Sunder, a young male was diagnosed as sufering from acute myeloid leukemia. He was staed on induction chemotherapy with dosorubicin based regiments. Induction regimen was successful. Two months later, he presents to OPD with swelling of both the feet and breathlessness on climbing the stairs. He also complains the he had to wake up many times because of breathlessness. Which of the following is most likely responsible for this patient's symptoms?

(Ref: Katzung 11/e p952) Anthracyclines (daunorubicin, doxorubicin, eirubicin and idarubicin) can cause severe cardiotoxicity manifesting as dialted cardiomyopathy and arrhythmias. The anthracycline chemotherapeutic agents (doxorubicin, daunorubicin, epirubicin and idarubicin) form free radicals in the myocardium. Their most severe side effect is a cumulative doserelated dilated cardiomyopathy. It presents with symtoms of left and right ventricular CHF.