Fetal right ventricular myocardial function is better preserved by fibrillatory arrest during fetal cardiac bypass.
BACKGROUND
Protection and preservation of fetal myocardial function are important for successful fetal intracardiac repair. Our objective was to determine fetal biventricular cardiac performance after two cardiac-arrest techniques.


METHODS
Three groups of midterm ovine fetuses underwent 90-minute bypass. A control group (no arrest shams, n = 3), and two groups that included 20 minutes of arrest, using fibrillatory (n = 3) or blood cardioplegia (n = 3), were compared. Blood cardioplegia consisted of 4:1 cold blood to crystalloid solution induction every 10 minutes, followed by a warm shot terminal dose before clamp removal. Myocardial function variables from biventricular intracardiac pressure catheters, and 3-axes cardiac sonomicrometry, fetal hemodynamics, and arterial blood gases were continuously recorded. Fetal myocardium was collected for troponin-I analysis at 90 minutes. Statistical analysis was by two-way analysis of variance for repeated measures.


RESULTS
Compared with sham, right ventricular myocardial contractility was reduced with plegia but not fibrillation at 90 minutes after arrest: dP/dt max (511 ± 347 vs 1208 ± 239, p < 0.01) and preload-recruitable stroke work (7.2 ± 8.5 vs 32.3 ± 14.6, p < 0.01). Right ventricular end diastolic pressure-volume relationship (ventricular stiffness) worsened by 90 minutes for plegia vs fibrillation (0.84 ± 0.18 vs 0.25 ± 0.16, p < 0.05). There were no differences in left ventricle performance between groups. Fetal heart rate increased in shams by 30 minutes after arrest compared with both arrest groups (p < 0.05). Right ventricular troponin-I degradation increased with plegia, but not fibrillation, compared with sham (p < 0.05).


CONCLUSIONS
In vivo, fetal right ventricular contractile function deteriorates with a common blood-plegia regimen. Fibrillatory arrest better preserves right ventricular function, the dominant ventricle in fetal life, for short arrest periods.
Petrucci
Orlando
O
Division of Cardiothoracic Surgery, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA.
Baker
R Scott
RS
Lam
Christopher T
CT
Reed
Casey A
CA
Duffy
Jodie Y
JY
Eghtesady
Pirooz
P
D000818:Animals; D002314:Cardioplegic Solutions; D002315:Cardiopulmonary Bypass / Q000379:methods*; D005260:Female; D005333:Fetus / Q000601:surgery*; D006324:Heart Arrest, Induced / Q000379:methods*; D006330:Heart Defects, Congenital / Q000601:surgery*; D006439:Hemodynamics; D011247:Pregnancy; D020127:Recovery of Function; D012756:Sheep; D014693:Ventricular Fibrillation / Q000378:metabolism*; D016278:Ventricular Function, Right
D002314:Cardioplegic Solutions