Effect of total scar burden on contrast-enhanced magnetic resonance imaging on response to cardiac resynchronization therapy

It was shown that improvement in left ventricular (LV) function and reverse remodeling after cardiac resynchronization therapy (CRT) were greater in patients with nonischemic cardiomyopathy than in those with ischemic cardiomyopathy. The aim of this study is to evaluate the influence of scar burden on response to CRT. We included 34 patients with ischemic cardiomyopathy (New York Heart Association class 3.1 +/- 0.4, LV ejection fraction 23 +/- 7%). Contrast-enhanced magnetic resonance imaging was used to determine total scar burden, using a 17-segment model with a 5-point hyperenhancement scale (from score 0 = no hyperenhancement, indicating no scar, to score 4 = hyperenhancement >76%, transmural scar). Linear regression analysis showed a significant correlation (r = -0.91, p <0.05) between total scar burden at baseline and change in LV end-systolic volume after 6 months of CRT. Also, patients not responding to CRT had significantly more scar tissue than responders. A scar burden >1.20 resulted in complete functional nonresponse. In conclusion, total scar burden, assessed using contrast-enhanced magnetic resonance imaging, is an important factor influencing response to CRT and may be included in the selection process for CRT candidates.     

Relationship between left ventricular lead position using a simple radiographic classification scheme and long-term outcome with resynchronization therapy

BACKGROUND: Benefit from cardiac resynchronization therapy (CRT) is likely influenced by the location of the left ventricular (LV) lead. PURPOSE: To evaluate the association of LV lead position with outcome after CRT. METHODS: Two-hundred and fifty patients with LV dysfunction, New York Heart Association (NYHA) class III (68%) or IV (32%) symptoms, and QRS durations > or =120 ms were followed for a median of 30 months post-CRT. LV lead position was categorized as anterior (n = 20, 8%), lateral (n = 128, 51%), or posterior (n = 102; 41%) using postero-anterior and lateral postoperative chest radiographs. RESULTS: Median age was 69 years and most (68%) had ischemic LV dysfunction. Clinical response, defined by a > or =1 NYHA class reduction, was lower in patients with an anterior (30%) versus lateral (76%) or posterior (73%) lead position (p = 0.001). An anterior versus nonanterior position was independently associated with a two to three-fold higher risk for nonresponse to CRT, cardiovascular death, death from worsening heart failure or cardiac transplantation, and death from any cause. Repositioning of the LV lead from an anterior to a nonanterior position in seven patients who had not clinically responded to CRT after > or =6 months resulted in clinical improvement in all cases. CONCLUSIONS: An anterior versus nonanterior LV lead position is independently associated with an increased likelihood of nonresponse to CRT and a higher risk of serious outcomes. Repositioning of an anteriorly placed LV lead to a nonanterior position should be considered in CRT nonresponders.     

The Impact of Myocardial Viability on the Clinical Outcome of Cardiac Resynchronization Therapy

Introduction: Around 30% of patients do not respond to cardiac resynchronization therapy (CRT). Nonischemic cardiomyopathy has been identified as an independent predictor of response to CRT, probably due to the absence of compact scar.
Methods and results: The relationship between cardiac scar, ischemia, and hibernation (both at the left-ventricular pacing site and as a total burden) and response to CRT was studied in patients with ischemic cardiomyopathy using the perfusion-viability positron emission tomography (PET) test.
Sixty-six patients with ischemic cardiomyopathy and traditional criteria for CRT were included. All patients underwent PET scan prior to CRT. Using PET, the amount and location of scarred, ischemic, and hibernating myocardium were characterized. No revascularization was indicated. Responders were defined by an improvement of left-ventricular ejection fraction (LVEF) ≥ 5% and/or New York Heart Association (NYHA) class ≥ 1 degree.
During a mean follow-up of 26.2 ± 22.2 months, there was a significant improvement in NYHA class and reverse remodeling in patients with the LV lead inserted remotely from the scar. However, reverse remodeling of a similar degree was present also in patients with extensive scarring including the lateral wall. The presence of ischemia, hibernation, or nontransmural scar at the pacing-site did not significantly modify the outcome of CRT as compared with viable myocardium. There were only 38% of CRT-nonresponders. Neither the extent of scar, ischemia, hibernation, or viability predicted outcome or mortality. Twenty patients died during the follow-up, one patient underwent heart transplant.
Conclusions: At follow-up, response to CRT is observed regardless of the presence of extensive scarring. Left ventricular (LV) pacing at sites with ischemia, hibernation, or nontransmural scar does not appear to modify the effect of CRT as compared to viable tissue.     

