title: Left ventricular markers of global dyssynchrony predict limited exercise capacity in heart failure, but not in patients with preserved ejection fraction.
abstract: BACKGROUND
  The aim of this study was to prospectively examine echocardiographic parameters that correlate and predict functional capacity assessed by 6 min walk test (6-MWT) in patients with heart failure (HF), irrespective of ejection fraction (EF).
  
  
  METHODS
  In 147 HF patients (mean age 61 ± 11 years, 50.3% male), a 6-MWT and an echo-Doppler study were performed in the same day. Global LV dyssynchrony was indirectly assessed by total isovolumic time - t-IVT [in s/min; calculated as: 60 - (total ejection time + total filling time)], and Tei index (t-IVT/ejection time). Patients were divided into two groups based on the 6-MWT distance (Group I: ≤ 300 m and Group II: >300 m), and also in two groups according to EF (Group A: LVEF ≥ 45% and Group B: LVEF < 45%).
  
  
  RESULTS
  In the cohort of patients as a whole, the 6-MWT correlated with t-IVT (r = -0.49, p < 0.001) and Tei index (r = -0.43, p < 0.001) but not with any of the other clinical or echocardiographic parameters. Group I had lower hemoglobin level (p = 0.02), lower EF (p = 0.003), larger left atrium (p = 0.02), thicker interventricular septum (p = 0.02), lower A wave (p = 0.01) and lateral wall late diastolic myocardial velocity a' (p = 0.047), longer isovolumic relaxation time (r = 0.003) and longer t-IVT (p = 0.03), compared with Group II. In the patients cohort as a whole, only t-IVT ratio [1.257 (1.071-1.476), p = 0.005], LV EF [0.947 (0.903-0.993), p = 0.02], and E/A ratio [0.553 (0.315-0.972), p = 0.04] independently predicted poor 6-MWT performance (<300 m) in multivariate analysis. None of the echocardiographic measurements predicted exercise tolerance in HFpEF.
  
  
  CONCLUSIONS
  In patients with HF, the limited exercise capacity, assessed by 6-MWT, is related mostly to severity of global LV dyssynchrony, more than EF or raised filling pressures. The lack of exercise predictors in HFpEF reflects its multifactorial pathophysiology.
authors.affiliation: Service of Cardiology, Clinic of Internal Medicine, University Clinical Centre of Kosova, Rrethi i Spitalit, p.n., Prishtina, Kosova. ganibajraktari@yahoo.co.uk
authors.forename: Gani
authors.initials: G
authors.lastname: Bajraktari
authors.forename: Arlind
authors.initials: A
authors.lastname: Batalli
authors.forename: Afrim
authors.initials: A
authors.lastname: Poniku
authors.forename: Artan
authors.initials: A
authors.lastname: Ahmeti
authors.forename: Rozafa
authors.initials: R
authors.lastname: Olloni
authors.forename: Violeta
authors.initials: V
authors.lastname: Hyseni
authors.forename: Zana
authors.initials: Z
authors.lastname: Vela
authors.forename: Besim
authors.initials: B
authors.lastname: Morina
authors.forename: Rina
authors.initials: R
authors.lastname: Tafarshiku
authors.forename: Driton
authors.initials: D
authors.lastname: Vela
authors.forename: Premtim
authors.initials: P
authors.lastname: Rashiti
authors.forename: Edmond
authors.initials: E
authors.lastname: Haliti
authors.forename: Michael Y
authors.initials: MY
authors.lastname: Henein
mesh_terms: D015331:Cohort Studies; D015897:Comorbidity; D004452:Echocardiography / Q000706:statistics & numerical data; D005080:Exercise Test / Q000706:statistics & numerical data; D017079:Exercise Tolerance; D005260:Female; D006333:Heart Failure / Q000175:diagnosis* / Q000453:epidemiology* / Q000503:physiopathology; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D011379:Prognosis; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013318:Stroke Volume; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis* / Q000453:epidemiology* / Q000503:physiopathology; D015022:Yugoslavia / Q000453:epidemiology