Clinical Effectiveness of Cardiac Resynchronization and Implantable Cardioverter-Defibrillator Therapy in Men and Women With Heart Failure

Mortality Benefit Among Primary Prevention Implantable Cardioverter-Defibrillator Recipients on Contemporary Heart Failure Treatment

BACKGROUND

Past clinical trials have shown the benefit of implantable cardioverter-defibrillators (ICDs) for reducing sudden cardiac death in at-risk patients. However, heart failure management and ICD technology have changed since these trials were first published. An updated assessment of ICD mortality benefit is needed.

OBJECTIVES

The purpose of this study was to compare mortality rates between patients with a primary prevention (PP) indication for an ICD who did or did not receive an ICD using a contemporary, real-world data set.

METHODS

Data was obtained from a large electronic health record data set covering patients in the United States from 2012 through 2020 who had a PP indication for an ICD and survived at least 1-year postindication.

RESULTS

A total of 25,296 patients were identified as having a PP indication for ICD implantation, of which 2,118 (8.4%) were treated with an ICD within a year. Treated patients were younger than nontreated patients (age 63.4 years vs 66.1 years) with a smaller proportion of women (25.0% vs 36.7%). After 4-to-1 propensity matching, treated patients had similar clinical characteristics to nontreated patients. A Cox proportional hazard model estimated a 24.3% lower risk of all-cause mortality in patients when treated vs not treated with an ICD (HR: 0.757; 95% CI: 0.678-0.835; P <0.001). There was no detectable difference in ICD benefit between patients with ischemic and nonischemic heart disease (P = 0.50).

CONCLUSIONS

ICD treatment of patients with a PP indication is associated with improved mortality even in the context of evolving adjunctive HF treatment, consistent with earlier landmark trials.

Does sex affect the risk of 30-day all-cause mortality in cardiogenic shock?

BACKGROUND

Mortality rates following CS have stagnated on an unacceptably high level. Limited data regarding the prognostic value of sex in patients suffering from CS is available. Therefore, this study aims to investigate the prognostic value of sex in patients with cardiogenic shock (CS).

METHODS

Consecutive patients with CS of any cause were included from 2019 to 2021. Prognosis of females was compared to males regarding 30-day all-cause mortality. Further risk stratification was performed according to the presence or absence of CS related to acute myocardial infarction (AMI). Kaplan-Meier and multivariable Cox proportional regression analyses were used for statistics.

RESULTS

From a total of 273 CS patients (AMI-CS: 49%; non-AMI-CS: 51%), 60% were males and 40% females. The risk of 30-day all-cause mortality did not differ among males and females (56% vs. 56%; log rank p = 0.775; HR = 1.046; 95% CI 0.756-1.447; p = 0.785). Even after multivariable adjustment, sex was not associated with prognosis in CS patients (HR = 1.057; 95% CI 0.713-1.564; p = 0.784). Comparable risks of short-term mortality in both sexes were observed irrespective of the presence of AMI-related CS (64.0% vs. 64.6%; log rank p = 0.642; HR = 1.103; 95% CI 0.710-1.713; p = 0.664) and non-AMI-related CS (46.2% vs. 49.2%; log rank p = 0.696; HR = 1.099; 95% CI 0.677-1.783; p = 0.704).

CONCLUSION

Sex was not associated with the risk of 30-day all-cause mortality in CS patients irrespective of CS etiology. (clinicaltrials.gov identifier: NCT05575856).

Sex differences in acute cardiovascular care: a review and needs assessment

Despite significant progress in the care of patients suffering from cardiovascular disease, there remains a persistent sex disparity in the diagnosis, management, and outcomes of these patients. These sex disparities are seen across the spectrum of cardiovascular care, but, are especially pronounced in acute cardiovascular care. The spectrum of acute cardiovascular care encompasses critically ill or tenuous patients with cardiovascular conditions that require urgent or emergent decision-making and interventions. In this narrative review, the disparities in the clinical course, management, and outcomes of six commonly encountered acute cardiovascular conditions, some with a known sex-predilection will be discussed within the basis of underlying sex differences in physiology, anatomy, and pharmacology with the goal of identifying areas where improvement in clinical approaches are needed.

Heart Size Corrected Electrical Dyssynchrony and Its Impact on Sex-Specific Response to Cardiac Resynchronization Therapy

BACKGROUND

Women are less likely to receive cardiac resynchronization therapy, yet, they are more responsive to the therapy and respond at shorter QRS duration. The present study hypothesized that a relatively larger left ventricular (LV) electrical dyssynchrony in smaller hearts contributes to the better cardiac resynchronization therapy response in women. For this, the vectorcardiography-derived QRS area is used, since it allows for a more detailed quantification of electrical dyssynchrony compared with conventional electrocardiographic markers.

