ISOLATED NONCOMPACTION OF THE MYOCARDIUM IN ADULTS

Objective: To describe the entity of isolated ventricular noncompactio n (IVNC) and present a series of cases of this rare disorder in an adu lt population. Material and Methods: We review a 10-year experience wi th the diagnosis of IVNC and discuss the clinical, echocardiographic, and pathologic features of this condition. Echocardiographic diagnosti c criteria included the absence of coexisting cardiac abnormalities, t he presence of prominent and excessive trabeculations of one or more v entricular wall segments, and intertrabecular spaces perfused from the ventricular cavity. Pathologic examination focused on regions with ex aggerated trabeculations and deep intertrabecular spaces. Results: IVN C is an unexplained arrest of myocardial morphogenesis previously enco untered mainly in pediatric patients. Among 37,555 transthoracic echoc ardiographic studies performed at our hospital between January 1984 an d October 1993, 17 cases of IVNC were identified in adult subjects (14 men and 3 women, 18 to 71 years of age). The mean time from onset of symptoms to correct diagnosis was 3.5 +/- 5.7 years, and the mean dura tion of follow-up was 30 +/- 28 months. Common clinical symptoms were heart failure, ventricular arrhythmias, and a history of embolic event s. Two-dimensional echocardiography revealed 10 patients with left ven tricular and 7 (41%) with biventricular IVNC. During a 6-year follow-u p period, eight patients died and two underwent heart transplantation. Conclusion: Although the diagnosis of IVNC in an adult population is often delayed because of similarities with more frequently diagnosed c onditions, two-dimensional echocardiography will facilitate the diagno sis of IVNC in this subset of patients. Because of the high incidence of heart failure, ventricular arrhythmias, and embolization in adults with IVNC, early diagnosis is important.