Left ventricular synchrony and function in pediatric patients with definitive pacemakers.
BACKGROUND
Chronic right ventricular pacing (RVP) induces a dyssynchronous contraction pattern,producing interventricular and intraventricular asynchrony. Many studies have shown the relationship of RVP with impaired left ventricular (LV) form and function.


OBJECTIVE
The aim of this study was to evaluate LV synchrony and function in pediatric patients receiving RVP in comparison with those receiving LV pacing (LVP).


METHODS
LV systolic and diastolic function and synchrony were evaluated in 80 pediatric patients with either nonsurgical or postsurgical complete atrioventricular block, with pacing from either the RV endocardium (n = 40) or the LV epicardium (n = 40). Echocardiographic data obtained before pacemaker implantation, immediately after it, and at the end of a mean follow-up of 6.8 years were analyzed.


RESULTS
LV diastolic function did not change in any patient during follow-up. LV systolic function was preserved in patients with LVP. However, in children with RVP the shortening fraction and ejection fraction decreased from medians of 41% ± 2.6% and 70% ± 6.9% before implantation to 32% ± 4.2% and 64% ± 2.5% (p < 0.0001 and p < 0.0001), respectively, at final follow-up. Interventricular mechanical delay was significantly larger with RVP (66 ± 13 ms) than with LVP (20 ± 8 ms). Similarly, the following parameters were significantly different in the two groups: LV mechanical delay (RVP: 69 ± 6 ms, LVP: 30 ± 11 ms, p < 0.0001); septal to lateral wall motion delay (RVP: 75 ± 19 ms, LVP: 42 ± 10 ms, p < 0.0001); and, septal to posterior wall motion delay (RVP: 127 ± 33 ms, LVP: 58 ± 17 ms, p < 0.0001).


CONCLUSIONS
Compared with RV endocardium, LV epicardium is an optimal site for pacing to preserve cardiac synchrony and function.
Michel
M
Cabrera Ortega
Adel Eladio
AE
Gonzales Morejón
Giselle
G
Serrano Ricardo
D000293:Adolescent; D054537:Atrioventricular Block / Q000628:therapy; D001706:Biopsy / Q000379:methods; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D002648:Child; D058407:Electroencephalography Phase Synchronization / Q000502:physiology*; D004699:Endocardium / Q000473:pathology; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D010138:Pacemaker, Artificial; D010496:Pericardium / Q000473:pathology; D011446:Prospective Studies; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology* / Q000628:therapy; D016277:Ventricular Function, Left / Q000502:physiology*