Usefulness of QRS duration to predict response to cardiac resynchronization therapy in patients with end-stage heart failure

Despite current selection criteria, 20% to 30% of patients treated with cardiac resynchronization therapy (CRT) do not benefit. It has been suggested that QRS duration may not be the optimal criterion to select patients for CRT. The objective of this study was to systematically evaluate the predictive value of QRS duration for response to CRT in a large group of consecutive patients. A total of 242 patients with heart failure scheduled for implantation of a CRT device were studied. Selection criteria for CRT included moderate to severe heart failure (New York Heart Association classes III to IV), left ventricular ejection fraction (LVEF)120 ms. Before CRT implantation, QRS duration and clinical status were assessed, and 2-dimensional echocardiography (LV volumes and LVEF) was performed. Clinical status and changes in LVEF and LV volumes were reassessed at 6-month follow-up. After 6 months of CRT, 68% of patients were classified as clinical responders (improvement of >or=1 grade in New York Heart Association class) and 60% as echocardiographic responders (decrease>10% in LV end-systolic volume). At baseline, no significant differences were observed in QRS duration between clinical responders and nonresponders and between echocardiographic responders and nonresponders. No significant relation was demonstrated between baseline QRS duration and improvement in clinical and echocardiographic variables at 6-month follow-up. In conclusion, baseline QRS duration is not predictive for clinical and echocardiographic responses to CRT at 6-month follow-up. Better predictors for CRT response are needed.     

Clinical and electrocardiographic predictors of a positive response to cardiac resynchronization therapy in advanced heart failure.

AIMS: Cardiac resynchronization therapy (CRT) is an effective treatment for refractory congestive heart failure (CHF). However, up to 30% of patients do not respond to CRT. The aim of this study was to identify clinical and electrocardiographic (ECG) predictors of a positive response to CRT. METHODS AND RESULTS: This retrospective study included 139 consecutive patients successfully implanted with a CRT device (mean age, 68+/-9 years, 113 men). At baseline, 69% of patients were in New York Heart Association (NYHA) functional class III, and 31% in class IV, mean left ventricular ejection fraction was 21+/-6%, and mean QRS duration was 188+/-28 ms. In each patient, left and right ventricular leads were placed to attain the shortest QRS duration during biventricular stimulation. Patients were classified at 6 months as responders to CRT (n=100) if they were alive, they had not been re-hospitalized for management of CHF, and the NYHA class had decreased by 1 point, and/or peak VO(2) or 6 min hall-walk increased by >10%. All others were classified as non-responders (n=38; one patient was lost to follow-up). Uni- and multivariate logistic regression analyses were performed to detect a pre- or intra-operative predictor of a positive response to CRT. Among multiple demographic, clinical, and ECG variables, the amount of QRS shortening (DeltaQRS) associated with biventricular stimulation was the only independent predictor of a positive (37+/-23 ms) vs. negative (11+/-23 ms) response to CRT (P<0.001). CONCLUSION: A positive response to CRT was observed in 73% of patients at 6 months and predicted only by DeltaQRS.     

