation

Answer

Patent ductus arteriosus

Answer

Rupture of sinus of Valsalva

Answer

Systemic arteriovenous fistula

Question 8

Which of the following represents the earliest ECG changes in a patient with Hypokalemia?

Accepted Answer

Flattening of T wave

Answer

Pseudo-P-Pulmonale

Answer

Development of U wave

Answer

Fusion of TU waves

Question 9

A 58-year-old man with no prior cardiac history presents with retrosternal chest pain starting at rest and lasting 30 minutes. The pain radiates to the left arm and is associated with diaphoresis and dyspnea. His blood pressure is 150/90 mm Hg, pulse 100/min, the heart sounds are normal, and the lungs are clear to auscultation. Which of the following is the next most appropriate investigation?

Accepted Answer

Electrocardiogram (ECG)

Answer

CT scan - chest

Answer

Chest X-ray (CXR)

Answer

Cardiac troponin

Question 10

A patient of myocardial infarction dies within the first few hours of infarction due to which of the following complications?

Accepted Answer

Cardiac failure

Answer

Ventricular fibrillation

Answer

Atrial fibrillation

Answer

Cardiac tamponade

Cardiology — MCQs

Cardiology — MCQs

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