cardiac resynchronization therapy

Tissue Doppler imaging (TDI) is a useful echocardiographic technique to evaluate global and regional myocardial systolic as well as diastolic function. It can also be used to quantify right ventricular and left atrial function. Recent studies have demonstrated its utility as a diagnostic as well as prognostic tool in different cardiac conditions including coronary artery disease, heart failure (both systolic and diastolic), valvular heart disease, cardiomyopathies as well as constrictive pericarditis. TDI measurements are also helpful to identify patients who will benefit from cardiac resynchronisation therapy. Even though it is reproducible and relatively easy to obtain, it is underutilised in routine clinical practice. TDI is readily available on most commercially available echocardiographic systems, and we recommend that TDI be used for routine clinical echocardiographic evaluation of patients.

This document is available on the World Wide Web sites of the American College of Cardiology (www.acc.org), the American Heart Association (my.americanheart.org), and the Heart Rhythm Society (www.hrsonline.org). For copies of this document, please contact the Elsevier Inc. Reprint Department via fax (212-633-3820) or e-mail (reprints@elsevier.com). Multiple copies, modification, alteration, enhancement, and/or distribution of this document are not permitted without the express permission of the American College of Cardiology. Requests may be completed online via the Elsevier site (http://www.elsevier.com/about/policies/author-agreement/obtaining-permission).

Although the majority of Class III congestive heart failure (HF) patients treated with cardiac resynchronization therapy (CRT) show a clinical benefit, up to 40% of patients do not respond to CRT. This paper reports the design of the MultiPoint Pacing (MPP) trial, a prospective, randomized, double-blind, controlled study to evaluate the safety and efficacy of CRT using MPP compared to standard biventricular (Bi-V) pacing. A maximum of 506 patients with a standard CRT-D indication will be enrolled at up to 50 US centers. All patients will be implanted with a CRT-D system (Quartet LV lead Model 1458Q with a Quadra CRT-D, Abbott) that can deliver both MPP and Bi-V pacing. Standard Bi-V pacing will be activated at implant. At 3 months postimplant, patients in whom the echocardiographic parameters during MPP are equal or better than during Bi-V pacing are randomized (1:1) to either an MPP or Bi-V arm. The primary safety endpoint is freedom from system-related complications at 9 months. E...

First-degree atrioventricular (AV) block in relation to the outcome of cardiac resynchronization therapy (CRT) has not been well examined. Patients who received a CRT defibrillator or pacemaker between January 2002 and September 2010 at Mayo Clinic were classified into 2 groups: normal PR interval and prolonged PR interval. Standard sensed (100 milliseconds) and paced (130 milliseconds) AV delay was programmed after CRT. Clinical presentations and echocardiography were assessed before CRT and at a median of 6 months after CRT. The normal PR interval group (n=199) had greater improvements in heart failure functional class (mean [SD], 0.7 [0.8] vs 0.5 [0.9]; P=.03) and left ventricular ejection fraction (9.4% [12.4%] vs 5.9% [9.5%]; P=.007) than the prolonged PR group (n=204). Compared with prolonged PR interval, the presence of normal PR interval was associated with a greater improvement in heart failure.

left ventricular (LV) mechanical dyssynchrony (LVMD) has emerged as a therapeutic target using cardiac resynchronization therapy (CRT) in chronic heart failure patients. Current methods used to evaluate LVMD are technically challenging and do not assess all the components of LVMD simultaneously. We analysed real-time 3D speckle tracking (3DST) echocardiography as a novel method to assess LVMD. three-dimensional ST was performed in 60 unselected patients (71 ± 9 years old; 39% with ischaemic cardiomyopathy) who were referred to optimize and to control of a CRT device; implanted according to current guidelines (9 added to be excluded from the protocol). Two standardized conditions [right ventricular (RV) versus an optimized biventricular (BiV) pacing modality] were tested. These two pacing modalities lead to two distinct electrical activation patterns. We sought to test the capability of 3DST to distinguish these two patterns. The LV ejection fraction was 24 ± 9 in the RV mode and 29 ...

