Timing of cardiac resynchronization therapy implantation

Cardiac rhythm devices in heart failure with reduced ejection fraction - role, timing, and optimal use in contemporary practice. European Journal of Heart Failure expert consensus document

Guidelines for management of heart failure with reduced ejection fraction (HFrEF) emphasize personalized care, patient engagement, and shared decision-making. Medications and cardiac rhythm management (CRM) devices are recommended with a high level of evidence. However, there are significant disparities: patients who could benefit from devices are frequently referred too late or not at all. Misconceptions about device therapy and the notion that the needs of patients (especially the prevention of sudden cardiac death) can now be met by expanding drug therapies may play a role in these disparities. This state-of-the-art review is produced by members of the DIRECT HF initiative, a patient-centred, expert-led educational programme that aims to advance guideline-directed use of CRM devices in patients with HFrEF. This review discusses the latest evidence on the role of CRM devices in reducing HFrEF mortality and morbidity, and provides practical guidance on patient referral, device selection, implant timing and patient-centred follow-up.

Evolving Indications, Challenges, and Advances in Cardiac Resynchronization Therapy for Heart Failure

Cardiac resynchronization therapy (CRT) via biventricular pacing has markedly improved heart failure outcomes over the past two decades. However, some patients show no clinical improvement or evidence of reverse remodeling following device implantation. Challenges include suboptimal patient selection, limitations in the characterization of conduction disease (especially nonspecific interventricular conduction delays), procedural constraints, inappropriate device programming, and delayed referral. Moreover, there remains no formal consensus on evaluating and characterizing CRT efficacy. Underutilization persists among women and minoritized racial and ethnic groups. Targeted research addressing unmet needs has led to evolving guideline indications. Novel electrocardiographic and imaging techniques are continually being developed to improve patient selection and alternate pacing strategies have emerged. Conduction system pacing may allow for a more physiologic approach to CRT. Observational studies and small clinical trials have shown comparable or superior efficacy of conduction system pacing over traditional biventricular pacing; however, more studies are needed. LAY SUMMARY: Cardiac resynchronization therapy via biventricular pacing has transformed heart failure management over the past two decades. This review examines persistent challenges in clinical practice and evolving guideline recommendations. Key issues, including refining patient selection, better characterizing conduction abnormalities, and optimizing device programming, were highlighted. Emerging evidence suggests conduction system pacing as a physiologic alternative to biventricular pacing, with early studies showing promising outcomes. However, rigorous clinical trials are needed to confirm these findings and guide future practice. Advancing CRT necessitates continued innovation and strategies to improve equity and access across diverse populations.

Implementation of guideline-recommended therapies in heart failure with reduced ejection fraction according to heart failure duration: An analysis of 55 581 patients from the Swedish Heart Failure (SwedeHF) Registry

AIMS

Guidelines recommend immediate initiation of all four class I guideline-directed medical therapies, renin-angiotensin system inhibitors (RASI) or angiotensin receptor-neprilysin inhibitors (ARNI), beta-blockers, mineralocorticoid receptor antagonists (MRA) and sodium-glucose cotransporter 2 inhibitors (SGLT2i) following the diagnosis of heart failure (HF) with reduced ejection fraction (HFrEF). The extent to which this occurs in new-onset HFrEF is unclear. We assessed guideline-recommended therapies during the first year following a HFrEF diagnosis.

METHODS AND RESULTS

The Swedish HF Registry was linked to additional national registries. In patients with HFrEF (ejection fraction <40%), clinical characteristics and HF treatment from when they were available and recommended in guidelines were assessed according to time from HF diagnosis (<3, 3 to <6, 6-12 and >12 months). Of 55 581 patients with HFrEF enrolled between 2000 and 2021, 54%, 5.8%, 4.8% and 36% had an HF duration of <3, 3 to <6, 6-12 and >12 months, respectively. Patients with shorter HF duration were younger, had lower New York Heart Association class and had fewer cardiovascular comorbidities. Within 3 months, 3 to <6 months, 6-12 months and >12 months from HF diagnosis, 93%, 92%, 90% and 89% were on RASI or ARNI, 9.8%, 17%, 19% and 22% on ARNI alone, 35%, 43%, 44% and 46% on MRA, 92%, 92%, 92% and 91% on beta-blockers, and 26%, 30%, 19% and 28% on SGLT2i, respectively. Additionally, 18% received cardiac resynchronization therapy/implantable cardioverter-defibrillator >12 months after diagnosis.

