Placement In Cardiac Resynchronization Therapy Research Articles

Image-guided left ventricular lead placement in cardiac resynchronization therapy: focused on image fusion methods.

Cardiac resynchronization therapy is an effective and widely accessible treatment for patients with advanced, drug-refractory heart failure. It has been shown to reverse maladaptive ventricular remodeling, increase exercise capacity, and lower hospitalization and mortality rates. However, there still exists a considerable proportion of patients who do not respond favorably to the therapy. Tailored left ventricular (LV) lead positioning instead of empiric implantation is thought to have the greatest potential to increase response rates. In our paper, we focus on the rationale for guided LV lead implantation and provide a review of the non-invasive imaging modalities applicable for navigation during LV lead implantation, with special attention to the latest achievements in the field of multimodality imaging and image fusion techniques. Current limitations and future perspectives of the concept are discussed as well.

An image fusion tool for echo-guided left ventricular lead placement in cardiac resynchronization therapy: Performance and workflow integration analysis.

The response rate to cardiac resynchronization therapy (CRT) may be improved if echocardiographic-derived parameters are used to guide the left ventricular (LV) lead deployment. Tools to visually integrate deformation imaging and fluoroscopy to take advantage of the combined information are lacking. An image fusion tool for echo-guided LV lead placement in CRT was developed. A personalized average 3D cardiac model aided visualization of patient-specific LV function in fluoroscopy. A set of coronary venography-derived landmarks facilitated registration of the 3D model with fluoroscopy into a single multimodality image. The fusion was both performed and analyzed retrospectively in 30 cases. Baseline time-to-peak values from echocardiography speckle-tracking radial strain traces were color-coded onto the fused LV. LV segments with suspected scar tissue were excluded by cardiac magnetic resonance imaging. The postoperative augmented image was used to investigate: (a) registration accuracy and (b) agreement between LV pacing lead location, echo-defined target segments, and CRT response. Registration time (264±25seconds) and accuracy (4.3±2.3mm) were found clinically acceptable. A good agreement between pacing location and echo-suggested segments was found in 20 (out of 21) CRT responders. Perioperative integration of the proposed workflow was successfully tested in 2 patients. No additional radiation, compared with the existing workflow, was required. The fusion tool facilitates understanding of the spatial relationship between the coronary veins and the LV function and may help targeted LV lead delivery.

Electrically vs. imaging-guided left ventricular lead placement in cardiac resynchronization therapy: a randomized controlled trial

To test in a double-blinded, randomized trial whether the combination of electrically guided left ventricular (LV) lead placement and post-implant interventricular pacing delay (VVd) optimization results in superior increase in LV ejection fraction (LVEF) in cardiac resynchronization therapy (CRT) recipients. Stratified according to presence of ischaemic heart disease, 122 patients were randomized 1:1 to LV lead placement targeted towards the latest electrically activated segment identified by systematic mapping of the coronary sinus tributaries during CRT implantation combined with post-implant VVd optimization (intervention group) or imaging-guided LV lead implantation by cardiac computed tomography venography, 82Rubidium myocardial perfusion imaging and speckle tracking echocardiography targeting the LV lead towards the latest mechanically activated non-scarred myocardial segment (control group). Follow-up was 6 months. Primary endpoint was absolute increase in LVEF. Additional outcome measures were changes in New York Heart Association class, 6-minute walk test, and quality of life, LV reverse remodelling, and device related complications. Analysis was intention-to-treat. A larger increase in LVEF was observed in the intervention group (11 ± 10 vs. 7 ± 11%; 95% confidence interval 0.4-7.9%, P = 0.03); when adjusting for pre-specified baseline covariates this difference did not maintain statistical significance (P = 0.09). Clinical response, LV reverse remodelling, and complication rates did not differ between treatment groups. Electrically guided CRT implantation appeared non-inferior to an imaging-guided strategy considering the outcomes of change in LVEF, LV reverse remodelling and clinical response. Larger long-term studies are warranted to investigate the effect of an electrically guided CRT strategy.

