Cardiology Practice Questions

Q: A 58-year-old man presents with chest pain and sweating. His ECG shows ST elevation in leads II, III, and aVF. What is the most likely location of the myocardial infarction?

Inferior wall. Detailed Analysis: ***Inferior wall*** - **ST elevation** in leads **II, III, and aVF** is the classic electrocardiographic finding for an **inferior wall myocardial infarction** [1]. - These leads correspond to the **diaphragmatic surface** of the heart, supplied primarily by the **right coronary artery** (RCA) in most individuals. *Anterior wall* - An **anterior wall myocardial infarction** typically shows **ST elevation** in leads **V1-V4** [2]. - This region is usually supplied by the **left anterior descending** (LAD) coronary artery. *Posterior wall* - A **posterior wall myocardial infarction** is often characterized by **ST depression** in leads **V1-V3** and prominent R waves, which are reciprocal changes to posterior ST elevation [2]. - This area is usually supplied by the **circumflex artery** or a dominant RCA. *Lateral wall* - A **lateral wall myocardial infarction** is indicated by **ST elevation** in leads **I, aVL, V5, and V6** [1]. - The lateral wall is primarily supplied by the **circumflex artery** or marginal branches of the LAD. *Symptoms* - Presenting symptoms such as chest pain and sweating (signs of sympathetic activation) are characteristic of acute myocardial ischemia [3].

Q: A 70-year-old man with a long history of hypertension presents with sudden severe chest pain radiating to the back. CT angiography shows aortic dissection. What is the most common predisposing factor?

Hypertension. ***Hypertension*** - A **long history of hypertension** is the most significant predisposing factor for aortic dissection, as it increases the wall stress of the aorta [1]. - It can lead to **degeneration of the aortic media**, making it more susceptible to dissections [1]. *Bicuspid aortic valve* - While it can lead to **aortic stenosis** and other complications, it is not the **most common** predisposing factor for aortic dissection. - This condition primarily affects younger individuals, whereas dissection is more associated with **older age** and chronic hypertension. *Atherosclerosis* - Atherosclerosis contributes to **cardiovascular disease** but does not directly lead to aortic dissection as primarily as hypertension does. - It affects atherosclerotic plaque formation rather than the **structural integrity** of the aorta, which is pivotal in dissections [1]. *Marfan syndrome* - Although it is associated with aortic dissection [1], it is less common compared to **hypertension** in the general population. - Marfan syndrome is a genetic disorder, affecting connective tissue, which leads to dissection but is not as prevalent as chronic high blood pressure.

Q: A patient with a mechanical heart valve in the aortic position and a history of gastrointestinal bleeding requires anticoagulation. What is the best strategy?

Warfarin with proton pump inhibitor. Warfarin with proton pump inhibitor - **Warfarin** is essential for patients with **mechanical heart valves** to prevent thrombotic complications [2]. - The addition of a **proton pump inhibitor (PPI)** reduces the risk of **gastrointestinal bleeding**, which is a significant concern for anticoagulated patients with a history of GI bleeding. Warfarin with a standard INR target - While **warfarin** is appropriate for the mechanical valve, a **standard INR target** may not sufficiently mitigate the risk of recurrent GI bleeding in a patient with a history of such events [1]. - A more nuanced approach, such as adding a PPI, is often required to balance the benefits of anticoagulation against the bleeding risk. Switch to a different anticoagulant - **Direct oral anticoagulants (DOACs)** are generally **contraindicated** for patients with **mechanical heart valves** due to increased thrombotic risk. - There is currently no other anticoagulant proven to be as effective and safe as warfarin for mechanical heart valves [2]. Stop anticoagulation therapy - **Stopping anticoagulation** in a patient with a **mechanical aortic valve** would lead to a very high risk of **thrombosis**, **stroke**, and potentially **valve dysfunction** [2]. - The risk of major thrombotic events far outweighs the bleeding risk in this scenario, making cessation of therapy unsafe.

