The relationship of left ventricular trabeculation to ventricular function and structure over a 9.5-year follow-up: the MESA study

Abstract

Background: Left ventricular (LV) trabeculation is highly variable among individuals and is increased in some diseases (e.g., congenital heart disease or cardiomyopathies), but its significance in population-representative individuals is unknown.

Objectives: The goal of this study was to determine if excessive LV trabeculation in population-representative individuals is associated with preceding changes in cardiac volumes and function.

Methods: For technical reasons, the extent of trabeculation, which is expressed as the ratio of noncompacted to compacted (NC/C) myocardium, was measured on cardiac magnetic resonance (CMR) long-axis cine images in 2,742 participants in the MESA (Multi-Ethnic Study of Atherosclerosis) (mean age 68.7 years; 52.3% women; 56.4% with hypertension; 16.8% with diabetes) at examination 5. These were considered in quintiles of trabeculation extent; the NC/C ratio of quintile 5 was 2.46 to 5.41. We determined the relationship between the maximal NC/C ratio and the preceding change (9.5 years between examinations 1 and 5) in end-systolic volume indexed (ESVi) to body surface area. Secondary analyses assessed the associations between the maximal NC/C ratio and preceding changes in end-diastolic volume indexed (EDVi) to body surface area and the ejection fraction (EF).

Results: Over 9.5 years, the ESVi decreased by 1.3 ml/m(2), the EDVi decreased by 5.1 ml/m(2), and the EF decreased by 0.6% (p < 0.0001). Even in subjects with excessive trabeculation, there were no clinically relevant differences in LV volumes and systolic function changes among the quintiles of trabeculation extent.

Conclusions: Greater extent of, and even excessive, LV trabeculation measured in end-diastole in asymptomatic population-representative individuals appeared benign and was not associated with deterioration in LV volumes or function during an almost 10-year period.

Keywords: cardiac magnetic resonance; left ventricular function; left ventricular trabeculations.

Figure 1. Flow diagram of exclusion process

Exclusion criteria of subjects from the Multi-Ethnic Study of Atherosclerosis (MESA) for this study. CMR – cardiovascular magnetic resonance.

Figure 2. Measurement of NC/C ratios

Example of end-diastolic four chamber steady state free precession image of a participant with very high maximal NC/C ratio (=4.2) in the Multi-Ethnic Study of Atherosclerosis exam 5. Red arrows show measurements of compacted myocardium, yellow arrows represent measurements of the non-compacted (trabeculated) layer.

Figure 3. Changes in cardiac volumes and function

Changes in left ventricular volumes and function between MESA exam 1 and exam 5 and the relationship to the extent of LV trabeculation (in quintiles) at exam 5 presented in two different ways: The bottom panel shows box and whisker plots and the lack of clinically relevant change in volume or function; the top panel shows similar slopes for the quintiles of trabeculation extent with regards to volumes and function between both exams. Boxes represent the interquartile range (IQR) and whiskers are within 1.5 *IQR, outliers are plotted as points. The line within the box represents the median. NC/C non-compaction to compaction. * - p<0.05; ** - p<0.01; *** - p<0.001