Underwent Cardiac Resynchronization Therapy Device Research Articles

The Loop Technique in Cardiac Resynchronization Therapy: A Prospective Cohort Study.

A new approach called the loop technique has been proven safe and effective for repeated intraoperative transvenous left ventricular (LV) lead dislocations during cardiac resynchronization therapy (CRT) in a 3-year follow-up. This study aimed to report on the 5-year safety and effectiveness of the loop technique. This study was a prospective cohort study. Forty-four patients who underwent CRT device implantation at the Cardiology Department of Shaanxi Provincial People's Hospital between January 2013 and June 2019 were included. Data on patient demographics, medical history, laboratory test results, and echocardiography images at admission were collected. The loop technique was performed with repeated intraoperative dislocations of the LV lead. The intraoperative CRT parameters were also recorded. All patients were followed for 5 years. Several auxiliary examinations were performed during follow-up. The 44 patients were divided into the traditional operation group (n=36, 81.8%) and loop technique group (n=8, 18.2%). The baseline patient characteristics were almost balanced. During the 5-year follow-up, 8 (22.2%) patients in the traditional operation group and 2 (25.0%) patients in the loop technique group died. No lead dislocation or other complications related to CRT were observed. There were no significant differences in mortality rate (P=0.87), cardiac function (P=0.56), echocardiographic indices, threshold (P=0.58), or impedance (P=0.22) of the LV lead. There were no significant differences in the threshold and impedance between postoperative, 3-year, and 5-year follow-ups in the loop technique group (P=0.53). The loop technique is an ideal solution for repeated intraoperative LV lead dislocation during CRT implantation.

Dual versus conventional cardiac resynchronization: A pilot study

Background: Systolic heart failure treatment now includes cardiac resynchronization therapy (CRT) as a necessary element. CRT has been shown to have advantageous impacts on mortality, hospitalization rates, and quality of life. Approximately 30% of patients fail to respond to traditional CRT implantation. Aims and Objectives: This study aimed to compare the outcome of dual resynchronization by placing the right ventricular pacing lead at His bundle or left bundle branch area against conventional CRT. Materials and Methods: This longitudinal follow-up study of a total of 35 patients undergoing CRT device placement for assessment of safety, efficacy, and feasibility of the procedure and post-procedural complications and correlation with parameters obtained from electrocardiogram and echocardiography parameters in a tertiary care set up in India. Results: Among this matched population (mean age 64 years) there was a higher responder rate with the newer technique of dual resynchronization compared to conventional CRT (83% vs. 70%). Conclusion: Dual resynchronization therapy is feasible and safe and provides better electrical resynchronization compared to conventional CRT and could be a better alternative, especially when suboptimal electrical resynchronization is obtained.

Usefulness of Decapolar catheter via femoral approach on CS cannulation during CRT device implantation.

IntroductionCardiac resynchronization therapy (CRT) device insertion comprises of a transvenous pacing lead implanted in posterolateral branch of the coronary sinus (CS) for left ventricular (LV) pacing, in addition to leads in the right ventricle and right atrium. In patients undergoing CRT device implantation, failure of CS cannulation was earlier reported to be around 10% but has come down to about 4% in recent years. Although the use of electrophysiology (EP) catheter has been reported during CRT procedures but femoral approach to place decapolar catheter as fluoroscopic guide for CS ostium cannulation during LV lead implantation has not been evaluated.Materials and methodsThe aim of the study was to compare fluoroscopy time during CRT procedure between conventional technique and using decapolar EP catheter via femoral approach as fluoroscopic marker to cannulate CS.ResultsThis study included 21 patients. Group 1 (using decapolar catheter) had 12 patients and group 2 (using the conventional technique) had 9 patients. CS cannulation was successful in all 21 cases. The mean fluoroscopy time for the CS cannulation and LV lead placement in group 1 was 10.7 (±1.03) min and in group 2 was 19.1 (±1.51) min. This difference in mean fluoroscopy time for the CS cannulation and LV lead placement was statistically significant with p < .05.ConclusionThis study highlights the usefulness of decapolar catheter via femoral approach as a fluoroscopic guide for CS cannulation during CRT device implantation. The decreased fluoroscopic time results in decreased radiation exposure to not only the patient but also to the operator.

Clinical significance of the albumin-bilirubin score in patients with heart failure undergoing cardiac resynchronization therapy.