CONCLUSIONS

Most patients received RASI and beta-blockers in the first months following HFrEF diagnosis. Use of ARNI, MRA and SGLT2i was limited, both in the early and later time periods. Our findings suggest that strategies to improve guideline-directed use of HFrEF therapies remain urgently needed.

Device-therapy in chronic heart failure: Cardiac contractility modulation versus cardiac resynchronization therapy

AIMS

Cardiac implantable electrical devices such as cardiac resynchronization therapy with defibrillator (CRT-Ds) or cardiac contractility modulation (CCMs) are therapy options for patients with symptomatic heart failure (HF) and reduced left ventricular ejection fraction (LVEF) despite optimal medical treatment. As yet, a comparison between both devices has not been performed.

METHODS AND RESULTS

The Mannheim Cardiac Resynchronization Therapy Registry (MARACANA) and the Mannheim Cardiac Contractility Modulation Observational Study (MAINTAINED) included all patients who received CRTs or CCMs in our medical centre between 2012 and 2021. For the present analysis, we retrospectively compared patients provided with either CRT-Ds (n = 220) or CCMs with additional defibrillators (n = 105) regarding New York Heart Association classification (NYHA), LVEF, tricuspid annular plane systolic excursion (TAPSE), QRS-width and other HF modification aspects after 12 months. Before implantation, CCM patients presented with lower LVEF (23.6 ± 6.2 vs. 26.3 ± 6.5%) and worse NYHA (3.03 ± 0.47 vs. 2.81 ± 0.48, both P < 0.05), compared with CRT-D patients. Follow-up improvements in NYHA (2.43 ± 0.67 vs. 2.28 ± 0.72), LVEF (30.5 ± 10.7 vs. 35.2 ± 10.5%) and TAPSE (17.2 ± 5.2 vs. 17.1 ± 4.8 to 18.9 ± 3.4 vs. 17.3 ± 3.6 mm, each P < 0.05) were comparable. The intrinsic QRS-width was stable with CCM (109.1 ± 18 vs. 111.7 ± 19.7 ms, P > 0.05), while the paced QRS-width with CRT-D after 12 months was lower than intrinsic values at baseline (157.5 ± 16.5 vs. 139.2 ± 16 ms, P < 0.05). HF hospitalizations occurred more often for CCM than CRT-D patients (45.7 vs. 16.8%/patient years, odds ratio 4.2, P < 0.001).

CONCLUSIONS

Chronic heart failure patients could experience comparable 12-month improvements in functional status and ventricular reverse remodelling, with appropriately implanted CCMs and CRT-Ds. Differences in HF hospitalization rates may be due to the more advanced HF of CCM patients at implantation.

Cardiac resynchronization therapy (CRT) nonresponders in the contemporary era: A state-of-the-art review

In the 2000s, cardiac resynchronization therapy (CRT) became a revolutionary treatment for heart failure with reduced left ventricular ejection fraction (HFrEF) and wide QRS. However, about one-third of CRT recipients do not show a favorable response. This review of the current literature aims to better define the concept of CRT response/nonresponse. The diagnosis of CRT nonresponder should be viewed as a continuum, and it cannot rely solely on a single parameter. Moreover, baseline features of some patients might predict an unfavorable response. A strong collaboration between heart failure specialists and electrophysiologists is key to overcoming this challenge with multiple strategies. In the contemporary era, new pacing modalities, such as His-bundle pacing and left bundle branch area pacing, represent a promising alternative to CRT. Observational studies have demonstrated their potential; however, several limitations should be addressed. Large randomized controlled trials are needed to prove their efficacy in HFrEF with electromechanical dyssynchrony.

Implantable Cardioverter Defibrillator and Resynchronization Therapy in Patients With Overt Chronic Kidney Disease: JACC State-of-the-Art Review

Heart failure and chronic kidney disease are common and clinically important conditions that regularly coexist. Electrophysiologic changes of advanced heart failure often result in abnormal conduction, causing dyssynchronous contraction, and development of ventricular arrhythmias, which can lead to sudden cardiac arrest. In the last 2 decades, implantable cardioverter-defibrillator and cardiac resynchronization therapy devices have been developed to address these complications. However, when the coexisting chronic kidney disease is advanced, the associated pathophysiologic cardiovascular changes can alter the efficacy and safety of those interventions and complicate the management. This review explores the impact of comorbid advanced heart failure and advanced chronic kidney disease on the efficacy and safety of implantable cardioverter-defibrillator and cardiac resynchronization therapy, the currently available evidence, and potential future directions.

