Standard and novel echocardiographic imaging techniques to assess cardiac dyssynchrony in pediatric patients with cardiac disease

Cardiac resynchronisation therapy (CRT) has emerged as a valuable tool in the
management of patients with heart failure and QRS prolongation. Improvement in
cardiac function, quality of life and life expectancy have been reported in the
majority of patients who qualify for CRT.(1) Inclusion criteria for CRT used in
large clinical trials are NYHA-class III to IV, QRS-duration >=120-130 ms and
depressed left ventricular ejection fraction <= 35%. However, 20% to 30% of the
patients who meet these criteria do not respond to CRT.(1) Effort has been made
to better predict the success of CRT. Many single-centre studies evaluated
inter-and intraventricular dyssynchrony, using various echocardiographic
techniques and pointed out that the severity of left ventricular
(LV)-dyssynchrony is a good predictor for response to CRT.(2-4) The results
from the multicenter Prospect-study, however revealed that currently no single
echocardiographic measurement assessing dyssynchrony can predict an improved
response to CRT.(5) Recently, novel echocardiographic parameters have been
proposed such as triplane tissue Doppler imaging,(6) real time 3D
echocardiography(7) and speckle tracking strain imaging,(8) which may better
identify the potential responders to CRT. The excellent outcomes of CRT in
selected adult patients have raised interest to apply CRT in pediatric patients
with cardiac disease. Over the past decades the survival and life expectancy of
pediatric patients with congenital and acquired heart disease has increased
dramatically. However, in patients with corrected congenital heart disease,
heart failure is one of the major causes of late mortality.(9) Data on the role
of CRT in the management of heart failure in patients with a congenital heart
defect are scarce. CRT has been used in the immediate post-operative period
after correction of a congenital heart defect and improved cardiac output and
narrowed QRS-duration were observed.(10-12) Furthermore, Dubin et al. evaluated
the acute effect of CRT in chronic right ventricular (RV) failure and
demonstrated the feasibility of RV-CRT in improving RV function and decreasing
QRS-duration.(13) Reports on the long-term beneficial effects of CRT as
treatment for chronic heart failure in children and adults with a congenital
heart defect are limited.(14-16) Recently, a retrospective international
multicenter study evaluated the use of CRT in paediatric patients with acquired
or congenital heart disease.(17) One-hundred-and-three pediatric patients or
patients with congenital heart disease in whom CRT was initiated were included
and CRT induced increase in ejection fraction and decreased QRS-duration.
Inclusion criteria were heterogeneous and only 54% of the patients met the
criteria for CRT in adults.(17) Thus the criteria for initiation of CRT in the
paediatric population and in adult patients with congenital heart disease are
unclear. The large randomized adult CRT trials evaluated the effectiveness of
CRT in patients with a mean age over 60 years with mostly ischemic heart
disease. These data cannot simply be translated to a young population with
either dilated cardiomyopathy or a wide variety of congenital heart defects .
Cardiac failure in the pediatric population not only includes the failing LV
but also the failing univentricular heart with either RV or LV morphology, the
failing systemic RV in congenitally corrected transposition or after atrial
switch procedure and the failing pulmonary RV in patients with corrected
tetralogy of Fallot. In addition, substantial number of pediatric CRT
candidates have cardiac failure related to conventional pacemaker therapy for
postoperative or congenital atrioventricular block. In each of the above
mentioned patient groups CRT has shown to be beneficial.(17) However, most
pediatric studies also emphasize the need for better patient selection to avoid
over- or underuse of CRT in children. Data in children on the role of
evaluation of cardiac dyssynchrony to predict the response to CRT are very
limited. Case reports and small case series in children







with CHD have demonstrated improved cardiac synchronization after CRT. Other
studies have evaluated the presence of cardiac dyssynchrony in adult patients
with (repaired) congenital heart disease.(18;19) Data on the evaluation of
cardiac dyssynchrony in pediatric patients with cardiac disease is scarce and
most of the standard and novel echocardiographic techniques to assess
dyssynchrony are no part of the routine echocardiographic examination of
pediatric patients. Therefore, the extent of cardiac dyssynchrony, the role of
dyssynchrony in cardiac dysfunction and the evolution of dyssynchrony over time
are unclear in the specific groups of pediatric patients with congenital or
acquired heart disease.
Reference List


