Outcome Of Cardiac Resynchronization Therapy Research Articles

Speckle Tracking Echocardiography in Patients with Non-Ischemic Dilated Cardiomyopathy Who Undergo Cardiac Resynchronization Therapy: A Narrative Review.

Non-ischemic dilated cardiomyopathy (DCM) represents a significant cause of heart failure, defined as the presence of left ventricular (LV) dilatation and systolic dysfunction unexplained solely by abnormal loading conditions or coronary artery disease. Cardiac resynchronization therapy (CRT) has emerged as a cornerstone in the management of heart failure, particularly in patients with DCM. However, identifying patients who will benefit the most from CRT remains challenging. Speckle tracking echocardiography (STE) has garnered attention as a non-invasive imaging modality that allows for the quantitative assessment of myocardial mechanics, offering insights into LV function beyond traditional echocardiographic parameters. This comprehensive review explores the role of STE in guiding patient selection and optimizing outcomes in CRT for DCM. By assessing parameters such as LV strain, strain rate, and dyssynchrony, STE enables a more precise evaluation of myocardial function and mechanical dyssynchrony, aiding in the identification of patients who are most likely to benefit from CRT. Furthermore, STE provides valuable prognostic information and facilitates post-CRT optimization by guiding lead placement and assessing response to therapy. Through an integration of STE with CRT, clinicians can enhance patient selection, improve procedural success rates, and ultimately, optimize clinical outcomes in patients with DCM. This review underscores the pivotal role of STE in advancing personalized management strategies for DCM patients undergoing CRT.

Predicting the response to cardiac resynchronization therapy using in silico heart models: pilot study of comparison between in silico and real cardiac resynchronization therapy outcomes

Abstract Background Cardiac resynchronization therapy (CRT) is treatment for patients with heart failure and left ventricular (LV) dyssynchrony. The objective of this study is to evaluate the feasibility of an in silico electromechanical heart model to predict CRT outcomes. Methods The three-dimensional heart geometries of 11 patients (age, 64.0±10.7 years, 4 men) with CRT were constructed from cardiac computed tomography images. We coupled cardiac electrical excitation and mechanical contraction with vascular hemodynamics using a lumped parameter model. We predicted the LV end-diastolic and end-systolic volumes and LV ejection fraction (LVEF) after CRT implantation using the in silico CRT simulation model. We compared the in silico CRT outcomes with the real CRT outcomes. Results Two patients were in silico CRT responders, and those 2 patients were also real CRT responders. Nine patients were in silico CRT non-responders, 8 who were real CRT non-responders, and 1 who was a real CRT responder. The in silico CRT outcomes agreed with the real CRT outcomes in 10 of 11 patients. The positive and negative predictive values and accuracy of the in silico CRT model were 100%, 88.9%, and 90.9%, respectively. Conclusion The in silico CRT simulation model is feasible for predicting real CRT outcomes.In silico CRT simulation model generatioAn example (patient No. 2) of LV (black

Association between amount of biventricular pacing and heart failure status measured by a multisensor implantable defibrillator algorithm

Abstract Background Achieving a high biventricular pacing percentage (BiV%) is crucial for optimizing outcomes in cardiac resynchronization therapy (CRT). The HeartLogic index, a multiparametric heart failure (HF) risk score, incorporates implantable defibrillator (ICD)-measured variables and has demonstrated its predictive ability for impending HF decompensation. Purpose This study aimed to investigate the relationship between daily BiV% in CRT ICD patients and their HF status, assessed using the HeartLogic algorithm. Methods The HeartLogic algorithm was activated in 306 patients across 26 centers, with a median follow-up of 26 months (25th–75th percentile: 15-37). Results During the follow-up period, 619 HeartLogic alerts were recorded in 186 patients. Overall, daily values associated with the best clinical status (highest first heart sound, intrathoracic impedance, patient activity; lowest combined index, third heart sound, respiration rate, night heart rate) were associated with a BiV% exceeding 99%. We identified 455 instances of BiV% dropping below 98% after consistent pacing periods. Longer episodes of reduced BiV% (hazard ratio: 2.68; 95% CI: 1.02-9.72; P=0.045) and lower BiV% (hazard ratio: 3.97; 95% CI: 1.74-9.06; P=0.001) were linked to a higher risk of HeartLogic alerts. BiV% drops exceeding 7 days predicted alerts with 90% sensitivity (95% CI [74%-98%]) and 55% specificity (95% CI [51%-60%]), while BiV% ≤96% predicted alerts with 74% sensitivity (95% CI [55%-88%]) and 81% specificity (95% CI [77%-85%]). Conclusions A clear correlation was observed between reduced daily BiV% and worsening clinical conditions, as indicated by the HeartLogic index. Importantly, even minor reductions in pacing percentage and duration were associated with an increased risk of HF alerts.Time to event