Despite emerging recognition of interactions between heart failure (HF) and liver dysfunction, the impact of cardiac hepatopathy on patients with HF undergoing cardiac resynchronization therapy (CRT) has not been fully elucidated. Albumin-bilirubin (ALBI) score is a new assessment of liver function. The relationship between liver dysfunction severity based on ALBI score and clinical outcomes of patients with HF receiving CRT is unclear. Clinical records of 274 patients who underwent CRT device implantation between March 2003 and October 2020 were retrospectively investigated. ALBI score was calculated based on serum albumin and total bilirubin levels obtained before CRT device implantation. Patients were divided into three groups based on ALBI score: first tertile (ALBI ≤ - 2.62, n = 91)), second tertile (- 2.62 < ALBI < - 2.13, n = 92), and third tertile (ALBI ≥ - 2.13, n = 91). The study endpoint was all-cause mortality. The third tertile group had more advanced NYHA functional class, lower hemoglobin levels, and higher total bilirubin, aspartate aminotransferase, γ-glutamyl transferase, and N-terminal Pro-B-type natriuretic peptide levels (all p < 0.05). The third tertile group also had a higher prevalence of moderate or severe tricuspid regurgitation and higher tricuspid regurgitation pressure gradient (all p < 0.05). CRT response rates were significantly lower in the third tertile group. During a median (interquartile range) follow-up of 30 (9-60) months, 104 (37.9%) patients died. The third tertile group had significantly higher rates of all-cause mortality (log-rank p < 0.001). Higher ALBI score was significantly associated with all-cause mortality, even after adjusting for clinically relevant factors, a conventional validated risk score, and echocardiographic parameters related to right HF (all p < 0.01). Higher ALBI score before CRT device implantation is associated with HF severity, hepatic congestion and impairment due to right HF, lower CRT response, and higher all-cause mortality in CRT recipients.

Impact of adaptive cardiac resynchronization therapy in patients with systolic heart failure: Beyond QRS duration and morphology

BackgroundMechanical and electrical restoration by cardiac resynchronization therapy (CRT) with adaptive pacing algorithm (aCRT) in heart failure patients with a moderately wide (120–149 ms) QRS has not been fully evaluated. The purpose of this study was to investigate the therapeutic effect of aCRT compared with conventional biventricular CRT (BiV-CRT) regardless of QRS morphology. MethodsSeventeen consecutive patients with a QRS ≥120 ms, regardless of morphology, underwent CRT device implantation with an aCRT pacing algorithm. Propensity score matched analysis was performed to evaluate the impact of aCRT on the improvement in mechanical and electrical parameters after CRT device implantation using historical controls (HC) from the clinical registry of BiV-CRT (START trial). ResultsLeft ventricular (LV) volume significantly decreased after CRT in all patients in both the aCRT and HC groups. The difference in relative reduction of LV end-systolic volume (LVESV) was not significantly different between the 2 arms. QRS shortening after CRT was significantly greater in the aCRT group than in the BiV-CRT group, and the difference was prominent in patients with a moderately wide QRS (120–149 ms). In patients with a moderately wide QRS, the relative reduction in LVESV [39 (29–47)% vs. 2 (−6–20)%, p = 0.04] and proportion of LV volume responders (90% vs. 38%, p = 0.04) were significantly greater in the aCRT group than in the HC group. The proportion of volume responders was not significantly different in patients with a wide QRS (≥150 ms). ConclusionsThe aCRT algorithm improved electrical and mechanical parameters in patients with a moderately wide QRS, regardless of QRS morphology.

Machine Learning Prediction of Cardiac Resynchronisation Therapy Response From Combination of Clinical and Model-Driven Data.

