Temporary epicardial ventricular stimulation in patients with atrial fibrillation: acute effects of ventricular pacing site on bypass graft flows.
OBJECTIVE
Data on coronary artery bypass grafts flows in patients with atrial fibrillation (AF) requiring epicardial ventricular pacing is lacking. This study aimed to evaluate the optimal epicardial ventricular pacing site in patients with AF following coronary artery bypass surgery (CABG).


METHODS
In 23 consecutive patients (mean age = 69.2 +/- 1.9 years, gender = 62% male, ejection fraction [EF]= 50.4 +/- 2.1%) monoventricular stimulations (VVI) were tested with a constant pacing rate of 100 bpm. The impact of ventricular pacing on bypass graft flow (transit-time flow probe) and pulsatility index (PI) were measured after lead placement on the mid paraseptal region of the right (RVPS) and the left (LVPS) ventricle, on the right inferior wall (RVIW), and on the right ventricular outflow tract (RVOT). In addition, hemodynamic parameters were measured. Patients served as their own control.


RESULTS
Comparison of all tested pacing locations revealed that RVOT stimulation provided the highest bypass grafts flows (59.9 +/- 6.1 mL/min) and PI (2.2 +/- 0.1) when compared with RVPS (51.3 +/- 4.7 mL/min, PI = 2.6 +/- 0.2), RVIW (54.0 +/- 5.1 mL/m; PI = 2.4 +/- 0.2), and LVPS (53.1 +/- 4.5 mL/min; PI = 2.3 +/- 0.1), respectively (p < 0.05). When analyzing patients according to their preoperative LV function (group I = EF > 50%; group II = EF < 50%), higher bypass graft flows were observed with RVOT pacing in patients with lower EF (p = n.s.).


CONCLUSIONS
Temporary RVOT pacing facilitates optimal bypass graft flows when compared with other ventricular pacing sites and should be the preferred method of temporary pacing in cardiac surgery patients with AF. Especially in patients with low EF following CABG, RVOT pacing may improve myocardial oxygen conditions for the ischemic myocardium and enhance graft patency in the early postoperative period.
Madershahian
Navid
N
Department of Cardiothoracic Surgery, Cologne University Heart Centre, Kerpener Strasse 62, Cologne, Germany. navid.madershahian@web.de
Liakopoulos
Oliver J
OJ
Wittwer
Thorsten
T
Wippermann
Jens
J
Kuhn-Regnier
Ferdinand
F
Naraghi
Hamid
H
Wahlers
Thorsten
T
D000368:Aged; D001281:Atrial Fibrillation / Q000628:therapy*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D001026:Coronary Artery Bypass; D003326:Coronary Circulation; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D011673:Pulsatile Flow; D013318:Stroke Volume; D016276:Ventricular Function