Q: A 45-year-old male presents with palpitations and dizziness. His ECG shows a regular, narrow complex tachycardia at 180 bpm. Carotid massage and adenosine are ineffective. What is the likely diagnosis?

Focal atrial tachycardia. ***Focal atrial tachycardia*** - This is a **narrow complex tachycardia** that is typically **regular** and can be resistant to **adenosine** and **carotid massage**, making it a likely diagnosis when these vagal maneuvers are ineffective. - ECG often shows discrete **P waves** with an abnormal morphology and axis, followed by narrow QRS complexes, which distinguishes it from reentrant tachycardias that typically lack clear P waves. *Atrial fibrillation* - Characterized by an **irregularly irregular rhythm** and the **absence of distinct P waves** on ECG, which contradicts the described regular rhythm [1]. - While it can cause palpitations and dizziness, the lack of regularity rules it out in this scenario. *Atrial flutter* - Typically presents with a **sawtooth pattern** of P waves, known as flutter waves, which are not mentioned here. - Though it can be regular, it often responds to adenosine by slowing the ventricular rate, revealing the flutter waves, which did not occur after adenosine in this case. *Atrioventricular nodal reentrant tachycardia* - This is often a **regular, narrow complex tachycardia** [1] that is typically **terminated by vagal maneuvers** or **adenosine** which were ineffective in this patient. - The P waves are usually hidden within the QRS complex or appear immediately after it (pseudo-R' or pseudo-S waves), rather than clearly visible as in focal atrial tachycardia.

Q: Sinus bradycardia with myocardial infarction is best treated with:

Atropine. ***Atropine*** - **Atropine** is a **parasympatholytic agent** that blocks acetylcholine's action on muscarinic receptors, increasing heart rate. - It is the **first-line treatment** for hemodynamically significant **bradycardia** in the context of **myocardial infarction** to improve cardiac output [2]. *Dopamine* - While dopamine can increase heart rate and blood pressure, it is typically used for **hemodynamically unstable bradycardia** unresponsive to atropine. - Its **vasoconstrictive effects** can increase myocardial oxygen demand, which might be detrimental in **myocardial infarction**. *Isoproterenol* - **Isoproterenol** is a **non-selective beta-agonist** that increases heart rate and contractility. - Its use in **myocardial infarction** is generally avoided due to significant **tachycardic** and **arrhythmogenic effects**, which can worsen myocardial ischemia. *Temporary pacing* - **Temporary pacing** is reserved for **severe, symptomatic bradycardia** that is **refractory to pharmacological management** (e.g., atropine, dopamine) [2]. - It is an **invasive procedure** and not the initial treatment for sinus bradycardia with myocardial infarction unless other measures fail [1].

Q: A 40-year-old male presents with severe chest pain, hypotension, and distended neck veins. His ECG shows electrical alternans. What is the most likely diagnosis?

Pericardial tamponade. ***Pericardial tamponade*** - The combination of **chest pain**, **hypotension**, and **distended neck veins** (Beck's triad), along with **electrical alternans** on ECG, is highly indicative of pericardial tamponade. - **Electrical alternans** is caused by the heart "swinging" within the fluid-filled pericardial sac, leading to beat-to-beat variations in QRS amplitude. *Myocardial infarction* - While it can cause **chest pain** and **hypotension**, **distended neck veins** and **electrical alternans** are not typical findings. - ECG usually shows **ST-segment elevation** or depression, and/or **T-wave inversion**, depending on the type and location of the infarction. *Pulmonary embolism* - It can cause **chest pain** and **hypotension**, but **distended neck veins** are less common and typically associated with right heart strain, and **electrical alternans** is not a characteristic ECG finding. - ECG often shows **S1Q3T3 pattern** or **right bundle branch block**, acute right ventricular strain, and sinus tachycardia. *Aortic dissection* - It presents with severe, tearing **chest pain** that may radiate to the back and can cause **hypotension** due to hypovolemic shock (rupture into the pericardium/pleural space) or cardiac tamponade. - However, **electrical alternans** is not a direct consequence of aortic dissection, though it may occur if dissection leads to significant pericardial effusion and tamponade.

