Cardiac resynchronization as therapy for congestive cardiac failure in children dependent on chronic cardiac pacing

Left ventricular epicardial pacing achieved hyper-responsiveness in young children with dilated cardiomyopathy with left bundle branch block

Aims

The management of heart failure (HF) in young children is challenging. The present study aimed to clarify the effect of left univentricular epicardial pacing on dilated cardiomyopathy with left bundle branch block (LBBB) in children.

Methods and results

A total of five cases (30.86 ± 16.39 months, three female) of children weighing 5.8–15 kg with dilated cardiomyopathy and LBBB were included in this study. LBBB in one child occurred after device closure of peri‐membranous ventricular septal defects, and the remaining four were idiopathically discovered early after birth. Before implantation, all children suffered from refractory HF and cardiac dilatation; the left ventricular ejection fraction was 33.48 ± 5.84% with Ross Heart Failure Classification III–IV. Electrical and mechanical dyssynchrony were observed in all children with QRS duration >140 ms and prolonged septal‐to‐left posterior wall motion delay. Left univentricular epicardial pacing was successfully implanted via left axillary minithoracotomy in the five children. Sensed atrioventricular delays (83 ± 15 ms) were optimized by velocity time integral of aortic blood flow before discharge. During the follow‐up period (10.8 ± 2.68 months), the dilated failing heart was reversed significantly in terms of decreased left ventricular dimension (55.62 ± 3.46 vs. 38.94 ± 3.69 mm, P = 0.005), while the left ventricular ejection fraction improved to 60.18 ± 8.78% (P = 0.006).

Conclusions

In young children with low body weight, if HF is caused by or related to LBBB, left ventricular epicardial pacing still has an excellent effect.

Role of cardiac pacing in congenital complete heart block

INTRODUCTION

Congenital complete heart block affects 1/15,000 live-born infants, predominantly due to atrioventricular nodal injury from maternal antibodies of mothers with systemic lupus erythermatosus or Sjogren's syndrome. The majority of these children will need a pacemaker implanted prior to becoming young adults. This article will review the various patient and technical factors that influence the type of pacemaker implanted, and the current literature on optimal pacing practices. Areas covered: A literature search was performed using PubMed, Embase and Web of Science. Data regarding epicardial versus transvenous implants, pacing-induced ventricular dysfunction, alternative pacing strategies (including biventricular pacing, left ventricular pacing, and His bundle pacing), and complications with pacemakers in the pediatric population were reviewed. Expert commentary: There are numerous pacing strategies available to children with congenital complete heart block. The risks and benefits of the initial implant should be weighed against the long-term issues inherent with a life-time of pacing.

Cardiac resynchronisation therapy in paediatric and congenital heart disease: differential effects in various anatomical and functional substrates

Background:

Cardiac resynchronisation therapy (CRT) is increasingly used in children in a variety of anatomical and pathophysiological conditions, but published data are scarce.

Objective:

To record current practice and results of CRT in paediatric and congenital heart disease.

Design:

Retrospective multicentre European survey.

Setting:

Paediatric cardiology and cardiac surgery centres.

Patients:

One hundred and nine patients aged 0.24–73.8 (median 16.9) years with structural congenital heart disease (n = 87), congenital atrioventricular block (n = 12) and dilated cardiomyopathy (n = 10) with systemic left (n = 69), right (n = 36) or single (n = 4) ventricular dysfunction and ventricular dyssynchrony during sinus rhythm (n = 25) or associated with pacing (n = 84).

Interventions:

CRT for a median period of 7.5 months (concurrent cardiac surgery in 16/109).

Main outcome measures:

Functional improvement and echocardiographic change in systemic ventricular function.

Results:

The z score of the systemic ventricular end-diastolic dimension decreased by median 1.1 (p<0.001). Ejection fraction (EF) or fractional area of change increased by a mean (SD) of 11.5 (14.3)% (p<0.001) and New York Heart Association (NYHA) class improved by median 1.0 grade (p<0.001). Non-response to CRT (18.5%) was multivariably predicted by the presence of primary dilated cardiomyopathy (p = 0.002) and poor NYHA class (p = 0.003). Presence of a systemic left ventricle was the strongest multivariable predictor of improvement in EF/fractional area of change (p<0.001). Results were independent of the number of patients treated in each contributing centre.

Conclusion:

Heart failure associated with ventricular pacing is the largest indication for CRT in paediatric and congenital heart disease. CRT efficacy varies widely with the underlying anatomical and pathophysiological substrate.

Mechanical Dyssynchrony in Children with Systolic Dysfunction Secondary to Cardiomyopathy: A Doppler Tissue and Vector Velocity Imaging Study

OBJECTIVE

Mechanical dyssynchrony is common in adults with heart failure and its presence predicts response to cardiac resynchronization therapy. However, mechanical dyssynchrony and its quantification by echocardiography have not been extensively studied in children with cardiomyopathy. We investigated mechanical dyssynchrony in children with systolic dysfunction secondary to cardiomyopathy using Doppler tissue imaging (DTI) and vector velocity imaging (VVI).

METHODS

We used DTI and VVI to quantify mechanical dyssynchrony in 22 children with systolic dysfunction secondary to cardiomyopathy and in 25 healthy control subjects. We analyzed DTI results corrected for cardiac dimensions and evaluated correlation between electrical and mechanical dyssynchrony and between mechanical dyssynchrony and systolic function.

RESULTS

DTI and VVI revealed significant mechanical dyssynchrony among children with cardiomyopathy. Intraventricular and interventricular delays as defined by DTI, and the SD of time to peak velocity, strain, and strain rate as defined by VVI were 2 to 3 times higher in patients with cardiomyopathy as compared with control subjects. There was no significant relationship between electrical and mechanical dyssynchrony.

CONCLUSIONS

Children with systolic dysfunction secondary to cardiomyopathy have mechanical dyssynchrony, unrelated to electrical dyssynchrony, which can be measured by recent echocardiographic techniques including DTI and VVI. Children with cardiomyopathy and mechanical dyssynchrony are potential candidates for cardiac resynchronization therapy.

Re: Systematic placement of left-sided pacing leads as an appealing option for cardiac resynchronization as treatment of congestive cardiac failure in children dependent on chronic cardiac pacing

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