Left ventricular dyssynchrony predicts response and prognosis after cardiac resynchronization therapy

OBJECTIVES: This study was designed to predict the response and prognosis after cardiac resynchronization therapy (CRT) in patients with end-stage heart failure (HF). BACKGROUND: Cardiac resynchronization therapy improves HF symptoms, exercise capacity, and left ventricular (LV) function. Because not all patients respond, preimplantation identification of responders is needed. In the present study, response to CRT was predicted by the presence of LV dyssynchrony assessed by tissue Doppler imaging. Moreover, the prognostic value of LV dyssynchrony in patients undergoing CRT was assessed. METHODS: Eighty-five patients with end-stage HF, QRS duration >120 ms, and left bundle-branch block were evaluated by tissue Doppler imaging before CRT. At baseline and six months follow-up, New York Heart Association functional class, quality of life and 6-min walking distance, LV volumes, and LV ejection fraction were determined. Events (death, hospitalization for decompensated HF) were obtained during one-year follow-up. RESULTS: Responders (74%) and nonresponders (26%) had comparable baseline characteristics, except for a larger dyssynchrony in responders (87 +/- 49 ms vs. 35 +/- 20 ms, p < 0.01). Receiver-operator characteristic curve analysis demonstrated that an optimal cutoff value of 65 ms for LV dyssynchrony yielded a sensitivity and specificity of 80% to predict clinical improvement and of 92% to predict LV reverse remodeling. Patients with dyssynchrony >/=65 ms had an excellent prognosis (6% event rate) after CRT as compared with a 50% event rate in patients with dyssynchrony <65 ms (p < 0.001). CONCLUSIONS: Patients with LV dyssynchrony >/=65 ms respond to CRT and have an excellent prognosis after CRT.     

Positioning of left ventricular pacing lead guided by intracardiac echocardiography with vector velocity imaging during cardiac resynchronization therapy procedure

LV Lead Positioning Guided by ICE With Vector Velocity Imaging . Introduction: Intraoperative modality for “real‐time” left ventricular (LV) dyssynchrony quantification and optimal resynchronization is not established. This study determined the feasibility, safety, and efficacy of intracardiac echocardiography (ICE), coupled with vector velocity imaging (VVI), to evaluate LV dyssynchrony and to guide LV lead placement at the time of cardiac resynchronization therapy (CRT) implant. Methods: One hundred and four consecutive heart failure patients undergoing ICE‐guided (Group 1, N = 50) or conventional (Group 2, N = 54) CRT implant were included in the study. For Group 1 patients, LV dyssynchrony and resynchronization were evaluated by VVI including visual algorithms and the maximum differences in time‐to‐peak (MD‐TTP) radial strain. Based on the findings, the final LV lead site was determined and optimal resynchronization was achieved. CRT responders were defined using standard criteria 6 months after implantation. Results: Both groups underwent CRT implant with no complications. In Group 1, intraprocedural optimal resynchronization by VVI including visual algorithms and MD‐TTP was a predictor discriminating CRT response with a sensitivity of 95% and specificity of 89%. Use of ICE/VVI increased number of and predicted CRT responders (82% in Group 1 vs 63% in Group 2; OR = 2.68, 95% CI 1.08–6.65, P = 0.03). Conclusion: ICE can be safely performed during CRT implantation. “Real‐time” VVI appears to be helpful in determining the final LV lead position and pacing mode that allow better intraprocedural resynchronization. VVI‐optimized acute resynchronization predicts CRT response and this approach is associated with higher number of CRT responders. (J Cardiovasc Electrophysiol, Vol. 22, pp. 1034‐1041, September 2011)     

Relationship between QRS duration and left ventricular dyssynchrony in patients with end-stage heart failure