METHODS

Data from a multicenter registry of 725 cardiac resynchronization therapy patients (median follow-up, 4.2 years [interquartile range, 2.7-6.1]) were analyzed. Baseline electrical dyssynchrony was evaluated using the QRS area and the corrected QRS area for heart size using the LV end-diastolic volume (QRSarea/LVEDV). Impact of the QRSarea/LVEDV ratio on the association between sex and LV reverse remodeling (LV end-systolic volume change) and sex and the composite outcome of all-cause mortality, LV assist device implantation, or heart transplantation was assessed.

RESULTS

At baseline, women (n=228) displayed larger electrical dyssynchrony than men (QRS area, 132±55 versus 123±58 μVs; P=0.043), which was even more pronounced for the QRSarea/LVEDV ratio (0.76±0.46 versus 0.57±0.34 μVs/mL; P<0.001). After multivariable analyses, female sex was associated with LV end-systolic volume change (β=0.12; P=0.003) and a lower occurrence of the composite outcome (hazard ratio, 0.59 [0.42-0.85]; P=0.004). A part of the female advantage regarding reverse remodeling was attributed to the larger QRSarea/LVEDV ratio in women (25-fold change in β from 0.12 to 0.09). The larger QRSarea/LVEDV ratio did not contribute to the better survival observed in women. In both volumetric responders and nonresponders, female sex remained strongly associated with a lower risk of the composite outcome (adjusted hazard ratio, 0.59 [0.36-0.97]; P=0.036; and 0.55 [0.33-0.90]; P=0.018, respectively).

CONCLUSIONS

Greater electrical dyssynchrony in smaller hearts contributes, in part, to more reverse remodeling observed in women after cardiac resynchronization therapy, but this does not explain their better long-term outcomes.

Implantable cardioverter defibrillators - the past, present and future

Since their formal introduction in 1980, implantable cardioverter defibrillators (ICDs) have undergone innumerable design modifications through several generations. They are indispensable today in successfully managing fatal ventricular arrhythmias. Their role in averting sudden cardiac death is recognized beyond doubt. Their applications and indications have continuously expanded over the last two decades. This article reviews the salient features in the evolution of ICDs, their current indications, recent advances and future directions. With more advanced detection algorithms, the potential integration with leadless pacing, and the possibility to serve as a remote monitoring device to recognize atrial fibrillation, acute ischemia, or electrolyte imbalance, the application of ICDs is rapidly evolving.

Modulação da Contratilidade Cardíaca

Pacientes com insufi ciência cardíaca (IC) vêm se benefi ciando da terapia elétrica por meio de marcapassos convencionais quando associada à bradicardia e à terapia de ressincronização cardíaca ou com fração de ejeção rebaixada e presença de QRS maior que 150 ms, principalmente na presença de bloqueio de ramo esquerdo. Outros grupos de pacientes com IC apresentam limitações ao tratamento com eletroterapia. No entanto, um conceito antigo tem tomado espaço no tratamento de um grupo de pacientes que fi ca fora das diretrizes nacionais e internacionais para eletroterapia na IC: a modulação da contração cardíaca. Este artigo tem como objetivo apresentar a revisão das evidências científi cas já produzidas e publicadas acerca dessa nova modalidade de tratamento da IC.

Modulation of Heart Contractility

Patients with heart failure (HF) are being benefi ted by electric therapy through conventional pacemakers when associated to bradycardia and cardiac resynchronization therapy or with low ejection fraction and presence of QRS longer than 150 ms, mainly in the presence of left branch block. Other groups of patients with HF present limitations regarding electrotherapy. However, an old concept has gained space in the treatment of patients who are outside the national and international guidelines for electrotherapy in HF: the modulation of heart contractility. This article has the purpose of presenting a review of already produced scientifi c evidence regarding this new modality for HF treatment

CRT Optimization: What Is New? What Is Necessary?

Cardiac resynchronization therapy (CRT) has proven to improve quality of life, reduce heart failure hospitalization, and prolong life in selected heart failure patients with reduced ejection fraction, on optimal medical therapy and with electrical dyssynchrony. To ensure maximal benefit for CRT patients, optimization of care should be implemented. This begins with appropriate referring as well as selecting patients, knowing that the presence of left bundle branch block and QRS ≥ 150 ms is associated with the greatest reverse remodeling. The LV lead, preferably quadripolar, is best targeted in a postero-lateral position. After implantation, optimal device programming should aim for maximal biventricular pacing and in selected cases further electrical delay optimization might be of use. Even as important, is the implementation of thorough multidisciplinary heart failure care with medication uptitration, remote monitoring, rehabilitation, and patient education. The role of newer pacing strategies as endocardial or His-bundle pacing remains the subject of ongoing investigation.