(1) Bax JJ, Abraham T, Barold SS, Breithardt OA, Fung JW, Garrigue S
et al. Cardiac resynchronization therapy: Part 1--issues before device
implantation. J Am Coll Cardiol 2005; 46(12):2153-2167.
(2) Gorcsan J, III, Kanzaki H, Bazaz R, Dohi K, Schwartzman D.
Usefulness of echocardiographic tissue synchronization imaging to predict acute
response to cardiac resynchronization therapy. Am J Cardiol 2004;
93(9):1178-1181.
(3) Bax JJ, Marwick TH, Molhoek SG, Bleeker GB, van Erven L, Boersma E
et al. Left ventricular dyssynchrony predicts benefit of cardiac
resynchronization therapy in patients with end-stage heart failure before
pacemaker implantation. Am J Cardiol 2003; 92(10):1238-1240.
(4) Bax JJ, Bleeker GB, Marwick TH, Molhoek SG, Boersma E, Steendijk P
et al. Left ventricular dyssynchrony predicts response and prognosis after
cardiac resynchronization therapy. J Am Coll Cardiol 2004; 44(9):1834-1840.
(5) Chung ES, Leon AR, Tavazzi L, Sun JP, Nihoyannopoulos P, Merlino J
et al. Results of the Predictors of Response to CRT (PROSPECT) trial.
Circulation 2008; 117(20):2608-2616.
(6) Van de Veire NR, Yu CM, Ajmone-Marsan N, Bleeker GB, Ypenburg C,
De Sutter J et al. Triplane tissue Doppler imaging: a novel three-dimensional
imaging modality that predicts reverse left ventricular remodelling after
cardiac resynchronisation therapy. Heart 2008; 94(3):e9.
(7) Marsan NA, Bleeker GB, Ypenburg C, Ghio S, Van de Veire NR, Holman
ER et al. Real-time three-dimensional echocardiography permits quantification
of left ventricular mechanical dyssynchrony and predicts acute response to
cardiac resynchronization therapy. J Cardiovasc Electrophysiol 2008;
19(4):392-399.
(8) Delgado V, Ypenburg C, van Bommel RJ, Tops LF, Mollema SA, Marsan
NA et al. Assessment of left ventricular dyssynchrony by speckle tracking
strain imaging comparison between longitudinal, circumferential, and radial
strain in cardiac resynchronization therapy. J Am Coll Cardiol 2008;
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(9) Oechslin EN, Harrison DA, Connelly MS, Webb GD, Siu SC. Mode of
death in adults with congenital heart disease. Am J Cardiol 2000;
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(10) Janousek J, Vojtovic P, Hucin B, Tlaskal T, Gebauer RA, Gebauer R
et al. Resynchronization pacing is a useful adjunct to the management of acute
heart failure after surgery for congenital heart defects. Am J Cardiol 2001;
88(2):145-152.
(11) Zimmerman FJ, Starr JP, Koenig PR, Smith P, Hijazi ZM, Bacha EA.
Acute hemodynamic benefit of multisite ventricular pacing after congenital
heart surgery. Ann Thorac Surg 2003; 75(6):1775-1780.
(12) Pham PP, Balaji S, Shen I, Ungerleider R, Li X, Sahn DJ. Impact
of conventional versus biventricular pacing on hemodynamics and tissue Doppler
imaging indexes of resynchronization postoperatively in children with
congenital heart disease. J Am Coll Cardiol 2005; 46(12):2284-2289.
(13) Dubin AM, Feinstein JA, Reddy VM, Hanley FL, Van Hare GF,
Rosenthal DN. Electrical resynchronization: a novel therapy for the failing
right ventricle. Circulation 2003; 107(1

Routine evaluation of dyssynchrony in pediatric patients with cardiac disease
is feasible using standard and novel echocardiographic techniques.
The extent of cardiac dyssynchrony and its influence on cardiac function
differs between groups of pediatric patients with specific cardiac disease.
In each specific patient group of pediatric patients with cardiac disease
dedicated criteria for initiation of CRT should be published.

prospective patient based study

Echocardiography is a non-invasive and safe imaging tool and poses no risks of
any damage. The burden is minimal as the patient/healthy controls is examined
in the supine position during 60 minutes.