Background: Up to 30–50% of chronic heart failure patients who underwent cardiac resynchronization therapy (CRT) do not respond to the treatment. Therefore, patient stratification for CRT and optimization of CRT device settings remain a challenge.Objective: The main goal of our study is to develop a predictive model of CRT outcome using a combination of clinical data recorded in patients before CRT and simulations of the response to biventricular (BiV) pacing in personalized computational models of the cardiac electrophysiology.Materials and Methods: Retrospective data from 57 patients who underwent CRT device implantation was utilized. Positive response to CRT was defined by a 10% increase in the left ventricular ejection fraction in a year after implantation. For each patient, an anatomical model of the heart and torso was reconstructed from MRI and CT images and tailored to ECG recorded in the participant. The models were used to compute ventricular activation time, ECG duration and electrical dyssynchrony indices during intrinsic rhythm and BiV pacing from the sites of implanted leads. For building a predictive model of CRT response, we used clinical data recorded before CRT device implantation together with model-derived biomarkers of ventricular excitation in the left bundle branch block mode of activation and under BiV stimulation. Several Machine Learning (ML) classifiers and feature selection algorithms were tested on the hybrid dataset, and the quality of predictors was assessed using the area under receiver operating curve (ROC AUC). The classifiers on the hybrid data were compared with ML models built on clinical data only.Results: The best ML classifier utilizing a hybrid set of clinical and model-driven data demonstrated ROC AUC of 0.82, an accuracy of 0.82, sensitivity of 0.85, and specificity of 0.78, improving quality over that of ML predictors built on clinical data from much larger datasets by more than 0.1. Distance from the LV pacing site to the post-infarction zone and ventricular activation characteristics under BiV pacing were shown as the most relevant model-driven features for CRT response classification.Conclusion: Our results suggest that combination of clinical and model-driven data increases the accuracy of classification models for CRT outcomes.

Monocyte Subsets in Patients with Chronic Heart Failure Treated with Cardiac Resynchronization Therapy.

Background: The exact role of individual inflammatory factor in heart failure with reduced ejection fraction (HFrEF) remains elusive. The study aimed to evaluate three monocyte subsets (classical-CD14++CD16−, intermediate-CD14++CD16+, and nonclassical-CD14+CD16++) in HFrEF patients and to assess the effect of the cardiac resynchronization therapy (CRT) on the changes in monocyte compartment. Methods: The study included 85 patients with stable HFrEF. Twenty-five of them underwent CRT device implantation with subsequent 6-month assessment. The control group consisted of 23 volunteers without HFrEF. Results: The analysis revealed that frequencies of non-classical-CD14+CD16++ monocytes were lower in HFrEF patients compared to the control group (6.98 IQR: 4.95–8.65 vs. 8.37 IQR: 6.47–9.94; p = 0.021), while CD14++CD16+ and CD14++CD16− did not differ. The analysis effect of CRT on the frequency of analysed monocyte subsets 6 months after CRT device implantation showed a significant increase in CD14+CD16++ (from 7 IQR: 4.5–8.4 to 7.9 IQR: 6.5–9.5; p = 0.042) and CD14++CD16+ (from 5.1 IQR: 3.7–6.5 to 6.8 IQR: 5.4–7.4; p = 0.017) monocytes, while the frequency of steady-state CD14++CD16− monocytes was decreased (from 81.4 IQR: 78–86.2 to 78.2 IQR: 76.1–81.7; p = 0.003). Conclusions: HFrEF patients present altered monocyte composition. CRT-related changes in the monocyte compartment achieve levels observed in controls without HFrEF.

Relationship of Mechanical Dyssynchrony and LV Remodeling With Improvement of Mitral Regurgitation After CRT

ObjectivesThe aim of this study was to explore the association between mechanical dyssynchrony of the left ventricle before cardiac resynchronization therapy (CRT) and improvement of mitral regurgitation (MR) after CRT. BackgroundMR is very frequent among patients with dilated cardiomyopathy and conduction delay. MethodsEchocardiograms (pre-CRT and 12 ± 3.8 months thereafter) of 314 patients with dilated cardiomyopathy and any degree of MR, who underwent CRT device implantation according to guidelines, were analyzed. Left ventricular (LV) mechanical dyssynchrony was assessed by apical rocking (ApRock) and septal flash (SF), while MR severity was graded from I to IV on the basis of vena contracta width, regurgitation jet size, and proximal isovelocity surface area. ResultsAt baseline, 30% of patients presented with severe MR (grade III or IV). In 62% of patients, MR decreased after CRT, and these patients more frequently had left bundle branch block, had more severe MR, had more dilated left ventricles, had lower ejection fractions, and more often had ApRock and SF. Reverse remodeling was more frequent among patients with MR reduction (ΔLV end-systolic volume −35.5% ± 27.2% vs −4.1% ± 33.2%; P < 0.001). In a multivariable logistic stepwise regression, only ApRock (odds ratio [OR]: 3.8; 95% CI: 1.7-8.5; P = 0.001), SF (OR: 3.6; 95% CI: 1.6-7.9; P = 0.002), and baseline MR (OR: 1.4; 95% CI: 1.0-1.9; P = 0.046) remained significantly associated with MR reduction. ConclusionsApRock, SF, and severity of MR at baseline are strongly associated with MR reduction after CRT, while LV reverse remodeling is its underlying mechanism. Therefore, in patients with heart failure with LV dyssynchrony on optimal medical treatment, CRT should be the primary treatment attempt for relevant MR.

