Match the following
A. Atrial fibrillation
B. Atrial flutter
C. PSVT
D. Ventricular tachycardia
Q2
A patient with a history of hypertension presents with atrial fibrillation, shortness of breath, and bilateral basal crackles on auscultation. Which of the following would be the least important in the management of this patient?
Q3
A patient is pulseless with the following rhythm shown in the ECG. What is the next best step in management?
Q4
Match the following ECG findings (1-4) with their corresponding arrhythmias (A-D):
1. Sawtooth pattern in leads II, III, aVF with regular ventricular response
2. Irregularly irregular rhythm with absent P waves
3. Narrow QRS tachycardia with abrupt onset/termination
4. Wide QRS tachycardia with AV dissociation
A. Atrial fibrillation
B. PSVT (Paroxysmal Supraventricular Tachycardia)
C. Atrial flutter
D. Ventricular tachycardia
What is the correct matching?
Q5
A 45-year-old male is brought into the emergency department by emergency medical services. The patient has a history of substance abuse and was found down in his apartment lying on his right arm. He was last seen 24 hours earlier by his mother who lives in the same building. He is disoriented and unable to answer any questions. His vitals are HR 48, T 97.6, RR 18, BP 100/75. You decide to obtain an EKG as shown in Figure 1. Which of the following is most likely the cause of this patient's EKG results?
Q6
A previously healthy 22-year-old woman comes to the emergency department because of several episodes of palpitations that began a couple of days ago. The palpitations are intermittent in nature, with each episode lasting 5–10 seconds. She states that during each episode she feels as if her heart is going to “spin out of control.” She has recently been staying up late to study for her final examinations. She does not drink alcohol or use illicit drugs. She appears anxious. Her temperature is 37°C (98.6°F), pulse is 75/min, and blood pressure is 110/75 mm Hg. Physical examination shows no abnormalities. An ECG is shown. Which of the following is the most appropriate next step in management?
Q7
A 23-year-old patient who has recently found out she was pregnant presents to her physician for her initial prenatal visit. The estimated gestational age is 10 weeks. Currently, the patient complains of recurrent palpitations. She is gravida 1 para 0 with no history of any major diseases. On examination, the blood pressure is 110/60 mm Hg heart rate, heart rate 94/min irregular, respiratory rate 12/min, and temperature 36.4°C (97.5°F). Her examination is significant for an opening snap before S2 and diastolic decrescendo 3/6 murmur best heard at the apex. No venous jugular distension or peripheral edema is noted. The patient’s electrocardiogram (ECG) is shown in the image. Cardiac ultrasound reveals the following parameters: left ventricular wall thickness 0.4 cm, septal thickness 1 cm, right ventricular wall thickness 0.5 cm, mitral valve area 2.2 cm2, and tricuspid valve area 4.1 cm2. Which of the following statements regarding this patient’s management is correct?
Q8
A 52-year-old woman presents with decreased exercise tolerance and difficulty breathing on exertion and while sleeping at night. She says that she requires 2 pillows to sleep at night to alleviate her shortness of breath. These symptoms started 6 months ago and are gradually increasing in severity. She does not have any chronic health problems. She has smoked 15 cigarettes per day for the past 20 years and drinks alcohol occasionally. Vital signs include: blood pressure 110/70 mm Hg, temperature 36.7°C (98.0°F), and regular pulse 90/min. On physical examination, the first heart sound is loud, and there is a low pitched rumbling murmur best heard at the cardiac apex. This patient is at high risk of developing which of the following complications?
Q9
A 63-year-old woman is brought to the emergency department 1 hour after the onset of right-sided weakness. She was eating breakfast when suddenly she could not lift her spoon. She cried out to her husband but her speech was slurred. For the past 4 months, she has been more anxious than usual and felt fatigued. She used to exercise regularly but had to give up her exercise routine 3 months ago because of lightheadedness and shortness of breath with exertion. She has a history of hypertension. She is a tax accountant and has had increased stress at work recently. She takes lisinopril daily and alprazolam as needed. Her temperature is 37.2°C (99.0°F), pulse is 138/min, respirations are 14/min, and blood pressure is 146/86 mm Hg. Her lungs are clear to auscultation bilaterally and she has an S1 with variable intensity. On neurologic examination, she has a right facial droop and 2/5 strength in the right shoulder, elbow, wrist, and fingers. Sensation is diminished in the right face and arm. Further evaluation is most likely to show which of the following?
