Cardiology Practice Questions

Q: A patient presents with a regular wide QRS complex tachycardia (QRS >0.12 seconds) at a rate of 160 bpm. The ECG shows AV dissociation with fusion beats and capture beats. What is the most likely cardiac condition?

Ventricular tachycardia. ***Ventricular tachycardia*** - **Ventricular tachycardia (VT)** is a common cause of **wide QRS complex tachycardia**, originating from the ventricles. - The ECG typically shows a regular, rapid rhythm with **QRS complexes >0.12 seconds**. - Discriminating features that support VT over SVT with aberrancy include: **AV dissociation**, **fusion beats** (partial ventricular activation from both a sinus and ventricular impulse), **capture beats** (a narrow QRS complex occurring during the tachycardia when a sinus impulse briefly captures the ventricles), **concordance** in precordial leads, and a QRS duration >0.14 seconds. *Atrial fibrillation* - **Atrial fibrillation** presents as an **irregularly irregular rhythm** with no distinct P waves. - While it can manifest as tachycardia, the QRS complex is typically **narrow**, unless there is an accessory pathway or bundle branch block. *Atrial flutter* - **Atrial flutter** is characterized by a **"sawtooth" pattern of P waves** (flutter waves) in the inferior leads. - The ventricular rhythm can be regular or irregular, but the QRS complex is usually **narrow**. *Supraventricular tachycardia (SVT)* - **Supraventricular tachycardia (SVT)** typically presents with a **narrow QRS complex** (<0.12 seconds) as it originates above the ventricles. - A wide QRS can occur in SVT with **aberrancy** (e.g., bundle branch block), but the presence of AV dissociation, fusion beats, or capture beats strongly favors ventricular tachycardia over SVT with aberrancy.

Q: Which murmur increases on standing?

HOCM. ***HOCM*** - Standing decreases **venous return** and **left ventricular volume**, which reduces the size of the LV outflow tract and thus exacerbates the obstruction in **hypertrophic obstructive cardiomyopathy (HOCM)**, making the murmur louder [1]. - This maneuver is a key diagnostic feature as reduced preload intensifies the dynamic obstruction. *MR* - **Mitral regurgitation (MR)** is typically a volume overload lesion, and standing (which reduces preload) generally causes the murmur to **decrease** in intensity due to less blood volume ejected back into the atrium [3]. - The murmur of MR is usually a holosystolic murmur radiating to the axilla [3]. *MS* - **Mitral stenosis (MS)** is a fixed obstruction to left ventricular filling. Changes in preload (like standing) do not significantly alter the gradient across the mitral valve or the intensity of the murmur [2]. - Its characteristic murmur is a **mid-diastolic rumble** with an opening snap [1]. *VSD* - A **ventricular septal defect (VSD)** murmur is caused by blood flowing from the high-pressure left ventricle to the low-pressure right ventricle. Standing, by reducing systemic vascular resistance, would typically cause the murmur to **decrease** in intensity as less blood shunts left-to-right. - The murmur is usually a **holosystolic murmur** best heard at the lower left sternal border.

Q: Identify the condition in the ECG based on the provided image.

Atrial flutter. ***Atrial flutter*** - The distinctive **sawtooth pattern** between QRS complexes is characteristic of atrial flutter, representing rapid and regular atrial depolarization. - The ventricular response here appears to be a 4:1 block, meaning every fourth flutter wave is conducted to the ventricles, resulting in a regular ventricular rhythm. *Atrial fibrillation* - Characterized by **irregularly irregular R-R intervals** and the absence of distinct P waves, replaced by chaotic fibrillatory waves. - The ECG shows a regular ventricular rhythm with clear flutter waves, which is not consistent with atrial fibrillation. *Arrhythmia* - This is a broad term for any abnormal heart rhythm. While atrial flutter is an arrhythmia, this option is too general and does not identify the specific condition. - The question asks to identify the specific condition, not just categorize it as an abnormal rhythm. *Cardiomyopathy* - Cardiomyopathy refers to diseases of the **heart muscle** that can lead to heart failure or arrhythmias, but it is a structural diagnosis, not an ECG rhythm diagnosis. - An ECG for cardiomyopathy might show signs like chamber enlargement, Q waves, or conduction disturbances, but not the specific sawtooth pattern seen in this tracing.

