A 76-year-old man with a history of heart failure and atrial fibrillation presents with dyspnea and peripheral edema. Vital signs show BP 148/92 mmHg, HR 118 bpm, RR 22/min, and SpO2 92% on room air. Echocardiography reveals ejection fraction of 35%. He denies chest pain. He is started on digoxin. Which of the following best describes the primary direct molecular action of this drug on cardiac myocytes?
- A)L type calcium channel blockade
- B)Adenosine A1 receptor activation
- C)Digoxin inhibition of Na+/K+ ATPaseGABARITO
- D)Beta 1 receptor antagonism
- E)Amiodarone potassium channel blockade
Explicação
Digoxin inhibition of Na+/K+ ATPase is correct. Inhibition of the pump raises intracellular sodium, which decreases Na+/Ca2+ exchanger activity and increases intracellular calcium available for contraction. Digoxin also increases vagal tone, helping slow AV no... Ver explicação completa e trilha adaptativa →