title: Haemodynamic impact of the left ventricular pacing site during graded ischaemia in an open-chest pig model.
abstract: OBJECTIVE
  In post-operative setting after cardiac surgery, the choice of the optimal ventricular pacing site remains an issue, particularly in patients with ischaemic cardiomyopathy. We aimed to investigate the impact of the left ventricular (LV) pacing site in an animal model of incremental myocardial ischaemia.
  
  
  RESULTS
  Three epicardial LV pacing leads were implanted in 10 pigs [LV1 in the territory of the left anterior descending (LAD) artery, LV2 in the lateral border of this territory, LV3 in an anatomically opposed position]. A two-dimensional strain echocardiogram was performed at baseline and during two levels of incremental ischaemia, corresponding to 30 and 70% reduction of coronary flow in the LAD, during spontaneous sinus rhythm (SR) and during LV1, LV2, LV3, and multi-LV (LV1 + LV2 + LV3) pacing. At baseline (n = 10), LV + dP/dt(max) was decreased (P < 0.01) during LV1, LV2, LV3, and multi-LV pacing compared with SR. At first level of ischaemia (n = 7; 3 animals died from ventricular fibrillation), LV1 pacing (ischaemic area) induced a significant decrease in LV + dP/dt(max) compared with SR, LV2, LV3, and multi-LV pacing (P < 0.05). At second level of ischaemia (n = 6), LV1 pacing induced a significant decrease in LV + dP/dt(max) associated with an increase in the extent of myocardium with echocardiographic post-systolic shortening compared with SR, LV2, LV3, or multi-LV pacing (P < 0.05). In contrast, multi-LV pacing induced a significant haemodynamic improvement compared with SR, LV1, LV2, and LV3 (P < 0.05).
  
  
  CONCLUSIONS
  Pacing within an ischaemic area has detrimental impact on acute global and regional LV function. More studies are needed to assess the impact of multi-LV pacing in chronic ischaemic conditions.
authors.affiliation: INSERM U 441, University Bordeaux 2, CHU de Bordeaux, France. bordacharp@hotmail.com
authors.forename: Pierre
authors.initials: P
authors.lastname: Bordachar
authors.forename: Louis
authors.initials: L
authors.lastname: Labrousse
authors.forename: Jean-Benoit
authors.initials: JB
authors.lastname: Thambo
authors.forename: Patricia
authors.initials: P
authors.lastname: Reant
authors.forename: Stephane
authors.initials: S
authors.lastname: Lafitte
authors.forename: Mark D
authors.initials: MD
authors.lastname: O'Neill
authors.forename: Pierre
authors.initials: P
authors.lastname: Jais
authors.forename: Michel
authors.initials: M
authors.lastname: Haissaguerre
authors.forename: Jacques
authors.initials: J
authors.lastname: Clementy
authors.forename: Pierre
authors.initials: P
authors.lastname: Dos Santos
mesh_terms: D000818:Animals; D002304:Cardiac Pacing, Artificial / Q000009:adverse effects / Q000379:methods*; D003326:Coronary Circulation / Q000502:physiology; D004195:Disease Models, Animal; D006339:Heart Rate / Q000502:physiology; D008297:Male; D017202:Myocardial Ischemia / Q000150:complications / Q000503:physiopathology* / Q000628:therapy*; D013552:Swine; D018487:Ventricular Dysfunction, Left / Q000209:etiology / Q000517:prevention & control; D016277:Ventricular Function, Left / Q000502:physiology*