Abstract 17918: High Resolution Measurement of Tissue Velocity: Studies in Developing Hearts and in Patients with Left Ventricular Noncompaction
Left ventricular noncompaction (LVN) is a cardiomyopathy characterized by excessive trabeculations at the apex. Some patients have a malignant course with heart failure, ventricular arrhythmias and thromboembolic complications, but others have a more benign course and remain asymptomatic for years. We hypothesize that contraction and relaxation are prolonged in patients with clinically significant LVN as well as in normal developing hearts, as measured using high resolution tissue velocity.
Methods: Thirty-nine patients were initially studied using 2-dimensional echocardiograms. Subjects included 17 normals (ages 10 weeks through 17 years, 7 females), and 22 patients with possible LVN (ages 3 weeks through 33 years, 13 females). Standard 2-dimensional and M-mode echocardiograms were performed on IE-33 (Philips, Andover, MA), Vivid 7 or Vivid Q (GE Ultrasound, Wauwatosa, WI) ultrasound machines. Echocardiograms were subsequently evaluated using customized software written in MATLAB (MathWorks, Natick, MA), capable of simultaneously tracking approximately 50 individual points of myocardium during contraction, relaxation and the rest period preceding the next contraction.
Results: In controls, contraction was 55%, relaxation was 42%, and the rest period was 3% of the cardiac cycle in infants. These values were not significantly different in infants with LVN. Beyond infancy, contractions were not different in LVN vs. control (45% vs. 42%). However relaxation was significantly longer (31% vs. 20%, P<0.007), and the rest period was significantly shorter (25% vs. 38%, P<0.007).
Conclusions: High resolution measurements of LV tissue velocity indicate that contractions are not prolonged either in infants or in older patients with LVN vs. control. In contrast, relaxation is prolonged and the rest period prior to the next contraction is shortened in infants compared to older patients, as well as in patients beyond infancy with LVN compared to controls.
- © 2012 by American Heart Association, Inc.