Effects of Chronic Right Ventricular Pacing in Children With Advanced Atrioventricular Block

Effects of Chronic Right Ventricular Pacing in Children With Advanced Atrioventricular Block

Recent studies have shown that chronic stimulation of the right ventricle can cause deleterious effects to cardiac function and synchronicity. The occurrence and consequences of this phenomenon in children and young patients with cardiac pacemaker due to advanced atrioventricular block (AVB) are still unknown.

Thus, our aims is to assess the chronic effects of cardiac pacing in children and young patients with advanced AVB and its impact on clinical, functional and echocardiographic parameters.

This is a prospective cohort study that will include patients younger than 18 years-old at initial pacemaker implantation due to advanced AVB.

The design of the study will involve the following stages:

1. Screening and enrollment: patients will be selected consecutively during ambulatory care at our Institution or by the database of the Surgical Unity of Cardiac Pacing;
2. Clinical and laboratory evaluation: patient history, clinical evaluation, serum levels of neurohormonal and inflammatory biomarkers of heart failure, clinical and laboratory investigation of autoimmune rheumatic diseases, quality of life (SF-36, CHQ-PF50) and six-minute walk test;
3. Evaluation of ventricular function and cardiac synchronicity: Tissue Doppler (TDI) and real-time three-dimensional echocardiography (RT3DE);
4. Follow-up: patients will be monitored during 24 months.

The main end-points are:

• Clinical and functional changes (NYHA functional class)
• Heart failure hospitalization
• Quality of life
• Overall and cardiac mortality
• Cardiac resynchronization therapy and heart transplantation

Inclusion Criteria:

• Age <18 years at initial pacemaker implantation
• Advanced AV block with /without congenital heart defects
• Time under cardiac pacing superior than one year
• Unicameral or atrioventricular pacing in single right ventricle site
• Informed consent of the patient or responsible

Exclusion Criteria:

• Bifocal or biventricular pacing
• Discontinuing use of the device for recovery of atrioventricular conduction
• Cardiac transplantation
• Inability to participate in the study procedures