Cardiac resynchronisation for patients with heart failure due to left ventricular systolic dysfunction - a systematic review and meta-analysis

Correlation of body mass index and responder status in heart failure patients after cardiac resynchronization therapy: Does the obesity paradox exist?

Aims: We investigated the influence of body mass index (BMI) on the prevalence of responder status in chronic heart failure patients after cardiac resynchronization therapy (CRT).

Methods: Data on 169 patients with resynchronization therapy were analyzed. Patients were categorized on the basis of the BMI measured at device implantation according to the WHO classification, as normal (BMI: 18.5–24.9 kg/m2), overweight (BMI: 25–29.9 kg/m2) or obese (BMI:≥30 kg/m2). Patients were considered responders if left ventricular ejection fraction was increased by at least 5% at 6-month follow-up.

Results: The mean age in the study population was 60.9±10.86 years (females 29%). The BMI subgroups did not exhibit any significant differences in baseline characteristics (age, gender, left ventricular ejection fraction or NYHA class). Elevated BMIs were associated with higher prevalence of responder status (overweight: 71.4%, obese: 63.0%) relative to subjects with a normal BMI (44.7%) (p=0.015).

Conclusions: In this CRT population, overweight status was associated with a more favorable response to CRT, indicating that the response may possibly be influenced by factors other than those directly related to the heart status or the technical details of the CRT.

Clinical trials update from the Heart Failure Society of America Meeting 2009: FAST, IMPROVE-HF, COACH galectin-3 substudy, HF-ACTION nuclear substudy, DAD-HF, and MARVEL-1

This article presents findings and a commentary on late-breaking trials presented during the meeting of the Heart Failure Society of America in September 2009. Unpublished reports should be considered as preliminary, since analyses may change in the final publication. The FAST trial showed somewhat better performance of intrathoracic impedance for prediction of deterioration in patients with heart failure (HF) when compared with daily weighing. The IMPROVE-HF study reported the benefits of education on the management of patients with systolic HF. Galectin-3 appeared a useful method for improving risk stratification of patients with chronic HF in a substudy of the COACH trial. A nuclear substudy of the HF-ACTION trial failed to demonstrate that resting myocardial perfusion imaging, a measure of myocardial scar and viability, was clinically useful. A small randomized controlled trial (DAD-HF) suggested that the use of low-dose dopamine in patients with acutely decompensated HF was associated with less deterioration in renal function and less hypokalaemia. The MARVEL-1 trial raises further concerns about the safety of myoblast transplantation in ischaemic HF.

Cardiac resynchronization therapy in patients with ischemic versus non-ischemic heart failure: Differential effect of optimizing interventricular pacing interval

BACKGROUND

Whether sequential biventricular pacing provides substantial benefits over conventional simultaneous stimulation remains unclear, particularly regarding the differences between ischemic and non-ischemic patients. The purpose of this study was to evaluate the acute effect of interventricular pacing interval (V-V) optimization on left ventricular (LV) systolic performance and dyssynchrony in ischemic versus non-ischemic patients.

METHODS

Sixty-nine consecutive patients underwent cardiac resynchronization therapy. Within 3 days after implantation, V-V was optimized by measuring (every 20-millisecond interval) LV systolic performance (LV outflow-tract velocity-time-integral, LVOT VTI) and LV dyssynchrony (using tissue Doppler imaging). Optimal pacing configuration was the one achieving maximal increase in LVOT VTI.

RESULTS

Optimized sequential pacing provided a significant improvement in LVOT VTI compared to simultaneous stimulation (from 138 +/- 42 to 163 +/- 38 mm, P < .001) and was associated with a significant reduction in LV dyssynchrony (from 33 +/- 31 to 19 +/- 24 milliseconds, P < .001). The increase in LVOT VTI and LV ejection fraction after implantation was greater in non-ischemic as compared to ischemic patients (P < .001). However, V-V optimization yielded a larger improvement in LV systolic performance in ischemic patients (P = .03). Consequently, the 2 groups showed comparable response after V-V optimization. A significant correlation was observed between LV scar tissue and optimal V-V interval (r = 0.58, P < .001), with a larger extent of scar related to a larger level of LV preactivation, probably reflecting slow intra-LV conduction.

