Cardiology — MCQs
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Which condition is associated with a left axis deviation of -30° to -60°?
In Marfan's syndrome, Aortic aneurysm occurs most commonly in:
In which condition is paradoxical splitting of the second heart sound observed?
Which biomarker is typically elevated in the plasma of patients with chronic heart disease?
What is a characteristic finding in athletes' hearts, also known as athletic syndrome?
Which study is known for identifying major coronary risk factors?
Which of the following complications is commonly associated with mitral valve prolapse?
What is the most common cause of dissecting hematoma?
All of the following statements about the third heart sound (S3) are true, except:
Which components of cigarette smoke are known to contribute to coronary artery disease?
Cardiology Indian Medical PG Practice Questions and MCQs
Question 1551: Which condition is associated with a left axis deviation of -30° to -60°?
- A. Left ventricular hypertrophy (LVH) (Correct Answer)
- B. Right ventricular hypertrophy (RVH)
- C. Aortic stenosis (AS)
- D. Left atrial enlargement (LAE)
Explanation: ***Left ventricular hypertrophy (LVH)*** - **Left ventricular hypertrophy** often leads to an increased mass of the left ventricle, causing the electrical axis to shift leftward, potentially resulting in **left axis deviation** between -30° and -90° [1]. - The electrical activity generated by the hypertrophied left ventricle dominates, pulling the mean QRS vector towards the **left and inferior direction** [1]. *Right ventricular hypertrophy (RVH)* - **Right ventricular hypertrophy** typically causes a **right axis deviation**, pushing the electrical axis beyond +90° [1]. - The increased muscle mass of the right ventricle pulls the electrical vector towards the **right and inferior direction**. *Aortic stenosis (AS)* - While **aortic stenosis** can *cause* **left ventricular hypertrophy** due to increased afterload, it is not the direct ECG finding. LVH is the direct ECG manifestation. - The primary ECG change in AS is often **LVH**, which consequently leads to **left axis deviation**, but AS itself is a valvular disease. *Left atrial enlargement (LAE)* - **Left atrial enlargement** primarily affects the P wave, causing changes such as a **notched P wave (P mitrale)** or a prolonged P wave duration. - While LAE can occur with conditions that cause LVH, it does not directly lead to **left axis deviation** of the QRS complex.
Question 1552: In Marfan's syndrome, Aortic aneurysm occurs most commonly in:
- A. Ascending aorta (Correct Answer)
- B. Descending aorta
- C. Abdominal aorta
- D. Arch of aorta
Explanation: ***Ascending aorta*** - The **ascending aorta** is the most common site for aortic aneurysm and dissection in Marfan syndrome due to cystic medial degeneration weakening the vessel wall [1]. - This predisposition is linked to defects in the **fibrillin-1 gene (FBN1)**, severely impacting the structural integrity of the arterial media primarily in the ascending aorta [1]. *Descending aorta* - While possible, **descending aortic** involvement is less common than ascending aortic involvement in Marfan syndrome [2]. - Aneurysms here are more frequently associated with atherosclerosis or other connective tissue disorders. *Abdominal aorta* - **Abdominal aortic aneurysms** are relatively rare in Marfan syndrome and are more typically seen in older patients with atherosclerosis [3]. - The disease primarily affects the elastic tissue content, which is most abundant in the proximal aorta. *Arch of aorta* - Aortic arch aneurysms can occur, but they are still less frequent than those in the **ascending aorta** as the primary initial site of dilation and dissection in Marfan syndrome. - Arch involvement often represents an extension of a more proximal ascending aortic pathology.
Question 1553: In which condition is paradoxical splitting of the second heart sound observed?
