Cardiac Cycle

A 52-year-old man presents with exertional chest pain and dyspnea. On examination, a late systolic murmur is heard at the apex, preceded by a mid-systolic click. Echocardiography confirms mitral valve prolapse with mild regurgitation. Which investigation is most appropriate to assess the risk of sudden cardiac death and guide management in this patient?

Which finding best distinguishes the rapid ventricular filling phase from the slow ventricular filling phase (diastasis) of the cardiac cycle?

Which feature best distinguishes the isovolumetric contraction phase from the isovolumetric relaxation phase of the cardiac cycle?

A 52-year-old man with a history of hypertension presents to the emergency department with acute onset chest pain radiating to the left arm and diaphoresis. His ECG shows ST elevation in leads II, III, and aVF. His blood pressure is 145/92 mmHg, heart rate 98/min, and respiratory rate 20/min. Troponin I is elevated at 2.8 ng/mL (normal <0.04). What is the most appropriate immediate next step in management?

A 65-year-old woman with atrial fibrillation (AF) and a rapid ventricular response (HR 120 bpm) presents to the emergency department. She is haemodynamically stable. Which drug is the first-line choice for acute rate control in this patient?