INTRODUCTION: Patients with end-stage heart failure and a wide QRS complex are considered candidates for cardiac resynchronization therapy (CRT). However, 20% to 30% of patients do not respond to CRT. Lack of left ventricular dyssynchrony may explain the nonresponse. Accordingly, we evaluated the presence of left ventricular dyssynchrony using tissue Doppler imaging (TDI) in 90 consecutive patients with heart failure. METHODS AND RESULTS: Ninety patients with severe heart failure (left ventricular ejection fraction <35%, New York Heart Association class III-IV) were prospectively evaluated. Based on QRS duration, 30 consecutive patients with a narrow QRS complex were included (QRS duration 150 ms). All patients underwent TDI to assess left ventricular dyssynchrony. Extensive left ventricular dyssynchrony was defined as an electromechanical delay on TDI between the septum and lateral wall, the so-called septal-to-lateral delay, of >60 ms. Severe dyssynchrony was observed in 27% of patients with narrow QRS complex, 60% with intermediate QRS duration, and 70% with wide QRS complex. No relation existed between QRS duration and septal-to-lateral delay. CONCLUSION: From 30% to 40% of heart failure patients with QRS duration >120 ms do not exhibit left ventricular dyssynchrony, which may explain the nonresponse to CRT. Alternatively, 27% of patients with heart failure and a narrow QRS complex show significant left ventricular dyssynchrony and may be candidates for CRT.     

双心室再同步治疗后无应答发生率及原因分析

目的 观察本中心双心室再同步治疗(CRT)术后无应答的发生率,并分析可能导致无应答的原因.方法 2001年3月至2009年5月119例患者行CRT治疗(男96例,年龄34～82岁),NYHA心功能Ⅲ～Ⅳ级,左心室射血分数≤35%,随访6个月以上.结果 119例患者中,7例在CRT置人后6个月内因不同原因死亡,112例完成6个月以上的随访,无应答发生率为28.57%.多因素logistic回归分析提示心力衰竭病程、肺动脉高压、血清肌酐值增高、完全性右束支传导阻滞及心室电极导线置人位置均是CRT无应答的独立危险因素.在CRT术后6个月时,CRT应答组心力衰竭的常规治疗药物明显减少,主要是洋地黄和利尿剂与无应答组比较差异有统计学意义(P＜0.01＝.结论 CRT术后无应答的发生率为28.57%.完全性右束支传导阻滞虽然也有QRS时限明显增宽,但CRT术后无应答的发生率明显增高.左心室电极导线的位置是决定CRT术后无应答发生的重要环节,心大静脉不宜做左心室电极导线置入的部位.     

Septal to posterior wall motion delay fails to predict reverse remodeling or clinical improvement in patients undergoing cardiac resynchronization therapy.

OBJECTIVES: The aim of this study was to test the hypothesis that a longer septal-to-posterior wall motion delay (SPWMD) would predict greater reverse remodeling and an improved clinical response in heart failure patients randomized to cardiac resynchronization therapy (CRT) in the CONTAK-CD trial. BACKGROUND: The SPWMD predicted clinical benefit with CRT in two previous studies from the same center. METHODS: In this retrospective analysis of the CONTAK-CD trial, SPWMD was measured from the baseline echocardiogram of 79 heart failure patients (ejection fraction 22 +/- 7%, QRS duration 159 +/- 27 ms, 72% ischemic, 84% male) randomized to CRT and compared with six-month changes in echocardiographic and clinical parameters. Patients with a left ventricular end-systolic volume index (LVESVI) reduction of at least 15% were considered responders. RESULTS: The feasibility and reproducibility of performing the SPWMD measurements were poor. Larger values for SPWMD did not correlate with six-month changes in left ventricular end-diastolic volume index (p = 0.26), LVESVI (p = 0.41), or left ventricular ejection fraction (p = 0.36). Responders did not have a significantly different SPWMD than non-responders (p = 0.26). The SPWMD did not correlate with measures of clinical improvement. At a threshold of SPWMD >130 ms, the test characteristics to predict reverse remodeling or a clinical response were inadequate. CONCLUSIONS: The previous findings that SPWMD predicts reverse remodeling or clinical improvement with CRT were not reproducible in patients randomized in the CONTAK-CD trial.     

