Does biventricular pacing provide a superior cardiac output compared to univentricular pacing wires after cardiac surgery?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether biventricular pacing provides a superior cardiac output compared to univentricular pacing wires after cardiac surgery. Using the reported search, 439 papers were found from which 13 papers represented the best evidence on the subject. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes and results are tabulated. We conclude that in 9 of the 13 papers presented, significant increases in the cardiac index and mean arterial pressure were found with biventricular pacing. In the four negative studies, which included an experimental study, the patients tended to have normal or better ejection fractions and narrow QRS complexes. Up to a 22% increase in Cardiac Index was reported in the positive studies. Exact pacing wire placement varies and some studies caution that if in the wrong place, the index can actually drop. Transoesophageal flow volume loops have been used to guide placement. Benefits seem greatest in patients with a poor ejection fraction and a wide QRS complex.