Cardiology — MCQs

Cardiology Indian Medical PG Practice Questions and MCQs

Question 1491: 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 1492: What is the most common cause of sudden death in patients with sarcoidosis?

A. Pneumonia
B. Cor pulmonale
C. Liver failure
D. Arrhythmias (Correct Answer)

Explanation: ***Arrhythmias*** - **Cardiac sarcoidosis** can lead to granulomatous infiltration of the myocardium, disrupting the **cardiac conduction system**. - This disruption can result in various **arrhythmias**, including **ventricular tachycardia** and **ventricular fibrillation**, which are frequent causes of sudden cardiac death [2]. *Pneumonia* - While sarcoidosis can affect the lungs, leading to **pulmonary fibrosis** and increased susceptibility to infection, **pneumonia** is not the most common cause of sudden death in these patients. - Death from pneumonia is typically due to **respiratory failure** which is often preceded by a period of illness rather than being sudden. *Cor pulmonale* - **Cor pulmonale** (right heart failure due to lung disease) can develop in advanced pulmonary sarcoidosis due to **pulmonary hypertension**. - While a serious complication, it generally leads to a more **gradual decline** in cardiac function rather than sudden death. *Liver failure* - **Hepatic involvement** in sarcoidosis is common, with granulomas found in the liver, but **liver failure** as a direct cause of sudden death is rare [1]. - Significant liver dysfunction usually progresses over time, leading to more chronic symptoms.

Question 1493: Low QRS voltage on ECG indicates ?

A. Pulmonary embolism
B. Pericardial effusion (Correct Answer)
C. Cor pulmonale
D. Infective endocarditis

Explanation: ***Pericardial effusion*** - A significant **pericardial effusion** can lead to low QRS voltage on ECG because the fluid surrounding the heart acts as an electrical insulator, dampening the electrical signals [1]. - This dampening effect reduces the amplitude of the QRS complexes recorded on the electrocardiogram [1]. *Pulmonary embolism* - While pulmonary embolism can cause various ECG changes (e.g., **S1Q3T3 pattern**, right axis deviation), it typically does not directly cause low QRS voltage. - The primary hemodynamic impact is on the right side of the heart and does not involve fluid accumulation around the heart to dampen electrical signals. *Cor pulmonale* - **Cor pulmonale** is right ventricular hypertrophy secondary to lung disease; ECG usually shows signs of **right ventricular hypertrophy** (e.g., tall R waves in V1, right axis deviation). - This condition is associated with increased electrical activity in the right ventricle, generally leading to larger, not smaller, QRS complexes in relevant leads. *Infective endocarditis* - **Infective endocarditis** affects heart valves and can cause rhythm disturbances or conduction blocks due to myocardial involvement or abscess formation. - It does not directly affect the electrical conductivity of the heart in a way that would cause generalized low QRS voltage.

Question 1494: What is the Ankle-Brachial Pressure Index (ABPI) value that indicates imminent risk of necrosis?

A. < 0.6
B. 0.3 (critical ischemia)
C. 0.6 - 0.9 (indicates moderate arterial disease)
D. < 0.3 (Correct Answer)

Explanation: ***< 0.3*** - An **ABPI value less than 0.3** signifies **severe critical limb ischemia**, indicating a very high risk of tissue necrosis and limb loss [1]. - At this level, **resting pain** is common, and spontaneous **ulceration or gangrene** is highly probable due to severely compromised blood flow [1]. *0.3 (critical ischemia)* - While 0.3 is generally considered a range of **critical limb ischemia**, an ABPI *strictly less than 0.3* implies an even more severe and acute risk of necrosis [1]. - This value represents a significant stage of arterial disease, but slightly higher than the most imminent risk scenario where necrosis is almost guaranteed. *< 0.6* - An ABPI of **less than 0.6** indicates **moderate to severe peripheral arterial disease (PAD)**, where intermittent claudication is common [1]. - While concerning, it does not typically represent the immediate threat of tissue necrosis as values closer to 0.3 or below do. *0.6 - 0.9 (indicates moderate arterial disease)* - An **ABPI between 0.6 and 0.9** suggests **moderate peripheral arterial disease**, often associated with **claudication symptoms** on exertion [1]. - This range typically does not indicate an imminent risk of necrosis; while blood flow is reduced, it is usually sufficient to prevent tissue death at rest.

Question 1495: 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 1496: 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 1497: 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 1498: 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 1499: The S2 heart sound is best appreciated in:

A. 2nd right intercostal space (Correct Answer)
B. 4th left intercostal space
C. 5th left intercostal space
D. 3rd left intercostal space

Explanation: ***2nd right intercostal space*** - The **S2 heart sound** is produced primarily by the closure of the **aortic and pulmonic valves** [1]. - The **aortic component (A2)** is best heard at the **right upper sternal border** (2nd right intercostal space), where the aorta is closest to the chest wall [2]. *4th left intercostal space* - This area is typically associated with the **tricuspid valve area**, where tricuspid murmurs and S3/S4 sounds related to the right ventricle can be more prominent. - While heart sounds can be heard here, it is not the primary location for appreciating the S2 sound. *5th left intercostal space* - This is the **mitral area** or **apex**, where the apical impulse is felt and the S1 heart sound (mitral component) is best heard [2]. - The S2 sound is much less prominent here compared to the base of the heart. *3rd left intercostal space* - This is often referred to as **Erb's point**, where murmurs of both aortic and pulmonic origin can sometimes be heard. - While S2 can be heard here, the **2nd right intercostal space** is superior for primarily appreciating the aortic component of S2, and the 2nd left intercostal space for the pulmonic component [2].

Question 1500: 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].

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Coronary Artery Disease and Angina

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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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Pulmonary Hypertension

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Non-invasive Cardiac Diagnostics

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Preventive Cardiology

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Cardiology — MCQs

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