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.

Outflow of traffic from the national capital Kuala Lumpur to the north,south and east coast highways using flow,speed and density relationships

The functional relationships between flow （veh/km）, density （veh/h） and speed （kin/h） in traffic congestion have a long history of research. However, their findings and techniques persist to be relevant to this day. The analysis is pertinent, particularly in finding the best fit for the three major highways in Malaysia, namely the KL-Karak Highway, KL-Seremban Highway and KL-Ipoh Highway. The trans-logarithm function of density-speed model was compared to the classical models of Greenshields, Greenberg, Underwood and Drake et al. using data provided by the Transport Statistics Malaysia 2014. The results of regression analysis revealed that the Greenshields and Greenberg models were statistically significant. The trans-logarithm function was also tested and the results were nonetheless without exception. Its usefulness in addition to statistical significance related to the derived economic concepts of maximum speed and the related number of vehicles, flow and density and the limits of free speed were relevant in comparing the individual levels of traffic congestion between highways. For instance, KL-Karak Highway was least congested compared to KL-Seremban Highway and KL-Ipoh Highway. Their maximum speeds, based on three lanes carriage capacity of one direction, were 33.4 km/h for KL-Karak, 15.9 km/h for KL-Seremban, and 21.1 km/h for KL-Ipoh. Their corresponding flows were approximated at 1080.9 veh/h, 1555.4 veh/h, and 1436.6 veh/h.