Q: Which direct oral anticoagulant (DOAC) is recommended as a first-line treatment for reducing the risk of stroke in patients with atrial fibrillation and has demonstrated a lower risk of major bleeding compared to warfarin?

Apixaban. ***Apixaban*** - **Apixaban** is a **direct oral anticoagulant (DOAC)** widely recommended as a first-line agent for stroke prevention in non-valvular atrial fibrillation (AF). - The **ARISTOTLE trial** demonstrated that apixaban was superior to warfarin in reducing stroke/systemic embolism and had significantly **lower rates of major bleeding** and intracranial hemorrhage. - Its **twice-daily dosing** and favorable safety profile make it a preferred choice among DOACs. *Rivaroxaban* - **Rivaroxaban** is also a **DOAC** used for stroke prevention in atrial fibrillation. - While effective, the **ROCKET-AF trial** showed non-inferiority to warfarin but did not demonstrate the same reduction in major bleeding as apixaban. - It requires **once-daily dosing** and should be taken with food. *Lisinopril* - **Lisinopril** is an **ACE inhibitor** primarily used to treat hypertension and heart failure. - It does not have anticoagulant properties and does not directly reduce the risk of stroke in atrial fibrillation. *Atorvastatin* - **Atorvastatin** is a **statin medication** used to lower cholesterol and reduce the risk of atherosclerotic cardiovascular events. - It does not prevent cardioembolic stroke from atrial fibrillation; its primary role is in managing dyslipidemia.

Q: In a 60-year-old man with chronic heart failure, what is the most likely cause of decreased exercise tolerance?

Decreased cardiac output. ***Decreased cardiac output*** - **Chronic heart failure** is characterized by the heart's inability to pump sufficient blood to meet the body's metabolic demands, directly leading to **decreased cardiac output**. [1] - Reduced cardiac output limits oxygen delivery to muscles during exertion, causing **fatigue** and decreased **exercise tolerance**. [1] *Increased systemic vascular resistance* - While **increased systemic vascular resistance (SVR)** can occur in heart failure as a compensatory mechanism (due to activation of the **renin-angiotensin-aldosterone system** and sympathetic nervous system), it primarily raises afterload and further impedes cardiac output, rather than being the direct cause of exercise intolerance. - The direct cause of reduced exercise capacity is the resultant **lowered cardiac output**, which this increased resistance contributes to. *Decreased total peripheral resistance* - **Decreased total peripheral resistance** would typically improve cardiac output by reducing afterload, and thus would not be a cause of decreased exercise tolerance in chronic heart failure. - In fact, in chronic heart failure, compensatory mechanisms often lead to **increased**, not decreased, peripheral resistance. *Increased stroke volume due to compensatory mechanisms* - In heart failure, the **stroke volume** is typically **reduced** due to impaired contractility or filling. [1] - While compensatory mechanisms like **Frank-Starling law** (increased preload) can transiently increase stroke volume, chronic heart failure is fundamentally marked by a **failing heart** and an overall inability to maintain adequate stroke volume and cardiac output, especially during exertion. [1]

Q: A 35-year-old male experiences sudden chest pain and shortness of breath. An ECG reveals ST-segment elevation. What is the most likely underlying physiological process?