Q10
Two days after an uncomplicated laparoscopic abdominal hernia repair, a 46-year-old man is evaluated for palpitations. He has a history of hypertension, type 2 diabetes mellitus, and a ventricular septal defect that closed spontaneously as a child. His father has coronary artery disease. Prior to admission, his only medications were hydrochlorothiazide and metformin. He currently also takes hydromorphone/acetaminophen for mild postoperative pain. He is 180 cm (5 ft 11 in) tall and weighs 100 kg (220 lb); BMI is 30.7 kg/m2. His temperature is 37.0°C (99°F), blood pressure is 139/85 mmHg, pulse is 75/min and irregular, and respirations are 14/min. Cardiopulmonary examination shows a normal S1 and S2 without murmurs and clear lung fields. The abdominal incisions are clean, dry, and intact. There is mild tenderness to palpation over the lower quadrants. An electrocardiogram is obtained and shown below. Which of the following is the most likely cause of this patient's ECG findings?
Arrhythmias US Medical PG Practice Questions and MCQs
Question 1: Match the following
A. Atrial fibrillation
B. Atrial flutter
C. PSVT
D. Ventricular tachycardia
A. A-1, B-2, C-3, D-4
B. A-2, B-1, C-3, D-4 (Correct Answer)
C. A-1, B-2, C-4, D-3
D. A-4, B-3, C-2, D-1
E. A-2, B-1, C-4, D-3
Explanation: ***A-2, B-1, C-3, D-4***
- Image 2 shows irregularly irregular QRS complexes with no discernible P waves, which is characteristic of **atrial fibrillation**.
- Image 1 shows a "sawtooth" pattern of atrial activity, indicative of **atrial flutter**.
- Image 3 displays a narrow complex tachycardia with a very regular rhythm, consistent with **PSVT**.
- Image 4 demonstrates wide, regular QRS complexes without clear P waves, which is the hallmark of **ventricular tachycardia**.
*A-1, B-2, C-3, D-4*
- This option incorrectly matches atrial fibrillation with the "sawtooth" pattern (image 1) and atrial flutter with the irregularly irregular rhythm (image 2).
- Atrial fibrillation is characterized by the absence of discrete P waves and irregular ventricular response (image 2), while atrial flutter shows organized atrial activity with a "sawtooth" pattern (image 1).
*A-1, B-2, C-4, D-3*
- This option misidentifies image 1 as atrial fibrillation and image 2 as atrial flutter, which are reversed.
- It also incorrectly matches PSVT with image 4 (ventricular tachycardia) and ventricular tachycardia with image 3 (PSVT).
*A-2, B-1, C-4, D-3*
- This option correctly identifies atrial fibrillation (A-2) and atrial flutter (B-1), but incorrectly swaps the ventricular and supraventricular tachycardias.
- Image 3 shows narrow complex tachycardia (PSVT), not the wide complex pattern of ventricular tachycardia seen in image 4.
*A-4, B-3, C-2, D-1*
- This option incorrectly matches all the rhythms to the wrong images, demonstrating a fundamental misunderstanding of their characteristic ECG features.
- For example, it matches atrial fibrillation to image 4 (ventricular tachycardia) and ventricular tachycardia to image 1 (atrial flutter).
Question 2: A patient with a history of hypertension presents with atrial fibrillation, shortness of breath, and bilateral basal crackles on auscultation. Which of the following would be the least important in the management of this patient?
A. Start on anticoagulants
B. Start β-blocker
C. Cardioversion to correct rhythm if hemodynamically remains unstable even after medical management
D. IV Digoxin for control rate (Correct Answer)
E. Administer diuretics for fluid overload
Explanation: ***IV Digoxin for control rate***
- While **Digoxin** can be used for **rate control in atrial fibrillation**, its role is limited, especially in patients with **congestive heart failure** due to its delayed onset of action and narrow therapeutic window.
