Diastolic Dyssynchrony in Pediatric Dilated Cardiomyopathy

Abstract

SUMMARY D ilated cardiomyopathy is the most common cardiomyopathy worldwide. Mechanical dyssynchrony is an important contributor to left ventricular (LV) dysfunction in cardiomyopathy both in adults and in children with dilated cardiomyopathy (DCM). Cardiac resynchronization therapy (CRT) is a novel and promising non pharmacologic therapy for patients with advanced heart failure and wide QRS morphology. However, one third of the patients receiving CRT have shown no symptomatic improvement and may actually develop adverse left ventricular (LV) remodeling, resulting in further severe symptomatic impairment. In addition, LV mechanical dyssynchrony has been proven to occur even in patients with preserved QRS duration. The aim of the study was to evaluate the role of RT3DE in evaluating mechanical systolic and diastolic dyssynchrony and their impact on global systolic and diastolic LV function in pediatric DCM patients. Also, to study the correlation between biochemical markers (MMP 2 and CITP) of LV remodeling and values of dyssynchrony. The study was conducted on two groups, one of DCM patients and the other of matched age normal children (control group) with a mean age of 4.6±3.0 years old. Two thirds of our patients (60%) had a NYHA class of II, while (36.7%) had a NYHA class of III and only (3.3%) had a NYHA class of IV. In our study the DCM patients showed a wide QRS duration (with a mean of 100±22.9 ms) in ECG when compared to the control group. 2D echocardiography showed that the DCM patients had a lower EF together with a higher ESV and EDV in the DCM patients when compared to the control group. Also Using RT3DE, the DCM group showed a lower EF and a higher ESV and EDV in the DCM group. Using Bland-Altman plot for agreement between 2D- and 3D-echocardiography, we found a large difference between upper and lower limits of agreement between 2D- and 3D-echocardiography as regards EDV, ESV and EF. In multiple studies, the use of real time 3D echocardiography has been shown to be more reproducible as compared with 2D based assessment. Tissue Doppler imaging is the most commonly used technique for quantifying dysfunction. In our study, DCM patients showed the presence of global LV dysfunction with a higher Tei index than the control group. Also, DCM patients showed a higher E/E´ ratio denoting the presence of LV diastolic dysfunction.