Patients receiving cardiac resynchronization therapy defibrillators (CRT-Ds) are likely to undergo one or more device replacements, mainly for battery depletion. We assessed the economic impact of battery depletion on the overall cost of CRT-D treatment from the perspectives of the healthcare system and the hospital. We also compared devices of different generations and from different manufacturers in terms of therapy cost. We analysed data on 1792 CRT-Ds implanted in 1399 patients in 9 Italian centres. We calculated the replacement probability and the total therapy cost over 6 years, stratified by device generation and manufacturer. Public tariffs from diagnosis-related groups were used together with device prices and hospitalization costs. Generators were from 3 manufacturers: Boston Scientific (667, 37%), Medtronic (973, 54%), and St Jude Medical (152, 9%). The replacement probability at 6 years was 83 and 68% for earlier- and recent-generation devices, respectively. The need for...

The RAFT (Resynchronization in Ambulatory Heart Failure Trial) demonstrated that cardiac resynchronization therapy (CRT) reduced both mortality and heart failure hospitalizations in patients with functional class II or III heart failure and widened QRS. We examined the influence of CRT on ventricular arrhythmias in patients with primary versus secondary prophylaxis defibrillator indications. All ventricular arrhythmias among RAFT study participants were downloaded and adjudicated by 2 blinded reviewers with an overreader for disagreements and committee review for remaining discrepancies. Incidence of ventricular arrhythmias among patients randomized to CRT-D versus implantable cardioverter defibrillator (ICD) were compared within the groups of patients treated for primary prophylaxis and for secondary prophylaxis. Of 1798 enrolled patients, 1764 had data available for adjudication and were included. Of these, 1531 patients were implanted for primary prophylaxis, while 233 patients w...

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 > or =120 ms who may have interventricular and intraventricular dyssynchrony correctible by cardiac resynchronization therapy (CRT). The latter is usually achieved with biventricular 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 cannulate the CS, over the wire leads with passive fixation mechanism, and surgical placement methods. Device-specific CRT features include optimizing heart failure through insurance 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 suc...

Mitral regurgitation by the volumetric method consistently decreased after CRT: regurgitant volume from 40 ± 20 ml to 24 ± 17 ml and regurgitant fraction from 40 ± 12% to 25 ± 14% (both: p < 0.001 vs. baseline). Normal controls had uniform segmental time-to-peak strain, with a ...

Coronary sinus mapping is commonly used to evaluate left atrial activation. Herein, we propose to use it to assess which right ventricular pacing modality produces the shortest left ventricular activation times (R-LVtime) and the narrowest QRS widths. Three study groups were defined: 54 controls without intraventricular conduction disturbances; 15 patients with left bundle branch block, and other 15 with right bundle branch block. Left ventricular activation times and QRS widths were evaluated among groups under sinus rhythm, right ventricular apex, right ventricular outflow tract and high output septal zone (SEPHO). Left ventricular activation time was measured as the time elapsed from the surface QRS onset to the most distal left ventricular deflection recorded at coronary sinus. During the above stimulation modalities, coronary sinus mapping reproduced electrical differences that followed mechanical differences measured by tissue doppler imaging. Surprisingly, 33% of the patients...

The development of both electrical reverse remodeling and mechanical reverse remodeling (ERR+MRR) after cardiac resynchronization therapy (CRT) implantation could reduce the incidence of lethal arrhythmia, hence the prediction of ERR+MRR is clinically important.Methods and Results:Eighty-three patients (54 male; 67±12 years old) with CRT >6 months were enrolled. ERR was defined as baseline intrinsic QRS duration (iQRSd) shortening ≥10 ms in lead II on ECG after CRT, and MRR as improvement in LVEF ≥25% on echocardiography after CRT. Acute ECG changes were measured by comparing the pre-implant and immediate post-implant ECG. Ventricular arrhythmia episodes, including ventricular tachycardia and ventricular fibrillation, detected by the implanted device were recorded. Patients were classified as ERR only (n=12), MRR only (n=23), ERR+MRR (n=26), or non-responder (ERR- & MRR-, n=22). On multivariate regression analysis, difference between baseline intrinsic QRS and paced QRS duration ...