Multimodality imaging for real-time image-guided left ventricular lead placement during cardiac resynchronization therapy implantations

This study was performed to evaluate the feasibility of intra-procedural visualization of optimal pacing sites and image-guided left ventricular (LV) lead placement in cardiac resynchronization therapy (CRT). In fifteen patients (10 males, 68 ± 11 years, 7 with ischemic cardiomyopathy and ejection fraction of 26 ± 5%), optimal pacing sites were identified pre-procedurally using cardiac imaging. Cardiac magnetic resonance (CMR) derived scar and dyssynchrony maps were created for all patients. In six patients the anatomy of the left phrenic nerve (LPN) and coronary sinus ostium was assessed via a computed tomography (CT) scan. By overlaying the CMR and CT dataset onto live fluoroscopy, aforementioned structures were visualized during LV lead implantation. In the first nine patients, the platform was tested, yet, no real-time image-guidance was implemented. In the last six patients real-time image-guided LV lead placement was successfully executed. CRT implant and fluoroscopy times were similar to previous procedures and all leads were placed close to the target area but away from scarred myocardium and the LPN. Patients that received real-time image-guided LV lead implantation were paced closer to the target area compared to patients that did not receive real-time image-guidance (8 mm [IQR 0–22] vs 26 mm [IQR 17–46], p = 0.04), and displayed marked LV reverse remodeling at 6 months follow up with a mean LVESV change of −30 ± 10% and a mean LVEF improvement of 15 ± 5%. Real-time image-guided LV lead implantation is feasible and may prove useful for achieving the optimal LV lead position.

Preoperative CT of cardiac veins for planning left ventricular lead placement in cardiac resynchronization therapy.

BackgroundSuccessful cardiac resynchronization therapy (CRT) requires appropriate left ventricular (LV) lead placement on a suitable segment of the free LV wall. Current guidelines suggest targeted...

Mechanical Activation Computation from Fluoroscopy for Guided Cardiac Resynchronization Therapy.

Congestive heart failure is associated with significant morbidity and mortality, as first line treatments are not always effective in improving symptoms and quality of life. Furthermore, 30-50% of patients who are treated with cardiac resynchronization therapy (CRT), a minimally invasive intervention, do not respond when assessed by objective criteria such as cardiac remodeling. Positioning of the left ventricular lead in the latest activating myocardial region is associated with the best outcome. Cardiac magnetic resonance (CMR) imaging can detect scar tissue and interventricular dyssynchrony; improving the outcome of CRT. However, MR is currently not standard modality for CRT due to its cost and limited availability. This paper explores a novel method to exploit interventional X-ray fluoroscopy set up in CRT procedures to gain information on mechanical activation of the myocardium by tracking the movement of vessels overlying to left ventricular myocardium. Fluoroscopic images were labelled, to track branch movement and determine the motion along the main principal component associated with cardiac motion, to optimize lead placement in CRT. A comparison between MR- and fluoroscopy-derived mechanical activation was performed on 9 datasets, showing more than 66% agreement in 8 cases.

Comprehensive use of cardiac computed tomography to guide left ventricular lead placement in cardiac resynchronization therapy

BackgroundOptimal lead positioning is an important determinant of cardiac resynchronization therapy (CRT) response.ObjectiveThe 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.MethodsEighteen 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.ResultsFifteen 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%).ConclusionPreprocedural 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.

The Use of Cardiac Resynchronization Therapy in Cancer Patients with Heart Failure.