CONCLUSIONS

Optimized sequential biventricular pacing further increased LV systolic performance as compared to simultaneous stimulation, particularly in ischemic patients where the presence of a large scar was correlated with a larger LV preactivation.

Optimization and validation of radionuclide angiography phase analysis parameters for quantification of mechanical dyssynchrony

INTRODUCTION

Cardiac resynchronization therapy (CRT) has the potential to improve the outcome of patients suffering from mechanical dyssynchrony and heart failure. It has been suggested that accurate quantification of baseline extent of mechanical dyssynchrony may lead to pre-selection of patients likely to respond to CRT. The standard deviation from a phase histogram (phaseSD), synchrony (S) and entropy (E) are parameters obtained from phase analysis of planar radionuclide angiography (RNA) that may provide an accurate means of assessing mechanical dyssynchrony. In this paper, the ability of phaseSD, S, and E to detect mechanical dyssynchrony was investigated and optimal values for image smoothing, histogram noise thresholding, and bin size were defined. Finally, the intra- and inter-observer reproducibility of the methodology was assessed.

METHODS

PhaseSD, S, and E were calculated for 37 normal subjects (LVEF > 50%, end-diastolic volume < 120 mL, end-systolic volume < 60 mL, QRS < 120 ms, and normal wall motion) and 53 patients with mechanical dyssynchrony (LVEF < 30%, QRS > 120 ms, and typical LBBB). Receiver-operator characteristics (ROC) curves were created and the area under the curve (AUC), for each parameter, was determined using three different imaging filters (no filter and an order 5 Hann filter with cut-off of 5/50 and 10/50). The AUC was also determined using histogram threshold values varying between 0% and 50% (of the max amplitude value). Finally, AUC for E was determined for bins sizes varying between 1 degrees and 20 degrees . Inter- and intra-observer variability was calculated at optimal imaging values.

RESULTS

No smoothing was found to maximize the AUC. The AUC was independent of histogram threshold value. However, a value of 20% provided optimal visualization of the phase image. The AUC was also independent of bin size. At the optimal imaging values, the sensitivity and specificity for all parameters for detection of mechanical dyssynchrony was measured to be 89-100%. Inter- and intra-observer correlation coefficients >0.99 were found for phaseSD, S and E.

CONCLUSIONS

Optimized planar RNA phase analysis parameters, phaseSD, S, and E, were able to detect mechanical dyssynchrony with low inter- and intra-observer variability. Studies assessing the ability of these parameters to predict CRT outcome are required.

Palliative care in congestive heart failure

Symptoms and compromised quality of life prevail throughout the course of heart failure (HF) and thus should be specifically addressed with palliative measures. Palliative care for HF should be integrated into comprehensive HF care, just as evidence-based HF care should be included in end-of-life care for HF patients. The neurohormonal and catabolic derangements in HF are at the base of HF symptoms. A complex set of abnormalities can be addressed with a variety of interventions, including evidence-based HF care, specific exercise, opioids, treatment of sleep-disordered breathing, and interventions to address patient and family perceptions of control over their illness. Both potential sudden cardiac death and generally shortened length of life by HF should be acknowledged and planned for. Strategies to negotiate communication about prognosis with HF patients and their families can be integrated into care. Additional evidence is needed to direct care at the end of life, including use of HF medications, and to define management of multiple sources of distress for HF patients and their families.

Can monitoring of intrathoracic impedance reduce morbidity and mortality in patients with chronic heart failure? Rationale and design of the Diagnostic Outcome Trial in Heart Failure (DOT-HF)

BACKGROUND

Chronic heart failure is associated with frequent hospitalisations which are often due to volume-overload decompensation. Monitoring of intrathoracic impedance, measured from an implanted device, can detect increases in pulmonary fluid retention early and facilitate timely treatment interventions.

OBJECTIVE

The DOT-HF trial is designed to investigate if ambulatory monitoring of intrathoracic impedance together with other device-based diagnostic information can reduce morbidity and mortality in patients with chronic heart failure who are treated with cardiac resynchronization therapy (CRT) and/or an implantable defibrillator (ICD).

