LVNC or hyper-trabeculated LV, are we missing something?
Authors: Ahmed E , Mahfouz A , Hammouda T , Nasr A , Abdelfattah M A H , Wanees M O S , Elshall A H M , Shaaban M A H , Kamel O 
Published: May 2024

Abstract

Introduction
LVNC is a heterogeneous poorly understood entity characterized by prominent myocardial trabeculation.(1) It often overlaps with other phenotypes such as DCM, HCM.(2) Incidence of SCD is highly variable, however it may account for about 50% of all mortality in LVNC.(3) Risk stratification of SCD is a complex matter. Despite that current guidelines recommend following the same principles of 1ry prevention as in DCM based on similar CV mortality risk, it seems of utmost importance to identify additional features which could be specifically associated with LVNC and contributing to a higher risk of adverse events particularly ventricular arrhythmia (VA).

Purpose
To identify possible high risk features for prediction of ventricular arrhythmia in the form of documented NSVT, VT, or VF in LVNC.

Methods
This is a retrospective single centre cohort study of patients fulfilling the LVNC defining criteria from 2018 to 2023. Patients’ data were reviewed for family history of cardiomyopathies or SCD, clinical presentation, ECGs data in the form of QRS duration, QTc interval and Tp-e, Holter analysis, CIEDs interrogation if present and MRI data including LVEF, volumes, fibrosis burden and distribution, NC/C ratio, NC / LV global mass ratio, global longitudinal strain"GLS", global circumferential strain "GCS" , global radial strain "GRS" , extent of hypertrabeculation, RV involvement in the form of EF, volumes, hypertrabeculation.

Results
A total of 42 patients were included (34+/- 17 years of age, 57% males). 5 patients of our cohort were pediatrics. Mean LVEF 45%. LGE was detected in 14% of cases, RV involvement in 38 %. Ventricular arrhythmia were present in 15 patients (35%), of which 6 patients had malignant ventricular arrhythmia. LVEF, NC/LV global mass ratio, LVGLS, LVGCS were found to be significantly correlated with the occurrence of VA with cut-off values of &lt;43%, &gt;31%, &lt;-15 and &lt;-13.5 respectively. While positive FH, RV involvement, pattern, burden of LV fibrosis and ECG parameters didn’t significantly increase the incidence of VA. In a multivariate regression analysis NC to LV global mass ratio was the sole independent predictor of VA ( p value=0.024). ICDs were implanted in 10 cases, 8 were for 1ry prevention based on clinical judgement, 4 of them received appropriate ICD therapy.

Conclusion
LVNC is associated with increased risk of VA. In addition to clinical assessment and LVEF, CMR can add a different insight for risk stratification. Interestingly, LGE wasn’t associated with significantly increased risk of VA "taking into consideration LGE was found only in 14% of cases" highlighting the potential role the trabeculated myocardium in the pathophysiology of VA by altering the electrical stability of the heart. Finally, these findings could contribute in answering an ongoing question; Should LVNC with its unique characteristics be treated as a special entity with its own high-risk criteria for VA and SCD?LV NC/global mass ration and GLSDemographic,clinical,ECG and MRI data