Witte Klaus K A, Pipes Rebecca R, Nanthakumar Kumaraswamy, Parker John D
Division of Cardiology, University Health Network, University of Toronto, Canada.
J Card Fail. 2006 Apr;12(3):199-204. doi: 10.1016/j.cardfail.2005.12.003.
Cardiac resynchronization therapy (CRT) reduces symptoms and mortality in patients with left bundle branch block (LBBB) and severe chronic heart failure. There are few data demonstrating the effects of CRT on contemporary dyssynchrony variables in patients with advanced heart failure who have been chronically paced from the right ventricle (RV).
We reviewed baseline and follow-up clinical and echocardiographic data on patients receiving CRT in a single centre. Indices of global left ventricular (LV) function and dyssynchrony before and after CRT were measured. Patients were then divided into those receiving their first device (n = 39) and those receiving CRT as an upgrade to existing RV pacemakers (n = 32). Baseline demographic variables, indices of global LV function, symptomatic status, renal function, hemodynamics, and diuretic requirements were not different between previously paced patients and nonpaced patients. Mean length of RV pacing in the previously paced patients was 59 months (range 12-167 months). Patients in the previously paced group had a broader QRS complex than patients with intrinsic LBBB. Aortopulmonary delay of longer than 40 ms was present in 68% of all subjects, 67% had intraventricular septal and posterior wall motion delay longer than 130 ms, and 59% had an intraventricular delay as measured by tissue Doppler imaging of longer than 65 ms. There was no difference between paced and nonpaced patients for any of these measures of dyssynchrony. QRS duration was reduced to a greater extent in the previously paced patients than those with no previous device therapy. CRT led to important reductions in each dyssynchrony variable in both patients with previous RV pacing and those with intrinsic LBBB. The magnitude of these changes in measures of dyssynchrony was not different between the 2 groups. In all patients undergoing CRT, 50% had a reduction in furosemide dose at 3 months, 56% an improvement of at least 1 grade in New York Heart Association status, and 66% an improvement of at least 5% in LVEF. Divided by group, previously paced patients were no more or less likely than newly implanted patients to achieve one or more of these clinical outcomes.
Our data suggest that patients with RV pacing and heart failure have similar dyssynchrony as patients with intrinsic LBBB. CRT leads to improvements in LV global function, dyssynchrony variables and symptoms in patients chronically paced from the RV that are similar to those observed in patients with LBBB without preexisting devices.
心脏再同步治疗（CRT）可减轻左束支传导阻滞（LBBB）和严重慢性心力衰竭患者的症状并降低死亡率。关于CRT对长期右心室（RV）起搏的晚期心力衰竭患者当代不同步变量影响的数据较少。
我们回顾了在单一中心接受CRT治疗患者的基线及随访临床和超声心动图数据。测量了CRT前后左心室（LV）整体功能和不同步的指标。然后将患者分为首次接受装置治疗者（n = 39）和接受CRT作为现有RV起搏器升级者（n = 32）。既往起搏患者和未起搏患者在基线人口统计学变量、LV整体功能指标、症状状态、肾功能、血流动力学及利尿剂需求方面并无差异。既往起搏患者的RV起搏平均时长为59个月（范围12 - 167个月）。既往起搏组患者的QRS波群比原发性LBBB患者更宽。68%的所有受试者存在主动脉肺动脉延迟超过40毫秒，67%存在室间隔与后壁运动延迟超过130毫秒，59%通过组织多普勒成像测量的室内延迟超过65毫秒。在这些不同步测量指标中，起搏患者与未起搏患者之间没有差异。既往起搏患者的QRS时限比未接受过装置治疗的患者降低幅度更大。CRT使既往RV起搏患者和原发性LBBB患者的每个不同步变量都有显著降低。两组之间这些不同步测量指标变化的幅度并无差异。在所有接受CRT的患者中，50%在3个月时呋塞米剂量减少，56%纽约心脏协会心功能分级至少改善1级，66%左心室射血分数（LVEF）至少改善5%。按组划分，既往起搏患者实现这些临床结局中的一项或多项的可能性并不高于或低于新植入患者。
我们的数据表明RV起搏合并心力衰竭的患者与原发性LBBB患者具有相似的不同步情况。CRT可改善长期RV起搏患者的LV整体功能、不同步变量和症状，与未预先存在装置的LBBB患者所观察到的情况相似。
