A 56-year-old man presents to the emergency room with nausea, vomiting, muscle cramps, and weakness that began three days ago. Five days ago, he started taking Penicillin G for acute pharyngitis and has been using it regularly along with his other medications: lisinopril, atorvastatin, and spironolactone. On physical examination, he appears anxious and distressed, has difficulty walking, and shows decreased sensations and reflexes in all four extremities. Laboratory studies reveal a potassium level of 6.8 mmol/L. An ECG reveals changes consistent with hyperkalemia. Which of the following medications can contribute to this condition?

A 13 year-old female is brought to the emergency room because she has been spitting up blood stained sputum for the last three days. She is having shortness of breath even with a short walk and passing out with exertion. Often her skin, lips and nails turn a bluish tone. Physical examination shows cyanosis in the lips and digital clubbing in both upper extremities. On auscultation, first heart sound is normal and P2 is markedly accentuated; a soft holosystolic murmur is heard in the tricuspid area and a long diastolic murmur is heard in the pulmonary area. A chest x-ray showed right ventricular enlargement with filling in of the retrosternal air space; dilated central pulmonary arteries, abrupt attenuation and termination of peripheral pulmonary artery branches. ECG showed normal voltages and no beat-to-beat variation; it revealed the right atrial enlargement and right ventricular hypertrophy with a rightward axis. Echocardiogram corroborates the findings observed on chest x ray and ECG. Patient could not finish the 6-minute walk testing (6MWT). Which of the following is most likely found in this patient?

A 6-month-old boy is brought to your pediatric cardiology clinic for evaluation of a murmur that was heard during a routine check-up by his primary care physician. His mother reports that he is healthy and active, with no episodes of shortness of breath or frequent infections. On physical examination, he appears well-nourished and appropriately sized for his age. Auscultation reveals a harsh, holosystolic murmur at the left lower sternal border. There is no cyanosis or clubbing. An echocardiogram reveals a small, isolated ventricular septal defect (VSD) with a left-to-right shunt. What is the most appropriate next step in the management of this patient?

A 6 month-old boy is brought to your pediatric cardiology clinic for evaluation of a murmur heard by her primary care doctor. Her mother informs you that he is healthy and active. He is playful, no shortness of breath, and no childhood infections, not more than usual for other kids of his age. On physical examination, you note that the boy is well nourished and appropriately sized for his age. On auscultation of his heart, you heard a harsh, holosystolic murmur at the left lower sternal border. There is no cyanosis, no clubbing. What is the most valuable diagnostic tool to detect the cardiac anomaly in this boy?