Cardiology — MCQs

Cardiology Indian Medical PG Practice Questions and MCQs

Question 1481: Wide QRS complex (≥ 0.12 seconds) can be seen in various conditions. Which of the following is least likely to present with a wide QRS complex?

A. Left Anterior Fascicular Block (Correct Answer)
B. Hyperkalemia
C. Wolf Parkinson White Syndrome
D. Ventricular Tachycardia

Explanation: ***Left Anterior Fascicular Block*** - While a **Left Anterior Fascicular Block (LAFB)** does affect ventricular depolarization, it typically causes a **left axis deviation** and only *slight widening* of the QRS complex, usually less than 0.12 seconds. - The delay in conduction is primarily through one of the fascicles of the left bundle branch, not the entire ventricular conduction system. *Hyperkalemia* - Severe **hyperkalemia** can significantly impair myocardial conduction, leading to a **diffuse slowing of ventricular depolarization**. - This results in a **widened QRS complex** as the potassium levels increase, along with peaked T waves and eventually sine wave patterns. *Wolf Parkinson White Syndrome* - **Wolff-Parkinson-White (WPW) syndrome** involves an **accessory pathway** that bypasses the AV node, leading to pre-excitation of the ventricles [1, 2]. - This abnormal conduction pathway results in a **short PR interval** and a **delta wave**, which combines with normal ventricular activation to produce a **wide QRS complex** [2]. *Ventricular Tachycardia* - **Ventricular tachycardia (VT)** originates in the ventricles, bypassing the normal His-Purkinje system [3]. - This abnormal ventricular activation sequence leads to a **markedly widened QRS complex** (typically > 0.12 seconds) due to slow, muscle-to-muscle conduction [3].

Question 1482: Which of the following is least likely to be associated with broad complex tachycardia due to ventricular tachycardia?

A. Fusion beats
B. Capture beats
C. AV dissociation
D. Termination of tachycardia by carotid sinus massage (Correct Answer)

Explanation: ***Termination of tachycardia by carotid sinus massage*** - **Carotid sinus massage** typically slows or terminates **supraventricular tachycardias (SVTs)** by increasing vagal tone to the AV node. - While it might occasionally slow the ventricular rate in VT (if the SA node is still firing normally), it is very **unlikely to terminate** a re-entrant ventricular tachycardia itself [2]. *Fusion beats* - These occur when an impulse from the ventricles (VT) and an impulse from the atria (often sinus) depolarize the ventricles **simultaneously**, creating a QRS complex that is a blend of the two [1]. - Their presence is a strong indicator of **ventricular tachycardia** [1]. *AV dissociation* - This refers to the atria and ventricles beating independently, where the atrial rate is usually slower than the ventricular rate in VT [1]. - It is a **hallmark sign** of ventricular tachycardia, distinguishing it from most SVTs with aberrancy [1]. *Capture beats* - A capture beat occurs when an atrial impulse (often a sinus beat) successfully conducts through the AV node and depolarizes the ventricles during VT. - This results in a **narrower QRS complex** appearing periodically within the broad complex tachycardia, providing strong evidence for VT.

Question 1483: What are the potential clinical consequences of a large patent ductus arteriosus (PDA)?

A. All of the listed complications are potential consequences of PDA, depending on the clinical scenario. (Correct Answer)
B. Endocarditis
C. Eisenmenger syndrome
D. Congestive heart failure (CHF)

Explanation: A large **patent ductus arteriosus (PDA)** can lead to several serious clinical consequences due to the continuous left-to-right shunt. The severity and manifestation of these outcomes depend on the size of the PDA and the patient's individual response [1]. Potential complications include **congestive heart failure**, **pulmonary hypertension** progressing to **Eisenmenger syndrome**, and an increased risk of **infective endocarditis**. *Endocarditis* - The abnormal blood flow through a PDA creates **turbulent jets** that can damage the endothelial lining of the pulmonary artery or the ductus itself. - This damaged endothelium is susceptible to bacterial colonization, leading to **infective endocarditis**. *Eisenmenger syndrome* - A large PDA causes a **significant left-to-right shunt**, leading to chronic **pulmonary overcirculation** and increased pulmonary artery pressure. - Over time, this can lead to irreversible **pulmonary vascular disease** and the development of **Eisenmenger syndrome**, characterized by reversed shunt direction [1]. *Congestive heart failure (CHF)* - The continuous flow of blood from the aorta to the pulmonary artery through a large PDA increases the **volume load** on the left ventricle and the pulmonary circulation [1]. - This increased workload eventually leads to **left ventricular dilation** and dysfunction, resulting in symptoms of **congestive heart failure** such as tachypnea, poor feeding, and growth failure in infants [1].