Responders to cardiac resynchronization therapy with narrow or intermediate QRS complexes identified by simple echocardiographic indices of dyssynchrony: the DESIRE study

BACKGROUND: Cardiac resynchronization therapy (CRT) is recommended for patients with NYHA class III-IV refractory heart failure (HF), ejection fraction <35% and a QRS >120 ms. We attempted to identify responders to CRT from echocardiographic (echo) indices of mechanical dyssynchrony in patients with QRS<150 ms. METHODS AND RESULTS: The study enrolled 51 men and 9 women (mean age: 64.5 years) in NYHA class III (n=54) or IV (n=6) presenting with a mean ejection fraction: 25.7%, LV end-diastolic diameter: 69.1 mm, and QRS=121+/-19 ms. All patients were implanted with a CRT system and followed for 1 year. Implantation was preceded and followed by clinical, functional and Doppler (D)-echo evaluation. The primary combined endpoint included 1) death from any cause, 2) HF-related hospitalisations, and 3) NYHA class at 6 months. Before implant, 27 patients had > or =1 echo criterion of mechanical dyssynchrony (DES+ group) and 33 had no evidence of dyssynchrony (DES- group). At 12 months, 8 patients (4 per group) had died, 7 from HF. As regards the primary endpoint at 6 months, 33 patients (55%) had improved, 10 (16%) were unchanged, and 17 (29%) had deteriorated. Clinical improvement was observed in 19 of 27 DES+ (70%), versus 14 of 33 DES- (42%) patients (P<0.04). Baseline QRS duration did not predict response to CRT. CONCLUSIONS: In this population of HF patients with QRS<150 ms, the presence of mechanical dyssynchrony at baseline D-echo examination, but not the QRS width, predicted 6-month clinical response to CRT.     

Prediction of a Good Response to Cardiac Resynchronization Therapy in Patients with Severe Dilated Cardyomyopathy: Could Conventional Echocardiography Be the Answer after All?

Objectives: The aim of this study was to assess the performance of echocardiographic parameters to predict response to cardiac resynchronization therapy (CRT). Background: CRT reduces morbidity and mortality due to the proper selection of candidates for CRT. Methods: The 12‐month trial was performed on 70 optimally medicated patients with standard inclusion criteria: NYHA class III or IV heart failure, left ventricular ejection fraction (LVEF) ≤ 35%, and QRS ≥ 120 ms. All parameters were evaluated by conventional and tissue Doppler‐based methods. Indicator of positive CRT response was more than 20% in improvement of LVEF. Results: LVEF increased >20% in 42 patients. Out of 43 tested baseline echocardiographic parameters, 12 showed statistical difference between responders and nonresponders. Out of these 12 parameters, six (LVSV, LVSI, LVFS, RVd, VPMR, and PISA) had modest to moderately good ability to predict LVEF response with sensitivity ranging from 62.2% to 82.4%, and specificity ranging from 56.5% to 81.2%. For those parameters, the area under the receiver‐operating characteristic curve for positive response to CRT was ≤0.76. Multivariate regression analysis resulted in selection of LVSI and LVFS as possible predictive independent parameters for a good response. The cutoff value for LVSI was 38.7 mL/m² (P = 0.045) and for LVFS was 13% (P = 0.032). Conclusions: Contribution of LVSI and LVFS is to be confirmed in larger trials. Simplicity of their assessment by conventional echocardiography could be an argument for adding them to the inclusion criteria for CRT in severe heart failure patients. (Echocardiography 2012;29:267‐275)     

Comparison of efficacy of reverse remodeling and clinical improvement for relatively narrow and wide QRS complexes after cardiac resynchronization therapy for heart failure