Atrioventricular optimization improves cardiac resynchronization response in patients with long interventricular electrical delays: A pooled analysis of the SMART-AV and SMART-CRT trials

BACKGROUND

The utility of atrioventricular (AV) optimization (AVO) algorithms remains in question. A substudy of the SMART-AV trial found that patients with prolonged interventricular delays ≥70 ms were more likely to benefit from cardiac resynchronization therapy (CRT) with AVO. The SMART-CRT trial evaluated AVO on the basis of these results, but the study was underpowered.

OBJECTIVE

To increase statistical power, data from SMART-AV patients meeting the inclusion criterion of interventricular delay ≥70 ms were pooled with data from SMART-CRT to reassess AVO.

METHODS

SMART-CRT and SMART-AV were prospective, randomized, multicenter clinical trials. Patients in both studies were randomized to be programmed with an AVO algorithm (SmartDelay) or fixed AV delay (120 ms). Paired echocardiograms obtained at baseline and 6 months were compared, with CRT response defined as ≥15% reduction in left ventricular end-systolic volume.

RESULTS

A total of 451 complete patient data sets were pooled and analyzed. The baseline demographics between studies did not differ statistically in terms of age, sex, left ventricular ejection fraction, or left ventricular end-systolic volume. The AVO group had a greater proportion of CRT responders (SmartDelay, 73.9%; fixed, 63.1%; P = .014) and greater changes in measures of reverse remodeling. SmartDelay patients with a recommended sensed AV delay outside the nominal range (100-120 ms) had 2.3 greater odds of CRT response than fixed AV delay patients.

CONCLUSION

Greater CRT response and measures of reverse remodeling were observed in patients with SmartDelay enabled vs a fixed AV delay. This study supports the use of SmartDelay in patients with a CRT indication and interventricular delay ≥70 ms.

Machine learning-based prediction of 1-year all-cause mortality in patients undergoing CRT implantation: validation of the SEMMELWEIS-CRT score in the European CRT Survey I dataset

Aims

We aimed to externally validate the SEMMELWEIS-CRT score for predicting 1-year all-cause mortality in the European Cardiac Resynchronization Therapy (CRT) Survey I dataset-a large multi-centre cohort of patients undergoing CRT implantation.

Methods and results

The SEMMELWEIS-CRT score is a machine learning-based tool trained for predicting all-cause mortality in patients undergoing CRT implantation. This tool demonstrated impressive performance during internal validation but has not yet been validated externally. To this end, we applied it to the data of 1367 patients from the European CRT Survey I dataset. The SEMMELWEIS-CRT predicted 1-year mortality with an area under the receiver operating characteristic curve (AUC) of 0.729 (0.682-0.776), which concurred with the performance measured during internal validation [AUC: 0.768 (0.674-0.861), P = 0.466]. Moreover, the SEMMELWEIS-CRT score outperformed multiple conventional statistics-based risk scores, and we demonstrated that a higher predicted probability is not only associated with a higher risk of death [odds ratio (OR): 1.081 (1.061-1.101), P < 0.001] but also with an increased risk of hospitalizations for any cause [OR: 1.013 (1.002-1.025), P = 0.020] or for heart failure [OR: 1.033 (1.015-1.052), P < 0.001], a less than 5% improvement in left ventricular ejection fraction [OR: 1.033 (1.021-1.047), P < 0.001], and lack of improvement in New York Heart Association functional class compared with baseline [OR: 1.018 (1.006-1.029), P = 0.003].

Conclusion

In the European CRT Survey I dataset, the SEMMELWEIS-CRT score predicted 1-year all-cause mortality with good discriminatory power, which confirms the generalizability and demonstrates the potential clinical utility of this machine learning-based risk stratification tool.

The effect of sodium-glucose co-transporter 2 inhibitors on outcomes after cardiac resynchronization therapy

AIMS

The trials upon which recommendations for the use of cardiac resynchronization therapy (CRT) in heart failure used optimal medical therapy (OMT) before sodium-glucose co-transporter 2 inhibitors (SGLT2i). Moreover, the SGLT2i heart failure trials included only a small proportion of participants with CRT, and therefore, it remains uncertain whether SGLT2i should be considered part of OMT prior to CRT.