Absence of late gadolinium enhancement and outcomes of cardiac resynchronization therapy in non-ischemic dilated cardiomyopathy

Abstract Background Among patients with non-ischemic dilated cardiomyopathy (DCM) with indication for cardiac resynchronization therapy (CRT), there are no clear recommendations about who should receive a CRT-defibrillator (CRT-D) and who should have CRT-pacemaker (CRT-P). Absence of late gadolinium enhancement (LGE) at cardiac magnetic resonance (CMR) has a high negative predictive value for ventricular arrhythmias (VA) and sudden death (SD) in DCM and is a predictor of reverse remodelling in several scenarios. Purpose To evaluate the association between absence of LGE and VA/SD or echocardiographic response to CRT in DCM patients treated with CRT. Methods Multicenter retrospective observational cohort study including consecutive DCM patients with de-novo CRT implant and with available CMR. The primary endpoints were: 1) a combined arrhythmic endpoint including appropriate defibrillator therapies, sustained VA and sudden death. 2) echocardiographic response to CRT, intended as an increase ≥10% in left ventricular ejection fraction (LVEF). Results We included 167 patients, 55% males, with median QRS duration of 160ms and median LVEF of 25%. LGE was present in 46% of cases (LGE+). A CRT-D was implanted in 73% of patients. Median follow-up was 63 months. Of note, among patients without LGE (LGE-) we did not record any event of the combined arrhythmic endpoint. The cumulative incidence of the arrhythmic endpoint was significantly higher in LGE+ than in LGE- patients (25% vs 0%, p<0.001) and LGE was an independent predictor of this endpoint (adjusted HR 42, p<0.001). The proportion of responders to CRT was significantly higher in LGE- than in LGE+ cases (81% vs 53%, p<0.001); absence of LGE was the strongest predictor of echocardiographic response to CRT at multivariate analysis (adjusted OR 4.1, p=0.001). Super-responders (i.e. those with LVEF≥50% at follow-up) were also more frequent among LGE- than LGE+ patients (46% vs 21%, p=0.001) and absence of LGE was an independent predictor of LVEF normalization (HR 2.6, p=0.03). Conclusions Among DCM patients who receive CRT, those without LGE have an extremely low (or null in this case) arrhythmic risk and, at the same time, they have a high probability of echocardiographic response to CRT. Thus, LGE- patients could be ideal candidates for CRT-P instead of CRT-D.

Effectiveness of dynamic atrioventricular optimization during patient exercise in cardiac resynchronization therapy