Investigate the use of cardiac resynchronization therapy (CRT) in cancer patients with heart failure (HF); assess factors associated with ischemic and non-ischemic HF. Many newer cancer therapies are cardiotoxic; thus, the incidence of HF has been increasing in this high-risk patient population. CRT has beneficial effects on morbidity, mortality, and left ventricular function in patients with non-ischemic cardiomyopathy, yet cancer patients and survivors who develop severe HF and are eligible for CRT often do not receive it. Review of 2 years of echocardiography and electrocardiography data from cancer patients. Of 272 patients meeting inclusion criteria for CRT placement (LVEF ≤35%, QRS duration ≥120 ms), 131 (48.2%) had HF with ischemic etiology and 141 (51.8%) had HF with non-ischemic etiology. Most patients had solid tumors, including breast, lung, sarcoma, and lymphoma (73.2%, n=199). Only 21.3% (58/272; 27 ischemic; 31 non-ischemic) underwent CRT placement, who were mostly women and those with solid tumors. Non-ischemic HF was significantly associated with younger age (<65 years) (OR=0.91; 95% CI=0.87-0.95) and female sex (OR=2.5; 95% CI=1.1-6.0). As expected, ischemic HF was significantly associated with history of myocardial infarction, diabetes, and cardiovascular disease. CRT is underutilized in cancer patients with HF. Most of the cancer patients who did not receive CRT had non-ischemic HF secondary to chemotherapy. CRT may be less utilized in those patients due to shortened life expectancy, yet evidence suggests that CRT has beneficial effects on morbidity, mortality, and left ventricular function. Its use may improve patient quality of life and allow oncologists to continue cancer treatments that could prolong survival.

Imaging left-ventricular mechanical activation in heart failure patients using cine DENSE MRI: Validation and implications for cardiac resynchronization therapy.

To image late mechanical activation and identify effective left-ventricular (LV) pacing sites for cardiac resynchronization therapy (CRT). There is variability in defining mechanical activation time, with some studies using the time to peak strain (TPS) and some using the time to the onset of circumferential shortening (TOS). We developed improved methods for imaging mechanical activation and evaluated them in heart failure (HF) patients undergoing CRT. We applied active contours to cine displacement encoding with stimulated echoes (DENSE) strain images to detect TOS. Six healthy volunteers underwent magnetic resonance imaging (MRI) at 1.5T, and 50 patients underwent pre-CRT MRI (strain, scar, volumes) and echocardiography, assessment of the electrical activation time (Q-LV) at the LV pacing site, and echocardiography assessment of LV reverse remodeling 6 months after CRT. TPS at the LV pacing site was also measured by DENSE. The latest TOS was greater in HF patients vs. healthy subjects (112 ± 28 msec vs. 61 ± 7 msec, P < 0.01). The correlation between TOS and Q-LV was strong (r > 0.75; P < 0.001) and better than between TPS and Q-LV (r < 0.62; P ≥ 0.006). Twenty-three of 50 patients had the latest activating segment in a region other than the mid-ventricular lateral wall, the most common site for the CRT LV lead. Using a multivariable model, TOS/QRS was significantly associated with LV reverse remodeling even after adjustment for overall dyssynchrony and scar (P < 0.05), whereas TPS was not (P = 0.49). Late activation by cine DENSE TOS analysis is associated with improved LV reverse remodeling with CRT and deserves further study as a tool to achieve optimal LV lead placement in CRT. 1 Technical Efficacy: Stage 1 J. MAGN. RESON. IMAGING 2017;46:887-896.

Quantitative Analysis of Electro-Anatomical Maps: Application to an Experimental Model of Left Bundle Branch Block/Cardiac Resynchronization Therapy.

