Absence of myocardial fibers in the right ventricle is the essence of so-called Uhl's anomaly, which should be distinguished from the fatty replacement producing arrhythmogenic right ventricular dysplasia of the adolescent and young adult. In this report, we describe a newborn with nearly complete absence of the myocardium of the left ventricle. The infant died on the seventh day because of myocardial incompetence of the left ventricle, which was unable to open the aortic valve.

Progressive granulocytopenia (neutrophil count <1000/ml) developed in a newborn during treatment with propafenone (200 mg/m2) for recurrent paroxysmal supraventricular tachycardia. The total white blood cell count, however, remained within normal limits. The neutrophil count increased gradually after propafenone had been stopped. The time course of treatment and the development of granulocytopenia make it very likely, but not certain, that propafenone was the responsible agent. Pediatricians, and especially pediatric cardiologists, should be aware of this rare adverse effect when they consider treatment with propafenone in children with cardiac arrhythmias. Analysis of the white cell blood count, including a differential count, is recommended in all children in order to assess the true incidence of this adverse effect.