Abstract Background Cardiac resynchronization therapy (CRT) is considered the standard treatment for patients with heart failure and prolonged QRS duration. Recent studies suggest that atrioventricular delay (AVD) optimization can play a key role in QRS narrowing, thus improving CRT outcomes. For this purpose, device-based algorithms have been developed. In particular, the SyncAV algorithm continuously monitors the patient’s intrinsic AVD and dynamically adjusts the pacing AVD to allow fusion of the left ventricle pacing with intrinsic right ventricle depolarization. SyncAV optimization is usually performed in a single patient condition, i.e. at rest, and in a single operating scenario of the device, i.e. during atrial sensing. Purpose This study aims to compare QRS narrowing after AVD optimization using SyncAV in CRT-treated patients at rest, during moderate exertion, and during an increase in the atrial pacing rate. Methods This is a prospective, non-randomized, non-blinded, multicenter study. The study population consisted of patients in sinus rhythm, PR interval < 350 ms, and rest ventricular rate < 100 bpm. Within one month from the implant, patients were assessed for AVD optimization with SyncAV, selecting the offset (i.e. 10 to 40% AVD) that resulted in the shortest QRS duration (QRSd). Subsequently, patients performed moderate physical activity using a bicycle ergo-meter while a surface ECG was collected. QRSd was assessed once patients achieved a heart rate over 20 bpm to baseline heart rate, up to 100 bpm. Finally, QRSd narrowing was evaluated during a programmed increase in atrial pacing (i.e. >20 bpm of baseline atrial rate). Results Nine patients were treated with CRT and enrolled (age 67,3 ± 13,2 years; 66% male; LV ejection fraction 33,7±2,9 %; intrinsic QRSd 155,6 ± 12,7 ms) with intact atrioventricular conduction (PR interval 170,6±25,8 ms). The median SyncAV offset that provided the best QRSd reduction was 20 % (10 - 35%). Intrinsic QRSd was reduced to 132,7 ± 10,0 ms (-14,2±9,4%) with standard biventricular pacing and to 122,0 ± 11,2 ms (-21,2±8,5%) with SyncAV optimization. During exercise the mean heart rate was 88,1 bpm, the QRSd was reduced to 132,7 ± 10,0 ms (-14,2±9,4%) with standard biventricular pacing and to 124,9 ± 14,9 ms (-19,3±10,8 %) with SyncAV optimization. The mean heart rate during atrial pacing was 90 bpm with paced QRSd of 126,0 ±13,9 ms (-18,9±7,3% from baseline) with SyncAV optimization and paced PR interval of 198,2±22,7ms. Conclusion We evaluated the effectiveness of SyncAV for AVD optimization in out-of-clinic. This study demonstrates the possibility of narrowing the QRSd using SyncAV at several activity levels. Nevertheless, a deeper evaluation is needed to confirm our findings, investigating the SyncAV role in a larger population of patients.

Interaction of left ventricular size with the outcome of cardiac resynchronization therapy in Japanese patients.

We analyzed the influence of the QRS duration (QRSd) to LV end-diastolic volume (LVEDV) ratio on cardiac resynchronization therapy (CRT) outcomes in heart failure patients classified as III/IV per the New York Heart Association (NYHA) and with small body size. We proposed the hypothesis that the QRSd/LV size ratio is a better index of the CRT substrate. We enrolled 114 patients with advanced heart failure (NYHA class III/IV, and LV ejection fraction >35%) who received a CRT device, including those with left bundle branch block (LBBB) and QRSd ≥120 milliseconds (n = 60), non-LBBB and QRSd ≥150 milliseconds (n = 30) and non-LBBB and QRSd of 120-149 milliseconds (n = 24). Over a mean follow-up period of 65 ± 58 months, the incidence of the primary endpoint, a composite of all-cause death and hospitalization for heart failure, showed no significant intergroup difference (43.3% vs. 50.0% vs. 37.5%, respectively, p = .72). Similarly, among 104 patients with QRSd/LVEDV ≥ 0.67 (n = 54) and QRSd/LVEDV < 0.67 (n = 52), no significant differences were observed in the incidence of the primary endpoint (35.1% vs. 51.9%, p = .49). Nevertheless, patients with QRSd/LVEDV ≥ 0.67 showed better survival than those with QRSd/LVEDV < 0.67 (14.8% vs. 34.6%, p = .0024). Advanced HF patients with a higher QRSd/LVEDV ratio showed better survival in this small-body-size population. Thus, the risk is concentrated among those with a larger QRSd, and patients with a relatively smaller left ventricular size appeared to benefit from CRT.