INTRODUCTION: Cardiac resynchronization therapy (CRT) has been shown to reverse left ventricular (LV) remodeling and improve symptoms in heart failure patients with wide QRS complexes; however, its role in patients with mildly prolonged QRS complexes is unclear. This study investigated if CRT benefited patients with mildly prolonged QRS complexes >120 to 150 ms and explored if the severity of systolic asynchrony determined such a response. METHODS AND RESULTS: Fifty-eight patients (age 66 +/- 11 years, 66% male) who had undergone CRT were studied prospectively. Of these patients, 27 had QRS duration between 120 and 150 ms (group A), and 31 had QRS duration >150 ms (group B). Tissue Doppler echocardiography and clinical assessment were performed at baseline and 3 months after CRT. Both groups had significant reduction of LV volume and increased ejection fraction, +dP/dt, and sphericity index (all P < 0.05). These improvements were greater in group B and were explained by the higher prevalence of systolic intraventricular asynchrony. Significant reverse remodeling (reduction of LV end-systolic volume >15%) was evident in 46% of group A patients and 68% of group B patients. Improvement in clinical endpoints was observed in both groups (all P < 0.01), although the changes in metabolic equivalent and New York Heart Association functional class were greater in group B. In both groups, systolic asynchrony index (TS-SD) was the most important predictor of reverse remodeling (r =-0.78, P < 0.001) and was the only independent predictor in the multivariate model (beta=-1.80, confidence interval =-2.18 to -1.42, P < 0.001); QRS duration was not. A predefined TS-SD value >32.6 ms had a sensitivity of 94% and specificity of 83% to predict reverse remodeling. Improvement of intraventricular asynchrony after CRT was evident only in responders (P = 0.01). CONCLUSION: Improvement of LV remodeling and clinical status is evident after CRT in heart failure patients with QRS duration >120 to 150 ms. These responders are closely predicted by the severity of prepacing intraventricular asynchrony but not QRS duration.     

Combined longitudinal and radial dyssynchrony predicts ventricular response after resynchronization therapy.

OBJECTIVES: The purpose of this study was to test the hypothesis that a combined echocardiographic assessment of longitudinal dyssynchrony by tissue Doppler imaging (TDI) and radial dyssynchrony by speckle-tracking strain may predict left ventricular (LV) functional response to cardiac resynchronization therapy (CRT). BACKGROUND: Mechanical LV dyssynchrony is associated with response to CRT; however, complex patterns may exist. METHODS: We studied 190 heart failure patients (ejection fraction [EF] 23 +/- 6%, QRS duration 168 +/- 27 ms) before and after CRT. Longitudinal dyssynchrony was assessed by color TDI for time to peak velocity (2 sites in all and 12 sites in a subgroup of 67). Radial dyssynchrony was assessed by speckle-tracking radial strain. The LV response was defined as > or =15% increase in EF. RESULTS: One hundred seventy-six patients (93%) had technically sufficient baseline and follow-up data available. Overall, 34% were EF nonresponders at 6 +/- 3 months after CRT. When both longitudinal dyssynchrony by 2-site TDI (> or =60 ms) and radial dyssynchrony (> or =130 ms) were positive, 95% of patients had an EF response; when both were negative, 21% had an EF response (p < 0.001 vs. both positive). The EF response rate was lowest (10%) when dyssynchrony was negative using 12-site TDI and radial strain (p < 0.001 vs. both positive). When either longitudinal or radial dyssynchrony was positive (but not both), 59% had an EF response. Combined longitudinal and radial dyssynchrony predicted EF response with 88% sensitivity and 80% specificity, which was significantly better than either technique alone (p < 0.0001). CONCLUSIONS: Combined patterns of longitudinal and radial dyssynchrony can be predictive of LV functional response after CRT.     

The Use of Nuclear Imaging for Cardiac Resynchronization Therapy

Cardiac resynchronization therapy (CRT) has shown benefits in patients with end-stage heart failure, depressed left ventricular (LV) ejection fraction (≤ 35%), and prolonged QRS duration (≥ 120 ms). However, based on the conventional criteria, 20% to 40% of patients fail to respond to CRT. Studies have focused on important parameters for predicting CRT response, such as LV dyssynchrony, scar burden, LV lead position, and site of latest activation. Phase analysis allows nuclear cardiology modalities, such as gated blood-pool imaging and gated myocardial perfusion single photon emission computed tomography (GMPS), to assess LV dyssynchrony. Most importantly, GMPS with phase analysis has the potential of assessing LV dyssynchrony, scar burden, and site of late activation from a single acquisition, so that this technique may provide a one-stop shop for predicting CRT response. This article provides a summary on the role of nuclear cardiology in selecting patients for CRT, with emphasis on GMPS with phase analysis.     

