Mayhew Marc W, Slabaugh Jane E, Bubien Rosemary S, Kay G Neal
Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.
Pacing Clin Electrophysiol. 2003 Dec;26(12):2264-71. doi: 10.1111/j.1540-8159.2003.00357.x.
Several electrical configurations can be used for biventricular pacing to achieve cardiac resynchronization. Commercially approved biventricular pacing systems stimulate the RV with an endocardial lead and the LV with a unipolar lead positioned in the cardiac venous circulation using the tip electrodes of both leads linked as a common cathode. The distribution of current with this parallel circuit, split cathodal configuration is dependent on the separate impedances of the two leads. A total of 19 patients with left bundle branch block and congestive heart failure underwent implantation of a cardiac venous lead and standard bipolar right atrial and RV pacing leads. Stimulation thresholds and impedances were measured for the RV and LV in five electrical configurations: (1) unipolar LV from the cardiac venous lead; (2) bipolar LV using the tip electrode in the cardiac vein as the cathode and the ring electrode of the RV lead as the anode; (3) bipolar RV from the RV lead; (4) unipolar split cathodal stimulation of the cardiac venous and RV leads; and (5) bipolar split cathodal stimulation of the cardiac venous and RV leads. Repeat measurements of RV and LV thresholds were made from the pulse generator at 1-year follow-up. The LV stimulation threshold increased from 0.7 +/- 0.5 V in the unipolar configuration to 1.0 +/- 0.8 V in the unipolar split cathodal configuration (P = 0.01) and from 1.0 +/- 0.7 V in the bipolar configuration to 1.3 +/- 0.9 V in the bipolar split cathodal configuration (P < 0.001). The RV stimulation threshold increased from 0.3 +/- 0.2 V in the bipolar configuration to 0.5 +/- 0.2 V in the bipolar split cathodal configuration (P = 0.005). The bipolar impedance measured 874 +/- 299 Omega for the coronary venous lead, 705 +/- 152 for the RV lead, 442 +/- 87 in the split unipolar cathodal configuration, and 516 +/- 64 in the bipolar split cathodal configuration. At 1-year follow-up, the LV stimulation threshold was 1.8 +/- 1.6 in the unipolar split cathodal configuration and 2.4 +/- 1.6 in the bipolar split cathodal configuration (P = 0.003). The RV stimulation threshold at 1 year was 0.7 +/- 0.3 in the unipolar split cathodal configuration and 0.8 +/- 0.3 in the bipolar split cathodal configuration (P = 0.02). The split cathodal configuration significantly increases the apparent stimulation threshold for both the LV and the RV as compared with individual stimulation of either chamber alone. Programming to the bipolar split cathodal configuration further increases the apparent stimulation threshold. These observations support the development of pacing systems with separate LV and RV output circuits for resynchronization therapy.
几种电配置可用于双心室起搏以实现心脏再同步化。商业上批准的双心室起搏系统通过心内膜导线刺激右心室，通过置于心脏静脉循环中的单极导线刺激左心室，使用两根导线的尖端电极作为公共阴极相连。这种并联电路、分开阴极配置的电流分布取决于两根导线各自的阻抗。共有19例左束支传导阻滞和充血性心力衰竭患者接受了心脏静脉导线以及标准双极右心房和右心室起搏导线的植入。在五种电配置下测量了右心室和左心室的刺激阈值和阻抗：(1) 来自心脏静脉导线的单极左心室；(2) 使用心脏静脉中的尖端电极作为阴极、右心室导线的环状电极作为阳极的双极左心室；(3) 来自右心室导线的双极右心室；(4) 心脏静脉和右心室导线的单极分开阴极刺激；(5) 心脏静脉和右心室导线的双极分开阴极刺激。在1年随访时，从脉冲发生器对右心室和左心室阈值进行了重复测量。左心室刺激阈值在单极配置下从0.7±0.5 V增加到单极分开阴极配置下的1.0±0.8 V（P = 0.01），在双极配置下从1.0±0.7 V增加到双极分开阴极配置下的1.3±0.9 V（P < 0.001）。右心室刺激阈值在双极配置下从0.3±0.2 V增加到双极分开阴极配置下的0.5±0.2 V（P = 0.005）。冠状动脉静脉导线的双极阻抗测量值为874±299Ω，右心室导线为705±152Ω，单极分开阴极配置下为442±87Ω，双极分开阴极配置下为516±64Ω。在1年随访时，单极分开阴极配置下左心室刺激阈值为1.8±1.6，双极分开阴极配置下为2.4±1.6（P = 0.003）。1年时右心室刺激阈值在单极分开阴极配置下为0.7±0.3，双极分开阴极配置下为0.8±0.3（P = 0.02）。与单独对任一腔室进行刺激相比，分开阴极配置显著增加了左心室和右心室的表观刺激阈值。编程为双极分开阴极配置会进一步增加表观刺激阈值。这些观察结果支持开发具有单独左心室和右心室输出电路的起搏系统用于再同步治疗。