Question 1484: What does a -30 to -90 degree axis deviation indicate?

A. Left Axis Deviation (Correct Answer)
B. Right Axis Deviation
C. Normal Cardiac Axis
D. Extreme Right Axis Deviation

Explanation: ***Left Axis Deviation*** - A cardiac axis between **-30 and -90 degrees** is defined as **Left Axis Deviation (LAD)** [1]. - LAD is typically caused by conditions such as **left ventricular hypertrophy**, **inferior myocardial infarction**, or **left anterior fascicular block**. *Right Axis Deviation* - Right Axis Deviation generally refers to an axis between **+90 and +180 degrees**. - It is often associated with conditions like **right ventricular hypertrophy** or **left posterior fascicular block**. *Extreme Right Axis Deviation* - **Extreme Right Axis Deviation**, sometimes called "Northwest axis," indicates an axis between **-90 and -180 degrees**. - This is a rare finding, usually associated with severe conditions such as **ventricular tachycardia** or **pulmonary embolism**. *Normal Cardiac Axis* - A **normal cardiac axis** typically falls between **-30 and +90 degrees** [1]. - The given range of **-30 to -90 degrees** extends beyond the normal range, indicating an abnormal deviation.

Question 1485: Which of the following is a complication of Takayasu's arteritis?

A. None of the options
B. Intimal fibrosis
C. Renal hypertension (Correct Answer)
D. Coronary aneurysm

Explanation: Renal hypertension - Takayasu's arteritis often causes stenosis of the renal arteries, leading to renovascular hypertension [2]. - This complication arises from the inflammatory thickening and narrowing of large arteries, including those supplying the kidneys [3]. Intimal fibrosis - While intimal fibrosis is a pathological feature seen in Takayasu's arteritis due to chronic inflammation, it is part of the disease process rather than a direct clinical complication. - The fibrosis itself contributes to the stenosis and occlusion that cause clinical complications [1], but it is not a standalone complication. Coronary aneurysm - Though Takayasu's arteritis can affect coronary arteries, it typically causes stenosis or occlusion rather than aneurysm formation. - Coronary aneurysms are more characteristic of diseases like Kawasaki disease [3]. None of the options - This option is incorrect as renal hypertension is a well-known and significant complication of Takayasu's arteritis.

Question 1486: Which of the following arrhythmias is most commonly associated with alcohol binge in alcoholics?

A. Ventricular fibrillations
B. Ventricular premature contractions
C. Atrial flutter
D. Atrial fibrillation (Correct Answer)

Explanation: ***Atrial fibrillation*** - **Atrial fibrillation** is the most common arrhythmia associated with alcohol binge, often referred to as **"holiday heart syndrome"** [1]. - Alcohol can trigger AF by affecting **autonomic tone**, causing **electrolyte imbalances**, and direct **myocardial toxicity**, leading to electrical instability in the atria. *Ventricular fibrillations* - **Ventricular fibrillation** is a life-threatening arrhythmia that leads to cardiac arrest and is typically associated with **acute myocardial infarction** or severe **structural heart disease**, not commonly alcohol binge alone [3]. - While alcohol can increase the risk of other cardiac events, VF is not the primary arrhythmia directly induced by an alcohol binge [3]. *Ventricular premature contractions* - **Ventricular premature contractions (VPCs)** are common and can be triggered by various factors including stress, caffeine, and alcohol, but they are generally benign and not the most commonly reported serious arrhythmia from alcohol binge. - While an increase in VPCs might occur, they do not carry the same clinical significance or prevalence as AF in the context of acute alcohol consumption. *Atrial flutter* - **Atrial flutter** is another atrial arrhythmia that can be seen in patients with structural heart disease or hypertension, and can be precipitated by alcohol [2]. - However, **atrial fibrillation** is far more prevalent in acute alcohol-induced arrhythmias, making it a more common association than atrial flutter [1].

Question 1487: Most common cardiac defect in Turner syndrome

A. VSD
B. ASD
C. TOF
D. Coarctation of aorta (Correct Answer)

Explanation: ***Coarctation of aorta*** - **Coarctation of the aorta** is the most frequent cardiac defect found in individuals with **Turner syndrome**, occurring in approximately 10-20% of cases [1]. - This congenital narrowing of the aorta typically presents with **hypertension in the upper extremities** and diminished or absent pulses in the lower extremities [1]. *VSD* - **Ventricular septal defects (VSDs)** are common congenital heart defects but are not the *most common* defect associated with Turner syndrome. - VSDs involve a hole in the wall separating the two lower chambers of the heart, resulting in a **left-to-right shunt**. *ASD* - **Atrial septal defects (ASDs)** are relatively common congenital heart defects but are less frequent in Turner syndrome compared to coarctation of the aorta [2]. - An ASD involves a hole in the wall separating the two upper chambers of the heart, leading to a **left-to-right shunt**. *TOF* - **Tetralogy of Fallot (TOF)** is a complex congenital heart defect involving four specific abnormalities, but it is **rarely associated with Turner syndrome**. - TOF typically presents with **cyanosis** and can be diagnosed by an abnormal heart murmur and characteristic findings on echocardiography.

