Implication of QRS Prolongation and Its Relation to Mechanical Dyssynchrony in Idiopathic Dilated Cardiomyopathy in Childhood

Hsiao, Cheng Hui; Wang, Jou‐Kou; Lin, Min; Wu, En‐Ting; Chiu, Shuenn–Nan; Chiu, H. H.; Wu, Mei

doi:10.1016/j.amjcard.2008.08.044

Cited by 15 publications

(20 citation statements)

References 27 publications

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“…Mechanical dyssynchrony was present in all patients with QRS more than 120 ms but common in those with normal QRS also, particularly the intraLV dyssynchrony measurements using the standard of 32.6 ms [16]. The overall conclusion is that a wide QRS may increase a patient's risk for dyssynchrony but a normal QRS does not protect a pediatric patient with DCM from the problem, especially if there is significant systolic dysfunction.…”

Section: Noninvasive Methods To Assess Dyssynchrony In Dilated Cardiomentioning

confidence: 95%

“…This graph shows the similarity in percentage positive results from cardiac resynchronization therapy (CRT) in three pediatric studies done by Dubin [2], Cecchin [16], and Janousek [21] and a meta-analysis of adult studies done by Abraham [1]. An overall benefit was seen in the populations studied.…”

Section: Figure 3 Overall Cardiac Resynchronization Therapy Benefitmentioning

confidence: 96%

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Pacing treatment for dilated cardiomyopathy: optimization of resynchronization pacing in pediatrics

Greene

Berul

2010

Current Opinion in Cardiology

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CRT is becoming a valuable tool in the treatment of ventricular dyssynchrony and dilated cardiomyopathy in pediatric and congenital heart disease patients. Diagnostic advances in electrophysiology and echocardiography have enabled clinicians to more effectively evaluate, treat, and optimize device programming for patients before and after CRT. These modalities also allow more detailed data collection, which may aid in the refinement of indications and impact of CRT in this unique population.

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Section: Noninvasive Methods To Assess Dyssynchrony In Dilated Cardiomentioning

confidence: 95%

Section: Figure 3 Overall Cardiac Resynchronization Therapy Benefitmentioning

confidence: 96%

Pacing treatment for dilated cardiomyopathy: optimization of resynchronization pacing in pediatrics

Greene

Berul

2010

Current Opinion in Cardiology

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“…In some patients this may be explained by a lack of mechanical dyssynchrony despite the presence of electrical dyssynchrony. Conversely, mechanical dyssynchrony may exist in patients with a narrow or mildly prolonged QRS . Some authors have proposed that improved mechanical dyssynchrony must occur to respond to CRT .…”

Section: Basic Concepts Of Electromechanical Dyssynchronymentioning

confidence: 99%

Echocardiographic Assessment of Ventricular Synchrony in Congenital and Acquired Heart Disease in Children

Friedberg

Mertens

2013

Echocardiography

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Electromechanical dyssynchrony is an important consequence of and contributor to ventricular dysfunction. Echocardiography can be useful to assess the mechanisms underlying mechanical dyssynchrony, to evaluate the impact of mechanical dyssynchrony on ventricular function, and to try to predict the therapeutic response to cardiac resynchronization therapy (CRT). Mechanical dyssynchrony has been demonstrated in several pediatric acquired and congenital cardiac conditions, but experience is still limited. Moreover, the optimal method to identify dyssynchrony remains unclear, and data predicting the response to CRT in pediatrics are lacking. Understanding mechanisms of electromechanical dyssynchrony by echocardiography seems promising, at least in left bundle branch block (LBBB), but may be limited in children due to the uncommon occurrence of LBBB in this population. This review addresses the commonly used methods to diagnose mechanical dyssynchrony, discusses the emerging concepts on the mechanisms of the various types of mechanical dyssynchrony, and discusses the possible significance of mechanical synchrony in pediatric and acquired congenital heart disease.

