Dilated cardiomyopathy following right ventricular pacing for AV block in young patients: resolution after upgrading to biventricular pacing systems.
BACKGROUND
Cardiac resynchronization therapy (CRT) has been demonstrated to result in clinical improvement in older adult patients with dilated cardiomyopathy (DCM), specifically those with left bundle branch block and prolonged QRS duration. We sought to demonstrate the benefits of CRT on improvement in cardiac function and clinical outcome in young patients that developed congestive heart failure (CHF) and DCM following cardiac pacing for AV block.


RESULTS
We reviewed the charts of six patients who developed CHF or low cardiac output symptoms and DCM following implantation of right ventricular (RV)-based pacing systems for AV block, and subsequently underwent CRT. Patients ranged in age from 6 months to 23.7 years (mean: 11.3 +/- 3.6 years). AV block was congenital (3), post-surgery (2), and acquired (1). Pacing had been performed for 0.1-14.5 (7.6 +/- 2.4) years prior to development of DCM. Two patients required listing for cardiac transplantation. Following CRT: (1) QRS duration shortened from 204 +/- 15 to 138 +/- 10 msec, P = 0.002, (2) left ventricular ejection fraction improved from 34 +/- 6 to 60 +/- 2%, P = 0.003, and (3) left ventricular end diastolic dimension shortened from 5.5 +/- 0.8 to 4.3 +/- 0.5 cm, P = 0.03. All patients demonstrated clinical improvement and have been weaned from CHF medications and listing for cardiac transplantation.


CONCLUSIONS
CRT can benefit young patients that develop CHF and DCM following RV pacing for AV block. Upgrading to biventricular pacing systems should be considered early in the management of these patients prior to listing for cardiac transplantation.
Moak
Jeffrey P
JP
Department of Cardiology, Children's National Medical Center, Washington, DC 20010, USA. jmoak@cnmc.org
Hasbani
Keren
K
Ramwell
Carolyn
C
Freedenberg
Vicki
V
Berger
John T
JT
DiRusso
Gregory
G
Callahan
Patrick
P
D000293:Adolescent; D000328:Adult; D002304:Cardiac Pacing, Artificial / Q000009:adverse effects* / Q000379:methods*; D002311:Cardiomyopathy, Dilated / Q000150:complications / Q000628:therapy*; D002648:Child; D005260:Female; D006327:Heart Block / Q000150:complications / Q000628:therapy; D006333:Heart Failure / Q000209:etiology* / Q000517:prevention & control*; D006352:Heart Ventricles / Q000294:innervation; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D016896:Treatment Outcome