A 48-year-old patient with signs and symptoms of congestive hea failure presented to the emergency depament. Following stabilization, he was admitted and staed on an inotropic drug 4 months into therapy, the patient staed complaining of yellow scotomas and xanthopsia. An ECG was also conducted. What is the mechanism of action of the drug that was staed?: (A) B1 agonist, (B) PDE3 inhibitor, (C) Inhibition of Na-K ATPase pump, (D) B2 antagonist
Answer is C. The above ECG shows alternating narrow and broad QRS complex with negative T waves following a broad QRS suggestive of Ventricular BIGEMINY. Ventricular BIGEMINY is a type of VPC characterised by alternate VPC and sinus rhythm. It is also the most common arrhythmia caused by digoxin. Digoxin is an inotropic drug which inhibits Na-K ATPase pump and has been found to cause Visual disturbances in the form of xanthopsia and yellow scotomas.