CRT May Help Some Infants Recover After Biventricular Heart-Defect Surgery

Larry Hand

October 06, 2016

TORONTO, ON — Short-term cardiac resynchronization therapy (CRT) may improve blood pressure in infants who undergo undergo biventricular surgery for congenital heart disease, according to results of a small clinical trial published online September 26, 2016 in Heart Rhythm[1].

"These results are preliminary, as the study was small. Thus, it's power is limited. However, the implications are exciting," Dr Elizabeth A Stephenson (Hospital for Sick Children, Toronto, ON) told heartwire from Medscape. "This may well offer another maneuver to support the most vulnerable children after [cardiopulmonary] bypass when electrical dyssynchrony in the form of a widened QRS is present."

Stephenson and colleagues conducted a randomized trial involving 42 infants younger than 4 months who had had biventricular surgery for congenital heart disease and either standard care (n=21) or standard care plus CRT for 48 hours or until extubation (n=21). The most common indications for surgery were transposition of the great arteries with or without ventricular septal defect, tetralogy of Fallot, and coarctation of the aorta with ventricular septal defect.

Although the change in cardiac index (CI) did not differ between groups, the researchers observed a trend toward improvement in infants with wide QRS who received CRT (n=9) vs wide QRS controls (n=8), who experienced the smallest CI increase.

Infants with wide QRS who received CRT experienced significantly higher blood pressure than controls (+7.14 mm Hg, P=0.02).

Researchers found that infants with narrow QRS in both groups experienced a significant increase in CI.

The infants experienced no adverse events from pacing.

"Dyssynchrony, even when subtle, plays an important role in cardiac efficiency. While we think of CRT as a permanent pacing maneuver for chronic heart failure, temporary resynchronization may benefit children in the acute recovery period," Stephenson told heartwire .

"We are currently recruiting for a study examining the effects of CRT focusing on children with electrical dyssynchrony, as this study demonstrated they have the most benefit from temporary CRT, as anticipated," she said. "With this next phase of research we hope to better identify those children most likely to benefit, for whom it would be reasonable to propose CRT as a standard part of postoperative care."

The Labatt Family Heart Center at the Hospital for Sick Children supported this research. The authors reported no relevant financial relationships.

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