Predicting CRT outcome by combining markers from personalized ventricular models of electrophysiology and clinical data

Abstract Introduction Up to 30% of chronic heart failure (CHF) patients undergoing cardiac resynchronization therapy (CRT) do not respond to the treatment. Low CRT response can be associated with incorrect pacing lead positioning in ventricles and not accounting for individual structural changes in myocardium. Therefore, patient stratification for CRT, operation planning and optimization of CRT device settings remain a challenge. Purpose In this study, we develop a predictive model of CRT outcomes based on a combination of clinical data recorded in patients before CRT and on simulations of the response to biventricular pacing in personalized computational models of the ventricles. Methods We used retrospective data from 27 CHF patients who underwent CRT device implantation. CRT responders were defined using clinical data in a year after therapy as showing a decrease in the end-systolic volume of the left ventricle (LV) and an increase in the ejection fraction. For each patient, an anatomical model of the heart and torso was reconstructed from CT images and used to compute ventricular activation and ECGs without pacing and under bi-ventricular pacing with various locations of stimulating leads. For building a predictive model of patient response to CRT, we used clinical data before CRT (12 features in total per patient) together with model-derived biomarkers under biventricular pacing with clinical lead position (16 features in total per a model). Using nested stratified cross-validation, logistic regression models were fitted to various combinations of datasets. Results The best classifier using a complete set of clinical and simulation data showed an average accuracy = 0.78, ROC AUC = 0.78, sensitivity = 0.75, specificity = 0.8, that were much higher than in the model built on the clinical data only. When the best model was fitted to all data on biventricular pacing with clinical lead position, all ten clinical non-responders were truly classified by the model (Fig. 1, left). Using simulations with optimal lead location as input data for this model, seven out of the ten patients were predicted as responders (Fig. 1, right). Blue and orange colours indicate clinical responders and non-responders. Red circles and numbers mark some clinical non-responding patients that are predicted as responders using optimal TAT values. Conclusion Our pilot results show that combination of clinical and simulation data significantly increases the accuracy of classification models for CRT outcomes. Our results suggest that model predictions on the optimal ventricular lead location may essentially increase the probability of CRT success. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Russian Science Foundation Figure 1

Full blood count as potential predictor of outcomes in patients undergoing cardiac resynchronization therapy

Almost a third of patients fulfilling current guidelines criteria have suboptimal responses following cardiac resynchronization therapy (CRT). Circulating biomarkers may help identify these patients. We aimed to assess the predictive role of full blood count (FBC) parameters in prognosis of heart failure (HF) patients undergoing CRT device implantation. We enrolled 612 consecutive CRT patients and FBC was measured within 24 hours prior to implantation. The follow-up period was a median of 1652 days (IQR: 837–2612). The study endpoints were i) composite of all-cause mortality or transplant, and ii) reverse left ventricular (LV) remodeling. On multivariate analysis [hazard ratio (HR), 95% confidence interval (CI)] only red cell count (RCC) (p = 0.004), red cell distribution width (RDW) (p < 0.001), percentage of lymphocytes (p = 0.03) and platelet count (p < 0.001) predicted all-cause mortality. Interestingly, RDW (p = 0.004) and platelet count (p = 0.008) were independent predictors of reverse LV remodeling. This is the first powered single-centre study to demonstrate that RDW and platelet count are independent predictors of long-term all-cause mortality and/or heart transplant in CRT patients. Further studies, on the role of these parameters in enhancing patient selection for CRT implantation should be conducted to confirm our findings.