METHODS

Approximately 2400 patients will be randomised in a 1:1 fashion to a management strategy with access to the diagnostic information from the implantable device ("access arm"), or a "control arm", where this information is not made available. Study subjects fulfil standard indications for CRT and/or ICD as outlined in current guidelines. In the access arm, a fluid alert algorithm is used to give early warning of decreasing intrathoracic impedance indicating a high risk of an impending volume-overload decompensation. The primary endpoint of DOT-HF is the composite of all-cause mortality or heart failure hospitalisation. Secondary and exploratory endpoints include all-cause mortality, the impact on total health care utilization, quality of life and cost effectiveness. The study is expected to close recruitment during 2010 and to report in 2012.

Clinical trials update from the American College of Cardiology 2008: CARISMA, TRENDS, meta-analysis of Cox-2 studies, HAT, ON-TARGET, HYVET, ACCOMPLISH, MOMENTUM, PROTECT, HORIZON-HF and REVERSE

This article provides information and a commentary on trials relevant to the pathophysiology, prevention and treatment of heart failure, presented at the American College of Cardiology. Unpublished reports should be considered as preliminary data, as analyses may change in the final publication. CARISMA investigated the use of implantable loop recorders for detecting life-threatening arrhythmias in patients with LVSD after MI and found that brady- and ventricular tachy-arrhythmias predicted an adverse prognosis. The TRENDS study showed that the burden of atrial fibrillation detected by pacemakers or defibrillators predicted the risk of embolic events but not with sufficient precision to justify changes in anti-thrombotic management. A meta-analysis of six trials reported an increased cardiovascular risk associated with celecoxib, particularly for heart failure, which was related to dose and baseline cardiovascular risk. The HAT study failed to show a benefit of providing post-MI patients with a home defibrillator. MOMENTUM, a study of a device designed to augment aortic blood flow, was stopped early due to increased bleeding risk. Results from PROTECT support the use of rolofylline 30 mg/day in acute heart failure, a definitive study is now underway. Istaroxime, an agent that appears to have both inotropic and lusitropic effects, improved haemodynamics when added to standard therapy in patients stabilised after admission with heart failure in HORIZON-HF. The REVERSE study suggested that CRT improves ventricular function and reduces morbidity even in patients with few or no symptoms of heart failure and may delay or prevent worsening heart failure.

Noninvasive imaging of cardiac venous anatomy with 64-slice multi-slice computed tomography and noninvasive assessment of left ventricular dyssynchrony by 3-dimensional tissue synchronization imaging in patients with heart failure scheduled for cardiac resynchronization therapy

Objectives of this study were to perform a prospective head-to-head comparison between multi-slice computed tomography (MSCT) venography and invasive venography in cardiac resynchronization therapy (CRT) candidates as well as to evaluate the relation between left ventricular (LV) lead position and effect on LV dyssynchrony and immediate response to CRT. Twenty-one consecutive heart failure patients scheduled for CRT implantation were prospectively enrolled to undergo 64-slice MSCT to visualize the venous system, invasive venography during device implantation, and tri-plane tissue synchronization imaging (TSI) before and after implantation. Excellent agreement between MSCT and invasive venography was noted. No significant differences were observed between both techniques regarding vessel diameters. In 12 patients, a match was observed between the area of latest mechanical activation (on TSI) and LV lead position. These patients showed a significant decrease in LV dyssynchrony (43 +/- 7 ms to 11 +/- 9 ms, p <0.0001) with acute reduction in LV end-systolic volume (188 +/- 54 ml to 162 +/- 48 ml, p <0.01) and improvement in LV ejection fraction (22% +/- 9% to 34% +/- 9%, p <0.01). Patients with a mismatch between area of latest activation and LV lead position remained dyssynchronous without improvement in LV function. In conclusion, visualization of major tributaries of the coronary sinus was comparable between invasive venography and MSCT venography. Optimal LV lead positioning in a vein draining the area of latest mechanical activation (determined from tri-plane TSI) resulted in acute improvement of LV dyssynchrony and systolic function after CRT implantation.