Electro-anatomical maps (EAMs) are commonly acquired in clinical routine for guiding ablation therapies. They provide voltage and activation time information on a 3-D anatomical mesh representation, making them useful for analyzing the electrical activation patterns in specific pathologies. However, the variability between the different acquisitions and anatomies hampers the comparison between different maps. This paper presents two contributions for the analysis of electrical patterns in EAM data from biventricular surfaces of cardiac chambers. The first contribution is an integrated automatic 2-D disk representation (2-D bull’s eye plot) of the left ventricle (LV) and right ventricle (RV) obtained with a quasi-conformal mapping from the 3-D EAM meshes, that allows an analysis of cardiac resynchronization therapy (CRT) lead positioning, interpretation of global (total activation time), and local indices (local activation time (LAT), surrogates of conduction velocity, inter-ventricular, and transmural delays) that characterize changes in the electrical activation pattern. The second contribution is a set of indices derived from the electrical activation: speed maps, computed from LAT values, to study the electrical wave propagation, and histograms of isochrones to analyze regional electrical heterogeneities in the ventricles. We have applied the proposed methods to look for the underlying physiological mechanisms of left bundle branch block (LBBB) and CRT, with the goal of optimizing the therapy by improving CRT response. To better illustrate the benefits of the proposed tools, we created a set of synthetically generated and fully controlled activation patterns, where the proposed representation and indices were validated. Then, the proposed analysis tools are used to analyze EAM data from an experimental swine model of induced LBBB with an implanted CRT device. We have analyzed and compared the electrical activation patterns at baseline, LBBB, and CRT stages in four animals: two without any structural disease and two with an induced infarction. By relating the CRT lead location with electrical dyssynchrony, we evaluated current hypotheses about lead placement in CRT and showed that optimal pacing sites should target the RV lead close to the apex and the LV one distant from it.

A novel approach for left ventricular lead placement in cardiac resynchronization therapy: Intraprocedural integration of coronary venous electroanatomic mapping with delayed enhancement cardiac magnetic resonance imaging

Placing the left ventricular (LV) lead at a site of late electrical activation remote from scar is desired to improve cardiac resynchronization therapy (CRT) response. The purpose of this study was to integrate coronary venous electroanatomic mapping (EAM) with delayed enhancement cardiac magnetic resonance (DE-CMR) enabling LV lead guidance to the latest activated vein remote from scar. Eighteen CRT candidates with focal scar on DE-CMR were prospectively included. DE-CMR images were semi-automatically analyzed. Coronary venous EAM was performed intraprocedurally and integrated with DE-CMR to guide LV lead placement in real time. Image integration accuracy and electrogram parameters were evaluated offline. Integration of EAM and DE-CMR was achieved using 8.9 ± 2.8 anatomic landmarks and with accuracy of 4.7 ± 1.1 mm (mean ± SD). Maximal electrical delay ranged between 72 and 197ms (57%-113% of QRS duration) and was heterogeneously located among individuals. In 12 patients, the latest activated vein was located outside scar, and placing the LV lead in the latest activated vein remote from scar was accomplished in 10 patients and prohibited in 2 patients. In the other 6 patients, the latest activated vein was located in scar, and targeting alternative veins was considered. Unipolar voltages were on average lower in scar compared to nonscar (6.71 ± 3.45 mV vs 8.18 ± 4.02 mV [median ± interquartile range), P <.001) but correlated weakly with DE-CMR scar extent (R -0.161, P <.001) and varied widely among individual patients. Integration of coronary venous EAM with DE-CMR can be used during CRT implantation to guide LV lead placement to the latest activated vein remote from scar, possibly improving CRT.

Long‐Term Follow‐Up of Isolated Epicardial Left Ventricular Lead Implant Using a Minithoracotomy Approach for Cardiac Resynchronization Therapy

Transvenous left ventricular (LV) lead placement for cardiac resynchronization therapy is unsuccessful in 5-10% of reported cases. These patients may benefit from isolated surgical placement of an epicardial LV lead via minithoracotomy approach. To evaluate the success of this approach at long-term follow-up. Retrospective evaluation of all consecutive patients undergoing isolated epicardial LV lead placement after failed transvenous attempt over a 6-year period. Data collected on baseline parameters, procedural details, and outcome at follow-up (hospital stay, complications, mortality, and clinical response). Forty-two patients underwent epicardial lead implant. Five died within 1 year (11.9%): two (4.8%) died within 30-days post op (one from intraoperative hemorrhage, the other from multiple organ failure); 39 (95.1%) were admitted to the high dependency unit and transferred to the ward <24 hours. Median hospital stay was 3.4 ± 1.9 days. The overall complication rate was 17.5% (n = 7): 15.0% (n = 6) short term and 2.5% (n = 1) long term; these included three (7.5%) LV noncapture events all treated with reprogramming. There were two (5.0%) wound infections requiring oral antibiotics and two (5.0%) device infections requiring intravenous antibiotics (one had device resiting, the other developed septic shock requiring intensive care admission). Assessment of clinical response was possible in 34 (81.0%) at follow-up: 21 (61.8%) were responders and 13 (28.2%) nonresponders with no significant differences between these groups; no clinical predictors of response were identified. Isolated epicardial LV lead implant using minithoracotomy is relatively safe and effective at successful LV pacing. Response rate and postoperative recovery at long-term follow-up are reasonable in these high-risk patients.