METHODS AND RESULTS

We compared electrocardiogram (ECG) and echocardiographic responses to CRT as well as hospitalization and mortality rates in consecutive patients undergoing implantation at a large tertiary centre between January 2019 to June 2022 with and without SGLT2i treatment. Three hundred seventy-four participants were included aged 74.0 ± 11.5 years (mean ± standard deviation), with a left ventricular ejection fraction (LVEF) of 31.8 ± 9.9% and QRS duration of 161 ± 29 ms. The majority had non-ischaemic cardiomyopathy (58%) and were in NYHA Class II/III (83.6%). These characteristics were similar between patients with (n = 66) and without (n = 308) prior SGLT2i treatment. Both groups demonstrated similar evidence of response to CRT in terms of QRS duration shortening, and improvements in LVEF, left ventricular end-diastolic inner-dimension (LVIDd) and diastolic function (E/A and e/e'). While there was no difference in rates of hospitalization (for heart failure or overall), mortality was significantly lower in patients treated with SGLT2i compared with those who were not (6.5 vs. 16.6%, P = 0.049).

CONCLUSIONS

We observed an improvement in mortality in patients undergoing CRT prescribed SGLT2i compared with those not prescribed SGLT2i, despite similar degrees of reverse remodelling. The authors recommend starting SGLT2i prior to CRT implantation, where it does not delay implantation.

[Treatment with cardiac electronic implantable devices]

Cardiac device therapy provides not only treatment options for bradyarrhythmia but also advanced treatment for heart failure and preventive measures against sudden cardiac death. In heart failure treatment it enables synergistic reverse remodelling and reduces pharmacological side effects. Cardiac resynchronization therapy (CRT) has revolutionized the treatment of reduced left ventricular ejection fraction (LVEF) and left bundle branch block by decreasing the mortality and morbidity with improvement of the quality of life and resilience. Conduction system pacing (CSP) as an alternative method of physiological stimulation can improve heart function and reduce the risk of pacemaker-induced cardiomyopathy. Leadless pacers and subcutaneous/extravascular defibrillators offer less invasive options with lower complication rates. The prevention of infections through preoperative and postoperative strategies enhances the safety of these therapies.

COMPArison of Multi-Point Pacing and ConvenTional Cardiac Resynchronization Therapy Through Noninvasive Hemodynamics Measurement: Short- and Long-Term Results of the COMPACT-MPP Study

Invasive hemodynamic studies have shown improved left ventricular (LV) performances when cardiac resynchronization therapy/defibrillator is delivered through multipoint pacing (MPP). Nowadays, strategies have become available that allow studying the same hemodynamic parameters at a noninvasive level. The aim of the present study was to evaluate the clinical implication of using a patient-tailored approach for cardiac resynchronization therapy programming based on noninvasively assessed LV hemodynamics to identify the best biventricular pacing modality between standard single-site pacing (STD) and MPP for each patient. Therefore, 51 patients with heart failure (age 69 ± 9 years, 35 men, 27% ischemic etiology) implanted with cardiac resynchronization therapy/defibrillator underwent noninvasive LV function assessment through photoplethysmography before hospital discharge for addressing dP/dt and stroke volume in both pacing modalities (STD and MPP). The modality that performed better in terms of hemodynamic improvement was permanently programmed. Global longitudinal strain (GLS) was also assessed, and repeated at 3 months. Compared with intrinsic rhythm (928 ± 486 mm Hg/s), dP/dtmax showed a trend to increase in both biventricular pacing modes (1,000 ± 577 mm Hg/s in STD, 1,036 ± 530 mm Hg/s in MPP, p = NS). MPP was associated with a wider hemodynamic improvement than was STD and was the modality of choice in 34 of 51 patients (67%). GLS at predischarge did not differ between groups (-10.3 ± 3.8% vs -10.2 ± 3.5%), but significant improvement of ejection fraction at 1 month (34.4 ± 5.3%, p <0.001) and of GLS at 3 months (-12.9 ± 2.9%, p <0.005) was observed across the entire cohort. At 3 months, 77% of patients were classified as responders. Interestingly, long-term (3 years) follow-up unveiled a reduction in all-cause mortality in the MPP group compared with the STD group. In conclusion, cardiac resynchronization therapy programming guided by acute noninvasive hemodynamics favored MPP modality and caused short-term LV positive remodeling and improved long-term outcomes. Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT04299360.