Question 1488: In Left Ventricular Hypertrophy (LVH), what is the minimum value of SV1 + RV6 in mm that suggests the presence of LVH?

A. 25 mm
B. 30 mm
C. 35 mm (Correct Answer)
D. 45 mm

Explanation: 35 mm - A combined amplitude of **SV1 + RV6 ≥ 35 mm** on an ECG is a commonly used **Sokolow-Lyon criterion** for diagnosing LVH. - This criterion demonstrates a degree of **specificity** for LVH, although its sensitivity can be limited. 25 mm - This value is **too low** and would lead to a high number of **false positives** for LVH. - While some criteria consider smaller amplitudes, **25 mm is not a standard threshold** for the Sokolow-Lyon criteria. 30 mm - This value is **below the standard threshold** for the Sokolow-Lyon criteria, potentially leading to underdiagnosis. - The accepted cut-off for **SV1 + RV6** in adults is generally higher than 30 mm. 45 mm - While a value of **45 mm** would strongly suggest LVH, it is **not the minimum threshold** for the Sokolow-Lyon criteria. - Using this higher threshold would decrease sensitivity, potentially **missing some cases** of LVH.

Question 1489: Which of the following statements about continuous murmurs is incorrect?

A. Heard both in systole and diastole
B. Seen with coarctation of aorta (Correct Answer)
C. Peaks at S2
D. Increase on squatting

Explanation: ***Seen with coarctation of aorta*** - While coarctation of the aorta can produce a murmur, it is typically a **systolic ejection murmur**, not a continuous murmur [3]. - A continuous murmur implies flow throughout both systole and diastole, which is not characteristic of the pressure gradient across a coarctation. *Peaks at S2* - Continuous murmurs indeed often **peak around the second heart sound (S2)** [1] because the pressure gradient driving the flow is usually maximal during this period. - This peak intensity at S2 helps differentiate them from other types of murmurs. *Heard both in systole and diastole* - By definition, a continuous murmur is heard throughout **both systole and diastole**, without a clear break [2]. - This characteristic indicates a persistent pressure gradient allowing blood flow across a defect or vessel throughout the cardiac cycle. *Increase on squatting* - Squatting increases **venous return** and **systemic vascular resistance**, which generally intensifies most murmurs by increasing cardiac output and pressure gradients. - This maneuver is often used to assess the nature and severity of various cardiac murmurs [3], including continuous ones.

Question 1490: Low QRS voltage on ECG with left ventricular hypertrophy on Echocardiography suggests a diagnosis of:

A. Cardiac Amyloidosis (Correct Answer)
B. Infective endocarditis
C. Cor pulmonale
D. Pericardial effusion

Explanation: ***Cardiac Amyloidosis*** - **Low QRS voltage** on ECG despite echocardiographic evidence of **left ventricular hypertrophy** is a classic paradox seen in cardiac amyloidosis. - Amyloid deposits infiltrate the myocardium, increasing wall thickness but **reducing electrical activity transmission**. *Cor pulmonale* - Cor pulmonale involves **right ventricular hypertrophy** due to pulmonary hypertension, not primarily left ventricular hypertrophy. - While it can cause changes in ECG findings, the combination of low QRS voltage with LVH is not characteristic. *Infective endocarditis* - Infective endocarditis primarily affects heart valves and can cause vegetations, but it does not typically lead to **left ventricular hypertrophy** or **low QRS voltage** on ECG. - ECG findings in endocarditis are often related to conduction abnormalities or ischemia if embolization occurs. *Pericardial effusion* - A significant pericardial effusion can cause **low QRS voltage** on ECG due to the dampening effect of fluid around the heart [1]. - However, it does not typically cause **left ventricular hypertrophy**; rather, it can be associated with signs of tamponade or inflammation [1].

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Acute Coronary Syndromes

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Heart Failure

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Cardiac Arrhythmias

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Valvular Heart Diseases

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Cardiomyopathies

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Pericardial Diseases

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Congenital Heart Disease in Adults

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Hypertension and Hypertensive Emergencies

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