Abstract 179: Cardiac Resynchronization Therapy among Cancer Patients in the United States: Results from National Inpatient Sample

Background: Studies have shown that implantation of cardiac resynchronization therapy (CRT) devices could reduce morbidity and mortality in heart failure patients. Aims of this study are to examine the temporal trends and outcomes in CRT device implanted cancer survivors. Method: This study was a retrospective analysis of Nationwide Inpatient Sample during the period 2005-2014. Patients ≥18 years and who underwent CRT device implantation were included in the study. CCS codes 11-44 were used to identify cancer survivors. The International Classification of Diseases-9th Revision-Clinical Modification (ICD-9-CM) primary procedure codes 00.50 and 00.51 were used to identify patients with device implantation. Association between cancer diagnosis and in-hospital mortality and complications were determined using multivariable analyses. Result: During 2005 to 2014, a total of 392,758 inpatient CRT implantations were performed in the United States. Nearly 8.3% of these procedures were performed among patients with history of cancer. Number of procedures among cancer survivors decreased from 3127 in 2005 to 2115 in 2015. However, proportion of cancer patients undergoing CRT implantations increased from 6.8% in 2005 to 10.3% in 2014 (relative increase: 51.4%, P &lt;0.001). Overall in-hospital mortality was higher among cancer survivors (odds ratio (OR) 1.44, 95% confidence interval (95% CI) 1.01-2.10), compared to patients without a history of cancer. In addition, pericardial complications (OR 3.11, 95% CI 1.15-8.44), and vascular complications (OR 2.53, 95% CI 1.43-3.56) were observed more among cancer survivors. Discussion: Our study found that proportion of CRT implantations among cancer survivors increased from 6.8% to 10.3% during the study period. In addition, CRT implantations among cancer survivors were associated higher in-hospital complications. Strategies like prehabilitation and close collaboration between cardiologists and oncologists could improve outcome and general well-being of cancer survivors undergoing CRT implantations.

Cardiac resynchronization therapy-induced acute shortening of QRS duration predicts long-term mortality only in patients with left bundle branch block.

QRS narrowing with initiation of biventricular pacing might be an acute electrocardiographic indicator of correction of left bundle branch block (LBBB)-induced depolarization delay and asynchrony. However, its impact on prognosis remains controversial, especially in non-LBBB patients. Our goal was to evaluate the impact of QRS narrowing on long-term mortality and morbidity in a large cohort of patients undergoing cardiac resynchronization therapy (CRT) with different pre-implantation QRS types: LBBB, non-LBBB, and permanent right ventricular pacing. This study included consecutive patients who underwent CRT device implantation. Study endpoints: death from any cause or urgent heart transplantation and death from any cause/urgent heart transplantation or hospital admission for heart failure. All pre- and post-implantation electrocardiograms were analysed using digital callipers, high-amplitude augmentation, 100 mm/s paper speed, and global QRS duration measurement method. A total of 552 CRT patients entered the survival analysis. During the 9 years observation period, 232 (42.0%) and 292 (52.9%) patients met primary and secondary endpoints, respectively. QRS narrowing predicted survival in the Kaplan-Meier analysis only in patients with LBBB. Multivariate Cox regression model showed that QRS narrowing was the major determinant of both study endpoints, with hazard ratios of 0.46 and 0.43, respectively. There was a strong relationship between mortality risk and shortening/widening of the QRS, albeit only in the LBBB group. Patients with non-LBBB morphologies had unfavourable prognosis similar to that in LBBB patients without QRS narrowing. Acute QRS narrowing in patients with LBBB might be a desirable endpoint of CRT device implantation.

Three-dimensional interlead distance predicts response and outcomes after cardiac resynchronization therapy

Approximately one-third of patients do not respond favourably to cardiac resynchronization therapy (CRT). A longer distance between ventricular leads may improve response. To study the impact of the true three-dimensional interlead distance (ILD) on outcomes. Consecutive patients undergoing CRT device implantation were included prospectively. Interlead separation was measured from postprocedural anterior-posterior and lateral chest X-rays. The three-dimensional ILD was calculated using the Pythagorean theorem. Response to CRT was defined using a composite clinical score at 6 months. Forty-two patients were included (mean age 70±9 years; QRS duration 154±31ms; left ventricular ejection fraction 26±7%; 50% ischaemic). At 6 months, 71% of patients were considered to be responders. Responders had a significantly longer ILD (108±17 vs. 87±21mm; P=0.002). When the ILD was corrected for cardiac size, the optimal cut-off value was ≥ 0.53 for predicting response (sensitivity 83%, specificity 75%, area under the curve 0.84; P=0.0002). Similar results were obtained in a historical retrospective cohort. The use of proximal electrodes on the left ventricular lead was associated with a longer ILD in 95% of patients, compared with more distal pacing configurations. In the total cohort of 74 patients (median follow-up, 420 days), those with an indexed ILD ≥ 0.53 had a 70% reduction in risk of hospitalization for heart failure (P=0.004). Longer three-dimensional ILD corrected for cardiac size measured on chest radiographs can accurately predict response to CRT and outcomes. This simple variable may be used to identify optimal lead placement and pacing configuration during CRT implantation.

