Cardiac resynchronization therapy as an adjunct to conventional surgical treatment for heart failure

From March 2004 through October 2007, we prospectively evaluated the benefits of cardiac resynchronization therapy as an adjunct to conventional procedures in patients who were undergoing surgery for heart failure.Twenty severely symptomatic patients (14 men and 6 women, with a mean age of 70 +/- 8 years) who displayed advanced cardiomyopathy, QRS duration > or =130 ms, or mechanical dyssynchrony, underwent isolated or combined coronary artery revascularization and mitral valve overreduction. In all patients, an epicardial lead was secured to the left ventricular wall at the end of the procedure and its extremity was brought into a subclavian pocket. In 5 patients, a resynchronization device was implanted at the time of surgery; in 8, it was implanted at a later date; the remaining 7 patients are awaiting implantation. One patient died postoperatively of low-output syndrome. There was 1 noncardiac late death. Eighteen patients were alive at a mean postoperative follow-up of 21.6 +/- 15.2 months (range, 1-43 mo). There were no subsequent hospital admissions after discharge. New York Heart Association functional class and left ventricular performance were significantly and lastingly improved when cardiac resynchronization therapy was added to the surgical procedure. Despite the limitations inherent in the small number of patients and the relatively short duration of follow-up, this study suggests that patients with dilated cardiomyopathy and left ventricular dyssynchrony in whom surgical correction is indicated may benefit from cardiac resynchronization therapy using a resynchronization device connected to an epicardial lead secured to the left ventricle at the time of surgery.     

Cardiac resynchronization: a novel therapy for heart failure

Despite advances in medical therapy for patients with congestive heart failure, morbidity and mortality remain high. Conduction abnormalities, such as left bundle branch block, right bundle branch block, and nonspecific conduction delay, are observed commonly in patients with dilated cardiomyopathy. In patients with heart failure, the presence of intraventricular conduction delay is associated with more severe mitral regurgitation and worsened left ventricular systolic and diastolic function, and is an independent risk factor for increased mortality. Conventional dual-chamber (right atrial and right ventricular) pacing with a short atrioventricular delay was initially introduced as therapy for patients with advanced congestive heart failure to improve diastolic dysfunction and reduce mitral regurgitation. The acute beneficial hemodynamic effects observed in early, uncontrolled studies were not confirmed in subsequent randomized, controlled studies with longer follow-up. Cardiac resynchronization with novel biventricular (left and right ventricular) pacing systems has resulted in hemodynamic and functional benefits in patients with congestive heart failure and an underlying intraventricular conduction delay. Improvements in cardiac index, systolic blood pressure, and functional class have been reported with biventricular pacing, both acutely and at more than 1 year of follow-up. These encouraging preliminary results with biventricular pacing in patients with congestive heart failure will be validated in two prospective, randomized, controlled trials, Multicenter InSync Randomized Clinical Evaluation (MIRACLE) and Comparison of Medical Therapy, Pacing, and Defibrillation in Chronic Heart Failure (COMPANION). These studies are designed to evaluate the long-term efficacy of biventricular pacing in improving exercise capacity and in reducing morbidity and mortality in patients with advanced, symptomatic congestive heart failure. (c)2001 by CHF, Inc.     

Cardiac resynchronization therapy: overcoming ventricular dyssynchrony in dilated heart failure

Despite optimal medical therapy, dilated heart failure is associated with a dismal prognosis and relentless progression. Intraventricular conduction delay or bundle branch block is a marker of heart failure progression and worsening prognosis. Patients fitting this profile have been shown to benefit from a specific form of cardiac pacing now referred to as cardiac resynchronization therapy (CRT). This monograph is an in-depth review of the theory and consequences of ventricular dyssynchrony in dilated heart failure, and provides an overview of the major clinical trials of CRT. Practical considerations for achieving ventricular resynchronization are discussed, with an emphasis on biventricular pacing.     

心脏再同步治疗与室性心律失常

心脏再同步治疗(CRT)是慢性心力衰竭治疗的重要进展,大量临床研究证实,对于符合适应证的慢性心力衰竭患者,CRT能够逆转心肌重构,改善心功能,提高生活质量,降低死亡率[1-4].     