- A. Right Bundle Branch Block (RBBB)
- B. Left Bundle Branch Block (LBBB) (Correct Answer)
- C. Ventricular Septal Defect (VSD)
- D. Atrial Septal Defect (ASD)
Explanation: ***Left Bundle Branch Block (LBBB)*** - In LBBB, the **left ventricle** depolarizes and contracts *after* the right ventricle, causing the **aortic valve (A2)** to close *after* the **pulmonic valve (P2)** [1]. - During inspiration, right ventricular ejection time is prolonged, which further delays P2. However, in LBBB, A2 is already delayed, and the inspiratory delay of P2 can bring P2 closer to A2, or even cause them to merge, making the splitting *less wide* or *disappear* on inspiration, which is paradoxical. *Right Bundle Branch Block (RBBB)* - RBBB causes a **delay in right ventricular depolarization**, leading to a **delayed P2** (pulmonic valve closure). - This typically results in **wide and fixed splitting of S2**, where the splitting persists during expiration and widens further with inspiration, which is not paradoxical. *Ventricular Septal Defect (VSD)* - A VSD can cause a **loud holosystolic murmur** and may lead to increased pulmonary blood flow. - While it can affect the timing of heart sounds, it does not typically cause paradoxical splitting of S2. *Atrial Septal Defect (ASD)* - An ASD causes a **left-to-right shunt**, leading to chronic volume overload of the right ventricle and increased pulmonary blood flow. - This often results in a **widely fixed splitting of S2**, where the split between A2 and P2 is constant regardless of respiration, which is different from paradoxical splitting.
Question 1554: Which biomarker is typically elevated in the plasma of patients with chronic heart disease?
- A. Endothelin-1
- B. Troponin T
- C. B-type natriuretic peptide (BNP) (Correct Answer)
- D. Cortisol
Explanation: ***B-type natriuretic peptide (BNP)*** - **BNP** is a hormone secreted by **ventricular cardiomyocytes** in response to increased wall stretch and pressure overload, making it a strong indicator of **myocardial stress** and **chronic heart failure** [1]. - Elevated levels correlate with the **severity of heart failure**, aiding in diagnosis and prognosis [1]. *Endothelin-1* - **Endothelin-1** is a potent **vasoconstrictor** involved in vascular tone regulation and endothelial dysfunction. - While it can be elevated in conditions like **pulmonary hypertension** and **atherosclerosis**, it is not a primary diagnostic biomarker for chronic heart disease in general. *Troponin T* - **Troponin T** is a cardiac-specific protein that is released into the bloodstream following **myocardial injury or necrosis**. - While it is a crucial biomarker for **acute coronary syndromes** (e.g., heart attack), persistently elevated levels are not typical for stable chronic heart disease unless there is ongoing subclinical myocardial damage. *Cortisol* - **Cortisol** is a **stress hormone** produced by the adrenal glands, involved in metabolism, immune response, and blood pressure regulation. - While chronic stress can impact cardiovascular health, cortisol itself is not a specific diagnostic biomarker for chronic heart disease.
Question 1555: What is a characteristic finding in athletes' hearts, also known as athletic syndrome?
- A. Increased amplitude of QRS (Correct Answer)
- B. Decreased QT interval
- C. U-waves
- D. Bradycardia
Explanation: ***Increased amplitude of QRS*** - In **athletes' hearts**, the heart muscle (myocardium) undergoes physiological adaptations, including **left ventricular hypertrophy**, which leads to an **increased amplitude of the QRS complex** on an ECG. - This is a normal and beneficial adaptation that enhances cardiac output and efficiency during exercise. *Bradycardia* - While **bradycardia** (a slower heart rate) is very common in athletes due to increased **vagal tone** and improved cardiac efficiency, it is not the most direct characteristic finding *on an ECG* reflecting the structural changes of athletic heart syndrome. - Bradycardia is a rate finding, not a waveform amplitude change reflecting myocardial mass. *Decreased QT interval* - A **decreased QT interval** is not a typical characteristic of an athlete's heart; in fact, there is usually no significant change or a slight prolongation due to bradycardia, but it remains within normal limits. - A pathologically short QT interval can indicate specific genetic channelopathies, which are unrelated to athletic adaptation. *U-waves* - **U-waves** are small positive deflections sometimes seen after the T wave, often associated with **bradycardia** or **hypokalemia**. - While athletes can have bradycardia, U-waves are not a consistent or defining feature of an athlete's heart syndrome itself, and their presence can also indicate other conditions.