Prognosis associated with redo cardiac resynchronization therapy following complete device and lead extraction due to device-related infection.

An increase in the number of cardiac resynchronization therapy (CRT) device implantations worldwide has led to a consequent increase in the number of infections associated with the device, making extraction of the CRT device inevitable. Redo CRT implantation after treatment and recovery following device extraction is challenging. This study aimed to evaluate the success rate, complications, and long-term prognosis of redo CRT implantation, including the rates of subclavian, cava, and coronary sinus (CS) vein thrombosis as well as re-infection. Between 2007 and 2014, 1712 lead extractions were performed in 537 patients with device-related infection at Heart Center Brandenburg. Of the 537 patients, 125 (23%) underwent CRT device and lead extraction, including extraction of the left ventricular lead from the coronary sinus. Of these 125, 62 (50%) patients underwent redo CRT implantation (mean age, 68 ± 10 years); 34 patients had coronary artery disease (CAD) while 28 had dilated cardiomyopathy (DCM). The mean left ventricular ejection fraction was 27% ± 7%. The mean QRS duration of the left bundle branch block was 158 (range, 147-162) ms, and 25 patients had atrial fibrillation (AF). All these patients were followed up for a median duration of 29.6 (range, 15-43) months. In 53 of the 62 patients (85%), the CRT system was successfully re-implanted; however, the original CS vein could be used again only in 28 (45%) patients. The all-cause mortality rate was 7.1% after 1 year, and it was significantly higher in patients whose N-terminal pro B-type natriuretic peptide level was ≥3,000 pg/mL (P < 0.001), those who were aged ≥64 years (P = 0.028), those who had CAD (P = 0.042) or chronic kidney insufficiency (P = 0.001), those with AF (P = 0.001) and those whose blood cultures were positive for Staphylococcus aureus (P = 0.014). Redo CRT implantation after device extraction owing to device-related infection has a low success rate and shows a higher rate of re-infection than that observed in patients who undergo CRT implantation for the first time. Further, patients whose blood cultures are positive for S. aureus show a particularly poor outcome.

Safety of continuing warfarin therapy in patients undergoing cardiac resynchronization therapy device implantation

Background: Continuing warfarin therapy is considered safe for patient undergoing pacemaker or implantable cardioverter defibrillator procedures, but less evidence exists for patients undergoing cardiac resynchronization therapy (CRT) device implantation. Subjects and Methods: We retrospectively evaluated 136 consecutive patients who received a CRT device. Three periprocedural anticoagulation strategies were utilized: Group 1, continuation of therapeutic warfarin; Group 2, cessation of warfarin with heparin bridging; and Group 3, cessation of anticoagulation temporarily. Groups were compared on the incidence of complications. Results: Of the 136 patients, 87 (64%) were in Group 1, 18 (13%) were in Group 2, and 31 (23%) were in Group 3. Group 1 patients had an international normalized ratio of 2.3 ± 0.5, which was significantly higher than the other two groups. Coronary sinus dissection occurred in four patients: Three in Group 1 and one in Group 2, but no patient experienced pericardial effusion or tamponade. Group 2 experienced a higher incidence of pocket hematoma (P = 0.0065) and a longer length of hospital stay (P = 0.0069) than Group 1. Transient ischemic attack occurred in one patient in Group 3. Conclusion: Continuing warfarin with therapeutic international normalized ratio seems to be safe in individuals undergoing CRT device implantation.