- In a patient with **shortness of breath** and **bilateral basal crackles** (suggesting acute decompensated heart failure), rapid rate control with a **β-blocker** or **calcium channel blocker** is usually preferred for immediate symptom relief.
- Digoxin is not first-line therapy in this acute setting and is therefore the **least important** among the management options listed.
*Start on anticoagulants*
- **Anticoagulation** is crucial for patients with **atrial fibrillation** to prevent **thromboembolic events**, particularly strokes.
- Given the patient's history of **hypertension** and presence of **atrial fibrillation**, their **CHA2DS2-VASc score** is likely elevated, necessitating anticoagulation.
*Start β-blocker*
- **Beta-blockers** are first-line agents for **rate control in atrial fibrillation**, especially in patients with **hypertension** and signs of **heart failure**.
- They effectively reduce ventricular response rate, improve diastolic filling, and can alleviate symptoms like **shortness of breath**.
*Cardioversion to correct rhythm if hemodynamically remains unstable even after medical management*
- If a patient with **atrial fibrillation** and signs of **heart failure** remains **hemodynamically unstable** despite initial medical management (e.g., rate control, diuretics), **cardioversion** (electrical or pharmacological) is an essential intervention to restore sinus rhythm.
- This can acutely improve cardiac output and resolve symptoms of **decompensated heart failure**.
*Administer diuretics for fluid overload*
- **Diuretics** (e.g., furosemide) are essential for managing the **volume overload** in this patient, as evidenced by **bilateral basal crackles** and **shortness of breath**.
- Reducing preload helps improve **pulmonary congestion** and alleviates acute heart failure symptoms.
- Loop diuretics are a cornerstone of acute decompensated heart failure management.
Question 3: A patient is pulseless with the following rhythm shown in the ECG. What is the next best step in management?
A. Defibrillate and continue chest compression (Correct Answer)
B. Defibrillate and check pulse
C. Check pulse and give synchronized DC
D. Give synchronized DC and continue chest compressions
E. Start chest compressions and give epinephrine
Explanation: ***Defibrillate and continue chest compression***
- This scenario describes a **pulseless ventricular tachycardia (pVT)**, which is a **shockable rhythm**.
- Immediate defibrillation is crucial, followed by resuming **chest compressions** without delay, as per advanced cardiac life support (ACLS) guidelines.
- The correct sequence is: shock → immediate CPR for 2 minutes → rhythm/pulse check.
*Defibrillate and check pulse*
- While defibrillation is the correct initial intervention for a shockable rhythm, checking the pulse immediately after is incorrect.
- Chest compressions should be resumed immediately after a shock for 2 minutes before stopping to check a pulse.
- Minimizing interruptions in chest compressions is critical for survival.
*Check pulse and give synchronized DC*
- Checking a pulse before any intervention wastes critical time in a pulseless patient with a shockable rhythm; immediate defibrillation is indicated.
- Synchronized direct current (DC) cardioversion is used for unstable patients **with a pulse** (e.g., unstable ventricular tachycardia with a pulse), not for pulseless rhythms.
*Give synchronized DC and continue chest compressions*
- Synchronized DC cardioversion is inappropriate for a **pulseless rhythm**; unsynchronized defibrillation is required.
- Synchronization requires an R wave to time the shock, which is not feasible in pulseless VT management.
*Start chest compressions and give epinephrine*
- While chest compressions are essential, the **immediate priority** for a shockable rhythm (pVT/VF) is **defibrillation**.
- Epinephrine is given during CPR cycles (after the first shock), but defibrillation must come first for shockable rhythms.
- This would be the approach for **non-shockable rhythms** (PEA/asystole), not pulseless VT.
