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Characterization of Tachyarrhythmia Following Norwood Operation

Friday, October 19, 2012: 2:15 PM
Room 275-277 (Morial Convention Center)
Katja M. Gist, DO, MSCS1, Eleanor L. Schuchardt, MD2, Meghan Moroze3, Jonathan Kaufman, MD1, Eduardo da Cruz, MD1, Max B. Mitchell, MD4, David N. Campbell, MD1, James Jaggers, MD4 and Anthony C. McCanta, MD1, (1)Pediatrics, Heart institute, University of Colorado, Children's Hospital Colorado, Aurora, CO, (2)Pediatrics, University of Colorado, Children's Hospital Colorado, Aurora, CO, (3)Regis University, Denver, CO, (4)Surgery, Heart institute, University of Colorado, Children's Hospital Colorado, Aurora, CO

Purpose: Tachyarrhythmias are common following repair of congenital heart disease, and may be associated with increased morbidity and mortality. The purpose of this study was to determine the incidence of tachyarrhythmia in patients following Norwood operation.

Methods: Retrospective chart review of all patients who underwent stage I Norwood procedure from 1/1/2003 to 9/1/2011 (n=100). Data collected included demographics, shunt type (modified Blalock-Taussig shunt (mBTS) or right ventricle to pulmonary artery conduit (RVPA), surgical variables, type of tachycardia, interval since surgery, cycle length, and need for antiarrhythmic medication at discharge.

Results: Data regarding arrhythmia was available for 98 patients. Tachyarrhythmia occurred in 33/98 patients (34%). Six patients with a tachyarrhythmia died. Causes of mortality in those with a tachycardia included cardiac arrest (n=2) or circulatory collapse requiring ECMO (n=2), respiratory arrest (n=1) and dural sinus venous thrombosis (n=1). There was no significant difference in the incidence of arrhythmia based on shunt type (p=0.23) where 8/32 underwent palliation with mBTS, and 25/66 with a Sano shunt. The odds of arrhythmia in males were 9.3 times that of females (95% CI 2.9, 35.3)(p = 0.0004). Table 1 demonstrates the arrhythmia characteristics

Conclusion: Post-operative tachyarrhythmia is common after Norwood operation. Shunt type was not associated with tachycardia. Male gender was a significant risk factors associated with the development of tachyarrhythmia. It is possible that other factors could have contributed to tachycardia, including use of specific drugs such as milrinone. Further studies to elucidate these factors are necessary.

Table 1. Arrhythmia characteristics following Norwood procedure

Arrhythmia type

N

# with EKG

A-wire

Days since NP

CL (ms)

D/C on meds*

AET (irregular)

4

4

0

14 (12, 28)

280 (240, 320)

3/4 (75%)

AET

7

7

2

1 (1, 4)

290 (270, 320)

5/7 (71%)

AVRT

8

4

0

10.5 (8, 17)

285 (235, 328)

5/7 (71%)

AVRT – pre

2

2

0

8 (5, 11)

215 (210, 220)

1/1 (100%)

JET

3

3

3

4 (0, 5)

320 (280, 380)

1/1 (100%)

Atrial Flutter

2

2

2

10 (0, 19)

A-A: 145

V-V: 305

1/2 (50%)

VT

2

1

1

12

380

0/1 (%)

> 1 mechanism

5

5

2

2 (1, 13)

220 (220, 318)

4/4 (100%)

*Includes patients alive at discharge from the Norwood procedure. All data is represented as median with interquartile range if appropriate. AET = atrial ectopic tachycardia, AVRT = atrioventricular reentrant tachycardia, AVRT – pre = atrioventricular reentrant tachycardia with pre-excitation, JET = junctional ectopic tachycardia, VT = ventricular tachycardia, N = number of patients, # = those for which an EKG was available for review, A-wire = atrial wire EKG used for interpretation, NP = Norwood procedure, CL = cycle length, ms = milliseconds, D/C = discharge.