الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Approximately half of patients with heart failure (HF) have a preserved ejection fraction (HFpEF). Morbidity and mortality are similar to HF with reduced EF (HFrEF), yet therapies with unequivocal benefit in HFrEF have been shown not to be effective in HFpEF. Recent studies have shown that the pathophysiology of HFpEF, initially believed to be principally due to diastolic dysfunction, is more complex. Appreciation of this complexity has showed new lights onto how HFpEF patients might respond to traditional HF treatments, while also suggesting new applications for novel therapies and strategies (from et al.,2011).
While inherited long QT syndrome (LQTS) has historically been considered a purely electrical disease, echocardiographic studies over the past two decades have demonstrated a crude but replicable relationship between a prolonged QT interval and abnormal mechanical function. (Nador et al.,1991) Observational data paired with animal studies suggest that electrical transmural dispersion of repolarization, manifest on the surface electrocardiogram (ECG), can be associated with mechanical dispersion of left ventricular relaxation observed using comprehensive echocardiography. (Belardinelli et al.,2009).
P wave dispersion (PD) is related to the non homogenous and interrupted conduction of sinus impulses intra and inter-atrially. Currently, PD is described as a non invasive indicator of atrial fibrillation risk, which can be calculated easily on a 12-lead surface ECG. (Dilaveris et al.,2000).
Sauer et al., revealed in a sample of 84 consecutive outpatients referred for exercise echocardiography, a significant inverse linear association between the TpTe interval and tissue Doppler septal E’ velocity. This association persisted after adjustment for several important potential confounders, including age, QTc interval and left ventricular wall thickness. (Sauer et al.,2012).