Question 4: Match the following ECG findings (1-4) with their corresponding arrhythmias (A-D):
1. Sawtooth pattern in leads II, III, aVF with regular ventricular response
2. Irregularly irregular rhythm with absent P waves
3. Narrow QRS tachycardia with abrupt onset/termination
4. Wide QRS tachycardia with AV dissociation
A. Atrial fibrillation
B. PSVT (Paroxysmal Supraventricular Tachycardia)
C. Atrial flutter
D. Ventricular tachycardia
What is the correct matching?
A. A-2, B-1, C-3, D-4
B. A-1, B-2, C-4, D-3
C. A-2, B-3, C-1, D-4 (Correct Answer)
D. A-4, B-3, C-2, D-1
E. A-1, B-2, C-3, D-4
Explanation: The correct matching is **A-2, B-3, C-1, D-4**:
***C-1: Atrial flutter - Sawtooth pattern***
- Atrial flutter is characterized by a **sawtooth pattern** of flutter waves, particularly prominent in leads II, III, and aVF
- Represents rapid, organized atrial depolarization at 250-350 bpm
- Regular ventricular response due to **AV block** (commonly 2:1 or 4:1)
- The sawtooth pattern is the pathognomonic feature
***A-2: Atrial fibrillation - Irregularly irregular rhythm***
- Identified by an **irregularly irregular rhythm** with absent distinct P waves
- Replaced by chaotic fibrillatory waves showing disorganized atrial activity
- Ventricular rate is rapid and unpredictable
- No organized atrial pattern unlike the regular flutter waves
***B-3: PSVT - Narrow QRS with abrupt onset/termination***
- Presents with **narrow QRS complex tachycardia** (QRS < 0.12 seconds) with regular rhythm
- Atrial rate usually 150-250 bpm
- **Abrupt onset and termination** is the characteristic feature differentiating it from other supraventricular arrhythmias
- P waves may be hidden within or immediately after QRS complexes
***D-4: Ventricular tachycardia - Wide QRS with AV dissociation***
- Defined by **wide QRS complex tachycardia** (QRS > 0.12 seconds)
- **AV dissociation** is a key diagnostic feature showing independent atrial and ventricular activity
- Originates from ventricular tissue, not supraventricular structures
- Lacks the organized P wave patterns seen in atrial arrhythmias
Question 5: A 45-year-old male is brought into the emergency department by emergency medical services. The patient has a history of substance abuse and was found down in his apartment lying on his right arm. He was last seen 24 hours earlier by his mother who lives in the same building. He is disoriented and unable to answer any questions. His vitals are HR 48, T 97.6, RR 18, BP 100/75. You decide to obtain an EKG as shown in Figure 1. Which of the following is most likely the cause of this patient's EKG results?
A. Hypocalcemia
B. Hypercalcemia
C. Hypomagnesemia
D. Hypokalemia
E. Hyperkalemia (Correct Answer)
Explanation: ***Hyperkalemia***
- This patient's presentation with **bradycardia**, potential **rhabdomyolysis** from being "found down" and immobility, and the EKG showing changes like **peaked T waves** (often the first EKG sign) are all highly suggestive of hyperkalemia.
- Prolonged immobility (lying on arm for 24 hours) can lead to **muscle breakdown**, releasing significant intracellular potassium into the bloodstream.
*Hypocalcemia*
- Hypocalcemia typically manifests on EKG as **QT interval prolongation**, not peaked T waves or bradycardia.
- While some forms of muscle injury can affect calcium, it's not the primary EKG finding expected with rhabdomyolysis.
*Hypercalcemia*
- Hypercalcemia is associated with a **shortened QT interval** on EKG.
- It is unlikely to cause severe bradycardia or marked T wave changes as seen in profound hyperkalemia.
*Hypomagnesemia*
- Hypomagnesemia can cause various EKG changes, including **QT prolongation** and an increased risk of **torsades de pointes**, but not typically the peaked T waves characteristic of this scenario.
- It often coexists with hypokalemia but isn't the primary explanation for the EKG findings described.
*Hypokalemia*
- Hypokalemia is associated with **flattened T waves**, prominent **U waves**, and often **QT prolongation** as well as various arrhythmias.