Prognostic importance of postoperative QRS widening in patients with heart failure receiving cardiac resynchronization therapy

Landmark reports have suggested that patients with QRS widening immediately after cardiac resynchronization therapy (CRT) experienced less frequently reverse left ventricular remodeling during follow-up. We sought to investigate the relationship between postoperative QRS widening relative to baseline and mortality in a prospective cohort of heart failure patients receiving CRT. A 12-lead electrocardiogram was recorded for 237 heart failure patients (New York Heart Association class II to IV, left ventricular ejection fraction ≤35%, and QRS width ≥120 ms) before and immediately after CRT device implantation. The relationships between QRS widening, all-cause and cardiovascular mortality, and echocardiographic response to CRT were studied. During a median follow-up of 24 months, 39 patients died. Fifty patients (21%) experienced QRS widening after CRT [QRS(+) group]. During follow-up, all-cause mortality was higher in QRS(+) patients than in QRS(-) patients (36-month survival free from death 81% ± 7% vs 64% ± 16%; log rank, P = .029). After adjustment for important prognostic confounders, QRS(+) patients remained associated with an excess overall mortality (adjusted hazard ratio [HR] 2.67; 95% confidence interval 1.07-6.65; P = .035) and cardiovascular mortality (adjusted hazard ratio 3.63; 95% confidence interval 1.13-11.65; P = .03). QRS(+) patients were less frequent responders to CRT than were QRS(-) patients (20 [47%] vs 136 [83%]; P < .0001). Postoperative QRS widening relative to baseline after CRT is associated with a considerable increased mortality risk during follow-up. Whether QRS narrowing should be achieved to optimize CRT placement, and thereby increase the rate of CRT responders and improve outcome, deserves further research.

Multimodality imaging-guided left ventricular lead placement in cardiac resynchronization therapy: a randomized controlled trial.

Left ventricular (LV) lead position at the latest mechanically activated non-scarred myocardial LV region confers improved response to cardiac resynchronization therapy (CRT). We conducted a double-blind, randomized controlled trial to evaluate the clinical benefit of multimodality imaging-guided LV lead placement in CRT. Patients were allocated (1:1) to imaging-guided LV lead placement using cardiac computed tomography (CT) venography, 99m Technetium myocardial perfusion imaging, and speckle-tracking echocardiography radial strain to target the optimal coronary sinus (CS) branch closest to the non-scarred myocardial segment with latest mechanical activation (imaging group, n = 89) or to routine LV lead implantation in a posterolateral region with late electrical activation (control group, n = 93). The primary endpoint was clinical non-response to CRT [≥1 of the following after 6 months: (1) death, (2) heart failure hospitalization, or (3) no improvement in New York Heart Association class and <10% increase in 6-min walk distance]. Secondary outcomes included LV remodelling and the combination of all-cause mortality and hospitalization owing to heart failure during 1.8 ± 0.9 years. Analysis was intention-to-treat. In the imaging group, fewer patients reached the primary endpoint (26% vs. 42%, P = 0.02). More patients in the imaging group had the LV lead placed in the optimal CS branch (83% vs. 65%, P = 0.01). There were no between-group differences in reverse LV remodelling or the combined endpoint of death or hospitalizations for heart failure. Multimodality imaging-guided LV lead placement towards the CS branch closest to latest mechanically activated non-scarred myocardial LV segment reduces the proportion of clinical non-responders to CRT. Larger long-term multicentre studies are needed.

