palpitations

A 62-year-old man with a history of hypertension and type 2 diabetes mellitus presents to the emergency department complaining of palpitations and lightheadedness. He reports that the symptoms started suddenly about an hour ago. He denies any chest pain, shortness of breath, or syncope. His medications include metformin and lisinopril. On examination, he is alert and oriented. His blood pressure is 110/70 mmHg, heart rate is irregularly irregular at 140 bpm, respiratory rate is 18 breaths per minute, and oxygen saturation is 97% on room air. An ECG is performed, which shows an absence of P waves, irregularly irregular R-R intervals, and narrow QRS complexes. Which of the following is the most appropriate next step in the management of this patient?

A 25-year-old Aboriginal man presents to a remote clinic with increasing shortness of breath on exertion and palpitations over the past month. He recalls having a sore throat as a child but no specific diagnosis. On examination, his pulse is 95 bpm, blood pressure 110/70 mmHg, respiratory rate 20 breaths/min. Auscultation reveals a pansystolic murmur loudest at the apex, radiating to the axilla. There are no signs of heart failure currently. Considering the likely diagnosis and the patient's background, which of the following is the most appropriate initial investigation?

A 72-year-old man with a history of type 2 diabetes mellitus, hypertension, and chronic kidney disease (stage 3) presents with a 2-week history of exertional dyspnea and fatigue. He reports no chest pain but has noticed occasional palpitations. On examination, his blood pressure is 150/90 mmHg, heart rate is 110 bpm (irregularly irregular), respiratory rate is 20 breaths per minute, and oxygen saturation is 94% on room air. Cardiovascular examination reveals a variable intensity S1, no S3 or S4, and a soft systolic murmur at the apex. Lung fields are clear. An ECG shows absent P waves and irregularly irregular QRS complexes. Which of the following is the most appropriate next step in management?

A 45-year-old male with a history of hypertension presents with recurrent episodes of palpitations and near-syncope. His ECG during an episode shows a wide QRS complex tachycardia with a rate of 220 bpm. There is no evidence of structural heart disease on echocardiography. Which of the following is the most likely underlying mechanism of his arrhythmia?

A 45-year-old man with a history of hypertension presents to the emergency department with palpitations and lightheadedness. His ECG shows a regular narrow-complex tachycardia at a rate of 180 bpm. There are no visible P waves, and the QRS duration is 0.08 seconds. He is hemodynamically stable. Which of the following is the most appropriate initial management?

A 32-year-old woman presents to the clinic with a 2-week history of palpitations, anxiety, and weight loss despite an increased appetite. She also reports feeling hot and experiencing increased sweating. On examination, she has a fine tremor, warm moist skin, and a diffusely enlarged thyroid gland. Her heart rate is 110 bpm. Blood tests reveal suppressed TSH and elevated free T4. What is the most appropriate initial treatment for her condition?

A 62-year-old man presents to the emergency department with a history of palpitations and dizziness that started suddenly 2 hours ago. He has a history of hypertension and is on lisinopril. He denies chest pain, shortness of breath, or syncope. On examination, his blood pressure is 110/70 mmHg, heart rate is 150 bpm (irregular), respiratory rate is 18 breaths per minute, and temperature is 36.7°C. An ECG is performed, showing an irregularly irregular rhythm with no distinct P waves and a narrow QRS complex. Which of the following is the most appropriate initial management step?