Q: What is the immediate treatment for a hemodynamically unstable patient with supraventricular tachycardia (SVT)?

Cardioversion. ***Cardioversion*** * **Synchronized cardioversion** is the immediate treatment for hemodynamically **unstable** patients with **supraventricular tachycardia (SVT)** to quickly restore sinus rhythm and prevent cardiovascular collapse. * Hemodynamic instability includes symptoms such as **hypotension**, altered mental status, signs of shock, acute heart failure, or ischemic chest pain, directly caused by the arrhythmia. *Intravenous Diltiazem* * **Diltiazem** is a calcium channel blocker used for **rate control** in stable SVT, but it is not appropriate for unstable patients due to its slower onset of action and potential for further hypotension. * In hemodynamically unstable patients, delaying cardioversion to administer medications like diltiazem can worsen the patient's condition. *Intravenous Ibutilide* * **Ibutilide** is an antiarrhythmic drug used for recent-onset atrial fibrillation or flutter, but it is typically reserved for **hemodynamically stable** patients. * It is not the drug of choice for immediate management of unstable SVT as it has a slower onset and can potentially cause proarrhythmia. *Intravenous beta-blockers* * **Beta-blockers** are used for **rate control** in hemodynamically **stable** patients with SVT by blocking AV nodal conduction. * They are contraindicated in unstable patients as they can exacerbate hypotension, especially in those with reduced cardiac function.

Q: Which rhythm classification is best supported by this single-lead ECG tracing?

Regular narrow-complex supraventricular tachycardia. The tracing shows a rapid, regular rhythm with narrow QRS complexes, supporting the diagnosis of a regular narrow-complex supraventricular tachycardia. Ventricular tachycardia usually has wide QRS complexes, atrial fibrillation is irregularly irregular, and ventricular fibrillation is chaotic without organized QRS complexes. Because this is a stylized single-lead tracing and atrial activity is not clearly defined, a specific supraventricular mechanism—such as AV nodal reentrant tachycardia, AV reentrant tachycardia, or atrial tachycardia—cannot be determined reliably from the image alone.

Q: A patient presents with chest pain and an ECG showing ST-segment elevation. After treatment, the ECG shows resolution of ST-segment changes, but the patient continues to have chest pain. What is the most likely diagnosis?

Takotsubo cardiomyopathy. ***Takotsubo cardiomyopathy*** - Characterized by **transient ventricular dysfunction** (often apical ballooning) mimicking a heart attack, usually triggered by severe emotional or physical stress. - **Resolution of ST-segment elevation** but persistent chest pain after initial presentation, especially if coronary angiography is normal, strongly suggests this diagnosis. *Acute myocardial infarction* - While initially presenting with **ST-segment elevation** and chest pain, resolution of ST-segment changes without corresponding clinical improvement or complete resolution of symptoms would be unusual without reperfusion, and persistent pain might indicate ongoing ischemia or complications [1], [2]. - The key difference here is the **spontaneous resolution of ST elevation** while pain persists, and the absence of clear coronary artery occlusion in Takotsubo. *Myocarditis* - **Myocarditis** can cause chest pain and ECG abnormalities, including ST-segment elevation, but the specific pattern of resolution of ST changes with persistent pain and the typical trigger of emotional stress are less characteristic. - Diagnosis often involves **cardiac MRI** showing inflammation and is not characterized by the quick resolution of acute ECG changes seen here. *Pericarditis* - Pericarditis typically presents with **pleuritic chest pain** that is relieved by leaning forward, and diffused ST-segment elevation (often PR depression) followed by T-wave inversions. - The **resolution of ST-segment changes** mentioned, especially in the context of an initial ST elevation that might mimic an MI, does not fit the typical evolutionary ECG changes of pericarditis.

