title: [Influence of coronary revascularization on chronic ischemic stunning of the conduction system of the heart].
abstract: About one fourth of patients (pts) with coronary artery disease (CAD) referred for coronary bypass surgery (CABG) exhibits some kind of intraventricular conduction defect (IVCD).
  
  
  OBJECTIVE
  To assess CABG influence on the behavior of intraventricular conduction in pts submitted to CABG.
  
  
  METHODS
  Prospective study of 504 pts with severe CAD (3-vessel and/or left main trunk disease), divided in 2 groups (Gr) - GrA, composed of 252 pts with on-pump CABG, and GrB, with 252 pts submitted to off-pump CABG - whose pts were matched for age, gender, angiographic data, additive Euroscore, prior myocardial infarction, diabetes and hypertension. Other data (GrA vs GrB): nr of bypasses/pt 2.9 vs 2.4 (p<0.01); bypass to LAD 100% vs 100%; complete revascularization 60% vs 60%; left ventricular dysfunction 39% vs 34% (NS). Electrocardiographic study: pre-operative 12-lead ECG (within 72 hrs prior to CABG); post-operative (post-op) continuous ECG monitoring by telemetry (1 lead), including recording of data, until the discharge; post-op 12-lead ECG (up to 24 hrs after CABG), eventually repeated accordingly to the telemetric ECG evolution; ECG recordings were always performed by the same technician, with the same ECG recorder (25 mm/sec; 1 mV=10 mm). Results (GrA vs GrB): 1) Pre-operative IVCD 27% vs 24% (NS). 2) Post-op regression/abolition of IVCD (due to reversion of chronic stunning of the conduction system) 24%vs 28% (NS), occurring shortly (up to 24 hrs) after CABG termination in 95% of cases. IVCD aggravation/new IVCD 9.9% vs 0.8% (p<0.001). 3) Post-op IVCD: global figure 28% (+4.5%) vs 21% (-13%), p>0,05; stable IVCD + aggravated IV conduction 30% vs 18% (p<0.01). Post-op permanent pacing: 2 pts vs 0 pts.
  
  
  CONCLUSIONS
  1) A significant number (at least 24%) of pts with severe CAD and stable IVCD shows chronic ischemic stunning of the IV conduction system, which reverts after CABG. 2) Off-pump CABG (in opposition to on-pump CABG), by assuring a better intra-operative protection of the ventricular septum, promotes an improvement of intraventricular conduction in pts submitted to CABG.
authors.affiliation: Serviço de Cirurgia Cardiotorácica do Hospital de Santa Maria, Centro Hospitalar Lisboa Norte.
authors.forename: Alvaro
authors.initials: A
authors.lastname: Bordalo
authors.forename: Angelo
authors.initials: A
authors.lastname: Nobre
authors.forename: Filipe
authors.initials: F
authors.lastname: Pereira
authors.forename: Carlos
authors.initials: C
authors.lastname: Serpa
authors.forename: João
authors.initials: J
authors.lastname: Cravino
mesh_terms: D000368:Aged; D002908:Chronic Disease; D001026:Coronary Artery Bypass; D003324:Coronary Artery Disease / Q000150:complications / Q000601:surgery*; D005260:Female; D006329:Heart Conduction System; D006801:Humans; D008297:Male; D008875:Middle Aged; D017682:Myocardial Stunning / Q000150:complications / Q000601:surgery*; D011446:Prospective Studies