Usefulness of preimplantation B-type natriuretic peptide level for predicting response to cardiac resynchronization therapy

Nearly 1/3 of patients with heart failure (HF) fail to respond to cardiac resynchronization therapy (CRT). The purpose of this study was to evaluate the value of preimplantation brain natriuretic peptide (BNP) in predicting the clinical response to CRT. We retrospectively analyzed 164 patients who underwent CRT. Patients with New York Heart Association functional class III or IV HF symptoms despite maximal medical therapy, who were not on inotropic medications, had left ventricular ejection fraction < or =35%, and QRS duration >130 ms were included in the study. CRT response in patients who survived at 6-month follow-up was defined as no HF hospitalization and improvement of > or =1 grades in the New York Heart Association classification. BNP assays were performed before implantation and at 6-month follow-up. Patients had ischemic (47%) or nonischemic (53%) cardiopathy. Responders (n = 107) and nonresponders (n = 57) had similar baseline characteristics. Cardiac death and hospitalization for HF occurred in 5 (4.7%) and 18 (31.6%) patients, respectively. CRT responders compared with nonresponders exhibited higher preimplantation BNP levels (800 +/- 823 vs 335 +/- 348 pg/ml, p = 0.0002) and a significant reduction in the QRS duration after implantation (-6 +/- 34 vs +7 +/- 32 ms, p = 0.048). The preimplantation BNP was the only independent predictor of the CRT response (p = 0.001). A BNP value > or =447 pg/ml demonstrated a sensitivity of 62% and specificity of 79% in identifying CRT response. In a subgroup of 41 patients who underwent Doppler tissue imaging analysis, the preimplantation BNP was higher in patients presenting with intraventricular dyssynchrony (845 +/- 779 vs 248 +/- 290 pg/ml, p = 0.04). In conclusion, the preimplantation BNP value independently predicts CRT response and was superior to QRS duration reduction in identifying CRT responders.     

Left ventricular apical wall motion abnormality is associated with lack of response to cardiac resynchronization therapy in patients with ischemic cardiomyopathy.

BACKGROUND: Many patients with appropriate indications fail to respond to cardiac resynchronization therapy (CRT). OBJECTIVE: The purpose of our study was to determine the relationship between CRT response and preimplantation apical wall motion abnormality. METHODS: We analyzed data from 83 patients with ischemic cardiomyopathy who underwent CRT. All patients had New York Heart Association class III or IV symptoms despite maximal medical therapy, left ventricular ejection fraction (LVEF) < or =35%, and QRS duration > or =130 ms or <130 ms with left ventricular dyssynchrony. CRT responders at 6 months were defined as surviving patients with: (1) no hospitalization for heart failure, and (2) improvement of New York Heart Association classification. Patients underwent echocardiography before and 6 months after implantation to assess changes in regional wall motion and LVEF. RESULTS: At baseline, CRT responders (n = 39) and nonresponders (n = 44) had similar LVEF (22.9% +/- 6.9% vs 23.1% +/- 8.3%), QRS duration (159 +/- 43 ms vs 159 +/- 36 ms), and medical treatment. CRT nonresponders had a higher prevalence of preimplantation apical wall motion abnormality (68% vs 33%, P = .003). Patients with baseline apical wall motion abnormalities (n = 43) were less likely than others (n = 40) to show improvement in wall motion at 6 months (30% vs 81%, P < .001) or clinical response to CRT (31% vs 64%, P = .003). CONCLUSION: The presence of a preimplantation apical wall motion abnormality was associated with a lower rate of CRT response in patients with ischemic cardiomyopathy.     

