Ventricular arrhythmias — MCQs

An ECG from an 8-year-old male with neurosensory deafness and a family history of sudden cardiac arrest demonstrates QT-interval prolongation. Which of the following is this patient most at risk of developing?

A 62-year-old man is brought to the emergency department because of syncope. He reports sudden onset of palpitations followed by loss of consciousness while carrying his groceries to his car. He is unable to recall any further details and does not have any chest pain or dizziness. He has a history of hypertension, type 2 diabetes mellitus, gastroparesis, and osteoarthritis of the knees. Medications include lisinopril, metformin, and ondansetron as needed for nausea. He also takes methadone daily for chronic pain. Apart from an abrasion on his forehead, he appears well. His temperature is 37.2 °C (98.9 F), heart rate is 104/min and regular, and blood pressure is 135/70 mm Hg. While he is in the emergency department, he loses consciousness again. Telemetry shows polymorphic ventricular tachycardia with cyclic alteration of the QRS axis that spontaneously resolves after 30 seconds. Results of a complete blood count, serum electrolyte concentrations, and serum thyroid studies show no abnormalities. Cardiac enzymes are within normal limits. Which of the following is the most likely underlying cause of this patient's syncope?

A 29-year-old woman with Wolff-Parkinson-White syndrome presents to her cardiologist’s office for a follow-up visit. She collapsed at her job and made a trip to the emergency department 1 week ago. At that time, she received a diagnosis of atrial fibrillation with rapid ventricular response and hemodynamic instability. While in the emergency department, she underwent direct-current cardioversion to return her heart to sinus rhythm. Her current medications include procainamide. At the cardiologist’s office, her heart rate is 61/min, respiratory rate is 16/min, the temperature is 36.5°C (97.7°F), and blood pressure is 118/60 mm Hg. Her cardiac examination reveals a regular rhythm and a I/VI systolic ejection murmur best heard at the right upper sternal border. An ECG obtained in the clinic is shown. Which of the following is the most appropriate treatment to prevent further episodes of tachyarrhythmia?

A 25-year-old man presents to the emergency department complaining of palpitations, lightheadedness, and sweating. He just started working at an investment firm and has been working long hours to make a good impression. Today, he had a dozen cups of espresso to keep himself awake and working. He has never had such an episode before. His past medical history is unremarkable. His pulse is 150/min, blood pressure is 134/88 mm Hg, respirations are 12/min, and temperature is 36.7°C (98.0°F). ECG shows supraventricular tachycardia. Which of the following is the next best step in the management of this patient?

An investigator is comparing the risk of adverse effects among various antiarrhythmic medications. One of the drugs being studied primarily acts by blocking the outward flow of K+ during myocyte repolarization. Further investigation shows that the use of this drug is associated with a lower rate of ventricular tachycardia, ventricular fibrillation, and torsades de pointes when compared to similar drugs. Which of the following drugs is most likely being studied?

A 45-year-old man comes to the physician for a routine health maintenance examination. He feels well. He underwent appendectomy at the age of 25 years. He has a history of hypercholesterolemia that is well controlled with atorvastatin. He is an avid marathon runner and runs 8 miles per day four times a week. His father died of myocardial infarction at the age of 42 years. The patient does not smoke or drink alcohol. His vital signs are within normal limits. Cardiopulmonary examination shows no abnormalities. His abdomen is soft and nontender with a surgical scar in the right lower quadrant. Laboratory studies are within normal limits. An ECG is shown. Which of the following is the most likely diagnosis?

A 55-year-old man with a past medical history of obesity and hyperlipidemia suddenly develops left-sided chest pain and shortness of breath while at work. He relays to coworkers that the pain is intense and has spread to his upper left arm over the past 10 minutes. He reports it feels a lot like the “heart attack” he had a year ago. He suddenly collapses and is unresponsive. Coworkers perform cardiopulmonary resuscitation for 18 minutes until emergency medical services arrives. Paramedics pronounce him dead at the scene. Which of the following is the most likely cause of death in this man?

A 40-year-old woman comes to the physician for a 6-month history of recurrent episodes of chest pain, racing pulse, dizziness, and difficulty breathing. The episodes last up to several minutes. She also reports urinary urgency and two episodes of loss of consciousness followed by spontaneous recovery. There is no personal or family history of serious illness. She does not smoke or drink alcohol. Vitals signs are within normal limits. Cardiopulmonary examination shows no abnormalities. Holter monitoring is performed. ECG recordings during episodes of tachycardia show a QRS duration of 100 ms, regular RR-interval, and absent P waves. Which of the following is the most likely underlying cause of this patient's condition?

A 62-year-old woman presents to the emergency department complaining of fever, worsening fatigue, and muscle weakness for the previous 48 hours. The patient describes her muscle weakness as symmetric and worse in the upper limbs. Her past medical history is significant for long-standing diabetes type 2 complicated by stage 5 chronic kidney disease (CKD) on hemodialysis. She takes lisinopril, verapamil, metformin, and glargine. Today, the patient’s vital signs include: temperature 38.6°C (101.5°F), pulse 80/min, blood pressure 155/89 mm Hg, respirations 24/min, and 95% oxygen saturation on room air. The cardiac and pulmonary exams are unremarkable. The abdomen is soft and non-tender. Her strength is 3/5 in the upper extremities and 4/5 in the lower extremities and her sensation is intact. Deep tendon reflexes are absent in both the upper and lower limbs. A 12-lead electrocardiogram (ECG) is shown in the image below. Blood work is drawn and the patient is admitted and started on continuous cardiac monitoring. Based on the available information, what is the next best step in managing this patient?

A 42-year-old man is brought to the emergency department 20 minutes after the sudden onset of severe chest pain, diaphoresis, shortness of breath, and palpitations. His symptoms occurred while he was at a party with friends. He has smoked one pack of cigarettes daily for 24 years. He uses cocaine occasionally. The last use was three hours ago. He appears pale. His pulse is 110/min, blood pressure is 178/106 mm Hg, and respirations are 24/min. His pupils are dilated and react sluggishly to light. The lungs are clear to auscultation. An ECG shows tachycardia and ST segment elevation in leads II, III, and aVF. While recording the ECG, the patient loses consciousness. A photo of the ECG at that point is shown. Which of the following is the most appropriate next step in management?