CMR feature tracking–based left atrial mechanics predicts response to cardiac resynchronization therapy and adverse outcomes

BackgroundCardiac resynchronization therapy (CRT) is an established therapy for advanced heart failure (HF) with prolonged QRS duration. However, 30% of patients have shown no benefit from the treatment. ObjectiveThis study aimed to examine the value of left atrial (LA) mechanics by cardiac magnetic resonance (CMR) to predict response to CRT and clinical outcomes. MethodsA total of 163 CRT recipients with preimplantation CMR examination were retrospectively recruited. CMR feature tracking was used to evaluate LA size and function. The end points include (1) improvement of at least 5% in left ventricular ejection fraction combined with a reduction of at least 1 New York Heart Association functional class at 6-month follow-up and (2) any all-cause death or HF hospitalization during follow-up. ResultsOverall, 82 (50.3%) were CRT responders. CRT nonresponders had larger LA and worse LA reservoir and booster pump function than did responders (P < .001 for all). LA structural (maximum volume index < 47 mL/m2) and functional (booster pump strain > 8.5%) criteria were incremental to traditional indicators in detecting CRT response (χ2, 40.83 vs 9.98; P < .001). During follow-up (median 41 months), survival free from death or HF hospitalization increased with the number of positive LA criteria (log-rank, P < .001). After adjustment for clinical confounders, the absence of the 2 criteria remained associated with a considerably increased risk of death or HF hospitalization (adjusted hazard ratio 6.2; 95% confidence interval 2.15–17.88; P = .001). ConclusionThe preprocedure LA mechanics evaluated using CMR may be useful to predict response to CRT and improve risk stratification in CRT recipients.

Clinical characteristics and outcome of cardiac resynchronization therapy for heart failure in National Hospital of Sri Lanka from year 2005 to 2020 – a retrospective observational study

BackgroundCardiac resynchronization therapy (CRT) has been a well-established treatment modality for moderate to severe left ventricular systolic dysfunction with left ventricular desynchrony. This is the pioneering study that analyses the cohort who underwent CRT implantation at the National Hospital of Sri Lanka (NHSL) in Colombo from 2005 to 2020.ObjectivesThis study was carried out to describe socio-demographic factors, improvements in clinical outcome (symptoms, electrocardiographic, and echocardiographic features), and post-CRT complications in the study population, as well as to determine the efficacy of CRT in heart failure.MethodA retrospective observational study was conducted on all the living patients who had undergone CRT implantation from 2005 to 2020. The data was gathered from all the consented patients who visited the device programming clinic using a physician-administered questionnaire and clinical records. Data was analyzed using SPSS 25, and significant statistics were assessed with the McNemer test, the Student T test, and the Chi-Squared test.ResultsThe study included 50 patients with a mean age of 52.82+/− 11.66 years and female predominance (56%, n = 28). Idiopathic dilated cardiomyopathy (50%, n = 25) was the leading etiological factor, followed by ischemic cardiomyopathy (28%, n = 14). Clinical symptoms have improved significantly with CRT implantation (p < 0.001). A significant improvement was found in NYHA functional class (p < 0.001, 95% CI = 0.072 to 0.284), QRS width (p < 0.001, 95% CI = 0.229 to 0.534), ejection fraction (p < 0.001, 95% CI = − 16.437 to − 8.504), and LV EDD (p < 0.001, 95% CI = 2.89 to 9.24). Post-CRT complications included lead malfunction (6%, n = 3) and chronic (14%, n = 7), bleeding or hematoma (2%, n = 1), pocket erosion or infection (6%, n = 3), and infective endocarditis (2%, n = 1).ConclusionAccording to the study, CRT significantly improves both clinical and functional outcomes in patients with moderate to severe heart failure.

The Year in Hungarian Cardiology 2023: Arrhythmias

In 2023, Hungary produced notable scientific publications focused on cardiac arrhythmias. This review highlights the most impactful papers, authored at least in part by Hungarians, featuring work conducted at Hungarian research sites and published in international peer-reviewed journals. We give a short overview regarding papers dealing with the role of imaging (different types of ultrasound, cardiac magnetic resonance imaging and electroanatomical mapping) in treating cardiac arrhythmias. We summarize the novelties of ischemic complications of atrial fibrillation (AF), cerebral safety of AF ablation, and current AF ablation techniques. Optimizing risk stratification of ventricular tachycardia (VT) ablation was a landmark paper of our “machine learning” research. Further studies have made significant strides in cardiac device therapy, notably through the groundbreaking BUDAPEST-CRT Upgrade Trial for heart failure, which demonstrated marked reductions in deaths and hospitalizations following Cardiac Resynchronization Therapy (CRT) upgrade procedures. Research on the impact of frailty on CRT outcomes has underscored the importance of tailored treatments. Artificial intelligence, particularly topological data analysis, has been crucial in personalizing CRT therapy. Additionally, advancements in remote monitoring and lead extraction techniques have mirrored the rapid evolution of cardiac technology and care.