Procedural Success of Left Ventricular Lead Placement for Cardiac Resynchronization Therapy

The goal of this study was to assess the contemporary and historical success rates of transvenous left ventricular (LV) lead placement for cardiac resynchronization therapy (CRT), their change over time, and the reasons for failure. In selected patients, CRT improves morbidity and mortality, but the placement of the LV lead can be technically challenging. A literature search was used to identify all studies reporting success rates of LV lead placement for CRT via the coronary sinus (CS) route. A total of 164 studies were identified, and a meta-analysis was performed. The studies included 29,503 patients: 74% (95% confidence interval [CI]: 72% to 76%) were male; their mean agewas 66 years (95% CI: 65 to 67); their mean New York Heart Association functional class was 2.8 (95% CI:2.7to 2.9); the mean LV ejection fraction was 26% (95% CI: 25% to 28%); and the mean QRS duration was 155 ms (95% CI: 150 to 160). The overall rate of failure of implantation of an LV lead was 3.6% (95% CI: 3.1 to 4.3). The rate offailure in studies commencing before 2005 was 5.4% (95% CI: 4.4% to 6.5%), and from 2005 onward it was 2.4% (95% CI: 1.9% to 3.1%; p<0.001). Causes of failure (reported for 39% offailures) also changed over time. Failure tocannulate and navigate theCS decreased from 53% to 30% (p=0.01), and the absence of any suitable, acceptable vein increased from 39% to 64% (p= 0.007). Theproportion of leads in a lateral or posterolateral final position (reported for 26% of leads) increased from 66% to 82% (p= 0.004). The reported rate of failure to place an LV lead via the CS has decreased steadily over time. A greater proportion of failures in recent studies are due to coronary venous anatomy that is unsuitable for this technique.

Active fixation of a thin transvenous left-ventricular lead by a side helix facilitates targeted and stable placement in cardiac resynchronization therapy.

Suboptimal placement, phrenic nerve stimulation, and dislodgements of left-ventricular (LV) leads are main challenges in cardiac resynchronization therapy. We investigated the handling, performance, safety, and stability for a novel 4Fr LV lead with a small side helix located proximal to the ring electrode for active fixation of the LV lead. The novel LV lead was successfully implanted in 103 of 106 patients. Patients with dislodged LV leads and with demanding coronary vein anatomies were included. The lead body was rotated clockwise to engage the active fixation side helix in the vein wall. The stimulating electrode was located in basal LV segment and middle LV segment in 54 and 46% of the patients, respectively. The lead was targeted to a vein concordant to the LV segment with latest mechanical activation. Concordant LV lead placement was achieved in 73% of the patients and in adjacent segment in 24%. The average pacing capture threshold (PCT) at implantation was 1.04 ± 0.6 V (n = 103) and at an average follow-up at 7 months, the PCT remained low and no dislodgements have been observed. During follow-up, four leads have been explanted without complications. Active fixation of this 4Fr LV lead by using a side helix, offers flexibility to place the lead precisely in targeted vein segments over a wide range of vein anatomies. The average LV pacing threshold was low at implantation and follow-ups. The lead seems to be extractable and no late dislodgements have been observed.

Parametric ultrasound and fluoroscopy image fusion for guidance of left ventricle lead placement in cardiac resynchronization therapy.

