Echocardiographic Evaluation of Cardiac Dyssynchrony in Patients with Congestive Heart Failure

The present study investigated the application of echocardiography to evaluation of cardiac dyssynchrony in patients with congestive heart failure（CHF）. A total of 348 consecutive CHF patients who were admitted for cardiac resynchronization（CRT） and presented with low ejection fraction（EF） and wide QRS duration were enrolled in this study, along with 388 healthy individuals. Dyssynchrony was assessed based on filling time ratio（FT/RR）, left ventricular pre-ejection delay（PED）, interventricular mechanical delay（IVMD）, longitudinal opposing wall delay（LOWD） and radial septal to posterior wall delay（RSPWD）. Response to CRT was defined as a ≥15% increase in EF. The results showed that FT/RR was decreased while PED, IVMD, LOWD and RSPWD were increased in the CHF group compared with the control group（P〈0.01）. In the CHF group, FT/RR was negatively correlated with the QRS duration, LV end-diastolic diameter（LVESd）, LV end-diastolic volume（LVEDV） and LV end-systolic volume（LVESV）（P〈0.01）, but positively with the LVEF（P〈0.01）. Additionally, PED, IVMD, LOWD and RSPWD were positively correlated with the QRS duration, LVESd, LVEDV and LVESV（P〈0.01）, but negatively with the LVEF（P〈0.01）. The CHF group was divided into three subgroups according to the varying degrees of LVEF. FT/RR decreased successively from the LVEF-1 group to the LVEF-2 group to the LVEF-3 group, while the PED, IVMD, LOWD and RSPWD successively increased in the same order（P〈0.01）. The CHF group was divided into three subgroups according to the varying degrees of QRS duration, and FT/RR decreased successively in a sequence from the QRS-1 group to the QRS-2 group to the QRS-3 group, while the PED, IVMD, LOWD and RSPWD successively increased in the same order（P〈0.01）. Speckle tracking radial dyssynchrony ≥130 ms was predictive of an EF response in patients in QRS-1 group（78% sensitivity, 83% specificity）, those in QRS-2 group（83% sensitivity, 77% specificity） and in QRS-3 group（89% sensitivity, 79% specificity）. In conclusion, echocardiography is a convenient and sensitive method for evaluating cardiac dyssynchrony in patients with CHF.

Alterations in myosin heavy chain isoform gene expression during the transition from compensatory hypertrophy to congestive heart failure in rats

Objective To explore the molecular mechanism underlying the decreased velocity of tension rise in rat myocardium during congestive heart failure (CHF) and left ventricular hypertrophy (LVH) induced by aortic stenosis.Methods The maximum velocity of tension rise (+dT/dtmax) was measured in left ventricular papillary muscle and the mRNA level of myosin heavy chain (MHC) isoforms in the left ventricle were detected by Northern blot analysis.Results The value of +dT/dtmax in CHF and LVH group were 64.17% and 37.15% lower than sham-operated controls (Sham) (P<0.01); values in the CHF group were 42.99% lower than that of LVH (P<0.01). The level of α-MHC mRNA in LVH was not different from that of the Sham (P>0.05), but decreased significantly in CHF to 42.3% of Sham and 56.1% of LVH (P<0.01). The level of β-MHC mRNA was up-regulated by 88.3% (P<0.01) in LVH compared with Sham and the level of β-MHC in CHF was 1.5-fold and 3.7-fold higher than that in LVH and Sham respectively (P<0.01). The ratio of α-MHC/β-MHC mRNA in LVH and CHF decreased to 42.4% and 9.8% respectively of the value in Sham (P<0.01). Correlation between α-MHC/β-MHC mRNA level and +dT/dtmax was analyzed which showed that these values were positively correlated with a correlation coefficient of 0.875 (P<0.01).Conclusion The decreased ratio of α-MHC/β-MHC mRNA was the major molecular mechanism underlying the decreased +dT/dtmax in CHF and LVH myocardium. The decreased ratio of α-MHC/β-MHC mRNA in LVH was mainly due to the up regulation of β-MHC mRNA while in CHF both down regulation of α-MHC and up regulation of β-MHC were involved.