Project description:BACKGROUND:Optimal lead positioning is an important determinant of cardiac resynchronization therapy (CRT) response. OBJECTIVE:The purpose of this study was to evaluate cardiac computed tomography (CT) selection of the optimal epicardial vein for left ventricular (LV) lead placement by targeting regions of late mechanical activation and avoiding myocardial scar. METHODS:Eighteen patients undergoing CRT upgrade with existing pacing systems underwent preimplant electrocardiogram-gated cardiac CT to assess wall thickness, hypoperfusion, late mechanical activation, and regions of myocardial scar by the derivation of the stretch quantifier for endocardial engraved zones (SQUEEZ) algorithm. Cardiac venous anatomy was mapped to individualized American Heart Association (AHA) bull's-eye plots to identify the optimal venous target and compared with acute hemodynamic response (AHR) in each coronary venous target using an LV pressure wire. RESULTS:Fifteen data sets were evaluable. CT-SQUEEZ-derived targets produced a similar mean AHR compared with the best achievable AHR (20.4% ± 13.7% vs 24.9% ± 11.1%; P = .36). SQUEEZ-derived guidance produced a positive AHR in 92% of target segments, and pacing in a CT-SQUEEZ target vein produced a greater clinical response rate vs nontarget segments (90% vs 60%). CONCLUSION:Preprocedural CT-SQUEEZ-derived target selection may be a valuable tool to predict the optimal venous site for LV lead placement in patients undergoing CRT upgrade.
Project description:BackgroundCardiac resynchronization therapy (CRT) is an established treatment in heart failure patients. However, a large proportion of patients remain nonresponsive to this pacing strategy. Left ventricular (LV) lead position is one of the main determinants of response to CRT. This study aims to clarify whether multimodality imaging guided LV lead placement improves clinical outcome after CRT.Methods/designThe ImagingCRT study is a prospective, randomized, patient- and assessor-blinded, two-armed trial. The study is designed to investigate the effect of imaging guided left ventricular lead positioning on a clinical composite primary endpoint comprising all-cause mortality, hospitalization for heart failure, or unchanged or worsened functional capacity (no improvement in New York Heart Association class and <10% improvement in six-minute-walk test). Imaging guided LV lead positioning is targeted to the latest activated non-scarred myocardial region by speckle tracking echocardiography, single-photon emission computed tomography, and cardiac computed tomography. Secondary endpoints include changes in LV dimensions, ejection fraction and dyssynchrony. A total of 192 patients are included in the study.DiscussionDespite tremendous advances in knowledge with CRT, the proportion of patients not responding to this treatment has remained stable since the introduction of CRT. ImagingCRT is a prospective, randomized study assessing the clinical and echocardiographic effect of multimodality imaging guided LV lead placement in CRT. The results are expected to make an important contribution in the pursuit of increasing response rate to CRT.Trial registrationClinicaltrials.gov identifier NCT01323686. The trial was registered March 25, 2011 and the first study subject was randomized April 11, 2011.
Project description:BackgroundCardiac resynchronization therapy (CRT) with biventricular epicardial (BV-CS) or endocardial left ventricular (LV) stimulation (BV-EN) improves LV hemodynamics. The effect of CRT on right ventricular function is less clear, particularly for BV-EN. Our objective was to compare the simultaneous acute hemodynamic response (AHR) of the right and left ventricles (RV and LV) with BV-CS and BV-EN in order to determine the optimal mode of CRT delivery.MethodsNine patients with previously implanted CRT devices successfully underwent a temporary pacing study. Pressure wires measured the simultaneous AHR in both ventricles during different pacing protocols. Conventional epicardial CRT was delivered in LV-only (LV-CS) and BV-CS configurations and compared with BV-EN pacing in multiple locations using a roving decapolar catheter.ResultsBest BV-EN (optimal AHR of all LV endocardial pacing sites) produced a significantly greater RV AHR compared with LV-CS and BV-CS pacing (P < 0.05). RV AHR had a significantly increased standard deviation compared to LV AHR (P < 0.05) with a weak correlation between RV and LV AHR (Spearman rs = -0.06). Compromised biventricular optimization, whereby RV AHR was increased at the expense of a smaller decrease in LV AHR, was achieved in 56% of cases, all with BV-EN pacing.ConclusionsBV-EN pacing produces significant increases in both LV and RV AHR, above that achievable with conventional epicardial pacing. RV AHR cannot be used as a surrogate for optimizing LV AHR; however, compromised biventricular optimization is possible. The beneficial effect of endocardial LV pacing on RV function may have important clinical benefits beyond conventional CRT.
