目的探讨心脏再同步化(CRT)加药物控制心室率治疗慢性心力衰竭(简称心衰)伴持续性心房颤动(房颤)的疗效,分析该类患者对CRT产生反应的关键原因。方法选择26例心衰合并房颤的患者接受最佳药物及CRT手术治疗。CRT加药物控制心室率16例(药...目的探讨心脏再同步化(CRT)加药物控制心室率治疗慢性心力衰竭(简称心衰)伴持续性心房颤动(房颤)的疗效,分析该类患者对CRT产生反应的关键原因。方法选择26例心衰合并房颤的患者接受最佳药物及CRT手术治疗。CRT加药物控制心室率16例(药物组),CRT加房室结消融10例(消融组)。随访1.2±0.2年后观察药物组临床参数(NYHA心功能分级,6 min步行距离),QRS波及超声心动图参数[左室射血分数(LVEF)、左室舒张末期内径(LVEDD)]的变化。结果药物组治疗后心功能分级降低(2.0±0.1 vs 3.0±0.2级),6 min步行距离增加(418.9±81.3 m vs 311.5±65.2 m),QRS波时限缩短(138.1±5.6 ms vs 169.6±4.4 ms)及LVEF增加(0.40±0.01 vs 0.23±0.01)、LVEDD减少(61.9±1.6 mm vs 69.0±1.2 mm),药物组起搏比例为0.90±0.04。其疗效与消融组无差异。结论对于心衰伴房颤患者,CRT加药物控制心室率与加房室结消融一样有效。该类患者对CRT产生反应的关键原因是药物良好的控制心室率及较高的双心室起搏比例。展开更多
Cooperative diversity is one of the most effective ways to mitigate the fading effect of wireless channels and obtain the spatial gain in wireless networks. In this paper, an optimal power allocation （OPA） scheme fo...Cooperative diversity is one of the most effective ways to mitigate the fading effect of wireless channels and obtain the spatial gain in wireless networks. In this paper, an optimal power allocation （OPA） scheme for a cooperative communication system using the amplify-and-forward （AF） transmit strategy with multiple relay users is proposed by minimizing the bit-error-rate （BER） at the destination under the constraint of the total transmit power of both the source user and the relay users. Simutation resutts indicate that the proposed power allocation method can achieve significant BER performance improvement than using the equal power allocation （EPA） scheme, while still attains low complexity. The system performance is improved significantly with the increasing of the number of relay users at high signal-noise ratio （SNR）. However, at low SNR, the system performance decreases when the relay number increases. Thus, an adaptive relay selection scheme may be used to choose the appropriate relay numbers in different transmission scenarios to provide system performance improvement and keep the power allocation scheme with low complexity.展开更多
文摘目的探讨心脏再同步化(CRT)加药物控制心室率治疗慢性心力衰竭(简称心衰)伴持续性心房颤动(房颤)的疗效,分析该类患者对CRT产生反应的关键原因。方法选择26例心衰合并房颤的患者接受最佳药物及CRT手术治疗。CRT加药物控制心室率16例(药物组),CRT加房室结消融10例(消融组)。随访1.2±0.2年后观察药物组临床参数(NYHA心功能分级,6 min步行距离),QRS波及超声心动图参数[左室射血分数(LVEF)、左室舒张末期内径(LVEDD)]的变化。结果药物组治疗后心功能分级降低(2.0±0.1 vs 3.0±0.2级),6 min步行距离增加(418.9±81.3 m vs 311.5±65.2 m),QRS波时限缩短(138.1±5.6 ms vs 169.6±4.4 ms)及LVEF增加(0.40±0.01 vs 0.23±0.01)、LVEDD减少(61.9±1.6 mm vs 69.0±1.2 mm),药物组起搏比例为0.90±0.04。其疗效与消融组无差异。结论对于心衰伴房颤患者,CRT加药物控制心室率与加房室结消融一样有效。该类患者对CRT产生反应的关键原因是药物良好的控制心室率及较高的双心室起搏比例。
基金supported by the National Natural Science Foundation of China (60972055)the Shanghai Educational Development Foundation (09CG40)the Science and Technology Commission of Shanghai Municipality (10220710300)
文摘Cooperative diversity is one of the most effective ways to mitigate the fading effect of wireless channels and obtain the spatial gain in wireless networks. In this paper, an optimal power allocation （OPA） scheme for a cooperative communication system using the amplify-and-forward （AF） transmit strategy with multiple relay users is proposed by minimizing the bit-error-rate （BER） at the destination under the constraint of the total transmit power of both the source user and the relay users. Simutation resutts indicate that the proposed power allocation method can achieve significant BER performance improvement than using the equal power allocation （EPA） scheme, while still attains low complexity. The system performance is improved significantly with the increasing of the number of relay users at high signal-noise ratio （SNR）. However, at low SNR, the system performance decreases when the relay number increases. Thus, an adaptive relay selection scheme may be used to choose the appropriate relay numbers in different transmission scenarios to provide system performance improvement and keep the power allocation scheme with low complexity.