Kiosk 4R-TC-03 - CMR Feature Tracking-based Left Atrial Mechanics Predicts Response to Cardiac Resynchronization Therapy and Adverse Outcomes

Kiosk 4R-TC-03 - CMR Feature Tracking-based Left Atrial Mechanics Predicts Response to Cardiac Resynchronization Therapy and Adverse Outcomes

Using artificial intelligence-enabled electrocardiogram to predict cardiac resynchronization therapy outcomes of left bundle branch area pacing.

Using artificial intelligence-enabled electrocardiogram to predict cardiac resynchronization therapy outcomes of left bundle branch area pacing.

Association of vectorcardiographic T-wave area with clinical and echocardiographic outcomes in cardiac resynchronization therapy.

Data on repolarization parameters in cardiac resynchronization therapy (CRT) are scarce. We investigated the association of baseline T-wave area, with both clinical and echocardiographic outcomes of CRT in a large, multi-centre cohort of CRT recipients. Also, we evaluated the association between the baseline T-wave area and QRS area. In this retrospective study, 1355 consecutive CRT recipients were evaluated. Pre-implantation T-wave and QRS area were calculated from vectorcardiograms. Echocardiographic response was defined as a reduction of ≥15% in left ventricular end-systolic volume between 3 and 12 months after implantation. The clinical outcome was a combination of all-cause mortality, heart transplantation, and left ventricular assist device implantation. Left ventricular end-systolic volume reduction was largest in patients with QRS area ≥ 109 μVs and T-wave area ≥ 66 μVs compared with QRS area ≥ 109 μVs and T-wave area < 66 μVs (P = 0.004), QRS area < 109 μVs and T-wave area ≥ 66 μVs (P < 0.001) and QRS area < 109 μVs and T-wave area < 66 μVs (P < 0.001). Event-free survival rate was higher in the subgroup of patients with QRS area ≥ 109 μVs and T-wave area ≥ 66 μVs (n = 616, P < 0.001) and QRS area ≥ 109 μVs and T-wave area < 66 μVs (n = 100, P < 0.001) than the other subgroups. In the multivariate analysis, T-wave area remained associated with echocardiographic response (P = 0.008), but not with the clinical outcome (P = 0.143), when QRS area was included in the model. Baseline T-wave area has a significant association with both clinical and echocardiographic outcomes after CRT. The association of T-wave area with echocardiographic response is independent from QRS area; the association with clinical outcome, however, is not.

R-Rʹ interval in the left bundle branch block predicts long-term outcomes after cardiac resynchronization therapy by estimating greater mechanical dyssynchrony and viable myocardium

BackgroundTypical left bundle branch block (LBBB) shows 2 peaks of the R wave, which reflect activation reaching the interventricular septum (R) and posterolateral wall (Rʹ) sequentially. ObjectiveThe purpose of this study was to investigate the relationship among R-Rʹ interval (RRʹ), mechanical dyssynchrony, extent of viable myocardium, and long-term outcomes in cardiac resynchronization therapy (CRT) candidates. MethodsThe study enrolled 49 patients (34 men; mean age: 69 ± 11 years) with LBBB who received CRT. The LBBB definition used requires the presence of mid-QRS notching in leads V1, V2, V5, V6, I, and aVL. Baseline evaluations were QRS duration (QRSd) and RRʹ measured from the 12-lead electrocardiogram; eyeball dyssynchrony (apical rocking and septal flash) and opposing-wall delay by speckle tracking from echocardiography, and extent of viable myocardium assessed by thallium-201 single-photon emission computed tomography. Primary outcomes included the combination of all-cause death and heart failure–related hospitalization. ResultsRRʹ predicted volumetric response better than QRSd (area under the curve 0.73 vs 0.67, respectively). The long RRʹ group (≥48 ms) revealed more frequent eyeball dyssynchrony and significantly greater radial (SL) and circumferential dyssynchrony (AP and SL) and %viable segment than the short RRʹ group. In multivariate regression analysis, only RRʹ ≥48 ms was independently associated with higher event-free survival rates following CRT (hazard ratio 0.21; P = .014). ConclusionThese findings suggest that RRʹ in complete LBBB was associated with mechanical dyssynchrony, extent of viable myocardium, and long-term outcomes following CRT.