Q: What is a potential cause of cardiogenic shock other than myocardial infarction (MI)?

Acute mitral regurgitation. ***Acute mitral regurgitation*** - **Acute mitral regurgitation** is a severe form of valvular heart disease where the mitral valve fails to close properly, leading to a sudden backflow of blood into the left atrium during systole. [1] - This significantly reduces **forward cardiac output** and increases left atrial pressure, which can rapidly lead to pulmonary edema and cardiogenic shock, even in the absence of MI. [1] *Ventricular septal rupture* - While a **ventricular septal rupture** can cause cardiogenic shock, it is typically a **complication of myocardial infarction**, meaning it would fall under MI as the underlying cause. [2] - This condition involves a hole in the septum separating the ventricles, leading to a shunt and increased workload on the right ventricle, causing cardiogenic shock. *Isolated right ventricular shock* - **Isolated right ventricular shock** is often caused by conditions like a **massive pulmonary embolism** or a right ventricular infarction. [2] - While it can lead to shock, it is distinct from general cardiogenic shock which often implies left ventricular dysfunction or severe myocardial compromise, and the question asks for a cause *other than* MI, which can cause right ventricular shock. *None of the options* - This option is incorrect because **acute mitral regurgitation** is a distinct and significant cause of cardiogenic shock, independent of MI. [1]

Q: Which condition is associated with the ECG pattern known as pseudo P pulmonale?

Hypercalcemia. ***Hypercalcemia*** - **Hypercalcemia** can cause a characteristic ECG pattern known as pseudo P pulmonale due to its effects on **myocardial repolarization**. - This condition leads to a **shortened QT interval** which causes the T wave to merge with the P wave, giving the appearance of a tall, peaked P wave. *Hypokalemia* - **Hypokalemia** typically presents with **flattened T waves**, prominent U waves, and ST-segment depression on an ECG [1]. - It can prolong repolarization, which is the opposite effect observed with pseudo P pulmonale [1]. *Hyponatremia* - **Hyponatremia** has a less defined direct effect on ECG patterns compared to other electrolyte imbalances. - Severe hyponatremia may lead to **QRS widening** or **bradycardia**, but not pseudo P pulmonale [1]. *Hypocalcemia* - **Hypocalcemia** characteristically causes **prolongation of the QT interval** on an ECG due to delayed ventricular repolarization [2]. - This is distinct from the shortened QT seen in hypercalcemia that contributes to pseudo P pulmonale.

Q: At what time frame does peripartum cardiomyopathy typically occur?

Within 5 months of delivery. ***Within 5 months of delivery*** - **Peripartum cardiomyopathy** is defined as the development of heart failure with **left ventricular systolic dysfunction** occurring during the **last month of pregnancy or within five months after delivery**. - The postpartum component extends up to **5 months (approximately 20 weeks)** after delivery, making this the most complete answer among the given options. - This timeframe is essential for differentiating **peripartum cardiomyopathy** from other forms of cardiomyopathy. *Within 6 weeks of delivery* - While this represents the traditional postpartum period and many cases do present within 6 weeks, the diagnostic definition of **peripartum cardiomyopathy** extends further to **5 months postpartum**. - This narrower timeframe would miss cases presenting between 6 weeks and 5 months, thus not encompassing the full diagnostic criteria. *Within 24 months of delivery* - This timeframe significantly exceeds the established diagnostic window for **peripartum cardiomyopathy**. - Heart failure presenting beyond 5 months postpartum would likely be classified as **dilated cardiomyopathy** or another form of cardiomyopathy with different underlying causes. *Within 7 days of delivery* - This is too narrow a window and represents only the immediate postpartum period. - While some cases can present acutely in the first week, the diagnostic definition allows for onset up to **5 months postpartum**, and limiting it to 7 days would miss the majority of cases.

