| BackgroundLeft ventricular non-compaction (LVNC) is a rare cardiomyopathy which was classified as a primary genetic disease by AHA, whereas defined as an unclassified cardiomyopathy by ESC. It had been hypothesized that LVNC might be due to intrauterine arrest of compaction of the loose interwoven meshwork that made up the fetal myocardial primordium. This abnormal morphogenesis induced the characteristics of two-layer myocardial structure (the outer was NC, and the inner was C) and impaired the normal cardiac function. With the awareness of this disease, some researches on clinical features, prognosis and imageology had been published in recent years. The major clinical manifestations of LVNC were heart failure, arrhythmias, thromboembolism and cardiac death. However, the results of different reports were inconsistent because of the small sample size, especially in our country. In the aspect of treatment, cardiac resynchronization therapy (CRT) had showed dramatically effective in LVNC patients with LBBB according to some case reports, but the mechanism and long-term prognosis of this high respond phenomenon were unclear. Except for these, marked trabeculation, chamber dilation and ventricular contractile impairment were presented in both LVNC and DCM, which sometimes made the differentiation difficult by manifestations and echocardiography. CMR had presented the characteristics of excellent resolution which was appropriate for evaluation of these diseases, and it was possible to disclose some novel parameters for differentiation. So it is significant to make some work devoted on these issues as mentioned above.Objectives1. To identify the clinical characteristics of patients with LVNC.2. To analyze the effectiveness of CRT on patients with LVNC.3. To measure the systolic compacta thickness in left ventricle using CMR and to assess its value in the differentiation between LVNC and DCM.Methods1. From January2006to April2013, the patients who fulfilled the Jenni echocardiographic diagnostic criteria of LVNC were enrolled in this study. Follow-up was carried on routinely. According to the LVEF value when the first time they were diagnosed as LVNC by echocardiography, these patients were divided into three different groups. We analyzed the differences among the three groups by comparing the echocardiographic chamber diameters and incidences of clinical events.2. From January2006to April2013, some patients with LVNC who satisfied the CRT indications received the intervention. Follow-up and program control were carried on routinely. We analyzed the condition of heart function by symptoms, QRS duration by electrocardiogram and chamber diameters by echocardiography between the pre-and post-operation.3. From December2008to April2013, the patients who fulfilled the Peterson CMR diagnostic criteria of LVNC, and the patients with DCM were enrolled in this study. Chamber diameters and ventricular ejection fractions were measured. The thicknesses of NC and C at end-diastole, the maximal systolic compacta thickness and LGE of each segment were assessed according to the17-segment model.Results1. Forty-eight patients (29males, and19females) who fulfilled the Jenni echocardiographic diagnostic criteria of LVNC were enrolled in this study. The mean onset age42.1±19.7years (range0.5-78years). The mean follow-up was25.8±21.6months.2. There were6patients whose direct relatives with history of cardiomyopathy or cardiac sudden death. The familial LVNC group showed higher mortality than the sporadic group (p<0.05).3. Twenty-three patients had moderate-severe heart failure (NYHAⅢ-Ⅳ). The majority of this cohort had an abnormal electrocardiogram (40/48,83.3%), and the arrhythmias were documented in36patients, including22patients with ventricular arrhythmias and16patients with conduction block. Four pieces of thromboembolism occurred in the period of follow-up. Of these patients,5patients died due to end-stage heart failure and cardiac sudden death, and1patient with severe heart failure received heart transplantation.4. The patients in moderate and severe depressed LVEF groups had a larger left ventricular diameter than the normal group (p<0.05), but there was no difference between the both abnormal groups. Patients with worse left ventricular systolic function had received more standard pharmacotherapy for ameliorating heart failure, warfarin for anticoagulation, and CRT for synchronization (all p<0.05). The incidence of documented ventricular arrhythmias was also higher in moderate and severe depressed LVEF groups (p<0.05). However, the results of thromboembolism and cardiac death didn’t present the significant difference among the three groups (both p<0.05).5. There were7patients (14.6%) receiving CRT for heart failure, consisting of6patients with LBBB, and the other with IVCD. One patient with LBBB was dead due to recurrent ventricular arrhythmias during the thoracotomy surgery for epicardial lead implantation. One patient with IVCD presented no significant effects for improvement of symptoms and heart function, and died after59months. The left5patients with LBBB had gotten excellent amelioration in aspects of clinical manifestations, QRS duration, and left ventricular diameters after CRT.6. The gender, onset age, RVEF, and incidences of complication events were similar in LVNC and DCM groups. Patients with DCM had markedly lower LVEF values (p<0.05).7. The apical lateral (n=12,57.1%) and apical inferior (n=11,52.4%) segments were the most common affected ones (NC/C>2.3). There were no significant differences in distributions of NC involved segments (NC>0) between the groups. The majority of involved segments in both groups were apical anterior, apical inferior and apical lateral segments.8. The maximal systolic compacta thickness in apical anterior, apical inferior and apical lateral segments was significantly reduced in LVNC group (all p<0.05), but spared mid-ventricular and basal segments. When standardized by body surface area, maximal systolic compacta thickness in apical anterior and lateral segments remained significantly reduced in LVNC group. The area under the ROC curve of the apical anterior segment was0.827(95%Cl:0.70-0.95). With a cutoff value of8.5mm, the sensitivity, specificity, positive and negative likelihood ratios for LVNC were76.2%,77.3%,3.36and0.31respectively.9. There was no difference for the rate of positive LGE in both groups, and positive LGE presented no correlation with clinical events.Conclusions1. The familial patients with LVNC had a higher mortality than the sporadic ones.2. The major clinical events of patients with LVNC were heart failure and arrhythmias. The five-year mortality rate of LVNC was12.5%, with causes of end-stage heart failure and cardiac sudden death.3. The patients with LVNC in worse left ventricular systolic function had larger left ventricular diameter by echocardiographic evaluation, as the incidence of ventricular arrhythmias. 4. The patients with LBBB satisfying the indication of CRT benefited a lot from this intervention.5. Patients with LVNC were more influenced by NC involvement, but presented better left ventricular systolic function than DCM patients. The most affected myocardial segments were apical lateral and apical inferior ones.6. Maximal systolic compacta thickness was significantly reduced in the apical regions of LVNC, especially in the anterior segment, which seemed to provide diagnostic help for the differential diagnosis of LVNC and DCM.7. Positive LGE didn’t predict the prognosis of LVNC. |