Question 1556: Which study is known for identifying major coronary risk factors?
- A. Framingham (Correct Answer)
- B. Stanford study
- C. North Kerala
- D. MONICA
Explanation: ***Framingham*** - The **Framingham Heart Study** is a landmark prospective cohort study that began in 1948 and has significantly contributed to our understanding of **cardiovascular disease risk factors**. [1] - It identified major risk factors such as **high blood pressure**, **high cholesterol**, **smoking**, obesity, diabetes, and physical inactivity. [2] *Stanford study* - While Stanford University has conducted numerous influential studies in cardiovascular health, there isn't one singular "Stanford study" widely recognized for initially identifying the major coronary risk factors in the same comprehensive way as Framingham. - Many Stanford studies focus on specific aspects of cardiovascular disease, such as interventions or genetic predispositions. *North Kerala* - "North Kerala" refers to a geographical region and is not associated with a specific, globally recognized study known for identifying major coronary risk factors. - Research conducted in specific regions like North Kerala might focus on local health issues or specific population groups. *MONICA* - The **MONICA (Multinational Monitoring of Trends and Determinants in Cardiovascular Disease) Project** was a WHO-coordinated study. - It monitored cardiovascular disease trends and risk factors across various populations but built upon the existing knowledge of risk factors identified by studies like Framingham.
Question 1557: Which of the following complications is commonly associated with mitral valve prolapse?
- A. Ventricular arrhythmia
- B. Stroke
- C. Infective endocarditis (Correct Answer)
- D. Mitral stenosis
Explanation: Mitral valve prolapse (MVP) involves myxomatous degeneration of the mitral valve leaflets, which can create a rough surface predisposing to bacterial adhesion and subsequent infective endocarditis [1]. While the overall risk is low, patients with MVP and accompanying mitral regurgitation or thickened leaflets are at higher risk [1]. Patients with valvular heart disease are generally susceptible to bacterial endocarditis, often associated with procedures or dental hygiene [2]. Stroke - Although MVP can sometimes be associated with embolic events (e.g., from thrombi forming on the prolapsing valve), stroke is not considered a commonly associated complication. - The risk of stroke is generally higher in MVP patients with concomitant atrial fibrillation or other cardiovascular risk factors. Mitral stenosis - Mitral valve prolapse is characterized by the displacement of mitral valve leaflets into the left atrium during systole, which can lead to mitral regurgitation [3], not stenosis. - Mitral stenosis involves narrowing of the mitral valve orifice, usually due to rheumatic fever, which is a different pathophysiology [4]. Ventricular arrhythmia - While palpitations (often benign supraventricular ectopy) are common in MVP, clinically significant ventricular arrhythmias are less common. - Severe ventricular arrhythmias are more typically seen with significant underlying myocardial disease or severe mitral regurgitation causing left ventricular dysfunction.
Question 1558: What is the most common cause of dissecting hematoma?
- A. Hypertension (Correct Answer)
- B. Marfan syndrome
- C. Iatrogenic causes
- D. Kawasaki disease
Explanation: ***Hypertension*** - **Chronic hypertension** is the most frequent cause of dissecting hematoma (aortic dissection) due to the constant high pressure stressing the arterial wall [1]. - It leads to **medial degeneration** and predisposition to intimal tear, allowing blood to enter the arterial wall [1]. *Marfan syndrome* - While Marfan syndrome is a significant risk factor for aortic dissection due to **connective tissue weakness** (cystic medial necrosis), it is much less common than hypertension [1]. - It primarily affects younger individuals with a genetic predisposition to **fibrillin-1 mutations**. *Iatrogenic causes* - These include complications from medical procedures like **cardiac catheterization** or surgery [1]. - Though a possible cause, iatrogenic dissection is relatively rare compared to spontaneous dissection due to hypertension [1]. *Kawasaki disease* - Kawasaki disease primarily causes **coronary artery aneurysms** in children. - It is not a common cause of aortic dissecting hematoma in adults.
