title: Morphological features of the P-waves at surface electrocardiogram as surrogate to mechanical function of the left atrium following a successful modified maze procedure.
abstract: OBJECTIVE
  Absent left atrium (LA) mechanical contraction may occur following the modified Cox-maze operation, and was found to impose a potential risk for the occurrence of thrombo-embolic stroke. It is unknown whether certain morphological P-wave characteristics can surrogate absent LA mechanical activity. The aim of this study was to evaluate the morphological features of the P-waves on the surface electrocardiogram (ECG) of patients who underwent the maze operation and to relate them to the contractile profile of the LA.
  
  
  RESULTS
  Electrocardiogram tracings of 150 consecutive patients that were in sustained sinus rhythm following the maze operation were evaluated. P-waves were scrutinized for morphology, duration, axis, and amplitude. Clinical, surgery-related, and echocardiographic data were collected and analysed. Forty-seven patients (31%) had no evidence of LA contraction at 3 months after surgery (baseline assessment) and on follow-up echocardiography. Multivariate analysis showed that a positive-only P-wave deflection at lead V1 (P = 0.03), a negative-only deflection at aVL, and a P-wave amplitude of ≤ 0.05 mV at the septal-anterior leads (P < 0.001 for both) were associated with absent LA mechanical contraction. In a secondary analysis, a risk score involving the above three parameters was developed for the prediction of stroke occurrence. Patients at the high-risk score group had a 30% survival freedom of stroke compared with 70% for patients at intermediate risk (P < 0.001).
  
  
  CONCLUSIONS
  Absent LA mechanical contraction following the modified maze operation may be accompanied by a distinguished pattern of the P-waves on the surface ECG.
authors.affiliation: Leviev Heart Center, Chaim Sheba Medical Center, 5265601 Tel Hashomer, Israel.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Buber
authors.forename: David
authors.initials: D
authors.lastname: Luria
authors.forename: Leonid
authors.initials: L
authors.lastname: Sternik
authors.forename: Rafael
authors.initials: R
authors.lastname: Kuperstein
authors.forename: Avishay
authors.initials: A
authors.lastname: Grupper
authors.forename: Ilan
authors.initials: I
authors.lastname: Goldenberg
authors.forename: Ehud
authors.initials: E
authors.lastname: Raanani
authors.forename: Micha S
authors.initials: MS
authors.lastname: Feinberg
authors.forename: Eyal
authors.initials: E
authors.lastname: Nof
authors.forename: Michael
authors.initials: M
authors.lastname: Eldar
authors.forename: Michael
authors.initials: M
authors.lastname: Glikson
mesh_terms: D000200:Action Potentials; D000368:Aged; D001281:Atrial Fibrillation / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D016279:Atrial Function, Left; D017115:Catheter Ablation / Q000009:adverse effects; D016009:Chi-Square Distribution; D003452:Cryosurgery / Q000009:adverse effects; D004562:Electrocardiography; D005260:Female; D006325:Heart Atria / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009200:Myocardial Contraction; D016017:Odds Ratio; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D020521:Stroke / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control; D013997:Time Factors; D016896:Treatment Outcome
keywords: Electrocardiogram; Left atrial activity; P-waves