Combined resynchronisation and implantable defibrillator therapy in left ventricular dysfunction: Bayesian network meta-analysis of randomised controlled trials

OBJECTIVE

To review the evidence base from randomised controlled trials of combined cardiac resynchronisation therapy and implantable cardioverter defibrillator therapy in left ventricular impairment and symptomatic heart failure.

DESIGN

Bayesian network meta-analysis.

DATA SOURCES

Medline, Embase, and Cochrane databases up to June 2006.

REVIEW METHODS

Two reviewers independently assessed trial eligibility and quality. Included trials compared cardiac resynchronisation therapy, implantable cardioverter defibrillator therapy, combined resynchronisation and implantable defibrillator therapy, and medical therapy alone, in patients with impaired left ventricular systolic function. Bayesian random effects network models were used to examine overall number of deaths.

RESULTS

12 studies including 1636 events in 8307 patients were identified. Combined cardiac resynchronisation and implantable cardioverter defibrillator therapy reduced the number of deaths by one third compared with medical therapy alone (odds ratio 0.57, 95% credible interval 0.40 to 0.80) but did not further improve survival when compared with implantable defibrillator therapy (0.82, 0.57 to 1.18) or resynchronisation (0.85, 0.60 to 1.22) therapy alone.

CONCLUSION

Evidence from randomised controlled trials is insufficient to show the superiority of combined cardiac resynchronisation and implantable cardioverter defibrillator therapy over cardiac resynchronisation therapy alone in patients with left ventricular impairment.

Left ventricular dyssynchrony assessed by two three-dimensional imaging modalities: phase analysis of gated myocardial perfusion SPECT and tri-plane tissue Doppler imaging

Purpose

To compare left ventricular (LV) dyssynchrony assessment by phase analysis from gated myocardial perfusion SPECT (GMPS) with LV dyssynchrony assessment by tri-plane tissue Doppler imaging (TDI). Baseline LV dyssynchrony assessed with standard deviation (SD) of time-to-peak systolic velocity of 12 LV segments (Ts-SD) with TDI has proven to be a powerful predictor of response to CRT. Information on LV dyssynchrony can also be provided by GMPS with phase analysis of regional LV maximal count changes throughout the cardiac cycle.

Methods

Forty heart failure patients, referred for evaluation of potential eligibility for CRT, underwent both 3D echocardiography, with tri-plane TDI, and resting GMPS. From tri-plane TDI, Ts-SD was used as a validated parameter of LV dyssynchrony and compared with different indices (histogram bandwidth, phase SD, histogram skewness and kurtosis) derived from phase analysis of GMPS.

Results

Histogram bandwidth and phase SD showed good correlation with Ts-SD (r=0.77 and r=0.74, p<0.0001, respectively). Patients with substantial LV dyssynchrony assessed with tri-plane TDI (Ts-SD ≥33 ms) had also significantly higher values of histogram bandwidth and phase SD.

Conclusions

The results of this study support the use of phase analysis by GMPS to evaluate LV dyssynchrony. Histogram bandwidth and phase SD showed the best correlation with Ts-SD assessed with tri-plane TDI and appeared the most optimal variables for assessment of LV dyssynchrony with GMPS.

Therapeutic and diagnostic role of electrical devices in acute heart failure

Electrical devices, Cardiac Resynchronization Therapy (CRT) pacemakers, the Implantable Cardiac Defibrillator (ICD) and a combination of both, constitute an important line of treatment in the therapy of moderate to severe chronic heart failure. The effectiveness of these devices in the treatment of acute decompensated heart failure has yet to be systematically evaluated. However, the beneficial clinical effects of CRT translate into a marked reduction of heart failure-related hospitalization. Devices also offer unique diagnostic applications by continuous measurement of clinically useful physiological parameters over time. Of particular interest, monitoring of intrathoracic impedance and right ventricular pressures allows to detect changes in volume load in an early stage prior to the development of clinical symptoms. This information could be helpful to stop further progression to acute cardiac decompensation and to avoid hospitalization and acute clinical events. Using modern telecommunication technology, patients can also be remotely monitored in their daily living environment. In consequence, the incorporation of device technology into heart failure management programs calls for a close cooperation between heart failure specialists and electrophysiologists. This review addresses therapeutic and diagnostic aspects of device therapies in the context of acute heart failure.