A new method using deep transfer learning on ECG to predict the response to cardiac resynchronization therapy

Background: Cardiac resynchronization therapy (CRT) has emerged as an effective treatment for heart failure patients with electrical dyssynchrony. However, accurately predicting which patients will respond to CRT remains a challenge. This study explores the application of deep transfer learning techniques to train a predictive model for CRT response. Methods: In this study, the short-time Fourier transform (STFT) technique was employed to transform ECG signals into two-dimensional images. A transfer learning approach was then applied to the MIT-BIT ECG database to pre-train a convolutional neural network (CNN) model. The model was fine-tuned to extract relevant features from the ECG images and then tested on our dataset of CRT patients to predict their response. Results: Seventy-one CRT patients were enrolled in this study. The transfer learning model achieved an accuracy of 72% in distinguishing responders from non-responders in the local dataset. Furthermore, the model showed good sensitivity (0.78) and specificity (0.79) in identifying CRT responders. The performance of our model outperformed clinic guidelines and traditional machine learning approaches. Conclusion: The utilization of ECG images as input and leveraging the power of transfer learning allows for improved accuracy in identifying CRT responders. This approach offers potential for enhancing patient selection and improving the outcomes of CRT.

Outcomes of cardiac resynchronization therapy in congenital heart disease: A meta-analysis and systematic review.

Cardiac resynchronization therapy (CRT) is a standard treatment for patients with heart failure with reduced ejection fraction. However, there is still a gap of evidence in congenital heart disease (CHD) patients regarding resynchronization therapy. We performed a meta-analysis and systematic review of CHD patients who received CRT implantation. We comprehensively searched the databases of MEDLINE, EMBASE, and Cochrane database from inception to June 2023. Studies that reported response rate to CRT, total mortality rate, change in QRS duration, change in left ventricular ejection fraction, and change in New York Heart Association functional class were included. A total of 14 studies were included in the study. There were 10 studies that reported response rates after implantation. The overall response rate to CRT in CHD patients was 68% (95% confidence interval [CI] 61%-75%, I2 32%). The response rates in patients with systemic right ventricle (RV), systemic left ventricle (LV), and single ventricle were 58% (95% CI 46%-70%, I2 0%), 80% (95% CI 74%-86% I2 14%), and 67% (95% CI 49%-80% I2 0%). Response to CRT in systemic RV was inferior to systemic LV with an odds ratio of 0.38 (95% CI 0.15-0.95, I2 38%). The total mortality rate from sevenstudies was 12% (95% CI 8%-18%, I2 55%). The parameters which represented ventricular dyssynchrony improved after CRT implantation. The overall response rate to CRT in CHD was 68%. Patients with systemic RV had a lower response rate to CRT when compared to patients with systemic LV. The total mortality rate after CRT implantation was 12%.

Techniques for Cardiac Resynchronization Therapy in Patients with Congenital Heart Disease.

Cardiac resynchronization therapy (CRT) for congenital heart disease has shown promising suucess as an adjunct to medical therapy for heart failure. While cardiac conduction defects and need for ventricular pacing are common in congential heart disease, CRT indications, techniques and long term outcomes have not been well establaished. This is a review of the techniques nad short term outcomes of CRT for the following complex congenital heart disease conditions: single ventricle physiology, systemic right ventricle, and the subpulmonic right ventricle.

