Predictors of Response to Cardiac Resynchronization Therapy in Pediatric Patients and Patients With Congenital Heart
Henry Chubb1, Douglas Mah2, Maully Shah3
1Division of Pediatric Cardiology, Department of Pediatrics (H.C., W.G., S.R.C., K.S.M., D.N.R., C.S.A., D.B.M., A.M.D.), Stanford University, CA.
Insights
Cardiac resynchronization therapy (CRT) improves systemic ventricular ejection fraction (SVEF) in pediatric patients with heart conditions. Lower SVEF, left ventricular involvement, and conduction delays predict a positive CRT response.
Area of Science:
- Pediatric Cardiology
- Congenital Heart Disease
- Electrophysiology
Background:
- Cardiac resynchronization therapy (CRT) is a key treatment for pediatric patients and those with congenital heart disease (CHD) experiencing reduced systemic ventricular ejection fraction (SVEF).
- Identifying optimal responders to CRT in this population remains a significant clinical challenge.
- This study sought to identify predictors of CRT response in children and CHD patients.
Purpose of the Study:
- To identify predictors of response to cardiac resynchronization therapy (CRT) in pediatric patients and those with congenital heart disease (CHD).
- To analyze factors associated with improved systemic ventricular ejection fraction (SVEF) following CRT.
- To evaluate the long-term efficacy of CRT in a cohort of young patients.
Main Methods:
- Retrospective analysis of 167 pediatric patients and CHD patients with SVEF <45% undergoing CRT.
- Primary outcome: ordinal response in SVEF (improved, unchanged, worse) at 6 or 12 months.
- Secondary outcome: propensity score-matched control cohort analysis with long-term SVEF trajectory.
Main Results:
- 64% of patients (150 total) showed improved SVEF (mean increase of 11%) post-CRT.
- Lower baseline SVEF, biventricular circulation, systemic left ventricle, and lateral wall conduction delay predicted positive CRT response.
- Patients with systemic right ventricles or without prior single-site pacemakers showed less SVEF improvement.
Conclusions:
- Cardiac resynchronization therapy (CRT) is effective in improving SVEF in pediatric and congenital heart disease populations.
- Predictors of positive CRT response include lower SVEF, systemic left ventricle, and specific conduction delays.
- CRT offers a valuable therapeutic option for selected pediatric patients with heart failure and dyssynchrony.
Background:
Cardiac resynchronization therapy (CRT) is an important therapeutic option in selected pediatric patients and patients with congenital heart disease with reduced systemic ventricular ejection fraction (SVEF). However, the identification of optimal responders is challenging. This study aimed to identify predictors of response to CRT in children and patients with congenital heart disease at 5 large quaternary referral centers.
Methods:
Patients were aged <21 or had congenital heart disease and had SVEF <45%, symptomatic heart failure, and significant electrical dyssynchrony before CRT. Primary outcome was defined as an ordinal response at 6 or 12 months: (1) improved SVEF (≥5%), (2) unchanged SVEF, and (3) worse SVEF. Secondary outcome utilized a propensity score-matched control cohort. Response to CRT was defined using the longitudinal trajectory of SVEF up to the latest follow-up.
Results:
In total, 167 eligible CRT recipients were identified across the 5 centers; 150 had comprehensive data at 6 or 12 months: 96 (64%) with improved SVEF, 26 (17%) unchanged, and 28 (19%) worsened. Mean increase in SVEF was 11% (interquartile range, 3%-21%). On univariable ordinal regression, lower SVEF (P=0.013), biventricular circulation (P=0.022), systemic left ventricle (P=0.021), and conduction delay to the lateral wall of the systemic ventricle (P=0.01) were associated with a positive response. For the assessment of the secondary outcome, 324 controls were identified. Median follow-up is 5.1 (interquartile range, 2.0-8.6) years. Almost all subgroups demonstrated improved SVEF trend with CRT, except those with systemic right ventricle (P=0.69) or without prior single-site pacemaker (P=0.20).
Conclusions:
CRT in children and patients with congenital heart disease frequently results in an improvement in SVEF. Those with lower SVEF, conduction delay to the lateral wall of the systemic ventricle, and those with a systemic left ventricle are most likely to respond.
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