Question 1559: All of the following statements about the third heart sound (S3) are true, except:
- A. Seen in Atrial Septal Defect (ASD)
- B. Seen in Ventricular Septal Defect (VSD)
- C. Occurs due to rapid filling of the ventricles during early diastole.
- D. Seen in Constrictive Pericarditis (Correct Answer)
Explanation: ***Seen in Constrictive Pericarditis*** - While constrictive pericarditis can lead to a diastolic sound, it's typically a **pericardial knock**, which is sharper and occurs earlier than an S3, due to abrupt halting of ventricular filling. - A true S3 is a low-pitched sound caused by turbulent blood flow into an overly compliant or volume-overloaded ventricle, which is not the primary mechanism in constrictive pericarditis. *Occurs due to rapid filling of the ventricles during early diastole.* - The S3 heart sound is precisely caused by the **rapid inflow of blood** into a dilated or poorly compliant ventricle during the early, rapid filling phase of diastole [1]. - This rapid distension causes vibrations in the ventricular wall, audible as S3, and is often associated with conditions causing **volume overload** or **ventricular dysfunction**. *Seen in Atrial Septal Defect (ASD)* - Patients with a large ASD have increased blood flow through the tricuspid valve, leading to **right ventricular volume overload** [2]. - This increased volume can cause an **S3** sound, particularly a **right ventricular S3**, due to rapid filling of the overloaded right ventricle [2]. *Seen in Ventricular Septal Defect (VSD)* - A significant VSD leads to a **left-to-right shunt**, increasing blood flow to the pulmonary circulation and subsequently returning to the left atrium and left ventricle. - This **left ventricular volume overload** can result in an audible **left ventricular S3**, reflecting rapid filling of the dilated left ventricle.
Question 1560: Which components of cigarette smoke are known to contribute to coronary artery disease?
- A. Nicotine, carbon monoxide, and tar (Correct Answer)
- B. Carbon monoxide and tar
- C. Carbon dioxide
- D. Tar and nicotine
Explanation: ***Nicotine, carbon monoxide, and tar*** - **Nicotine** directly affects the cardiovascular system by increasing **heart rate**, **blood pressure**, and causing **vasoconstriction**, as well as promoting atherogenesis [2]. - **Carbon monoxide** binds to hemoglobin with higher affinity than oxygen, forming **carboxyhemoglobin**, which reduces oxygen delivery to tissues, leading to **endothelial damage** and contributing to atherosclerosis [1]. - **Tar** contains various **carcinogens** and toxic chemicals that contribute to inflammation, oxidative stress, and lipid peroxidation, all of which are implicated in the development and progression of **atherosclerosis**. *Carbon monoxide and tar* - While both contribute significantly, this option **omits nicotine**, which is a major contributor to the cardiovascular effects of smoking. - Nicotine's direct impact on **vasoconstriction** and **atherogenesis** is a critical factor in coronary artery disease [2]. *Carbon dioxide* - **Carbon dioxide** is a product of respiration and combustion but is not considered a primary direct contributor to the pathogenesis of **coronary artery disease** from cigarette smoke in the same way as nicotine, carbon monoxide, and tar. - Its presence in smoke primarily relates to its role in **respiratory physiology** rather than direct vascular damage. *Tar and nicotine* - This option correctly identifies **tar** and **nicotine** as contributors but **omits carbon monoxide**, which plays a crucial role in reducing oxygen-carrying capacity and directly damaging the endothelium [1]. - The impact of **carbon monoxide** on cardiac oxygen supply is a significant mechanism in smoking-related cardiovascular disease [1].
Practice by Chapter
Coronary Artery Disease and Angina
Practice Questions
Acute Coronary Syndromes
Practice Questions
Heart Failure
Practice Questions
Cardiac Arrhythmias
Practice Questions
Valvular Heart Diseases
Practice Questions
Cardiomyopathies
Practice Questions
Pericardial Diseases
Practice Questions
Congenital Heart Disease in Adults
Practice Questions
Hypertension and Hypertensive Emergencies
Practice Questions
Pulmonary Hypertension
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Non-invasive Cardiac Diagnostics
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Preventive Cardiology
Practice Questions
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