Dilated cardiomyopathy in isolated congenital complete atrioventricular block: Early and long-term risk in children

OBJECTIVES We sought to identify the risk factors predicting the development of dilated cardiomyopathy (DCM) in patients with isolated congenital complete atrioventricular block (CCAVB). BACKGROUND Recently evidence has emerged that a subset of patients with CCAVB develop DCM. METHODS This was a retrospective study of 149 patients with CCAVB who had heart size and left ventricular (LV) function assessed by echocardiography and chest radiograph! over a follow-up period of 10 +/- 7 years. RESULTS Nine patients developed DCM at the age of 6.5 +/- 5 fears. No definite cause could be identified. In these nine patients, CCAVB was diagnosed in eight at 23 +/- 2.3 weeks gestation and in one at birth. Maternal SSA/SSB antibodies were confirmed in seven of the nine patients. Pacemakers were implanted in eight patients in the first month and in one patient at five years of age. The initial left ventricular end-diastolic dimension (LVEDD) was in the 96th +/- 2.6 percentile and the cardiothoracic (CT) ratio was 64 +/- 3.8% in the nine patients who developed DCM, and differed significantly in patients with CCAVB (p <0.005) who did not develop DCM. The LVEDD and CT ratio did not decrease in the patients with CCAVB and DCM, but decreased significantly in the patients with CCAVB without DCM (p <0.001) once pacing was initiated. Two patients with DCM died within two months of diagnosis; one patient is neurologically compromised; two patients received a heart transplant; and four patients are listed for heart transplantation. CONCLUSIONS Isolated CCAVB is associated with a long-term risk for the development of DCM. Risk factors may be SSA/SSB antibodies, increased heart size at initial evaluation and the absence of pacemaker-associated improvement. (J Am Cell Cardiol 2001;37:1129-34) (C) 2001 by the American College of Cardiology

Atrial pacing to estimate total sinoatrial conduction time in children

No data exist concerning the total sinoatrial conduction time (TSACT) in children that compare values determined by the atrial extrastimulation technique (TSACT S ) with those generated by the atrial pacing method (TSACT N ). In this study, TSACT in 55 patients, age 0.2–18.5, was measured using both techniques. TSACT N was performed at a mean 90% (TSACT N−90 ) ( n =32) or a mean 95% (TSACT N−95 and ( n =38) of sinus cycle length (SCL). When data generated during determination of TSACT N−90 and TSACT S were compared, SCL and recovery cycle length (REC) were similar for both techniques. Likewise, TSACT S (128±40 ms) and TSACT N−90 (126±74 ms) were not significantly different. Coefficient of correlation was r =0.82, p <0.001. Chi-square analysis demonstrated a strong association of normal and abnormal values between TSACT S and TSACT N−90 . In contrast, when values generated during TSACT N−95 and TSACT S were compared, TSACT S exceeded TSACT N−95 (137±38 vs 105±58 ms; p <0.001). Values for SCL and REC were similar while correlation between TSACT determined by the two techniques remained strong ( r =0.82, p <0.001). Despite a good correlation between TSACT N−90 and TSACT S , individual differences in magnitude and direction were noted between the two techniques.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/48109/1/246_2005_Article_BF02083705.pd