136-48: Unfavourable outcome after the upgrade of an implantable cardioverter defibrillator to cardiac resynchronization therapy

Background: Cardiac resynchronization therapy (CRT) improves survival in selected patients with heart failure (HF). As the potential survival benefit of CRT performed as an upgrade from a previously implanted cardioverter defibrillator (ICD) has not been explored, we evaluated total mortality after CRT upgrade in this context. Methods and results: A total of 31 patients (27 male, mean age:63.7 ± 9.6years) with structural heart disease underwent CRT device implantation as an upgrade of a previously implanted single or dual chamber ICD between 2004 and 2015 at our Institute. The indication for ICD implantation was prophylactic based on the MADIT II or SCD-HeFT criteria (in 13 patients) or secondary prevention after a sustained ventricular arrhythmia (in 18 patients). Mean left ventricular ejection fraction (LVEF) was 29.9 ± 7.8% and mean NYHA status was 2.4 ± 0.8 at the time of ICD implantation. No indication for CRT was present in any of these patients at the time of ICD implantation. CRT upgrade was performed after a mean follow-up of 3.9 ± 2.9 years based on the following indications: widening of the QRS complex (from 108 ± 20 to 158 ± 24 msec.) in 24, decreasing LVEF (from 41.5 ± 2.1 to 26.5 ± 2.1%) in the presence of LBBB in 2, and an increase in the need for right ventricular stimulation (burden >40%) in 5 patients. A significant reduction in the QRS width after CRT upgrade (from 160.3 ± 26 to 130.3 ± 23 msec., p < 0.001), an improvement in NYHA class (from 3.1 ± 0.8 to 2.5 ± 1.0, p = 0.16) and an increase in the mean LVEF (from 27.6 to 33.3%, p = 0.049) was observed including 4 patients (13%) who demonstrated an increase in LVEF above 10 % at the 1-year follow-up. 17/31 patients (55%) died during a mean follow-up of 19.0 ± 16.6 months after CRT upgrade. No statistically significant prognostic factor of survival was found among the patients' baseline data by using the Cox proportional hazard model.

Interleukin-6 signaling in patients with chronic heart failure treated with cardiac resynchronization therapy.

IntroductionIncreased expression of interleukin-6 (IL-6) has been described in left ventricular dysfunction in the course of chronic heart failure. Cardiac resynchronization therapy (CRT) is a unique treatment method that may reverse the course of chronic heart failure (CHF) with reduced ejection fraction (HF-REF). We aimed to evaluate the IL-6 system, including soluble IL-6 receptor (sIL-6R) and soluble glycoprotein 130 (sgp130), in HF-REF patients, with particular emphasis on CRT effects.Material and methodsThe study enrolled 88 stable HF-REF patients (63.6 ±11.1 years, 12 females, EF < 35%) and 35 comorbidity-matched controls (63.5 ±9.8 years, 7 females). Forty-five HF-REF patients underwent CRT device implantation and were followed up after 6 months. Serum concentrations of IL-6, sIL-6R and sgp130 were determined using ELISA kits.ResultsThe HF-REF patients had higher IL-6 (median: 2.6, IQR: 1.6–3.8 vs. 2.1, IQR: 1.4–3.1 pg/ml, p = 0.03) and lower sIL-6R concentrations compared to controls (median: 51, IQR: 36–64 vs. 53. IQR 44–76 ng/ml, p = 0.008). There was no significant difference between sgp130 concentrations. In the HF-REF group IL-6 correlated negatively with EF (r = –0.5, p = 0.001) and positively with BNP (r = 0.5, p = 0.008) and CRP concentrations (r = 0.4, p = 0.02). Patients who presented a positive response after CRT showed a smaller change of sIL-6R concentration compared to nonresponders (ΔsIL-6R: –0.2 ±7.1 vs. 7 ±14 ng/ml; p = 0.04).ConclusionsHF-REF patients present higher IL-6 and lower sIL-6R levels. IL-6 concentration reflects their clinical status. CRT-related improvement of patients’ functional status is associated with a smaller change of sIL-6R concentration in time.

