The role of cardiac resynchronization therapy for arterial switch operations complicated by complete heart block.
BACKGROUND
As mortality in patients with D-loop transposition of the great arteries (D-TGA) has decreased after the arterial switch operation (ASO), the focus has shifted to higher risk groups and outcomes that impact long-term morbidity and mortality, such as left ventricular (LV) dysfunction. We sought to examine the perioperative factors associated with LV dysfunction in patients with D-TGA and ventricular septal defects (VSD) after ASO.


METHODS
A retrospective study was made of all patients with D-TGA/VSD who underwent ASO/VSD closure from 2001 to 2011. Patients with prematurity, L-looped ventricles, and straddling atrioventricular valves were excluded. The primary endpoint was moderate or severe LV dysfunction measured by echocardiogram 2 months or more after surgery.


RESULTS
A total of 112 patients underwent ASO/VSD closure at a median age of 5 days. Median time of follow-up was 6.5 months, with no mortality noted. Six patients (8%) were noted to have at least moderate LV dysfunction. Risk factors were heart block requiring pacemaker placement (p<0.001) and length of intensive care unit admission (p=0.04). All 6 patients with heart block had an epicardial lead on the right ventricular free wall; 4 had moderate or severe LV dysfunction and underwent upgrade to cardiac resynchronization therapy (CRT); median time from initial pacemaker to CRT was 5 months. With a median follow-up of 5 months after CRT, LV function improved to normal (2 patients) or mild dysfunction (2 patients).


CONCLUSIONS
Left ventricular dysfunction after surgical repair for D-TGA/VSD is low, with heart block and pacemaker insertion playing a significant role. The LV function improved after patients were upgraded to a CRT device.
The Department of Cardiology, Boston Children's Hospital, Boston, Massachusetts 02115, USA. douglas.mah@cardio.chboston.org
Douglas Y
DY
Mah
Mark E
ME
Alexander
Puja
P
Banka
Dominic J
DJ
Abrams
John K
JK
Triedman
Edward P
EP
Walsh
Francis
F
Fynn-Thompson
John E
JE
Mayer
Frank
F
Cecchin
D000015:Abnormalities, Multiple / Q000175:diagnosis / Q000601:surgery*; D054537:Atrioventricular Block / Q000175:diagnosis / Q000209:etiology / Q000401:mortality / Q000628:therapy*; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D006348:Cardiac Surgical Procedures / Q000009:adverse effects / Q000379:methods*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006345:Heart Septal Defects, Ventricular / Q000000981:diagnostic imaging / Q000401:mortality / Q000601:surgery*; D017052:Hospital Mortality / Q000639:trends; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D010138:Pacemaker, Artificial; D011183:Postoperative Complications / Q000503:physiopathology / Q000628:therapy; D012189:Retrospective Studies; D018570:Risk Assessment; D015996:Survival Rate; D013997:Time Factors; D014188:Transposition of Great Vessels / Q000000981:diagnostic imaging / Q000401:mortality / Q000601:surgery*; D016896:Treatment Outcome; D014463:Ultrasonography; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000209:etiology / Q000628:therapy
21; 24; ASO; CRT; D-TGA; D-loop transposition of the great arteries; LV; LVEDV; LVEF; RV; VSD; arterial switch operation; cardiac resynchronization therapy; left ventricular; left ventricular ejection fraction; left ventricular end-diastolic volume; right ventricle; ventricular septal defect