Cardiac resynchronization therapy: retiming the failing right ventricle

Cardiac resynchronization therapy (CRT) improves symptoms, reduces hospitalization, and may decrease mortality in patients with moderate/severe heart failure and left bundle branch block. Whether CRT may have a role in the management of patients with adult congenital heart disease and a failing right (systemic) ventricle is unknown. We report the case of an adult patient with transposition of the great arteries and previous Mustard's repair, who successfully underwent CRT using a hybrid transvenous/epicardial approach. Exercise tolerance improved, right ventricular (systemic) ejection fraction improved, diuretic requirements reduced, and renal function improved. CRT may offer a new therapeutic option for this patient population.     

Cardiac resynchronization therapy in patients with congenital heart disease and systemic right ventricle

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Cardiac computed tomography-verified right ventricular lead position and outcomes in cardiac resynchronization therapy

Journal of Interventional Cardiac Electrophysiology - To evaluate the association between different right ventricular (RV) lead positions as assessed by cardiac computed tomography (CT) and...     

Cardiac resynchronization therapy and ventricular tachyarrhythmia burden

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Cardiac resynchronization therapy for treatment of heart failure in the elderly

Congestive heart failure affects 5 million patients each year and is more common in elderly patients. Cardiac resynchronization therapy (CRT) or biventricular pacing is the simultaneous pacing of both ventricles, an approach that can improve symptoms and survival in some heart failure (HF) patients. Although no randomized controlled trial has evaluated CRT specifically in elderly patients,many of the patients included in the landmark CRT trials were aged 70 and older. Data suggest that CRT is a safe and efficacious treatment of HF in geriatric patients.     

Cardiac resynchronization therapy for treatment of heart failure in the elderly

Congestive heart failure affects 5 million patients each year and is more common in elderly patients. Cardiac resynchronization therapy (CRT) or biventricular pacing is the simultaneous pacing of both ventricles, an approach that can improve symptoms and survival in some heart failure (HF) patients. Although no randomized controlled trial has evaluated CRT specifically in elderly patients, many of the patients included in the landmark CRT trials were aged 70 and older. Data suggest that CRT is a safe and efficacious treatment of HF in geriatric patients.     

Avoidance of right ventricular pacing in cardiac resynchronization therapy improves right ventricular hemodynamics in heart failure patients

Background: Cardiac resynchronization therapy (CRT) applied by pacing the left and right ventricles (BiV) has been shown to provide synchronous left ventricular (LV) contraction in heart failure patients. CRT may also be accomplished through synchronization of a properly timed LV pacing impulse with intrinsically conducted activation wave fronts. Elimination of right ventricular (RV) pacing may provide a more physiological RV contraction pattern and reduce device current drain. We evaluated the effects of LV and BiV pacing over a range of atrioventricular intervals on the performance of both ventricles.
Methods: Acute LV and RV hemodynamic data from 17 patients with heart failure (EF = 30 ± 1%) and a wide QRS (138 ± 25 msec) or mechanical dyssynchrony were acquired during intrinsic rhythm, BiV, and LV pacing.
Results: The highest LV dP/dt_max was achieved during LV pre- (LV paced prior to an RV sense) and BiV pacing, followed by that obtained during LV post-pacing (LV paced after an RV sense) and the lowest LV dP/dt_max was recorded during intrinsic rhythm. Compared with BiV pacing, LV pre-pacing significantly improved RV dP/dt_max (378 ± 136 mmHg/second vs 397 ± 136 mmHg/second, P < 0.05) and preserved RV cycle efficiency (61.6 ± 14.6% vs 68.6 ± 11.4%, P < 0.05) and stroke volume (6.6 ± 4.4 mL vs 9.0 ± 6.3 mL, P < 0.05). Based on LV dP/dt_max, the optimal atrioventricular interval could be estimated by subtracting 30 msec from the intrinsic atrial to sensed RV interval.
Conclusions: Synchronized LV pacing produces acute LV and systemic hemodynamic benefits similar to BiV pacing. LV pacing at an appropriate atrioventricular interval prior to the RV sensed impulse provides superior RV hemodynamics compared with BiV pacing.     

Cardiac resynchronization therapy for treatment of chronic heart failure.

Cardiac resynchronization therapy (CRT) by means of biventricular pacing is a fairly new procedure that has recently been approved by the United States Food and Drug Administration. Many promising studies have been published that suggest CRT improves patient quality of life (based on the Minnesota Living with Heart Failure Quality of Life Questionnaire), increases distance walked in 6 minutes, improves oxygen uptake, lowers New York Heart Association classification, decreases QRS duration, increases left ventricular ejection fraction, and increases peak oxygen consumption. These studies include the Multisite Stimulation in Cardiomyopathies (MUSTIC), the Multicenter InSync Randomized Clinical Evaluation (MIRACLE), the Pacing Therapy for Congestive Heart Failure (PATH-CHF) multicenter trial, the Medtronic Inc. InSync study, the Ventak CHF/Contak CD study, Vigor CHF and a small study conducted by Alonso and colleagues. There are also a number of studies that are still being conducted, such as the COMPANION trial, which will provide further insight into the effectiveness of cardiac resynchronization therapy.     

