A 62-year-old man with ischemic cardiomyopathy (LVEF 30%) and a prior myocardial infarction presents with sudden onset of a regular, wide-complex tachycardia at 160 bpm. ECG shows a QRS duration of 160 ms with uniform morphology, and he remains hemodynamically stable. Which of the following is the most likely mechanism of this arrhythmia?

A 65-year-old man is admitted to the ICU with acute decompensated heart failure. Continuous ECG monitoring reveals a wide-complex tachycardia at 150 beats per minute. The rhythm strip shows beat-to-beat variation in QRS morphology and axis. His corrected QT interval (QTc) is measured at 420 ms. Electrolytes are within normal limits. The patient is hemodynamically stable but symptomatic with palpitations and mild hypotension. Based on the ECG findings and clinical context, which of the following is the MOST appropriate classification of this arrhythmia?

A 65-year-old man with a history of heart failure with reduced ejection fraction (HFrEF, LVEF 25%) is admitted to the ICU with acute respiratory distress syndrome, intubated and on mechanical ventilation. He is receiving a norepinephrine infusion via a central venous catheter to maintain mean arterial pressure. During evening rounds, the continuous cardiac monitor alarms, showing sustained polymorphic ventricular tachycardia (PVT) that degenerates into ventricular fibrillation (VF), requiring immediate defibrillation. His baseline ECG showed normal sinus rhythm with left bundle branch block. A STAT ECG now reveals new ST-segment elevations in the inferior leads. Recent labs show potassium 3.8 mmol/L and magnesium 1.9 mg/dL. He is not on any QT-prolonging medications. Which of the following is the most likely precipitant of this patient’s ventricular arrhythmia?

A 16-year-old female presents for a routine follow-up in the cardiology clinic. She was recently diagnosed with congenital Long QT Syndrome after an exercise-triggered syncopal episode and an outpatient ECG showing a QTc of 520 ms. Her family history is notable for sudden cardiac death in a paternal aunt at a young age. She is currently asymptomatic, and her physical examination is unremarkable. Which of the following is the MOST appropriate first-line pharmacologic therapy for this patient’s Long QT Syndrome?

A 65-year-old man with ischemic cardiomyopathy (left ventricular ejection fraction 30%) is intubated and receiving a norepinephrine infusion in the cardiac intensive care unit. Telemetry suddenly shows a wide-complex tachycardia at 180 bpm, and he immediately becomes unresponsive with loss of blood pressure and a nonpalpable pulse. Among the following clinical presentations of ventricular arrhythmias, which represents the most life-threatening scenario?

A 62-year-old man with ischemic cardiomyopathy and NYHA Class II heart failure symptoms has an LVEF of 30% despite at least 6 months of guideline-directed medical therapy. He is 8 months post–myocardial infarction with no history of sustained ventricular arrhythmias or cardiac arrest. According to the 2017 AHA/ACC/HRS guidelines, which statement best characterizes the indication for ICD implantation in this patient?

A 62-year-old man with ischemic cardiomyopathy (LVEF 30%) and an anterior myocardial infarction 3 weeks ago is found to have a regular wide-complex tachycardia at 180 bpm on telemetry. He is alert and oriented with a palpable pulse of 180 bpm and blood pressure 105/60 mmHg (MAP 75 mmHg). A 12-lead ECG shows uniform QRS complexes measuring 0.16 seconds and no visible P waves. Next best step in management?

A 62-year-old man is admitted to the intensive care unit following resuscitation from cardiac arrest. He is found to be in sustained monomorphic ventricular tachycardia (VT) on continuous ECG monitoring. On examination, his blood pressure is borderline low at 90/60 mm Hg, he is confused with altered mental status, and shows signs of poor peripheral perfusion including cool extremities and delayed capillary refill. Laboratory studies reveal metabolic acidosis. Given this clinical presentation, what is the MOST appropriate classification of his arrhythmia and the immediate management step?

A 62-year-old man suddenly develops a regular, wide-QRS complex tachycardia at 180 bpm. He becomes hypotensive (BP 70/40 mmHg) and unresponsive to verbal stimuli but remains pulseless. Which of the following is the most appropriate immediate intervention?

A 65-year-old man presents to the intensive care unit with a 2-hour history of sustained monomorphic ventricular tachycardia. His history is notable for a myocardial infarction 3 years ago with resultant ischemic cardiomyopathy (left ventricular ejection fraction 35%). He is on metoprolol and lisinopril at home. On exam he is alert, blood pressure is 120/75 mm Hg, and there are no signs of acute heart failure or ongoing ischemia. Electrolytes and cardiac biomarkers are within normal limits. Given his stable clinical status, reduced LVEF, and structural heart disease, which intravenous antiarrhythmic agent is the MOST appropriate initial therapy?