- It is highly unlikely to cause the **peaked T waves** and **bradycardia** observed in this patient.
Question 6: A previously healthy 22-year-old woman comes to the emergency department because of several episodes of palpitations that began a couple of days ago. The palpitations are intermittent in nature, with each episode lasting 5–10 seconds. She states that during each episode she feels as if her heart is going to “spin out of control.” She has recently been staying up late to study for her final examinations. She does not drink alcohol or use illicit drugs. She appears anxious. Her temperature is 37°C (98.6°F), pulse is 75/min, and blood pressure is 110/75 mm Hg. Physical examination shows no abnormalities. An ECG is shown. Which of the following is the most appropriate next step in management?
A. Echocardiography
B. Pharmacologic cardioversion
C. Observation and rest (Correct Answer)
D. Electrical cardioversion
E. Cardiac catheter ablation
Explanation: ***Observation and rest***
- The ECG shows a **normal sinus rhythm with no acute abnormalities**, and the patient's symptoms are intermittent and brief, lasting only 5-10 seconds, which suggests **benign palpitations** possibly related to anxiety and stress (studying for finals, staying up late).
- Given the patient's **hemodynamic stability** (BP 110/75 mmHg, HR 75/min), normal physical examination, and absence of alarm symptoms (e.g., chest pain, syncope, severe dyspnea), a conservative approach with observation and reassurance is appropriate.
*Echocardiography*
- Echocardiography is typically reserved for ruling out **structural heart disease** when there are concerning features such as murmurs, signs of heart failure, or sustained rhythm disturbances.
- The patient's ECG is normal, her physical examination is unremarkable, and her symptoms are transient, making it unlikely that a structural abnormality is the cause.
*Pharmacologic cardioversion*
- Pharmacologic cardioversion is indicated for **sustained tachyarrhythmias** that are causing significant symptoms or are hemodynamically unstable, or for atrial fibrillation/flutter of recent onset.
- The patient's heart rate is normal (75/min), and her palpitations are brief and intermittent, indicating that she is not in a sustained tachyarrhythmia requiring cardioversion.
*Electrical cardioversion*
- Electrical cardioversion is used for **unstable tachyarrhythmias** causing hemodynamic compromise (e.g., hypotension, shock, acute heart failure) or for sustained tachyarrhythmias refractory to pharmacologic treatment.
- The patient is hemodynamically stable, her ECG shows no acute arrhythmia, and her symptoms are not severe enough to warrant immediate electrical intervention.
*Cardiac catheter ablation*
- Cardiac catheter ablation is a procedure typically performed to treat **recurrent, symptomatic tachyarrhythmias** that are refractory to antiarrhythmic medications or when long-term drug therapy is not desired.
- This is an invasive procedure and is not indicated for intermittent, brief palpitations in a hemodynamically stable patient with a normal ECG and no clear evidence of a significant arrhythmia.
Question 7: A 23-year-old patient who has recently found out she was pregnant presents to her physician for her initial prenatal visit. The estimated gestational age is 10 weeks. Currently, the patient complains of recurrent palpitations. She is gravida 1 para 0 with no history of any major diseases. On examination, the blood pressure is 110/60 mm Hg heart rate, heart rate 94/min irregular, respiratory rate 12/min, and temperature 36.4°C (97.5°F). Her examination is significant for an opening snap before S2 and diastolic decrescendo 3/6 murmur best heard at the apex. No venous jugular distension or peripheral edema is noted. The patient’s electrocardiogram (ECG) is shown in the image. Cardiac ultrasound reveals the following parameters: left ventricular wall thickness 0.4 cm, septal thickness 1 cm, right ventricular wall thickness 0.5 cm, mitral valve area 2.2 cm2, and tricuspid valve area 4.1 cm2. Which of the following statements regarding this patient’s management is correct?