Improved outcomes of cardiac resynchronization therapy with a defibrillator in systolic heart failure: Analysis of the Japan cardiac device treatment registry database

AbstractBackgroundTemporal change in outcomes of heart failure patients receiving cardiac resynchronization therapy with a defibrillator (CRT‐D) is unknown.MethodsWe assess outcomes and underlying heart diseases of patients receiving CRT‐D with analyzing database of the Japan cardiac device treatment registry (JCDTR) at the implantation year 2011–2015 and New JCDTR at the implantation year 2018–2021.ResultsProportion of nonischemic heart diseases was about 70% in both the groups (JCDTR: 69%; New JCDTR: 72%). Cardiac sarcoidosis increased with the rate of 5% in the JCDTR to 9% in the New JCDTR group. During an average follow‐up of 21 months, death from any cause occurred in 167 of 906 patients in the JCDTR group (18%) and 79 of 611 patients in the New JCDTR group (13%) (adjusted hazard ratio [aHR] in the New JCDTR group, 0.72; 95% confidence interval [CI]: 0.55–0.94; p = .017). The superiority was mainly driven by reduction in the risk of noncardiac death. With regard to appropriate and inappropriate implantable cardioverter–defibrillator (ICD) therapy, there was a significant reduction in the New JCDTR group versus the JCDTR group (aHR in the New JCDTR group, 0.76; 95% CI: 0.59–0.98; p = .032 for appropriate ICD therapy; aHR in the New JCDTR group, 0.24; 95% CI: 0.12–0.50; p &lt; .0001 for inappropriate ICD therapy).ConclusionsAll‐cause mortality was reduced in CRT‐D patients implanted during 2018–2021 compared to those during 2011–2015, with a significant reduction in noncardiac death.

A systematic review and meta-analysis of cardiac resynchronization therapy in inotrope-dependent heart failure: an update

Abstract Background Inotrope-dependent heart failure (HF) carries a poor prognosis. Advanced mechanical supports have been viewed as primary treatment modalities for these patients, but cardiac resynchronization therapy (CRT) is an emerging alternative. Whether CRT is viable in HF patients who require inotropic support is uncertain. Purpose To assess outcomes of CRT in end-stage inotrope-dependent HF. Methods Following PRISMA guidelines, we searched Medline, EMBASE, Scopus, and Cochrane Library until December 31st 2022, with the following terms: "end-stage heart failure," "catecholamine-dependent overt heart failure," "inotrope-dependent heart failure," "advanced heart failure," "New York Heart Association class IV," "NYHA class IV." These terms were combined with "cardiac resynchronization therapy" OR "CRT" OR "biventricular device". Studies were included if: 1) HF patients required on inotropic support at CRT implantation; 2) patients were at least 18 years old; and 3) provided a clear definition of "inotrope dependence" or "inability to wean." A meta-analysis with random effects was performed in R (Version 3.5.1) with data presented as mean ± standard error. Results 19 studies comprised of 386 inotrope-dependent HF patients (mean age 64.4 ± 1.2 years, 76.9% male, 54.6% non-ischemic cardiomyopathy, mean QRS duration 168.0 ± 4.6 ms, mean follow-up 778 ± 110.7 days) were included for meta-analysis. A large majority of patients survived until discharge at 90% (95% CI: 81.0%-96.8%, I2=51%, p=0.04, Figure 1A), 88.6% were weaned off inotropes (95% CI: 77.5%-96.8%, I2=64%, p&amp;lt;0.01), and mean time to discharge post-CRT was 7.8 days (95% CI: 3.9-11.7, I2= 84%, p&amp;lt;0.01). After one year of follow-up 69.5% survived (95% CI: 59.2%-78.9%, I2=53%, p=0.02, Figure 1B) and 59.1% (95% CI: 50.1%-67.8%, I2=58%, p&amp;lt;0.01, Figure 1C) were alive at the end of follow-up. During follow-up the mean number of hospital admission for HF was reduced by 1.87 (95% CI: 2.70-1.04, I2=77%, p=0.04). Post-CRT mean QRS duration was reduced by 29.0 ms (95% CI: 41.33-16.68, I2=69%, p=0.006, Fig) and mean left ventricular ejection fraction increased by 4.83% (95% CI: 3.09%-6.57%, I2=16%, p=0.31, Fig). The mean NYHA class post-CRT was 2.7 (95% CI: 2.5-3.0, I2=56%, p=0.03, Figure 2A), 39.6% (95% CI: 18,.7%-62.3%, I2=83%, p&amp;lt;0.01, Figure 2C) improved to NYHA class III and 34.6% (95% CI: 16.4%-55.2%, I2=79%, p&amp;lt;0.01, Figure 2D) improved to NYHA class II. Responders to CRT tended be male (85.7% vs. 40%, p=0.015), have a history of left bundle branch block (71.4% vs. 30%, p=0.036) or an increased left ventricular end-diastolic volume (274.3 mL vs. 225.9 mL, p=0.038). Conclusion(s) Our results suggest that CRT is an alternative option for end-stage inotrope-dependent HF, improving survival, NYHA status, and HF readmission. CRT responders appear to be male with evidence of preserved diastolic function or a history of a left bundle branch block.

