title: Prolonged total isovolumic time predicts cardiac events following coronary artery bypass surgery.
abstract: OBJECTIVE
  Left ventricular (LV) systolic dysfunction may be associated with compromised stroke volume, which may be caused by asynchrony, reflected on the prolongation of isovolumic time (t-IVT). To assess the prognostic role of Doppler echocardiographic measurements in predicting cardiac events after coronary artery bypass grafting (CABG).
  
  
  RESULTS
  The study included 74 patients undergoing routine CABG. A pre-CABG Doppler echocardiographic assessment of LV dimensions, filling and ejection was performed and t-IVT was determined as [60 - (total ejection time + total filling time)]. Follow-up period was 18 +/- 12 months. Of the 74 patients (age 65 +/- 16 years, 59 males), 29 underwent hospital admission for a cardiac event or died. There were no differences in age, gender, incidence of previous infarct or mitral regurgitation, LV-EDD (left ventricular end-diastolic dimension), left atrial or right ventricular size in patients with cardiac events compared with those without events. Left ventricular end-systolic dimension (LV-ESD) was greater (4.5 +/- 0.9 vs. 3.9 +/- 0.9 cm, P = 0.003), fractional shortening (FS) was lower (21 +/- 4 vs. 32 +/- 8%), E:A ratio and Tei index were higher (2.1 +/- 0.8 vs. 1.0 +/- 0.6 and 0.9 +/- 0.3 vs. 0.6 +/- 0.3, all P < 0.001), and t-IVT was longer (16 +/- 5 vs.10 +/- 4 s/min, P < 0.001) in patients with events. Multivariate predictors of post-CABG events (odds ratio 95% confidence interval) were low FS [0.66 (0.50-0.87), P < 0.001], high E:A ratio [l4.13 (1.17-14.60), P = 0.028], large LV-ESD [0.19 (0.05-0.84), P = 0.029], and long t-IVT [1.37 (1.02-1.84), P = 0.035].
  
  
  CONCLUSIONS
  Despite satisfactory surgical revascularization, long t-IVT and systolic dysfunction suggest persistent ventricular dyssynchrony that contributes to post-CABG cardiac events. Early assessment of such patients for potential benefit from electrical resynchronization may optimize their cardiac performance and hence clinical outcome.
authors.affiliation: Second Division of Cardiology, University Clinical Centre of Kosova, Prishtina, Kosovo.
authors.forename: Gani
authors.initials: G
authors.lastname: Bajraktari
authors.forename: Alison
authors.initials: A
authors.lastname: Duncan
authors.forename: John
authors.initials: J
authors.lastname: Pepper
authors.forename: Michael
authors.initials: M
authors.lastname: Henein
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001145:Arrhythmias, Cardiac / Q000209:etiology*; D016001:Confidence Intervals; D001026:Coronary Artery Bypass / Q000009:adverse effects*; D003324:Coronary Artery Disease / Q000150:complications* / Q000000981:diagnostic imaging / Q000601:surgery; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D017202:Myocardial Ischemia / Q000209:etiology*; D016017:Odds Ratio; D011379:Prognosis; D018570:Risk Assessment; D013318:Stroke Volume; D013997:Time Factors; D014463:Ultrasonography; D018487:Ventricular Dysfunction, Left / Q000209:etiology