A. Beta-blockers are the preferable drug class for rate control in this case. (Correct Answer)
B. The patient requires balloon commissurotomy.
C. It is critical to reduce the heart rate below 60/min because of physiological tachycardia later in pregnancy.
D. Warfarin should be used for thromboembolism prophylaxis.
E. It is reasonable to start diuretic therapy right at this moment.
Explanation: ***Beta-blockers are the preferable drug class for rate control in this case.***
- The patient presents with **atrial fibrillation** (irregular heart rate, palpitations, ECG findings) in early pregnancy, which requires rate control to optimize cardiac output and diastolic filling.
- **Beta-blockers** (such as metoprolol or labetalol) are the **preferred first-line agents** for rate control in pregnant patients with atrial fibrillation because they are relatively safe in pregnancy and effectively control ventricular rate.
- The patient has mild mitral stenosis findings (opening snap, diastolic murmur), but the **mitral valve area of 2.2 cm²** is essentially **normal** (normal MVA >2.0 cm²), so the primary concern is managing the atrial fibrillation.
- Rate control is particularly important in pregnancy due to increased cardiac demands and the need to optimize diastolic filling time.
*It is reasonable to start diuretic therapy right at this moment.*
- **Diuretics** are generally avoided in early pregnancy unless there is clear evidence of **pulmonary congestion** or **heart failure** with volume overload.
- This patient shows **no signs of fluid overload**: no jugular venous distension, no peripheral edema, normal blood pressure.
- Starting diuretics without volume overload can lead to **reduced placental perfusion** and potentially compromise fetal growth.
- Diuretics would be indicated if the patient develops signs of heart failure or pulmonary congestion later in pregnancy.
*The patient requires balloon commissurotomy.*
- **Balloon commissurotomy** is reserved for patients with **severe symptomatic mitral stenosis** (mitral valve area <1.5 cm²) who are refractory to medical management.
- With a **mitral valve area of 2.2 cm²**, the patient has essentially **normal valve area** (or at most very mild stenosis), making invasive intervention completely unnecessary.
- The patient's symptoms are due to **atrial fibrillation**, not hemodynamically significant mitral stenosis.
*It is critical to reduce the heart rate below 60/min because of physiological tachycardia later in pregnancy.*
- While rate control is important in atrial fibrillation, targeting a heart rate **below 60/min** is excessively low and can lead to **bradycardia** with reduced cardiac output.
- The appropriate target for rate control in atrial fibrillation is typically **60-80 bpm at rest** and **<110 bpm with activity**.
- Pregnancy physiologically increases heart rate by 10-20 bpm, so overly aggressive rate control (HR <60) would be detrimental to maternal and fetal perfusion.
- The goal is **adequate rate control**, not excessive bradycardia.
*Warfarin should be used for thromboembolism prophylaxis.*
- **Warfarin is teratogenic** and is **absolutely contraindicated** in the first trimester of pregnancy due to the risk of **fetal warfarin syndrome** (nasal hypoplasia, stippled epiphyses, CNS abnormalities).
- For pregnant patients with atrial fibrillation requiring anticoagulation, **unfractionated heparin** or **low-molecular-weight heparin (LMWH)** should be used during the first trimester.
- Warfarin may be considered in the **second and third trimesters** in select high-risk patients (such as mechanical valves), but should be switched back to heparin near term.
- This patient at 10 weeks gestation is in the critical first trimester period where warfarin must be avoided.
Question 8: A 52-year-old woman presents with decreased exercise tolerance and difficulty breathing on exertion and while sleeping at night. She says that she requires 2 pillows to sleep at night to alleviate her shortness of breath. These symptoms started 6 months ago and are gradually increasing in severity. She does not have any chronic health problems. She has smoked 15 cigarettes per day for the past 20 years and drinks alcohol occasionally. Vital signs include: blood pressure 110/70 mm Hg, temperature 36.7°C (98.0°F), and regular pulse 90/min. On physical examination, the first heart sound is loud, and there is a low pitched rumbling murmur best heard at the cardiac apex. This patient is at high risk of developing which of the following complications?