Project description:BackgroundIn cardiac resynchronization therapy, left ventricular (LV) lead placement at the desired position may be difficult due to abnormal coronary sinus (CS) and lateral vein anatomy. We present a case with difficult anatomy in which we used 'an indigenous snare' made from hardware used for coronary angioplasty procedures, which is available in any cardiac catheterization laboratory.Case summaryA 52-year-old man presented with dyspnoea due to chronic heart failure was evaluated for cardiac resynchronization therapy. The LV lead was difficult to advance into the only target lateral branch of the CS due to a combination of angulation and proximal stenosis. Balloon dilation was tried first, but we failed to track the LV lead. We formed a venovenous loop, advancing the coronary guidewire 0.014″ into the posterolateral vein; subsequently into the middle cardiac vein via a collateral. The wire was advanced into the CS and then to superior vena cava. The guidewire then snared through the same left subclavian vein and exteriorized by using indigenous snare. Over this loop, the LV lead of the cardiac resynchronization therapy with defibrillator device was implanted successfully.DiscussionWe have used the snare technique, with the use of a snare prepared from a coronary guidewire. Use of such an indigenous snare has not been described before in the literature. The hardware used in this case is routinely used for coronary angioplasty procedures in all catheterization labs. The importance of our case is that no special hardware like dedicated snare was required to negotiate the LV lead at its desired location.
Project description:Patients suffering from heart failure and left bundle branch block show electrical ventricular dyssynchrony causing an abnormal blood pumping. Cardiac resynchronization therapy (CRT) is recommended for these patients. Patients with positive therapy response normally present QRS shortening and an increased left ventricle (LV) ejection fraction. However, around one third do not respond favorably. Therefore, optimal location of pacing leads, timing delays between leads and/or choosing related biomarkers is crucial to achieve the best possible degree of ventricular synchrony during CRT application. In this study, computational modeling is used to predict the optimal location and delay of pacing leads to improve CRT response. We use a 3D electrophysiological computational model of the heart and torso to get insight into the changes in the activation patterns obtained when the heart is paced from different regions and for different atrioventricular and interventricular delays. The model represents a heart with left bundle branch block and heart failure, and allows a detailed and accurate analysis of the electrical changes observed simultaneously in the myocardium and in the QRS complex computed in the precordial leads. Computational simulations were performed using a modified version of the O'Hara et al. action potential model, the most recent mathematical model developed for human ventricular electrophysiology. The optimal location for the pacing leads was determined by QRS maximal reduction. Additionally, the influence of Purkinje system on CRT response was assessed and correlation analysis between several parameters of the QRS was made. Simulation results showed that the right ventricle (RV) upper septum near the outflow tract is an alternative location to the RV apical lead. Furthermore, LV endocardial pacing provided better results as compared to epicardial stimulation. Finally, the time to reach the 90% of the QRS area was a good predictor of the instant at which 90% of the ventricular tissue was activated. Thus, the time to reach the 90% of the QRS area is suggested as an additional index to assess CRT effectiveness to improve biventricular synchrony.
Project description:AimsLeft ventricular (LV) failure in left bundle branch block is caused by loss of septal function and compensatory hyperfunction of the LV lateral wall (LW) which stimulates adverse remodelling. This study investigates if septal and LW function measured as myocardial work, alone and combined with assessment of septal viability, identifies responders to cardiac resynchronization therapy (CRT).Methods and resultsIn a prospective multicentre study of 200 CRT recipients, myocardial work was measured by pressure-strain analysis and viability by cardiac magnetic resonance (CMR) imaging (n = 125). CRT response was defined as ≥15% reduction in LV end-systolic volume after 6 months. Before CRT, septal work was markedly lower than LW work (P < 0.0001), and the difference was largest in CRT responders (P < 0.001). Work difference between septum and LW predicted CRT response with area under the curve (AUC) 0.77 (95% CI: 0.70-0.84) and was feasible in 98% of patients. In patients undergoing CMR, combining work difference and septal viability significantly increased AUC to 0.88 (95% CI: 0.81-0.95). This was superior to the predictive power of QRS morphology, QRS duration and the echocardiographic parameters septal flash, apical rocking, and systolic stretch index. Accuracy was similar for the subgroup of patients with QRS 120-150 ms as for the entire study group. Both work difference alone and work difference combined with septal viability predicted long-term survival without heart transplantation with hazard ratio 0.36 (95% CI: 0.18-0.74) and 0.21 (95% CI: 0.072-0.61), respectively.ConclusionAssessment of myocardial work and septal viability identified CRT responders with high accuracy.
