Arterial baroreflex dysfunction after coronary artery bypass grafting.

Although uncommon, the incidence of ventricular arrhythmia is high in certain subsets of patients after coronary artery bypass grafting. Arterial baroreflex dysfunction has been linked to increased risk of ventricular arrhythmia and sudden cardiac death. The aim of the current study was to explore arterial baroreflex function during the early recovery phase and up to five months after surgery. Electrocardiogram and beat-to-beat blood pressures were registered in patients (n=92) undergoing coronary artery bypass grafting five weeks and five months after surgery. Healthy subjects (n=31) were examined for comparison. The arterial baroreflex sensitivity and the baroreflex effectiveness index were calculated. The baroreflex sensitivity and the baroreflex effectiveness index were reduced by 36% and 64%, respectively (P<0.01 for both) in patients five weeks after coronary artery bypass grafting compared to healthy subjects (HS). Values increased during follow-up but the baroreflex effectiveness index remained reduced by 55% in patients compared to HS five months after cardiac surgery (P<0.01). Arterial baroreflex dysfunction prevails both early and long-term after coronary artery bypass grafting. Reduced modulation of cardiac parasympathetic nervous activity could contribute to the increased risk of ventricular arrhythmia observed during the early recovery phase after cardiac surgery.