Complete heart block and polymorphic ventricular tachycardia complicating myocardial infarction after occlusion of the first septal perforator with coronary stenting.

We report a case of complete heart block (CHB) and polymorphic ventricular tachycardia (VT) which was associated with a modest-sized myocardial infarction (MI) following incidental occlusion of the first septal perforator (FSP) branch after stent deployment to the left anterior descending (LAD) coronary artery. These complications were successfully treated with temporary pacing and subsequently resolved with spontaneous recanalization of the first septal perforator. This case represents an interesting product of medical progress which defies the adverse natural history and poor prognosis of anteroseptal MI associated with CHB due to the small amount of myonecrosis associated with this event.

Acute myeloid leukemia evolving from essential thrombocythemia in two patients treated with hydroxyurea.

Essential thrombocythemia (ET) is an uncommon myeloproliferative disorder, which is thought to develop from a multipotent stem cell. Like other myeloproliferative diseases, ET is associated with an increased risk of development of acute leukemia (AL). However, the large majority of cases of leukemic transformation in ET are thought to be related to prior therapy, usually radioactive phosphorous or alkylating chemotherapy, and the development of AL in ET is extremely rare in the untreated patient. In this report, two cases of ET which evolved into AL without prior exposure to radiation or alkylating agents, and which were treated with long-term hydroxyurea therapy, are described. The first case had cytogenetic changes in the bone marrow suggestive of therapy-associated leukemia, and the second developed myelodysplastic syndrome on therapy which was likely chemotherapy-induced and led to acute leukemia. Prolonged used of hydroxyurea in patients with ET may lead to therapy-associated acute leukemia.