Project description:OBJECTIVES:The purpose of this study was to identify the optimal pacing site for the left ventricular (LV) lead in ischemic patients with poor response to cardiac resynchronization therapy (CRT). BACKGROUND:LV endocardial pacing may offer benefit over conventional CRT in ischemic patients. METHODS:We performed cardiac magnetic resonance, invasive electroanatomic mapping (EAM), and measured the acute hemodynamic response (AHR) in patients with existing CRT systems. RESULTS:In all, 135 epicardial and endocardial pacing sites were tested in 8 patients. Endocardial pacing was superior to epicardial pacing with respect to mean AHR (% change in dP/dtmax vs. baseline) (11.81 [-7.2 to 44.6] vs. 6.55 [-11.0 to 19.7]; p = 0.025). This was associated with a similar first ventricular depolarization (Q-LV) (75 ms [13 to 161 ms] vs. 75 ms [25 to 129 ms]; p = 0.354), shorter stimulation-QRS duration (15 ms [7 to 43 ms] vs. 19 ms [5 to 66 ms]; p = 0.010) and shorter paced QRS duration (149 ms [95 to 218 ms] vs. 171 ms [120 to 235 ms]; p < 0.001). The mean best achievable AHR was higher with endocardial pacing (25.64 ± 14.74% vs. 12.64 ± 6.76%; p = 0.044). Furthermore, AHR was significantly greater pacing the same site endocardially versus epicardially (15.2 ± 10.7% vs. 7.6 ± 6.3%; p = 0.014) with a shorter paced QRS duration (137 ± 22 ms vs. 166 ± 30 ms; p < 0.001) despite a similar Q-LV (70 ± 38 ms vs. 79 ± 34 ms; p = 0.512). Lack of capture due to areas of scar (corroborated by EAM and cardiac magnetic resonance) was associated with a poor AHR. CONCLUSIONS:In ischemic patients with poor CRT response, biventricular endocardial pacing is superior to epicardial pacing. This may reflect accessibility to sites that cannot be reached via coronary sinus anatomy and/or by access to more rapidly conducting tissue. Furthermore, guidance to the optimal LV pacing site may be aided by modalities such as cardiac magnetic resonance to target delayed activating sites while avoiding scar.
Project description:This is an unusual case of left atrioventricular groove strangulation by an abandoned epicardial pacing lead associated with mild left ventricular inflow obstruction, left atrial enlargement, and new atrial tachycardia that resolved with surgical lead removal. (Level of Difficulty: Intermediate.).
Project description:This registry was created to describe the experience of 76 Italian centres with a large cohort of recipients of multipoint pacing (MPP) capable cardiac resynchronization therapy (CRT) devices.A total of 507 patients in whom these devices had been successfully implanted were enrolled between August 2013 and May 2015. We analysed: (i) current clinical practices for the management of such patients, and (ii) the impact of MPP on heart failure clinical composite response and on the absolute change in ejection fraction (EF) at 6 months. Multipoint pacing was programmed to 'ON' in 46% of patients before discharge. Methods of optimizing MPP programming were most commonly based on either the greatest narrowing of the QRS complex (38%) or the electrical delays between the electrodes (34%). Clinical and echocardiographic follow-up data were evaluated in 232 patients. These patients were divided into two groups according to whether MPP was programmed to 'ON' (n = 94) or 'OFF' (n = 138) at the time of discharge. At 6 months, EF was significantly higher in the MPP group than in the biventricular-pacing group (39.1 ± 9.6 vs. 34.7 ± 7.6%; P < 0.001). Even after adjustments, early MPP activation remained an independent predictor of absolute increase in LVEF of ?5% (odds ratio 2.5; P = 0.001). At 6 months, an improvement in clinical composite score was recorded in a greater proportion of patients with MPP-ON than in controls (56 vs. 38%; P = 0.009). On comparing optimal MPP and conventional vectors, QRS was also seen to have decreased significantly (P < 0.001).This study provides information that is essential in order to deal with the expected increase in the number of patients receiving MPP devices in the coming years. The results revealed different practices among centres, and establishing the optimal programming that can maximize the benefit of MPP remains a challenging issue. Compared with conventional CRT, MPP improved clinical status and resulted in an additional increase in EF.http://www.clinicaltrial.gov/. Unique identifier: NCT02606071.