Is the Outcome of Cardiac Resynchronization Therapy Related to the Underlying Etiology?

Gasparini, Maurizio; Mantica, Massimo; Galimberti, Paola; Genovese, Luca; Pini, Daniela; Faletra, Francesco F.; Marchesina, Ugo La; Mangiavacchi, Maurizio; Klersy, Catherine; Gronda, Edoardo

doi:10.1046/j.1460-9592.2003.00011.x

Cited by 101 publications

(61 citation statements)

References 18 publications

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“…In addition, because a significant proportion of patient receiving CRT do not benefit, identifying these nonresponders is also important. 14,15,19,20 The present report describes a novel utility for real time 3D echocardiography (RT3DE). This imaging modality allows functional assessment of all 16 individual segments of the LV.…”

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confidence: 99%

Real-Time Three-Dimensional Echocardiography

et al. 2005

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confidence: 99%

Real-Time Three-Dimensional Echocardiography

et al. 2005

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“…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. 54,55 Differences in the relationship between electrical and mechanical dyssynchrony may explain these discrepant findings. Although studies in pediatric DCM have demonstrated mechanical dyssynchrony, they have not consistently demonstrated electrical dyssynchrony.…”

Section: Crt For the Failing LVmentioning

confidence: 99%

“…This is in contrast to studies in adult DCM patients demonstrating average QRSd >150 milliseconds, with no correlation with intraventricular mechanical dyssynchrony. [54][55][56] This difference highlights the importance of understanding the relationship between electrical and mechanical dyssynchrony to optimize patient selection criteria for CRT and to improve response to CRT.…”

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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“…20) The clinical applications of the pacing method known as CRT alone (CRT-P) began by using an epicardial lead in 1994. 21) Recent meta-analysis 11,22,23) demonstrated that CRT-P improved LVEF, QOL, and functional status, and reduced hospitalization for heart failure and mortality from all causes. However, it has not been determined whether CRT-P has a potential to suppress lethal arrhythmia or sudden cardiac death 22) (Figure 2).…”

Section: Dysfunction (Lvef 35%)mentioning

confidence: 99%