A. Cardiac arrhythmia (Correct Answer)
B. Infective endocarditis
C. Systemic thromboembolism
D. Pulmonary hypertension
E. Right heart failure
Explanation: ***Cardiac arrhythmia***
- The patient's symptoms, including **paroxysmal nocturnal dyspnea**, **orthopnea**, **exertional dyspnea**, and an apical **low-pitched rumbling diastolic murmur** with a **loud S1**, are highly suggestive of **mitral stenosis**.
- **Mitral stenosis** leads to increased **left atrial pressure** and progressive **left atrial enlargement**, making the left atrium particularly vulnerable to developing **atrial fibrillation**, which is the **most common complication** occurring in 30-40% of patients.
- Atrial fibrillation can cause palpitations, worsen heart failure symptoms, and significantly increase stroke risk.
*Infective endocarditis*
- While patients with **mitral stenosis** have an increased risk of endocarditis, this is a less common complication compared to atrial fibrillation.
- There are no signs of active infection such as fever, new murmur changes, or systemic inflammatory response in this presentation.
*Systemic thromboembolism*
- **Thromboembolism** is a serious complication of mitral stenosis, particularly when complicated by atrial fibrillation, but the **left atrial enlargement** and stasis that predispose to arrhythmias occur first.
- Without established atrial fibrillation, the immediate risk of arrhythmia development is higher than thromboembolic events.
*Pulmonary hypertension*
- **Pulmonary hypertension** develops as a consequence of chronic elevation in left atrial pressure transmitting back to the pulmonary vasculature.
- While this is a recognized complication, it typically develops later in the disease course, and **atrial fibrillation** remains the most common complication.
*Right heart failure*
- **Right heart failure** can occur secondary to pulmonary hypertension from long-standing mitral stenosis.
- This represents a later-stage complication, whereas atrial arrhythmias occur earlier and more frequently in the natural history of mitral stenosis.
Question 9: A 63-year-old woman is brought to the emergency department 1 hour after the onset of right-sided weakness. She was eating breakfast when suddenly she could not lift her spoon. She cried out to her husband but her speech was slurred. For the past 4 months, she has been more anxious than usual and felt fatigued. She used to exercise regularly but had to give up her exercise routine 3 months ago because of lightheadedness and shortness of breath with exertion. She has a history of hypertension. She is a tax accountant and has had increased stress at work recently. She takes lisinopril daily and alprazolam as needed. Her temperature is 37.2°C (99.0°F), pulse is 138/min, respirations are 14/min, and blood pressure is 146/86 mm Hg. Her lungs are clear to auscultation bilaterally and she has an S1 with variable intensity. On neurologic examination, she has a right facial droop and 2/5 strength in the right shoulder, elbow, wrist, and fingers. Sensation is diminished in the right face and arm. Further evaluation is most likely to show which of the following?
A. Irregularly irregular rhythm without P waves on ECG (Correct Answer)
B. Left-sided carotid stenosis on duplex ultrasound
C. Crescent-shaped hyperdense lesion on head CT
D. Intraparenchymal hyperdensity on head CT
E. Spikes and sharp waves in temporal region on EEG
Explanation: ***Irregularly irregular rhythm without P waves on ECG***
- The sudden onset of right-sided weakness and slurred speech suggests an **acute ischemic stroke**. The patient's history of lightheadedness, shortness of breath on exertion, and a pulse of 138/min with variable S1 intensity are highly suggestive of **atrial fibrillation (Afib)**, a common cause of cardioembolic stroke.
- An **irregularly irregular rhythm without P waves on ECG** is the hallmark finding of atrial fibrillation.
*Spikes and sharp waves in temporal region on EEG*
- **Spikes and sharp waves on EEG** are characteristic findings in **epilepsy**, particularly in the temporal lobe for temporal lobe epilepsy.
- While a seizure could present with focal neurological deficits, the sudden onset, persistent deficits, and history of cardiac symptoms make stroke more likely than an acute seizure as the primary etiology here.
*Left-sided carotid stenosis on duplex ultrasound*
- **Carotid stenosis** is a common cause of ischemic stroke, usually ipsilateral to the symptomatic side. However, the patient's symptoms are on the right side, suggesting a lesion in the **left cerebral hemisphere**.