Recent studies show that the response rate to cardiac resynchronization therapy (CRT) could be improved if the left ventricle (LV) is paced at the site of the latest mechanical activation, but away from the myocardial scar. A prototype system for CRT lead placement guidance that combines LV functional information from ultrasound with live x-ray fluoroscopy was developed. Two mean anatomical models, each containing LV epi-, LV endo- and right ventricle endocardial surfaces, were computed from a database of 33 heart failure patients as a substitute for a patient-specific model. The sphericity index was used to divide the observed population into two groups. The distance between the mean and the patient-specific models was determined using a signed distance field metric (reported in mm). The average error values for LV epicardium were [Formula: see text] and for LV endocardium were [Formula: see text]. The validity of using average LV models for a CRT procedure was tested by simulating coronary vein selection in a group of 15 CRT candidates. The probability of selecting the same coronary branch, when basing the selection on the average model compared to a patient-specific model, was estimated to be [Formula: see text]. This was found to be clinically acceptable.

Image-guided left ventricular lead placement in cardiac resynchronization therapy for patients with heart failure: a meta-analysis.

BackgroundHeart failure (HF) is a debilitating condition that affects millions of people worldwide. One means of treating HF is cardiac resynchronization therapy (CRT). Recently, several studies have examined the use of echocardiography (ECHO) in the optimization of left ventricular (LV) lead placement to increase the response to CRT. The objective of this study was to synthesize the available data on the comparative efficacy of image-guided and standard CRT.MethodsWe searched the PubMed, Cochrane, Embase, and ISI Web of Knowledge databases through April 2014 with the following combinations of search terms: left ventricular lead placement, cardiac resynchronization therapy, image-guided, and echocardiography-guided. Studies meeting all of the inclusion criteria and none of the exclusion criteria were eligible for inclusion. The primary outcome measures were CRT response rate, change in LV ejection fraction (LVEF), and change in LV end systolic volume (LVESV). Secondary outcomes included the rates of all-cause mortality and HF-related hospitalization.ResultsOur search identified 103 articles, 3 of which were included in the analysis. In total, 270 patients were randomized to the image-guided CRT and 241, to the standard CRT. The pooled estimates showed a significant benefit for image-guided CRT (CRT response: OR, 2.098, 95 % CI, 1.432–3.072; LVEF: difference in means, 3.457, 95 % CI, 1.910–5.005; LVESV: difference in means, −20.36, 95 % CI, −27.819 – −12.902).ConclusionsImage-guided CRT produced significantly better clinical outcomes than the standard CRT. Additional trials are warranted to validate the use of imaging in the prospective optimization of CRT.

73-Year-Old Man With Dyspnea on Exertion

dicine, te ester, o t in Care A 73-year-old man presented to the cardiology clinic in early fall for evaluation of shortness of breath that had worsened over the previous year. He had numerous comorbidities, including hypertension, hyperlipidemia, type 2 diabetes mellitus, medically complicated obesity, stage 3 chronic kidney disease, obstructive sleep apnea, and a 10-year history of nonischemic cardiomyopathy after biventricular pacemaker placement for cardiac resynchronization therapy (CRT). He was receiving maximal medical therapy for his heart failure. He had considerable improvement in his exercise tolerance with CRT, but over the preceding year he had noticed a marked decline in exercise capacity. He could now walk only 30 to 40 feet before becoming dyspneic, whereas a year before he had been able to walk twice this distance. His symptoms had worsened over the past few months, which he attributed to the summer heat. He did not have dyspnea at rest, orthopnea, paroxysmal nocturnal dyspnea, or exertional chest pain/pressure. He had gained about 9 kg over the past 2 years but had no increase in lower extremity edema. He was compliant with continuous positive airway pressure treatment and tolerated it well. He was a former smoker with an 11-pack-year history but had quit smoking more than 30 years ago. He had been seen by his local cardiologist 6 months before the current presentation, and his echocardiogram revealed no changes from previous testsddiffuse, mild reduction in systolic function with ejection fraction of 43%, grade 1/4 left ventricular diastolic dysfunction, and no regional wall motion or valvular abnormalities. No other imaging studies were obtained at that time, and a review of systems was otherwise unremarkable.

Snare system for left ventricular lead placement in cardiac resynchronization therapy

Snare system for left ventricular lead placement in cardiac resynchronization therapy