Measures of Dyssynchrony in the Left Ventricle of Healthy Children and Young Patients with Dilated Cardiomyopathy

Abstract

Background Doppler tissue imaging (DTI) may help identify children with dyssynchrony who could benefit from resynchronization therapy. However, few studies have quantified dyssynchrony measures in children, no study has investigated the relationship between age, heart rate and dyssynchrony measures in children, and no study has quantified cross-correlation delay in children. We hypothesized that measures of left ventricular dyssynchrony would correlate with age primarily due to correlation between heart rate and age, and that children with cardiomyopathy would have left ventricular dyssynchrony. Methods Sixty healthy children and 11 children with dilated cardiomyopathy were prospectively enrolled. Seven dyssynchrony measures were quantified: septal-lateral delay (SLD), peak velocity difference (MaxDiff), SD of times-to-peak in 12 segments in systole (Ts-SD) and diastole (Te-SD), and cross-correlation delay in systole (XCDsystole), diastole (XCDdiastole) and the whole-cycle (XCDwhole). Results The 7 dyssynchrony measures were either not correlated with age or only weakly correlated with age after correcting for heart rate using Bazett’s formula. SLD, MaxDiff and Ts-SD showed dyssynchrony in 57–85% of normals compared to 20% for XCDwhole and 3% for Te-SD. XCDsystole, XCDdiastole, XCDwhole, and Te-SD were elevated in children with dilated cardiomyopathy compared to controls. Conclusion Echocardiographic dyssynchrony measures should be corrected for heart rate using Bazett’s formula in children. Time-to-peak DTI dyssynchrony measures classify many healthy children as having an abnormality with the timing of left ventricular contraction, which suggests the methodology is not accurate in children. In preliminary studies, cross-correlation dyssynchrony measures show elevated systolic and diastolic measures of dyssynchrony in children with dilated cardiomyopathy compared to controls, which deserves further investigation to help identify children who may benefit from resynchronization therapy.

Response of Functional Mitral Regurgitation during Dobutamine Infusion in Relation to Changes in Left Ventricular Dyssynchrony and Mitral Valve Geometry

“…The time interval to-peak systolic velocity (Ts) was measured from the onset of the QRS complex to the peak of the myocardial systolic velocity during ejection period in each of the eight segments at rest and at peak stress. Ts was corrected for heart rate (Tscor) using Bazett's formula (Tscor=Ts/√R-R interval) to allow for comparison between the Ts of any segment at rest and peak stress 12,13. Dyssynchrony index (DI) was measured as the standard deviation of Tscor of all eight segments.…”

“…Ts was corrected for heart rate (Tscor) using Bazett's formula (Tscor=Ts/√R-R interval) to allow for comparison between the Ts of any segment at rest and peak stress. 12 , 13 Dyssynchrony index (DI) was measured as the standard deviation of Tscor of all eight segments. All time interval were calculated as the average of at least three consecutive cardiac cycles.…”

Assessment of left ventricular dyssynchrony by speckle tracking echocardiography in children with duchenne muscular dystrophy

“…The software provided an automatic calculation of time-to-peak delay for each segment, as represented in the shape of a 16-segment bull's eye model [18]. Due to known signi cant heart rate variability in children [21], all time-to-peak values were corrected using Bazett's formula, as recommended by Thomas et al [22].…”

Distribution of strain patterns in children with dilated cardiomyopathy

“…[15][16][17][18] Only one small study used STE and analyzed quantitative dyssynchrony measures. [15][16][17][18] Only one small study used STE and analyzed quantitative dyssynchrony measures.…”

“…Dyssynchrony has been described in children with DCM in several small studies, mainly using Doppler tissue imaging. [15][16][17][18] Only one small study used STE and analyzed quantitative dyssynchrony measures. They reported mechanical dyssynchrony in 76% of the children.…”