Electrical therapies in heart failure: Evolving technologies and indications

Device therapy for heart failure has rapidly evolved over 2 decades. The knowledge of indications, assessment lead and device technology has expanded to include CRT, leadless pacing and conduction system pacing such as His bundle and left bundle branch area pacing. But there is still a lack of evidence for these new technologies as well as for common indications such as atrial fibrillation and upgrading from a previous device. The role of personalized medicine will become increasingly important when selecting candidates for CRT, primary preventive ICD ablation procedures and emerging new devices such as cardiac contractility modulation (CCM). Rapidity of therapy is associated with outcome which will be a challenge. If properly implemented devices and drugs will have a large positive affect of HF outcomes.

Clinical outcomes and predictors of delayed echocardiographic response to cardiac resynchronization therapy

INTRODUCTION

The clinical outcomes and mechanisms of delayed responses to cardiac resynchronization therapy (CRT) remain unclear. We aimed to investigate the differences in outcomes and gain insight into the mechanisms of early and delayed responses to CRT.

METHODS

This retrospective study included 110 patients who underwent CRT implantation. Positive response to CRT was defined as ≥15% reduction of left ventricular (LV) end-systolic volume on echocardiography at 1 year (early phase) and 3 years (delayed phase) after implantation. The latest mechanical activation site (LMAS) of the LV was identified using two-dimensional speckle-tracking radial strain analysis.

RESULTS

Seventy-eight (71%) patients exhibited an early response 1 year after CRT implantation. Of 32 non-responders in the early phase, 12 (38%) demonstrated a delayed response, and 20 (62%) were classified as non-responders after 3 years. During the follow-up time of 10.3 ± 0.5 years, the delayed and early responders had a similar prognosis of mortality and heart failure (HF) hospitalization. In contrast, non-responders had a worse prognosis. Multivariate analysis revealed that a longer duration (months) between initial HF hospitalization and CRT (odds ratio [OR]: 1.126; 95% confidence interval [CI]: 1.036-1.222; p = .005), non-exact concordance of LV lead location with LMAS (OR: 32.744; 95% CI: 1.101-973.518; p = .044), and pre-QRS duration (OR: 0.901; 95% CI: 0.827-0.981; p = .016) were independent predictors of delayed response to CRT compared with early response.

CONCLUSION

The prognoses were similar regardless of the response time after CRT. A longer history of HF, suboptimal LV lead position, and shorter pre-QRS duration were related to delayed response than early response.

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

AIMS

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.

METHODS AND RESULTS

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.

CONCLUSION

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.

Medical Management and Device-Based Therapies in Chronic Heart Failure

Heart failure (HF) remains a major cause of morbidity and mortality worldwide. Major advancements in optimal guideline-directed medical therapy, including novel pharmacological agents, are now available for the treatment of chronic HF including HF with reduced ejection fraction and HF with preserved ejection fraction. Despite these efforts, there are several limitations of medical therapy including but not limited to: delays in implementation and/or initiation; inability to achieve target dosing; tolerability; adherence; and recurrent and chronic costs of care. A significant proportion of patients remain symptomatic with poor HF-related outcomes including rehospitalization, progression of disease, and mortality. Driven by these unmet clinical needs, there has been a significant growth of innovative device-based interventions across all HF phenotypes over the past several decades. This state-of-the-art review will summarize the current landscape of guideline-directed medical therapy for chronic HF, discuss its limitations including barriers to implementation, and review device-based therapies which have established efficacy or demonstrated promise in the management of chronic HF.

Time-trend treatment effect of cardiac resynchronization therapy with or without defibrillator on mortality: a systematic review and meta-analysis

AIMS

This study aimed to investigate the impact of cardiac resynchronization therapy with a defibrillator (CRT-D) on mortality, comparing it with CRT with a pacemaker (CRT-P). Additionally, the study sought to identify subgroups, evaluate the time trend in treatment effects, and analyze patient characteristics, considering the changing indications over the past decades.

