Tissue Doppler Changes in Pediatric Complete Heart Block Patients Who Are Chronically Paced

Abstract

Pediatric patients with complete heart block (CHB) often require pacemaker therapy. Adult studies have shown chronic right ventricular pacemaker therapy may be associated with decreased echocardiographic parameters and increased brain natriuretic peptide (BNP) values. The goal of this study was to determine if there are echocardiographic or BNP changes in a pediatric population that is chronically paced. Patients were recruited if they had CHB and had a pacemaker. Patients were excluded if they had congenital structural heart disease. Standard two-dimensional echocardiograms, including tissue Doppler imaging (TDI), were performed. BNP values were obtained. Nonparametric Spearman's rank correlation was used for analysis. Rho < or = 0.05 was considered significant. Eighteen patients (16.4 +/- 7.3 years) with CHB were studied. Age at implant was 8.6 +/- 6.6 years and length of pacing was 7.8 +/- 6.6 years. Pacing mode was VDD, DDD, DDDR, or VVIR. All patients were ventricularly paced >95% of the time. Ejection fraction was 58.5 +/- 7.5%. All BNP values were <40 pg/mL. There was no correlation between ejection fraction or BNP level with the length of pacing years. Pacing years significantly correlated with mitral and tricuspid E/A ratios (rho =-0.56, -0.56, respectively). Pacing years also correlated with right ventricular and interventricular TDI a wave (rho = 0.61 and 0.68, respectively). Furthermore, pacing years correlated with right ventricular TDI e/a ratio (rho =-0.58). Ejection fraction and BNP levels were not sensitive parameters in evaluating pediatric patients who are chronically paced. Subtle diastolic changes, especially of the right ventricle, were detected by TDI.