Abstract 4841: Natural History of Isolated Noncompaction of the Ventricular Myocardium in Adults. Data from the Società Italiana di Ecografia Cardiovascolare (SIEC) Registry
Isolated ventricular noncompaction (IVNC) is a rare cardiomyopathy commonly believed due to intrauterine arrest of compaction of the loosely interwoven meshwork of myocardial fibers. Most studies suggest that prognosis of IVNC is ominous. Typical complications include heart failure, thromboembolic complications and malignant ventricular arrhythmias. In order to obtain further data on the natural destiny of patients with IVNC we created an Italian national registry of IVNC under the sponsorship of the Società Italiana di Ecografia Cardiovascolare (SIEC). Data were collected through October 2004 up to October 2007. 246 patients were enrolled. We analyzed the clinical course of the 181 pts adult (> 18 yrs) population. Of these, 108 were males; mean age at inclusion was 49.6 ± 17.6 (18 – 90) yrs. Patients were divided into two diagnostic subgroups: symptom-based (i.e., symptomatic at enrollment; 90 pts, 50%), and nonsymptom-based diagnosis. Mean follow-up was 64.2 ± 74.7 (2 – 360) months. Major events (death, heart failure, thromboembolism, malignant ventricular arrhythmia) occurred in 69 pts (38%). Most events occurred in the symptom-based diagnosis subgroup (62 vs. 7 events; chi-square p<.0001). On univariate analysis LVEF < 31% (cutoff value obtained on receiver-operator curve) had a 71% sensibility and a 90% specificity in predicting major events. Left atrial dilatation (ie > 40 mm) was also predictive of events (chi-square p< .0001) both in the symptom based and in the non-symptom based subgroups. Conclusions: the overall natural history and prognosis of IVNC may be better than originally thought. Adults with incidental/familial diagnosis of IVNC have an encouraging prognosis, whereas those diagnosed with symptoms, LV severe systolic dysfunction or enlarged left atrium have a more severe prognosis.