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“…They often have mechanical dyssynchrony by echocardiography with potential substrate amenable to resynchronization. [50][51][52][53] However, Janousek et al 45 demonstrated that DCM was an independent predictor of nonresponse to CRT in pediatric patients. This is in contrast to the favorable results in the adult DCM population, which demonstrated even greater improvement in systolic function, reverse remodeling, and survival than the adult ischemic cardiomyopathy population.…”

Section: Crt For the Failing LVmentioning

confidence: 99%

“…23,45,[50][51][52] A study by Friedberg et al 51 demonstrated that 65% of pediatric DCM patients had mechanical dyssynchrony by echocardiography; however, the median QRSd was only 84 milliseconds, and the degree of mechanical dyssynchrony did not correlate with QRSd. Another study by Chen et al 53 showed that 18% of DCM patients have a QRSd >120 milliseconds, but the average QRSd for their entire cohort of 89 DCM patients was only 93 milliseconds. They also found that QRSd did not correlate with intraventricular mechanical dyssynchrony.…”

Section: Crt For the Failing LVmentioning

confidence: 99%

Cardiac Resynchronization Therapy for Pediatric Patients With Heart Failure and Congenital Heart Disease

Motonaga

Dubin

2014

Circulation

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1879C ardiac resynchronization therapy (CRT) is an effective treatment for adult patients with left ventricular (LV) failure. Large prospective, randomized, controlled trials have demonstrated that CRT results in improvement in cardiac function, LV reverse remodeling, decreased hospitalizations for heart failure (HF), improved quality of life, and decreased overall mortality.1-5 However, 30% of adult patients are nonresponders to CRT, spurring further evaluation of electromechanical dyssynchrony to determine optimal pacing sites and to improve CRT selection criteria for maximal response. 1,6 The positive response in adult HF prompted exploration of the use of CRT in pediatric HF patients. However, the effectiveness of CRT in the pediatric population is difficult to evaluate because of the complex anatomic substrates of congenital heart disease (CHD) and scar formation from multiple cardiac surgeries with a higher proportion of right bundle-branch block (RBBB) and right ventricular (RV) failure than in the adult population. The typical adult HF scenario of an LV ejection fraction (EF) ≤35% with a left bundle-branch block (LBBB) is uncommon in children; therefore, the adult selection criteria for CRT cannot be easily translated to pediatric patients. Furthermore, a small heterogeneous pediatric patient population hinders a systematic assessment of long-term benefit from CRT. Principles of CRTIn the normal heart, ventricular electrical activation spreads through the His-Purkinje system, which has unique rapid propagation properties and widespread distribution. This allows highly coordinated electrical activation between distant regions of both ventricles, resulting in highly synchronous mechanical contraction. Given the strong relationship between electrical excitation and mechanical contraction in the myocardium, it is not surprising that abnormal electrical activation results in abnormal mechanical contraction. 7,8 During a spontaneous or pacing-induced bundle-branch block, ventricular activation spreads primarily cell to cell through the surrounding myocardium, which can be up to 4 times slower than the specialized His-Purkinje system. 9,10 This results in asynchronous electrical activation and thus asynchronous mechanical contraction in which opposing regions of the ventricular wall become out of phase with each other. Energy generated by contraction of early activated regions is dissipated by relaxation of late-activated regions, leading to decreased energy efficiency, depressed pump function, and deleterious ventricular remodeling. 11-14Approximately 25% of adults with HF exhibit a LBBB with mechanical dyssynchrony. CRT has traditionally targeted this electrical and mechanical dyssynchrony with biventricular pacing.15 By simultaneously pacing both ventricles, CRT uniformly prolongs the time to maximum contraction in each ventricle as the activation wave fronts from both ventricles merge. 16,17 This results in a more coordinated contraction pattern, more homogeneous distribution of regional loading conditions ...

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Implication of QRS Prolongation and Its Relation to Mechanical Dyssynchrony in Idiopathic Dilated Cardiomyopathy in Childhood

Cited by 15 publications

References 27 publications

Pacing treatment for dilated cardiomyopathy: optimization of resynchronization pacing in pediatrics

Pacing treatment for dilated cardiomyopathy: optimization of resynchronization pacing in pediatrics

Echocardiographic Assessment of Ventricular Synchrony in Congenital and Acquired Heart Disease in Children

Cardiac Resynchronization Therapy for Pediatric Patients With Heart Failure and Congenital Heart Disease

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