Risk of cardiac arrhythmias and conduction abnormalities in patients with acute myocardial infarction receiving packed red blood cell transfusions.

Purpose: Although transfusion has been linked to the development of atrial fibrillation (AF) in cardiac surgical patients, this association has not been investigated in patients with acute myocardial infarction (AMI). Evidence supports an inflammatory mechanism in the development of AF, and red cell transfusions also elicit an inflammatory response. We therefore sought to evaluate whether packed red blood cell transfusion increases the risk of AF, ventricular tachycardia (VT), and other arrhythmias and conduction abnormalities in patients with AMI.

Materials And Methods: This is a retrospective study on patients with AMI and no prior history of AF, admitted to a critical care area and entered in Project Impact database from 08/2003-12/2007. Primary outcome measures were new-onset cardiac arrhythmias or conduction disturbances.

Results: Transfused patients had significantly higher incidences of AF (4.7% vs 1.3%, P = .008), cardiac arrest (9.5% vs 1.7%, P < .001) and heart block (3.4% vs 0.1%, P < .001), and a trend toward a higher incidence of VT (3.4% vs 1.3%, P = .058). Multivariate regression analysis confirmed transfusion as an independent risk factor for "non-lethal" cardiac events (AF/heart block; odds ratio [OR], 4.7 [1.9-11.9]; P = .001), "lethal" events (VT/cardiac arrest; OR, 2.4 [1.1-5]; P = .016), and all cardiac events (OR, 2.8 [1.5-65.1]; P = .001). Transfused patients had significantly longer length of stay (P < .0001) and significantly higher mortality rates than nontransfused patients (OR, 3 [1.7-5.5]; P < .001).

Conclusions: Packed red blood cell transfusion is independently associated with an increased risk of new-onset cardiac arrhythmias and conduction abnormalities in the setting of AMI, even after controlling for traditional risk factors.