Biventricular Pacing Study

Following cardiac surgery patients frequently have a requirement for cardiac pacing, either as a strategy to deal with arrhythmia or to optimize cardiac output during early recovery from cardiopulmonary bypass and cardiac manipulation. Typical approaches to placement of pacing leads result in a single lead being placed on the right ventricle. This approach leads to delayed activation of the left ventricle by the spread of excitation through gap junctions. This late, sometimes dyssynchronous activation of the 2 ventricles may attenuate the ability of pacing to improve hemodynamics. In this study we intend to analyze physiological signals around the transition between single site ventricular pacing and multisite pacing in combination with echocardiographic measurements and invasive measurement of oxygen consumption and laboratory parameters to assess whether objective data supports this intervention as being beneficial in improving cardiac output.