Left ventricular systolic dyssynchrony in acute decompensated heart failure

Abstract

Acute decompensated heart failure (ADHF) is a common and potentially fatal condition. Acute ischemia, hypertensive crisis, fluid retention, mitral regurgitation and tachyarrhythmias can precipitate ADHF, yet very often no clinical trigger was apparent [1]. Left ventricular systolic dyssynchrony (LVSD) is important in the pathogenesis of heart failure [2], yet evaluation of LVSD is usually performed in stable clinical conditions. Patients can have transient episodes of LVSD leading to acute elevation of LV filling pressure and pulmonary edema. Recent studies revealed that LVSD can change dynamically with exercise [3] and pharmacological stress [4,5]. Herein, acute LVSD may be a hidden triggering mechanism for ADHF. Echocardiography with tissue Doppler imaging (TDI) during episodes of ADHF can provide a better appreciation of acute LVSD. To test the hypothesis that patients who presented with ADHF may have more LVSD than those who had chronic stable heart failure (CSHF) without recent exacerbation, we prospectively performed echocardiography with TDI in 145 HF subjects, including 84 consecutive patients presented with ADHF (defined as acute respiratory distress with clinical and/or radiographic evidence of pulmonary edema; LV ejection fraction b 50%) requiring hospitalization, comparing them to 61 CSHF patients identified from outpatient database who had no HF exacerbation or hospitalization in the past 6 months. Patients with acute coronary syndrome, primary valvular disease, atrial fibrillation, and pacemaker implantation were excluded. Echocardiography (Vivid 7, VingmedGeneral Electric, Horten, Norway) was performed within 48 h of ADHF admission. Color-coded TDI (frame rate optimized to 100 Hz or higher) was used to assess LVSD. Myocardial velocity curves were reconstituted offl ine using the 12-segment (6-basal 6-mid) model[3] .T ime to peak systolicvelocityduringejection(Ts) wasmeasured foreachsegmentwith reference to the onset of QRS complex. The standard deviation of Ts (TsSD) of the 12 LV segments was calculated to evaluate LVSD. Significant LVSD was defined as Ts-SD N 33 ms as previously published [2] .L ongitudinal myocardial function was assessed by averaging the peak myocardial systolic (mean Sm) and early diastolic (mean Em) velocities at the 6 basal segments. LV and left atrial dimensions were measured according to guideline recommendations [6]. The effective regurgitant orifice (ERO) of any mitral regurgitation was calculated by the proximal isovelocity surface area method [7]. Group comparisons were performed by independent student's t test or Pearson χ 2 test as appropriate. Pearson