Abstract 16791: Conduction System Response to Cardiac Resynchronization Therapy

Background: Cardiac resynchronization therapy (CRT) can be an effective treatment for cardiomyopathy patients with intraventricular conduction delay. However, significant controversy remains over the effect of QRS duration shortening on CRT outcomes. We hypothesize that reduction in QRS duration following CRT implantation is associated with echocardiographic outcomes. Methods: We included all adult patients with structural heart disease and CRT followed at UCLA. We reviewed all available electrocardiograms (ECG) and echocardiograms. We excluded patients with CRT for complete heart block, congenital heart disease, and those without intrinsic QRS ECGs prior to CRT. Patients were categorized as left bundle branch block (LBBB) if Strauss criteria were met prior to CRT implantation. Other patterns (including right bundle branch block with QRS duration ≥150ms) were classified as IVCD. We evaluated QRS duration before and immediately after CRT implantation. Changes in QRS duration post-CRT implant were calculated in percentage change. Echocardiograms were evaluated for changes in left ventricular end diastolic dimension (LVIDD) and ejection fraction (LVEF) following CRT implantation. Results: We included 108 patients (mean age of implant 66.1±12.8 years, 65% male, 63% nonischemic cardiomyopathy). Of these, 44 patients (41%) had LBBB. After CRT, patients with LBBB had significant decrease in QRS duration (-9.3±17.0% vs +16.9±30.9%, p &lt; 0.001), improvement in LVEF (12.1±10.5% vs 1.85±10.7%, p &lt; 0.001) and reduction in LVIDD (-0.6±0.7cm vs 0.1±0.7cm, p &lt; 0.001) compared to patients with IVCD. Decrease in QRS duration was significantly correlated with both improvement in LVEF (Pearson r = 0.21, p = 0.037) and reduction in LVIDD (Pearson r = 0.28, p = 0.006). Conclusion: CRT resulted in significantly larger decrease in QRS duration amongst patients with LBBB compared to IVCD. QRS duration reduction was, in turn, significantly correlated with improvements in LVIDD and LVEF. This likely reflects the proximal nature of true LBBB, and the ability of CRT to utilize the remaining distal Purkinje system for impulse propagation. Further research on the electrical and mechanical response to CRT can help guide optimization of target populations.

Cardiac CT in CRT as a Singular Imaging Modality for Diagnosis and Patient-Tailored Management.

Between 30-40% of patients with cardiac resynchronization therapy (CRT) do not show an improvement in left ventricular (LV) function. It is generally known that patient selection, LV lead implantation location, and device timing optimization are the three main factors that determine CRT response. Research has shown that image-guided CRT placement, which takes into account both anatomical and functional cardiac properties, positively affects the CRT response rate. In current clinical practice, a multimodality imaging approach comprised of echocardiography, cardiac magnetic resonance imaging, or nuclear medicine imaging is used to capture these features. However, with cardiac computed tomography (CT), one has an all-in-one acquisition method for both patient selection and the division of a patient-tailored, image-guided CRT placement strategy. This review discusses the applicability of CT in CRT patient identification, selection, and guided placement, offering insights into potential advancements in optimizing CRT outcomes.