Electrocardiographic correlates of mechanical dyssynchrony in recipients of cardiac resynchronization therapy devices

The relationship between electrical and mechanical indices of cardiac dyssynchronization in systolic heart failure (HF) remains poorly understood. We examined retrospectively this relationship by using the daily practice tools in cardiology in recipients of cardiac resynchronization therapy (CRT) systems. We studied 119 consecutive patients in sinus rhythm and QRS ≥ 120 ms (mean: 160 ± 17 ms) undergoing CRT device implantation. P wave duration, PR, ePR (end of P wave to QRS onset), QT, RR-QT, JT and QRS axis and morphology were putative predictors of atrioventricular (diastolic filling time [DFT]/RR), interventricular mechanical dyssynchrony (IVMD) and left intraventricular mechanical dyssynchrony (left ventricular pre-ejection interval [PEI] and other measures) assessed by transthoracic echocardiography (TTE). Correlations between TTE and electrocardiographic measurements were examined by linear regression. Statistically significant but relatively weak correlations were found between heart rate (r=-0.5), JT (r=0.3), QT (r=0.3), RR-QT intervals (r=0.5) and DFT/RR, though not with PR and QRS intervals. Weak correlations were found between: (a) QRS (r=0.3) and QT interval (r=0.3) and (b) IVMD > 40 ms; and between (a) ePR (r=-0.2), QRS (r=0.4), QT interval (r=0.3) and (b) LVPEI, though not with other indices of intraventricular dyssynchrony. The correlations between electrical and the evaluated mechanical indices of cardiac dyssynchrony were generally weak in heart failure candidates for CRT. These data may help to explain the discordance between electrocardiographic and echocardiographic criteria of ventricular dyssynchrony in predicting the effect of CRT.

Comprehensive cardiac resynchronization therapy optimization in the real world

Cardiac resynchronization therapy (CRT) reduces morbidity and mortality in patients suffering from chronic heart failure (CHF). Optimal device programming is crucial for maximum patient benefit. The goal of the present study was to assess device settings from CHF patients undergoing CRT optimization in a "real world" setting, and to delineate parameters most frequently requiring adjustment. All patients who underwent CRT device implantation in the Cardiology Clinicat the University Hospital Zurich between January 2011 and September 2012 and in whom follow-up was available were included in this analysis. A total of 170 CHF patients were included in this analysis. True biventricular pacing was present in 44% of all patients, while QRS fusion was detected in 49.9%. The majority of the patients presented with suboptimal atrioventricular (AV) delays requiring adjustment. AV delays were therefore shortened due to the presence of QRS fusion in 53.3% and 38.1% of patients (sAV and pAV, respectively) or prolonged because of truncation of the A wave in the left ventricular inflow pulse wave Doppler measurement (17.5% and 28.4% for sAV and pAV, respectively). In contrast, interventricular delay (VV delay) was rarely changed (11.9%). In our "real world" cohort, a substantial proportion of patients presented to their first post-operative consultation with suboptimal device settings. Our data indicate that the opportunity to optimize device settings is frequently wasted in the "real world", underlining the necessity for expert device follow-up to deliver optimal care to this challenging group of heart failure patients.

Predictors for cardiac resynchronization therapy response: the importance of QRS morphology and left ventricular lead position.

Although cardiac resynchronization therapy (CRT) is a well-established treatment for a subset of patients with chronic heart failure, a considerable proportion of eligible patients still fail to benefit from this treatment. The aim of this study was to identify potential independent predictors for being a responder to CRT. A single-center, retrospective analysis was conducted in 193 consecutive patients with heart failure and wide QRS complex who successfully underwent CRT device implantation from January 2006 to October 2012. Clinical characteristics, left ventricular lead position (LV-Ps), electrocardiography and echocardiography were evaluated before and 12 months after CRT. Response to CRT was defined as an absolute increase of ≥ 5% in left ventricular ejection fraction (LVEF) compared with baseline at 12 months after CRT implantation without heart failure rehospitalization or any cause of death. There were 132 responders (68%) and 61 nonresponders (32%). By univariate logistic analysis, the presence of non-left bundle branch block (non-LBBB) and QRS duration, chronic atrial fibrillation (AF), history of ventricular tachycardia (VT), degree of tricuspid regurgitation and left atrium dimension (LAD) at baseline, ΔQRS duration, and LV-Ps were associated with predicting a response to CRT. However, on multivariate analysis, only optimal LV-Ps and presence of non-LBBB remained independently predictive for a CRT response, with an odds ratio of 2.53 (95% confidence interval [CI]: 1.13-5.66, P = 0.023), 0.15(95% CI: 0.05-0.45, P = 0.001), respectively. Kaplan-Meier analysis revealed that patients with nonoptimal LV-Ps or non-LBBB morphology had a significantly higher rate of mortality or heart failure rehospitalization as compared with those with optimal LV-Ps or LBBB morphology (P < 0.05).