- While **left-sided carotid stenosis** could cause a stroke affecting the right side of the body, the cardiac symptoms and examination findings (tachycardia, variable S1) make a cardioembolic source (like Afib) a more likely primary cause in this specific scenario.
*Crescent-shaped hyperdense lesion on head CT*
- A **crescent-shaped hyperdense lesion** on head CT is characteristic of a **subdural hematoma**, which is typically caused by trauma and results from venous bleeding.
- The patient's presentation of sudden-onset neurological deficits without trauma is inconsistent with a subdural hematoma.
*Intraparenchymal hyperdensity on head CT*
- An **intraparenchymal hyperdensity** on head CT indicates an **intracerebral hemorrhage**. While this can cause sudden neurological deficits, the patient's other symptoms, especially the rapid heart rate and variable S1, point more strongly towards an **ischemic event** secondary to an embolic source.
- An intracerebral hemorrhage is less likely given the absence of typical risk factors for hemorrhagic stroke (e.g., uncontrolled severe hypertension, anticoagulant use) and the strong indicators for a cardiac embolic source.
Question 10: Two days after an uncomplicated laparoscopic abdominal hernia repair, a 46-year-old man is evaluated for palpitations. He has a history of hypertension, type 2 diabetes mellitus, and a ventricular septal defect that closed spontaneously as a child. His father has coronary artery disease. Prior to admission, his only medications were hydrochlorothiazide and metformin. He currently also takes hydromorphone/acetaminophen for mild postoperative pain. He is 180 cm (5 ft 11 in) tall and weighs 100 kg (220 lb); BMI is 30.7 kg/m2. His temperature is 37.0°C (99°F), blood pressure is 139/85 mmHg, pulse is 75/min and irregular, and respirations are 14/min. Cardiopulmonary examination shows a normal S1 and S2 without murmurs and clear lung fields. The abdominal incisions are clean, dry, and intact. There is mild tenderness to palpation over the lower quadrants. An electrocardiogram is obtained and shown below. Which of the following is the most likely cause of this patient's ECG findings?
A. Hydromorphone administration
B. Hypokalemia (Correct Answer)
C. Accessory pathway in the heart
D. Atrial enlargement
E. Acute myocardial ischemia
Explanation: ***Hypokalemia***
- The ECG shows **prominent U waves**, which are characteristic of and most often associated with **hypokalemia**. The patient's history of being on **hydrochlorothiazide**, a thiazide diuretic, increases the risk of electrolyte disturbances, including hypokalemia.
- While the patient's pulse is 75/min and irregular, the primary finding on the ECG that points to hypokalemia is the presence of **U waves**, which can also predispose to arrhythmias.
*Hydromorphone administration*
- Opioids like hydromorphone can cause various side effects, but they typically **do not directly cause U waves** on an ECG or directly lead to the specific type of irregular rhythm seen with hypokalemia.
- Common cardiac side effects of opioids include **bradycardia** or **QT prolongation**, which are not consistently present or the most prominent finding here.
*Accessory pathway in the heart*
- An accessory pathway often presents with a **short PR interval** and a **delta wave** (pre-excitation) on ECG, indicative of conditions like Wolff-Parkinson-White syndrome. These findings are not described in the ECG provided or implied by the symptoms.
- While an accessory pathway can cause palpitations due to reentrant tachycardias, the specific ECG finding of prominent U waves is **not consistent** with an accessory pathway.
*Atrial enlargement*
- **Left atrial enlargement** can manifest as a **notched P wave** (P mitrale) or a **prolonged P wave duration** on ECG, while **right atrial enlargement** might show a **tall, peaked P wave** (P pulmonale).
- The ECG findings described (prominent U waves, irregular pulse) are not characteristic of either left or right atrial enlargement.
*Acute myocardial ischemia*
- Acute myocardial ischemia would typically present with ECG changes such as **ST segment elevation or depression**, **T wave inversions**, or **new Q waves**.
- While palpitations can be a symptom of ischemia, the described ECG findings, particularly the **prominent U waves**, are not indicative of acute myocardial ischemia.