心脏再同步治疗心力衰竭最新研究进展

心脏再同步治疗是一种非药物治疗心力衰竭的新方法。多项临床研究已证实,心脏再同步治疗可以显著改善患者的心功能,提高生活质量,减少患者的病死率及再住院率。     

Advances in Devices for Cardiac Resynchronization in Heart Failure

Patients with advanced heart failure have a high mortality and morbidity despite medical therapy. Depending on the underlying heart disease and severity of heart failure, 3.7 to 52.8% of patients have a QRS complex 120 ms who may have interventricular and intraventricular dyssynchrony correctible by cardiac resynchronization therapy (CRT). The latter is usually achieved with biventiricular pacing, with the left ventricular lead placed in a tributary of the coronary sinus (CS), with a reported success rate between 88–92%. The technical advances for implantation include preformed guide sheaths to canulate the CS, over the wire leads with passive fixation mechanism, and surgical placement methods.Device-specific CRT features include optimizing heart failure through ensurance of a high percentage of pacing, heart failure monitoring, atrioventricular and interventricular timing, and avoiding double ventricular sensing. Furthermore, arrhythmic co-morbidities of heart failure such as atrial fibrillation and ventricular tachyarrhythmias can also be managed. Recent prospective trials suggest that there is a 30% reduction in heart failure hospitalization with CRT, and preliminary results suggest a survival benefit with CRT and implantable cardioverter defibrillator over optimal medical therapy.     

Acute Hemodynamic Effects of Atrial Pacing with Cardiac Resynchronization Therapy

Background: Chronotropic incompetence is common among patients with advanced heart failure (HF), thus atrial pacing (AP) is frequently utilized in this population. The hemodynamic effects of AP during cardiac resynchronization therapy (CRT) have not been well studied.
Objective: The purpose of this study was to compare the acute hemodynamic response during CRT of AP with that during atrial sensing (AS).
Methods: This study included 26 patients undergoing CRT. At implant, invasive left ventricular (LV) dP/dt was measured by a micromanometer catheter during biventricular pacing in AS and AP modes at 5 different atrioventricluar delays (AVD), tested in randomized order. Postimplant, echocardiography was performed to obtain aortic and mitral flow velocity integrals at baseline (no CRT) and during CRT.
Results: Compared with intrinsic rhythm, CRT increased LV dP/dt by 11 ± 11% during AS (heart rate: 74 ± 13 bpm) and by 17 ± 11% during AP (heart rate: 86 ± 12 bpm, P < 0.001). The AVD associated with maximal hemodynamic response (AVD_max) during AP was 72 ± 40 ms longer than during AS. However, aortic and mitral flow velocity integrals decreased by 15–20% during AP. The aortic and mitral flow velocities at AVD_max for LV dP/dt_max were highly correlated with their maximum values (r > 0.98).
Conclusion: AP increases LV dP/dt during CRT, but requires a substantially longer AV delay. However, AP results in modest reductions of LV filling and stoke volume. Further studies are needed to assess the long-term impact of AP on HF functional status and LV remodeling.     

Cardiac Resynchronization Therapy is an Important Advance in the Management of Congestive Heart Failure

Cardiac resynchronization therapy (CRT) is an emerging therapy that improves symptoms and exercise tolerance in patients with advanced heart failure, left ventricular systolic dysfunction, and intraventricular conduction delay. By correcting the AV, interventricular, and intraventricular dyssynchrony induced by conduction disorders, controlled studies have shown that CRT improved functional status, decreased heart failure hospitalization rate, and might have a positive effect on left ventricular remodeling. Recent and preliminary data from the COMPANION trial suggest that CRT alone or in association with defibrillator capacity significantly reduced total mortality and hospitalization and that total mortality was significantly reduced only in the CRT plus implantable cardioverter defibrillator (ICD) group. Many questions remain unanswered, particularly the selection of responder patients. (J Cardiovasc Electrophysiol, Vol. 14, pp. S27-S29, September 2003, Suppl.)     

Cardiac Resynchronization Therapy

Cardiac resynchronization therapy (CRT) is a recently developed approach to treat dilated heart failure with discoordinate contraction. Such dyssynchrony typically stems from electrical delay that then translates into mechanical delay between the septal and lateral walls. Over the past decade, many studies have examined the pathophysiology of cardiac dyssynchrony, tested the effects of cardiac resynchronization on heart function and energetics,tested the chronic efficacy of this therapy to enhance symptoms and reduce mortality, and better established which patients are most likely to benefit. This brief review discusses these topics.     

Cardiac Resynchronization Therapy in Patients With Heart Failure and Narrow QRS Complexes

Background

Cross correlation analysis (CCA) using tissue Doppler imaging has been shown to be associated with outcome after cardiac resynchronization therapy (CRT) in patients with heart failure (HF) with wide QRS. However, its significance in patients with narrow QRS treated with CRT is unknown.