血浆氮末端-前体脑钠肽水平预测心脏再同步化治疗的近期临床疗效

目的:探讨血浆氮末端-前体脑钠肽(NT-proBNP)水平对心脏再同步化治疗(CRT)近期临床疗效的预测价值。方法:入选成功施行CRT的心力衰竭(心衰)患者42例,ELISA法测定血浆NT-proBNP水平。随访6个月,记录心功能分级、左室射血分数(LVEF)、左室舒张末期内径(LVEDd)、QRS间期及心血管事件(心衰再入院、恶性心律失常、心脏性猝死)。结果:入选患者中,CRT有反应者34例,无反应者8例,有效率达81%。CRT术前反应组血浆NT-proBNP水平低于无反应组(P<0.05)。CRT术后6个月反应组LVEF、LVEDd、QRS间期与无反应组比较,均差异有统计学意义(均P<0.01)。Logistic回归分析显示术前NT-proBNP能独立预测CRT临床疗效。术前NT-proBNP对CRT近期临床疗效判定的ROC曲线下面积为0.770,灵敏度为87.5%,特异度为55.9%。结论:血浆NT-proBNP水平可作为评价CRT近期临床疗效的指标。     

The influence of myocardial scar and dyssynchrony on reverse remodeling in cardiac resynchronization therapy.

AIM: The influence of location and extent of transmural scar and its relation with dyssynchrony in cardiac resynchronization therapy (CRT) was investigated as posterolateral scar tissue has been invoked as a cause of non-response to CRT. METHODS AND RESULTS: Fifty-seven patients eligible for CRT were assessed for transmural scar with gadolinium-enhanced MRI and for left ventricular (LV) dyssynchrony with tissue Doppler. After implant, both atrioventricular and interventricular pacing intervals were optimized. LV reverse remodeling was defined as >/=10% decrease in LV end-systolic volume after 3 months. Sixteen patients had transmural scar in the posterolateral (PL) area (LV lead location), 14 at a remote site (non-PL) and 27 patients had no scar. LV reverse remodeling was observed in respectively 25%, 64% and 89% (P = 0.0001). Univariate analyses showed a relation with LV dyssynchrony (P = 0.004) and with absence of PL scar (P = 0.04) but not with QRS duration and the extent of LV scar tissue. In multivariate analysis, only LV dyssynchrony (OR: 19.62; 95% CI: 2.5-151.9; P = 0.004) independently predicted LV reverse remodeling. CONCLUSION: In this study LV dyssynchrony remains the most important determinant of response to CRT, even in the presence of posterolateral scar provided atrioventricular and interventricular pacing intervals are optimized.     

慢性心力衰竭心脏再同步治疗超级反应患者的临床特征

目的接受心脏再同步治疗（CRT）的慢性心力衰竭患者中,部分患者心脏结构和功能显著改善,甚至可以恢复至接近正常,即所谓的超级反应患者（super－responders,SR）,本文回顾分析这些超级反应患者的临床特征,寻找有价值的CRT超级反应患者的预测指标。方法2005年6月至2010年1月在本中心因慢性心力衰竭植入CRT·P／CRT—D的患者共69例,其中有较完整随访资料的50例纳入本研究。CRT超级反应患者判断标准为左心室射血分数（LVEF）绝对值增加≥0．20。回顾性分析50例患者中超级反应患者和非超级反应患者的临床特征,比较两组患者之间的差异。结果平均随访时间（13．9±11．5）个月,达到超级反应标准患者11例（22％）,与术前相比LVEF显著升高（0．58±0．05对0．33±0．05,P〈0．001）。超级反应组和非超级反应组术前资料除性别（女性比例：8／11对11／39,P=0．013）、QRS时限[（163．2±19．3）ms对（140．2±29．1）ms,P=0．018]、左束支阻滞的比例（10／11对20／39,P＝0．04）外差异无统计学意义。多元logistic回归分析显示女性合并完全性左束支阻滞是CRT超级反应的惟一独立预测因子。结论CRT中超级反应患者以女性、QRS时限增宽以及合并左束支阻滞患者多见。女性合并左束支阻滞是CRT超级反应的独立预测因子。