Q: Downhill esophageal varices develop as a result of obstruction of which vein?

Superior vena cava. ***Superior vena cava*** - Downhill esophageal varices are caused by obstruction of the **superior vena cava (SVC)**, leading to increased pressure in the venous drainage of the upper esophagus. - The collateral circulation needed to bypass the SVC obstruction involves veins that drain into the **azygos system**, which then communicates with the esophageal veins. *Portal vein* - Obstruction of the **portal vein** or portal hypertension typically leads to **uphill esophageal varices**, affecting the lower esophagus [1]. - These varices are part of the collateral circulation formed to decompress the portal system, often seen in conditions like **cirrhosis** [1]. *Hepatic vein* - Obstruction of the **hepatic veins** (e.g., Budd-Chiari syndrome) causes blood to back up into the liver, leading to **portal hypertension** and potentially uphill esophageal varices. - This condition primarily affects the liver and causes a distinct clinical picture of ascites, hepatomegaly, and abdominal pain, not directly downhill varices. *Inferior vena cava* - Obstruction of the **inferior vena cava (IVC)** primarily affects venous return from the lower body and the liver (if above the hepatic veins). - While it can indirectly affect portal pressure if liver drainage is compromised, it is not the direct cause of esophageal varices, especially not the downhill type, which involves the superior venous drainage.

Question 1

A patient presents with a regular wide QRS complex tachycardia (QRS >0.12 seconds) at a rate of 160 bpm. The ECG shows AV dissociation with fusion beats and capture beats. What is the most likely cardiac condition?

Accepted Answer

Ventricular tachycardia

Answer

Atrial fibrillation

Answer

Atrial flutter

Answer

Supraventricular tachycardia (SVT)

Question 2

Which murmur increases on standing?

Accepted Answer

HOCM

Answer

MR

Answer

MS

Answer

VSD

Question 3

Identify the condition in the ECG based on the provided image.

Accepted Answer

Atrial flutter

Answer

Atrial fibrillation

Answer

Arrhythmia

Answer

Cardiomyopathy

Question 4

What is the immediate treatment for a hemodynamically unstable patient with supraventricular tachycardia (SVT)?

Accepted Answer

Cardioversion

Answer

Intravenous Diltiazem

Answer

Intravenous Ibutilide

Answer

Intravenous beta-blockers

Question 5

Which rhythm classification is best supported by this single-lead ECG tracing?

Accepted Answer

Regular narrow-complex supraventricular tachycardia

Answer

Ventricular tachycardia

Answer

Atrial fibrillation with rapid ventricular response

Answer

Ventricular fibrillation

Question 6

A patient presents with chest pain and an ECG showing ST-segment elevation. After treatment, the ECG shows resolution of ST-segment changes, but the patient continues to have chest pain. What is the most likely diagnosis?

Accepted Answer

Takotsubo cardiomyopathy

Answer

Acute myocardial infarction

Answer

Myocarditis

Answer

Pericarditis

Question 7

What is a potential cause of cardiogenic shock other than myocardial infarction (MI)?

Accepted Answer

Acute mitral regurgitation

Answer

Ventricular septal rupture

Answer

Isolated right ventricular shock

Answer

None of the options

Question 8

Which condition is associated with the ECG pattern known as pseudo P pulmonale?

Accepted Answer

Hypercalcemia

Answer

Hyponatremia

Answer

Hypocalcemia

Answer

Hypokalemia

Question 9

At what time frame does peripartum cardiomyopathy typically occur?

Accepted Answer

Within 5 months of delivery

Answer

Within 6 weeks of delivery

Answer

Within 24 months of delivery

Answer

Within 7 days of delivery

Question 10

Downhill esophageal varices develop as a result of obstruction of which vein?

Accepted Answer

Superior vena cava

Answer

Portal vein

Answer

Hepatic vein

Answer

Inferior vena cava

Cardiology — MCQs

Cardiology — MCQs

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