METHODS AND RESULTS

PubMed, CENTRAL, and Embase up to October 2021 were screened for studies comparing CRT-P and CRT-D, focusing on mortality. Altogether 26 observational studies were selected comprising 128 030 CRT patients, including 55 469 with CRT-P and 72 561 with CRT-D device. Cardiac resynchronization therapy with defibrillator was able to reduce all-cause mortality by almost 20% over CRT-P [adjusted hazard ratio (HR): 0.85; 95% confidence interval (CI): 0.76-0.94; P < 0.01] even in propensity-matched studies (HR: 0.83; 95% CI: 0.80-0.87; P < 0.001) but not in those with non-ischaemic aetiology (HR: 0.95; 95% CI: 0.79-1.15; P = 0.19) or over 75 years (HR: 1.08; 95% CI 0.96-1.21; P = 0.17). When treatment effect on mortality was investigated by the median year of inclusion, there was a difference between studies released before 2015 and those thereafter. Time-trend effects could be also observed in patients' characteristics: CRT-P candidates were getting older and the prevalence of ischaemic aetiology was increasing over time.

CONCLUSION

The results of this systematic review of observational studies, mostly retrospective with meta-analysis, suggest that patients with CRT-D had a lower risk of mortality compared with CRT-P. However, subgroups could be identified, where CRT-D was not superior such as non-ischaemic and older patients. An improved treatment effect of CRT-D on mortality could be observed between the early and late studies partly related to the changed characteristics of CRT candidates.

The evolving state of cardiac resynchronization therapy and conduction system pacing: 25 years of research at EP Europace journal

Cardiac resynchronization therapy (CRT) was proposed in the 1990s as a new therapy for patients with heart failure and wide QRS with depressed left ventricular ejection fraction despite optimal medical treatment. This review is aimed first to describe the rationale and the physiologic effects of CRT. The journey of the landmark randomized trials leading to the adoption of CRT in the guidelines since 2005 is also reported showing the high level of evidence for CRT. Different alternative pacing modalities of CRT to conventional left ventricular pacing through the coronary sinus have been proposed to increase the response rate to CRT such as multisite pacing and endocardial pacing. A new emerging alternative technique to conventional biventricular pacing, conduction system pacing (CSP), is a promising therapy. The different modalities of CSP are described (Hirs pacing and left bundle branch area pacing). This new technique has to be evaluated in clinical randomized trials before implementation in the guidelines with a high level of evidence.

Performance of a multi-sensor implantable defibrillator algorithm for heart failure monitoring in the presence of atrial fibrillation

AIMS

The HeartLogic Index combines data from multiple implantable cardioverter defibrillators (ICDs) sensors and has been shown to accurately stratify patients at risk of heart failure (HF) events. We evaluated and compared the performance of this algorithm during sinus rhythm and during long-lasting atrial fibrillation (AF).

METHODS AND RESULTS

HeartLogic was activated in 568 ICD patients from 26 centres. We found periods of ≥30 consecutive days with an atrial high-rate episode (AHRE) burden <1 h/day and periods with an AHRE burden ≥20 h/day. We then identified patients who met both criteria during the follow-up (AHRE group, n = 53), to allow pairwise comparison of periods. For control purposes, we identified patients with an AHRE burden <1 h throughout their follow-up and implemented 2:1 propensity score matching vs. the AHRE group (matched non-AHRE group, n = 106). In the AHRE group, the rate of alerts was 1.2 [95% confidence interval (CI): 1.0-1.5]/patient-year during periods with an AHRE burden <1 h/day and 2.0 (95% CI: 1.5-2.6)/patient-year during periods with an AHRE-burden ≥20 h/day (P = 0.004). The rate of HF hospitalizations was 0.34 (95% CI: 0.15-0.69)/patient-year during IN-alert periods and 0.06 (95% CI: 0.02-0.14)/patient-year during OUT-of-alert periods (P < 0.001). The IN/OUT-of-alert state incidence rate ratio of HF hospitalizations was 8.59 (95% CI: 1.67-55.31) during periods with an AHRE burden <1 h/day and 2.70 (95% CI: 1.01-28.33) during periods with an AHRE burden ≥20 h/day. In the matched non-AHRE group, the rate of HF hospitalizations was 0.29 (95% CI: 0.12-0.60)/patient-year during IN-alert periods and 0.04 (95% CI: 0.02-0.08)/patient-year during OUT-of-alert periods (P < 0.001). The incidence rate ratio was 7.11 (95% CI: 2.19-22.44).

CONCLUSION

Patients received more alerts during periods of AF. The ability of the algorithm to identify increased risk of HF events was confirmed during AF, despite a lower IN/OUT-of-alert incidence rate ratio in comparison with non-AF periods and non-AF patients.

