title: Left-ventricular electromechanical delay is prolonged in patients with postoperative atrial fibrillation.
abstract: OBJECTIVE
  Although several risk factors for postoperative atrial fibrillation (AF) have been proposed, it remains the most common complication after cardiac surgery, even in low-risk patients. There is still no single reliable and reproducible parameter for predicting AF, and no standardized recommendation exists for this issue. Electromechanical delay (excitation-contraction coupling delay) is the time delay from the electrical activation to the actual systolic motion, and it reflects abnormality in calcium-handling proteins, which is considered one mechanism of postoperative AF. We hypothesized that left-ventricular electromechanical delay (LVEMD) is correlated to postoperative AF and serially examined it by echocardiography.
  
  
  METHODS
  We prospectively included 16 patients with relatively low risk for AF, who underwent cardiac surgery. The inclusion criteria were younger than 80 years, an ejection fraction greater than 45%, a left-atrial dimension less than 50mm, and a brain natriuretic peptide (BNP) value less than 250 pg ml⁻¹. Postoperative AF for 10 postoperative days was monitored by 24-h electrocardiogram. The LVEMD was assessed by pulse-wave tissue Doppler echocardiography before and 1, 3, and 7 days after the operation. Serum BNP, adrenalin, and noradrenalin levels were also examined at the same time.
  
  
  RESULTS
  Postoperative AF was detected in six (37.5%) patients. There was no significant difference in heart rate, QRS duration, and serum hormones between the non-AF (n = 10) and AF (n = 6) groups. Although the preoperative LVEMD was comparable, that on postoperative day 1 of the AF group was significantly longer than that of the non-AF group (in the septal wall, 174 ± 50 vs 101 ± 36 ms, p = 0.020; in the lateral wall, 195 ± 71 and 111 ± 37 ms, p = 0.029). A LVEMD on postoperative day 1 greater than 150 ms well predicted postoperative AF (sensitivity, 75% and 75%; specificity, 100% and 86%, in septal and lateral LVEMDs, respectively).
  
  
  CONCLUSIONS
  LVEMD is prolonged in patients with postoperative AF. This could be a new predicting parameter for AF in low-risk patients.
authors.affiliation: Department of Cardiovascular Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Japan. y.shingu@nifty.com
authors.forename: Yasushige
authors.initials: Y
authors.lastname: Shingu
authors.forename: Suguru
authors.initials: S
authors.lastname: Kubota
authors.forename: Satoru
authors.initials: S
authors.lastname: Wakasa
authors.forename: Noriyoshi
authors.initials: N
authors.lastname: Ebuoka
authors.forename: Daisuke
authors.initials: D
authors.lastname: Mori
authors.forename: Tomonori
authors.initials: T
authors.lastname: Ooka
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Tachibana
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Matsui
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000209:etiology*; D015415:Biomarkers / Q000097:blood; D006348:Cardiac Surgical Procedures / Q000009:adverse effects* / Q000379:methods; D018619:Echocardiography, Doppler, Pulsed / Q000379:methods; D004837:Epinephrine / Q000097:blood; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood; D009638:Norepinephrine / Q000097:blood; D011446:Prospective Studies; D012307:Risk Factors; D013318:Stroke Volume / Q000502:physiology; D018487:Ventricular Dysfunction, Left / Q000150:complications* / Q000000981:diagnostic imaging
chemical_list: D015415:Biomarkers; D020097:Natriuretic Peptide, Brain; D009638:Norepinephrine; D004837:Epinephrine