Myocardial infarction. ***Myocardial infarction*** - **ST-segment elevation** on an ECG is a classic sign of an **ST-elevation myocardial infarction (STEMI)**, indicating transmural ischemia [2]. - This is caused by a complete and sustained occlusion of a **coronary artery**, leading to myocardial cell death [1] [3]. *Aortic dissection* - While it causes sudden severe chest pain, an aortic dissection typically presents with a **tearing or ripping pain** and often involves pulse deficits or blood pressure differentials. - ECG findings are usually non-specific or show signs of left ventricular hypertrophy, but **ST-segment elevation** is not characteristic. *Pulmonary embolism* - Pulmonary embolism presents with sudden chest pain and shortness of breath, but its hallmark ECG finding is often **tachycardia** and signs of right heart strain (e.g., S1Q3T3 pattern). - It does not typically cause **ST-segment elevation** unless it's a massive PE leading to severe myocardial ischemia secondary to profound hypotension. *Pericarditis* - Pericarditis causes chest pain that is often **sharp, pleuritic**, and relieved by leaning forward, and it can cause diffuse **ST-segment elevation** on ECG. - However, in pericarditis, the ST elevation is typically **concave up** and widespread, rather than localized to specific coronary territories as seen in myocardial infarction [3].

Question 1

What is the diagnostic utility of high-sensitivity troponin assays in the early detection of myocardial infarction?

Accepted Answer

High sensitivity and specificity for detecting myocardial infarction.

Answer

Low sensitivity; high specificity for detecting myocardial infarction.

Answer

High sensitivity; low specificity for detecting myocardial infarction.

Answer

Low sensitivity and specificity for detecting myocardial infarction.

Question 2

A 58-year-old man presents with chest pain and sweating. His ECG shows ST elevation in leads II, III, and aVF. What is the most likely location of the myocardial infarction?

Accepted Answer

Inferior wall

Answer

Anterior wall

Answer

Posterior wall

Answer

Lateral wall

Question 3

A 70-year-old man with a long history of hypertension presents with sudden severe chest pain radiating to the back. CT angiography shows aortic dissection. What is the most common predisposing factor?

Accepted Answer

Hypertension

Answer

Marfan syndrome

Answer

Bicuspid aortic valve

Answer

Atherosclerosis

Question 4

A patient with a mechanical heart valve in the aortic position and a history of gastrointestinal bleeding requires anticoagulation. What is the best strategy?

Accepted Answer

Warfarin with proton pump inhibitor

Answer

Warfarin with a standard INR target

Answer

Switch to a different anticoagulant

Answer

Stop anticoagulation therapy

Question 5

A 45-year-old male presents with palpitations and dizziness. His ECG shows a regular, narrow complex tachycardia at 180 bpm. Carotid massage and adenosine are ineffective. What is the likely diagnosis?

Accepted Answer

Focal atrial tachycardia

Answer

Atrial fibrillation

Answer

Atrial flutter

Answer

Atrioventricular nodal reentrant tachycardia

Question 6

Sinus bradycardia with myocardial infarction is best treated with:

Accepted Answer

Atropine

Answer

Isoproterenol

Answer

Dopamine

Answer

Temporary pacing

Question 7

A 40-year-old male presents with severe chest pain, hypotension, and distended neck veins. His ECG shows electrical alternans. What is the most likely diagnosis?

Accepted Answer

Pericardial tamponade

Answer

Myocardial infarction

Answer

Pulmonary embolism

Answer

Aortic dissection

Question 8

Which direct oral anticoagulant (DOAC) is recommended as a first-line treatment for reducing the risk of stroke in patients with atrial fibrillation and has demonstrated a lower risk of major bleeding compared to warfarin?

Accepted Answer

Apixaban

Answer

Lisinopril

Answer

Atorvastatin

Answer

Rivaroxaban

Question 9

In a 60-year-old man with chronic heart failure, what is the most likely cause of decreased exercise tolerance?

Accepted Answer

Decreased cardiac output

Answer

Decreased total peripheral resistance

Answer

Increased systemic vascular resistance

Answer

Increased stroke volume due to compensatory mechanisms

Question 10

A 35-year-old male experiences sudden chest pain and shortness of breath. An ECG reveals ST-segment elevation. What is the most likely underlying physiological process?

Accepted Answer

Myocardial infarction

Answer

Aortic dissection

Answer

Pulmonary embolism

Answer

Pericarditis

Cardiology — MCQs

Cardiology — MCQs

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