Tissue synchronisation imaging accurately measures left ventricular dyssynchrony and predicts response to cardiac resynchronisation therapy

BACKGROUND

Tissue synchronisation imaging (TSI) is a new technique to assess left ventricular (LV) dyssynchrony.

OBJECTIVES

The value of using TSI to automatically assess LV dyssynchrony compared with manual assessment of LV dyssynchrony from colour-coded tissue Doppler imaging (TDI), and to evaluate the value of TSI to predict response to cardiac resynchronisation therapy (CRT).

METHODS

60 symptomatic patients with heart failure with depressed LV ejection fraction (LVEF) and QRS >120 ms were evaluated clinically and echocardiographically at baseline and after 6 months of CRT. LV dyssynchrony was measured manually using velocity tracings from the colour-coded TDI and automatically using TSI. LV volumes and LVEF were assessed from two-dimensional echocardiography. Clinical responders had to exhibit an improvement in New York Heart Association functional class by > or =1 score and an improvement by > or =25% in 6 min walking distance after 6 months. Reverse LV remodelling was defined as a reduction of > or =15% LV end-systolic volume.

RESULTS

An excellent correlation was observed between LV dyssynchrony measured manually and automatically derived by TSI (r = 0.95, p<0.001). 34 patients showed clinical response after 6 months of CRT and 32 patients showed reverse remodelling. Baseline characteristics were comparable between responders and non-responders, except for more extensive LV dyssynchrony in the responders: 78 (26) vs 29 (29) ms (p<0.001) as assessed manually, and 79 (29) vs 28 (27) ms (p<0.001) as assessed with TSI. Using a cut-off value of 65 ms to define extensive LV dyssynchrony, TSI had a sensitivity of 81% with a specificity of 89% to predict reverse LV remodelling.

CONCLUSION

TSI allows automatic and reliable assessment of LV dyssynchrony and predicts reverse LV remodelling after CRT.

Triplane Tissue Doppler Imaging to Evaluate Mechanical Dyssynchrony Before and After Cardiac Resynchronization in a Patient with Congenitally Corrected Transposition of the Great Arteries

We report the case of a 13-year-old girl with congenitally corrected transposition of the great arteries. Since the implantation of a conventional pacemaker for acquired complete atrioventricular block, the patient experienced increased heart failure symptoms. Using triplane tissue Doppler imaging, significant intraventricular dyssynchrony induced by unilateral pacing and associated with diminished exercise capacity was demonstrated. A biventricular pacemaker was successfully implanted transvenously, leading to synchronous activation of the systemic ventricle and improved exercise capacity.

Cardiac resynchronization therapy or atrio-biventricular pacing—what should it be called?

Reduced cardiac efficiency caused by suboptimal synchronization of the heart's normal contraction might contribute to the development of or exacerbate heart failure. Conceptually and in practice cardiac dyssynchrony is complex. Recent studies have shown that atrio-biventricular pacing can improve cardiac synchrony in many patients and improve cardiac function, symptoms and exercise capacity, and reduce morbidity and mortality substantially. Randomized controlled trials, however, indicate that the severity of cardiac dyssynchrony, as conventionally measured, is a poor guide to treatment benefit and that correction of dyssynchrony accounts for only part of the benefit of atrio-biventricular pacing. Although some of the benefits of atrio-biventricular pacing might be mediated by cardiac resynchronization, much of the benefit could be mediated by mechanisms that are as yet unknown. Withholding atrio-biventricular pacing in patients who do not exhibit cardiac dyssynchrony on imaging but otherwise fulfil the entry criteria used in randomized controlled trials of this therapy could be unwise. Here, we examine the evidence that cardiac resynchronization is indeed the mechanism by which atrio-biventricular pacing exerts its effects.