Functional mitral regurgitation (FMR) is a common complication of left ventricle (LV) dysfunction and remodelling. Recently, it has been recognized as an independent prognostic factor in both ischaemic and non-ischaemic LV dysfunctions. In this review article, we discuss the mechanisms through which cardiac dyssynchrony is involved in FMR pathophysiologic cascade and how cardiac resynchronization therapy (CRT) can have therapeutic effects on FMR by reverting specific dyssynchrony pathways. We analyse recent clinical trials focusing on CRT impact on FMR in 'real-world' patients, the limits and future perspectives that could eventually generate new predictors of CRT response in terms of FMR reduction. Finally, we propose a practical diagnostic and therapeutic strategy for the management of symptomatic patients with severe LV dysfunction and concomitant 'prognostic' FMR.

Type 2 diabetes mellitus (T2DM) is a multi factorial disease, affecting clinical outcomes in failing heart patients treated by cardiac resynchronization therapy with a defibrillator (CRT-d). One hundred and ninety-five T2DM patients received a CRT-d treatment. Randomly the study population received a CRT-d via multipolar left ventricle (LV) lead pacing (n 99, multipolar group), vs a CRT-d via bipolar LV pacing (n 96, bipolar group). These patients were followed by clinical, and instrumental assessment, and telemetric device control at follow up. In this study we evaluated, in a population of failing heart T2DM patients, cardiac deaths, all cause deaths, arrhythmic events, CRT-d responders rate, hospitalizations for HF worsening, phrenic nerve stimulation (PNS), and LV catheter dislodgment events (and re-intervention for LV catheter re-positioning), comparing multipolar CRT-d vs bipolar CRT-d group of patients at follow up. At follow up there was a statistical significant difference ...

Eugene S. Chung, MD; Angel R. Leon, MD; Luigi Tavazzi, MD; Jing-Ping Sun, MD; Petros Nihoyannopoulos, MD; John Merlino, MD; William T. Abraham, MD; Stefano Ghio, MD; Christophe Leclercq, MD; Jeroen J. Bax, MD; Cheuk-Man Yu, MD, FRCP; John Gorcsan III, MD; ...

Metabolic syndrome (MS) is a multifactorial disease that can affect clinical outcomes in patients treated by Cardiac Resynchronization Therapy with a defibrillator (CRT-d).Ninety-one patients received a CRT-d. According to clinical diagnosis, the study population was divided into 46 MS (cases) versus 45 no MS (controls) patients. These patients were followed by clinical, instrumental assessment, and device telemetric interrogations at follow-up. The design of the study was to evaluate the functionality of the CRT-d leads, the arrhythmic events, the CRT-d response, and the clinical outcomes at follow-up.At follow-up, there was a statistical significant difference, comparing MS versus no MS patients regarding the sensing, pacing, and impedance thresholds of the right atrium, right ventricle, and left ventricle leads. There was a statistically significant difference in the percentage of CRT-d responders comparing MS (n = 16, 51%) versus no MS (n = 40, 77%) patients (P = 0.017). MS may ...

left ventricular (LV) mechanical dyssynchrony (LVMD) has emerged as a therapeutic target using cardiac resynchronization therapy (CRT) in chronic heart failure patients. Current methods used to evaluate LVMD are technically challenging and do not assess all the components of LVMD simultaneously. We analysed real-time 3D speckle tracking (3DST) echocardiography as a novel method to assess LVMD. three-dimensional ST was performed in 60 unselected patients (71 ± 9 years old; 39% with ischaemic cardiomyopathy) who were referred to optimize and to control of a CRT device; implanted according to current guidelines (9 added to be excluded from the protocol). Two standardized conditions [right ventricular (RV) versus an optimized biventricular (BiV) pacing modality] were tested. These two pacing modalities lead to two distinct electrical activation patterns. We sought to test the capability of 3DST to distinguish these two patterns. The LV ejection fraction was 24 ± 9 in the RV mode and 29 ...

This document is available on the World Wide Web sites of the American College of Cardiology (www.acc.org), the American Heart Association (my.americanheart.org), and the Heart Rhythm Society (www.hrsonline.org). For copies of this document, please contact the Elsevier Inc. Reprint Department via fax (212-633-3820) or e-mail (reprints@elsevier.com). Multiple copies, modification, alteration, enhancement, and/or distribution of this document are not permitted without the express permission of the American College of Cardiology. Requests may be completed online via the Elsevier site (http://www.elsevier.com/about/policies/author-agreement/obtaining-permission).