CLINICAL TRIAL REGISTRATION

http://clinicaltrials.gov/Identifier: NCT02275637.

Device Interventions for Heart Failure

Despite remarkable advances in drug therapy for heart failure (HF), the residual HF-related morbidity, mortality, and hospitalizations remain substantial across all HF phenotypes, and significant proportions of patients with HF remain symptomatic despite optimal drug therapy. Driven by these unmet clinical needs, the exponential growth of transcatheter interventions, and a recent shift in the regulatory landscape of device-based therapies, novel device-based interventions have emerged as a potential therapy for various phenotypes of HF. Device-based interventions can overcome some of the limitations of drug therapy (eg, intolerance, nonadherence, inconsistent delivery, and recurrent and long-term cost) and can target some HF-related pathophysiologic pathways more effectively than drug therapy. This paper reviews the current evolving landscape of device-based interventions in HF and highlights critical points related to implementation of these therapies in the current workflow of HF management.

Prognosis of CRT-treated and CRT-untreated unselected population with LBBB in Stockholm County

AIMS

Left bundle branch block (LBBB) might be the first finding of cardiovascular diseases but also the prerequisite for cardiac resynchronization therapy (CRT) in heart failure (HF) with reduced ejection fraction (HFrEF). The prognosis for patients with LBBB and the implications of CRT in an unselected real-world setting are the focus of our study.

METHODS AND RESULTS

A central electrocardiogram (ECG) database and national registers have been screened to identify patients with LBBB. Predictors of HF and the use of CRT were identified with Cox models. The hazard ratios (HRs) of death, cardiovascular death (CVD), and HF hospitalization (HFH) were estimated according to CRT use. Of 5359 patients with LBBB and QRS > 150 ms, median age 76 years, 36% were female. At the time of index ECG, 41% had a previous history of HF and 27% developed HF. Among 1053 patients with a class I indication for CRT, only 60% received CRT with a median delay of 137 days, and it was associated with a lower risk of death [HR: 0.45, 95% confidence interval (CI): 0.36-0.57], CVD (HR: 0.47, 95% CI: 0.35-0.63), and HFH (HR: 0.56, 95% CI: 0.48-0.66). The age of over 75 years and the diagnosis of dementia and chronic obstructive pulmonary disease were predictors of CRT non-use, while having a pacing/defibrillator device independently predicted CRT use.

CONCLUSION

In an unselected LBBB population, CRT is underused but of great value for HF patients. Therefore, it is crucial to find ways of better implementing and understanding CRT utilization and characteristics that influence the management of our patients.

Improved prognosis after cardiac resynchronization therapy over a decade

AIMS

The past decade has seen an increased delivery of cardiac resynchronization therapy (CRT) for patients with heart failure (HF). We explored whether clinical outcomes after CRT have changed from the perspective of an entire public healthcare system.

METHODS AND RESULTS

A national database covering the population of England (56.3 million in 2019) was used to explore clinical outcomes after CRT from 2010 to 2019. A total of 64 698 consecutive patients (age 71.4 ± 11.7 years; 74.8% male) underwent CRT-defibrillation [n = 32 313 (49.7%)] or CRT-pacing [n = 32 655 (50.3%)] implantation. From 2010-2011 to 2018-2019, there was a 76% increase in CRT implantations. During the same period, the proportion of patients with hypertension (59.6-73.4%), diabetes (26.5-30.8%), and chronic kidney disease (8.62-22.5%) increased, as did the Charlson comorbidity index (CCI ≥ 3 from 20.0% to 25.1%) (all P < 0.001). Total mortality decreased at 30 days (1.43-1.09%) and 1 year (9.51-8.13%) after implantation (both P < 0.001). At 2 years, total mortality [hazard ratio (HR): 0.72; 95% confidence interval (CI) 0.69-0.76] and total mortality or HF hospitalization (HR: 0.59; 95% CI 0.57-0.62) decreased from 2010-2011 to 2018-2019, after correction for age, race, sex, device type (CRT-defibrillation or pacing), comorbidities (hypertension, diabetes, chronic kidney disease, and myocardial infarction), or the CCI (HR: 0.81; 95% CI 0.77-0.85).

CONCLUSIONS

From the perspective of an entire public health system, survival has improved and HF hospitalizations have decreased after CRT implantation over the past decade. This prognostic improvement has occurred despite an increasing comorbidity burden.