心脏再同步治疗的研究进展

充血性心力衰竭是具有较高住院率和死亡率的一种严重的心血管疾病。充血性心力衰竭的主要治疗模式是基于抗神经激素和肾素-血管紧张素轴途径,这些药物治疗可缓解症状,有时亦会改善心脏结构异常,是心力衰竭治疗的基石。近30%的晚期心力衰竭患者伴有心脏电传导异常,导致心室收缩不同步。这种非同步收缩会导致心脏病理生理学改变,加重心力衰竭。因此,心脏起搏技术可能被用于恢复心室同步收缩。近来,国际上进行了一系列多中心临床研究表明,心脏再同步治疗可以改善患者心功能,提高患者运动耐量及生活质量。心脏再同步治疗在改善患者心脏结构和功能的同时,也明显降低心力衰竭恶化的危险。     

扩张性心肌病并心力衰竭患者双室同步起搏治疗对心率变异性的影响

观察双室同步起搏对扩张性心肌病并心力衰竭 (简称心衰 )患者心功能及心率变异性 (HRV)的影响。选择1 5例扩张性心肌病并顽固心衰患者 ,置入双室起搏器 ,观察心功能、HRV及血浆丙二醛、一氧化氮、内皮素 1、血管紧张素 Ⅱ的变化。结果 :心功能NYHA分级从术前 3.32± 0 .31级提高为 2 .1 8± 0 .33级 ,左室射血分数由 0 .2 9± 0 .0 3增至 0 .36± 0 .0 3(P <0 .0 5 ) ;2 4h正常RR间期均值标准差、相邻RR间期差值均方根、相邻RR间期差值 >5 0ms占正常RR间期数的百分比、总功率、低频及高频波段功率分别由 73± 8.1ms、4 1± 8.0ms2 、5 .3%± 1 .5 %、1 0 2 4± 4 1 3ms2 、1 1 5± 35ms2 及 4 8± 1 5ms2 增至 1 0 7± 1 3ms、70± 1 1ms2 、1 1 .3%± 3.4 %、1 92 1± 4 84ms2 、1 94± 35ms2 及 91± 2 9ms2 (P均 <0 .0 1 ) ;血浆丙二醛、内皮素 1分别由 4 31± 37nmol/L、83.1± 2 1ng/L降至 32 3± 2 9nmol/L、6 7.3± 1 6ng/L ,一氧化氮由 38.1± 7.6 μmol/L增至 5 1 .3± 9.2 μmol/L(P均 <0 .0 1 ) ,血管紧张素 Ⅱ无变化 (P >0 .0 5 )。结论 :同步起搏改善扩张性心肌病心衰患者心功能及HRV。     

双心室起搏逆转心脏结构重塑的临床观察

观察双心室同步起搏治疗慢性充血性心力衰竭 (简称心衰 )逆转心脏结构重塑的中远期疗效并探讨其可能机制。4例扩张性心肌病中晚期患者 ,心功能NYHA分级Ⅲ级 2例、Ⅳ级 2例 ,均伴有心室内阻滞。其中 3例置入三腔双心室起搏器、1例为四腔起搏。术后对心功能、二维超声心动图、动态心电图、心脏远达正侧位片等进行了 12～ 2 0个月的随访。所有双心室起搏器均一次性安置成功。随访资料显示 4例患者各房室内径 ,心胸比率缩小 ;心脏搏出量、左室射血分数等显著提高 ;二尖瓣返流、QRS波时限减少 ,NYHA分级提高到Ⅰ～Ⅱ级 ,6min步行距离明显增加。心脏结构重塑时间发生在术后 6个月内 ,以后结构趋于稳定。 4例中 1例猝死 ,无一例因严重心衰而住院或死亡。结论 :双心室起搏能逆转慢性心衰患者的心脏结构重塑 ,明显改善心功能 ,提高生活质量。     

Improved Right Ventricular Systolic Function After Cardiac Resynchronization Therapy in Patients With Heart Failure

BackgroundSince the introduction of cardiac resynchronization therapy (CRT) to improve left ventricular function, the effect of CRT on the right ventricle in patients with heart failure has not been well described.MethodsWe evaluated the effect of CRT on right ventricular systolic function in 20 patients (80% men; mean [SD] age, 58.5 [9.8] y) with cardiomyopathy and right ventricular systolic dysfunction (New York Heart Association class III or IV, left ventricular ejection fraction ≤35%, and QRS interval ≥120 ms). The median follow-up time was 15 months. Right ventricular systolic function, defined as a tricuspid annular plane systolic excursion (TAPSE) index of 16 mm or less, was evaluated in patients before and after CRT.ResultsTwelve (60%) patients had ischemic cardiomyopathy, and 12 (60%) patients had left bundle branch block detected using surface electrocardiogram. The mean (SD) QRS duration was 160.5 (24.4) ms. From before CRT to the time of follow-up after CRT, the mean (SD) ejection fraction increased significantly from 22.5% (5.6%) to 29.4% (7.4%) (P < .001). The mean (SD) TAPSE index also increased significantly from 13.70 (1.78) mm to 16.50 (4.77) mm (P = .018). Eleven (55%) patients showed improved right ventricular systolic function (TAPSE ≥16 mm) after CRT. Patients with a favorable right ventricular response to CRT were significantly older (64.6 [8.2] y vs 53.6 [8.4] y, respectively) and more likely to have nonischemic origin of cardiomyopathy than were patients with unimproved right ventricular function (66.7% vs 18.2%, respectively).ConclusionOur findings indicate that CRT is associated with improved right ventricular systolic function in patients with heart failure and right ventricular systolic dysfunction. Patients with nonischemic heart disease more often show improved right ventricular function after CRT.     