Cardiac resynchronization therapy: a breakthrough in heart failure management

Heart failure is now considered an epidemic. In patients with heart failure, electrical and mechanical dyssynchrony, evident primarily as prolongation of the QRS‐complex on the surface electrocardiogram, is associated with detrimental effects on the cardiovascular system at several levels. In the past 10 years, studies have demonstrated that by stimulating both cardiac ventricles simultaneously, or almost simultaneously [cardiac resynchronization therapy (CRT)], the adverse effects of dyssynchrony can be overcome. Here, we provide a comprehensive overview of different aspects of CRT including the rationale behind and evidence for efficacy of the therapy. Issues with regard to gender effects and patient follow‐up as well as a number of unresolved concerns will also be discussed.     

心脏再同步治疗在轻度心力衰竭患者中的应用

自1998年世界上首例心脏再同步治疗（ cardiac resynchronization therapy, CRT ）应用以来,CRT已逐渐成为伴有QRS时限延长的中重度（心功能Ⅲ～Ⅳ级（NYHA分级）]心力衰竭患者的标准治疗,     

Right ventricular cardiac resynchronization therapy in patients with right ventricular conduction delay and heart failure

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Cardiac resynchronization therapy: a new therapy for advanced congestive heart failure

Despite medical therapy, many patients with advanced systolic dysfunction remain highly symptomatic. In these patients the presence of a left bundle branch block on electrocardiogram indicates significant dyssynchrony of ventricular contraction. Cardiac resynchronization, by means of biventricular pacing, results in important clinical benefits. Due to the risk for malignant ventricular arrhythmias, this technology is best combined with an implantable cardioverter defibrillator.     

心脏再同步治疗与室性心律失常：诱发还是抑制

心脏再同步治疗（cardiac resynchronization therapy,GRT）是近年来慢性心力衰竭非药物治疗中的重要进展.一系列临床随机对照研究显示,CRT可明显降低心力衰竭患者的死亡率,并改善症状,减少住院率,提高生活质量[1-3].但是,CRT与窒性心律失常的关系及其机制仍未明确.     

Cardiac resynchronization therapy for the treatment of heart failure in patients with intraventricular conduction delay and malignant ventricular tachyarrhythmias

OBJECTIVES: This study was conducted to assess the safety and effectiveness of cardiac resynchronization therapy (CRT) when combined with an implantable cardioverter defibrillator (ICD). BACKGROUND: Long-term outcome of CRT was measured in patients with symptomatic heart failure (HF), intraventricular conduction delay, and malignant ventricular tachyarrhythmias (ventricular tachycardia/ventricular fibrillation [VT/VF]) requiring therapy from an ICD. METHODS: Patients (n = 490) were implanted with a device capable of providing both CRT and ICD therapy and randomized to CRT (n = 245) or control (no CRT, n = 245) for up to six months. The primary end point was progression of HF, defined as all-cause mortality, hospitalization for HF, and VT/VF requiring device intervention. Secondary end points included peak oxygen consumption (VO(2)), 6-min walk (6 MW), New York Heart Association (NYHA) class, quality of life (QOL), and echocardiographic analysis. RESULTS: A 15% reduction in HF progression was observed, but this was statistically insignificant (p = 0.35). The CRT, however, significantly improved peak VO(2) (0.8 ml/kg/min vs. 0.0 ml/kg/min, p = 0.030) and 6 MW (35 m vs. 15 m, p = 0.043). Changes in NYHA class (p = 0.10) and QOL (p = 0.40) were not statistically significant. The CRT demonstrated significant reductions in ventricular dimensions (left ventricular internal diameter in diastole = -3.4 mm vs. -0.3 mm, p < 0.001 and left ventricular internal diameter in systole = -4.0 mm vs. -0.7 mm, p < 0.001) and improvement in left ventricular ejection fraction (5.1% vs. 2.8%, p = 0.020). A subgroup of patients with advanced HF (NYHA class III/IV) consistently demonstrated improvement across all functional status end points. CONCLUSIONS: The CRT improved functional status in patients indicated for an ICD who also have symptomatic HF and intraventricular conduction delay.