Electrocardiogram Features of Left Ventricular Excessive Trabeculation with Preserved Cardiac Function in Light of Cardiac Magnetic Resonance and Genetics

Abstract

Background and Objectives: Although left ventricular excessive trabeculation (LVET) can cause heart failure, arrhythmia and thromboembolism, limited literature is available on the ECG characteristics of primary LVET with preserved left ventricular function (EF). We aimed to compare the ECG characteristics and cardiac MR (CMR) parameters of LVET individuals with preserved left ventricular EF to a control (C) group, to identify sex-specific differences, and to compare the genetic subgroups of LVET with each other and with a C population. Methods: In our study, we selected 69 LVET individuals (EF > 50%) without any comorbidities and compared them to 69 sex- and age-matched control subjects (42% females in both groups, p = 1.000; mean age LVET-vs-C: 38 ± 14 vs. 38 ± 14 years p = 0.814). We analyzed the pattern and notable parameters of the 12-lead ECG recordings. We determined the volumetric and functional parameters, as well as the muscle mass values of the left and right ventricles (LV, RV) based on the CMR recordings. Based on the genotype, three subgroups were established: pathogenic, variant of uncertain significance and benign. Results: In the LVET group, we found normal but elevated volumetric and muscle mass values and a decreased LV_EF, wider QRS, prolonged QTc, higher RV Sokolow index values and lower T wave amplitude compared to the C. When comparing MR and ECG parameters between genetic subgroups, only the QTc showed a significant difference. Over one-third of the LVET population had arrhythmic episodes and a positive family history. Conclusions: The subclinical morphological and ECG changes and the clinical background of the LVET group indicate the need for follow-up of this population, even with preserved EF.

Keywords: ECG; cardiac magnetic resonance imaging; cardiogenetics; left ventricular excessive trabeculation; noncomapction.

Figure 1

Threshold-based postprocessing method. The short-axis CMR image of an LVET individual with the threshold-based postprocessing method. The green highlight shows the LV, and the blue highlight shows the RV myocardial mass. The MassK algorithm analyzes each voxel and classifies them as either myocardial tissue or blood tissue; therefore, the highlighted myocardial tissue within the endocardial (red in the LV and yellow in the RV) border represents the TPM. Abbreviations: CMR, cardiac magnetic resonance imaging; LV, left ventricle; LVET, left ventricular excessive trabeculation; RV, right ventricle, TPM, trabeculated and papillary muscle mass.

Figure 2

ECG characteristics in the aspect of morphology and sex. QRS_duration: LVET male characteristic; LV_SI: male characteristic, LVET independent; RV_SI: LVET male characteristic; QTc: female characteristic, prolonged in LVET; T_amplitude: characteristic to healthy controls, sex independent. Abbreviations: LVET, left ventricular excessive trabeculation; C, control population; LV, left ventricle; RV, right ventricle; SI, Sokolow–Lyon index.

Figure 3

Comparisons of the (A) CMR and (B) ECG parameters between the genetic subgroups. Abbreviations: * significant at the p < 0.05 level; EDV, end-diastolic volume; EF, ejection fraction; ESV, end-systolic volume; i, indexed to body surface area; LV, left ventricle; LVET, left ventricular excessive trabeculation; QTc, corrected QT interval; RV, right ventricle; SI, Sokolow–Lyon index; SV, stroke volume; TM, total muscle mass; TPM, trabeculated and papillary muscle mass; VUS, variant of unknown significance.