Hemodynamic Benefit of Rest and Exercise Optimization of Cardiac Resynchronization Therapy

The optimal method of cardiac resynchronization therapy (CRT) optimization is as yet unknown. We sought to investigate the responses of optimization at rest and on exercise. This 2 stage study involved 59 patients (age 65 ± 10, 75% male), who had all recently undergone successful CRT implantation. In the first stage, the 6‐month response was compared between 30 individuals who underwent resting echocardiographic optimization of CRT [atrioventricular (AV delay) plus ventriculo‐ventricular delays (VV delay)], compared with the 29 who did not. In the second stage, a subset of 37 patients from the original cohort were randomized (double‐blind) to either resting echocardiographic optimization (n = 20) or exercise echocardiographic optimization (n = 17) and followed for a further 6 months. Clinical and echocardiographic data were collected at each stage. Patients undergoing rest optimization demonstrated improvement in almost all variables and significantly in B‐type natriuretic peptide (BNP) in contrast to those without optimization. In a linear regression model, the only significant predictor of BNP change was whether an individual underwent resting optimization or not (β = 0.38, P = 0.04). In those undergoing resting optimization, the degree of change in AV delay was correlated with improvement in left ventricle (LV) end‐diastolic volume (r² = 0.33, P < 0.01). Optimization on exercise was associated with a significant decrease in 6‐minute walk test compared to those randomized to rest optimization possibly due to inducing nonoptimization at rest. In conclusion, echocardiographic optimization of CRT at rest is superior to no optimization or optimization on exercise. Patients with the greatest change in AV delay to reach optimal may undergo greater LV remodeling.     

Cardiac Resynchronization Therapy as Rescue Therapy in End‐Stage Heart Failure: Illustration by Three‐Dimensional Speckle Tracking Strain Echocardiography

We report the case of a 73‐year‐old man admitted for refractory heart failure following implantation of a dual‐chamber pacemaker. Three‐dimensional (3D) echocardiography with speckle tracking area strain identified severe left ventricular (LV) dysfunction and LV dyssynchrony following right ventricular pacing. As the patient's clinical condition rapidly worsened despite optimal medical treatment, a cardiac resynchronization therapy (CRT) pacemaker was successfully implanted as rescue therapy. Symptoms rapidly regressed and echocardiographic assessment following CRT demonstrated an immediate improvement in LV systolic function, confirmed at 9‐month follow‐up with evidence of reverse remodeling. New imaging technologies such as 3D echocardiography with speckle tracking area strain may help to identify and follow up patients who will benefit from CRT as rescue therapy.     

Cardiac Resynchronization Therapy (and Multisite Pacing) in Pediatrics and Congenital Heart Disease: Five Years Experience in a Single Institution

Introduction: Clinical evidence supports the use of cardiac resynchronization therapy (CRT) in adults with heart failure, but experience in pediatrics and congenital heart disease (CHD) is limited in terms of patient numbers and follow-up. We sought to determine the functional assessment and clinical outcomes in pediatric and CHD CRT patients followed uniformly at one institution.
Methods: Retrospective review of 60 consecutive patients who underwent CRT between 2002 and 2007.
Results: At implantation, median age was 15.0 years (5 months to 47 years). Overall, 46 patients had CHD (77%) and 14 had dilated cardiomyopathy. Prior to CRT, 92% were on heart failure treatment drugs and 55% had pacemakers. Median follow-up time was 0.7 years (1 day–5.3 years). Median QRS width decreased from 149 to 120 ms (P < 0.001). Median ejection fraction (EF) increased from 36% to 42% (P < 0.001) and improvement was particularly evident in the group with CHD. Of note, 8 of 13 patients with single ventricle morphology had a "strong CRT response," defined as either an improvement of 2–3 ordinal points in NYHA classification and/or increased ventricular function by ≥ 10 EF units. Overall, an improvement in functional status was observed in 39 of 45 patients (87%) with sufficient follow-up data.
Conclusions: Children and CHD patients treated with CRT have acute improvement in ventricular function, but implantation may require individualized planning and unconventional approaches. Future important goals include preimplant determination of CRT responders in pediatric and CHD patients, optimizing lead placement and programing, as well as long-term CRT device management issues.