The effects of gender on electrical therapies for the heart: procedural considerations, results and complications: A report from the XII Congress of the Italian Association on Arrhythmology and Cardiostimulation (AIAC)

Use of cardiac implantable devices and catheter ablation is steadily increasing in Western countries following the positive results of clinical trials. Despite the advances in scientific knowledge, tools development, and techniques improvement we still have some grey area in the field of electrical therapies for the heart. In particular, several reports highlighted differences both in medical behaviour and procedural outcomes between female and male candidates. Women are referred later for catheter ablation of supraventricular arrhythmias, especially atrial fibrillation, leading to suboptimal results. On the opposite females present greater response to cardiac resynchronization, while the benefit of implantable defibrillator in primary prevention seems to be less pronounced. Differences on aetiology, clinical profile, and development of myocardial scarring are the more plausible causes. This review will discuss all these aspects together with gender-related differences in terms of acute/late complications. We will also provide useful hints on plausible mechanisms and practical procedural aspects.

Advances in Cardiovascular Health in Women over the Past Decade: Guideline Recommendations for Practice

Cardiovascular disease (CVD) remains the number one cause of death in women. It is estimated that 44 million women in the United States are either living with or at risk for heart disease. This article highlights the recent significant progress made in improving care, clinical decision-making, and policy implications for women with CVD. We provide our perspective supported by evidence-based advances in cardiovascular research and clinical care guidelines in seven areas: (1) primary CVD prevention and community heart care, (2) secondary prevention of CVD, (3) stroke, (4) heart failure and cardiomyopathies, (5) ischemia with nonobstructive coronary artery disease, (6) spontaneous coronary artery dissection, and (7) arrhythmias and device therapies. Advances in these fields have improved the lives of women living with and at risk for heart disease. With increase awareness, partnership with national organizations, sex-specific research, and changes in policy, the morbidity and mortality of CVD in women can be further reduced.

Sex-specific mortality differences in heart failure patients with ischemia receiving cardiac resynchronization therapy

Background

Recent studies have reported prognosis differences between male and female heart failure patients following cardiac resynchronization therapy (CRT). However, the potential clinical factors that underpin these differences remain to be elucidated.

Methods

A meta-analysis was performed to investigate the factors that characterize sex-specific differences following CRT. This analysis involved searching the Medline (Pubmed source) and Embase databases in the period from January 1980 to September 2016.

Results

Fifty-eight studies involving 33445 patients (23.08% of whom were women) were analyzed as part of this study. Only patients receiving CRT with follow-up greater than six months were included in our analysis. Compared with males, females exhibited a reduction of 33% (hazard ratio, 0.67; 95% confidence interval, 0.62–0.73; P < 0.0001) and 42% (hazard ratio, 0.58; 95% confidence interval, 0.46–0.74; P = 0.003) in all-cause mortality and heart failure hospitalization or heart failure, respectively. Following a stratified analysis of all-cause mortality, we observed that ischemic causes (p = 0.03) were likely to account for most of the sex-specific differences in relation to CRT.

Conclusion

These data suggest that women have a reduced risk of all-cause mortality and heart failure hospitalization or heart failure following CRT. Based on the results from the stratified analysis, we observed more optimal outcomes for females with ischemic heart disease. Thus, ischemia are likely to play a role in sex-related differences associated with CRT in heart failure patients. Further studies are required to determine other indications and the potential mechanisms that might be associated with sex-specific CRT outcomes.

Survival in Women Versus Men Following Implantation of Pacemakers, Defibrillators, and Cardiac Resynchronization Therapy Devices in a Large, Nationwide Cohort

Background

Whether outcomes differ between sexes following treatment with pacemakers (PM), implantable cardioverter defibrillators, and cardiac resynchronization therapy (CRT) devices is unclear.

Methods and Results

Consecutive US patients with newly implanted PM, implantable cardioverter defibrillators, and CRT devices from a large remote monitoring database between 2008 and 2011 were included in this observational cohort study. Sex‐specific all‐cause survival postimplant was compared within each device type using a multivariable Cox proportional hazards model, stratified on age and adjusted for remote monitoring utilization and ZIP‐based socioeconomic variables. A total of 269 471 patients were assessed over a median 2.9 [interquartile range, 2.2, 3.6] years. Unadjusted mortality rates (MR; deaths/100 000 patient‐years) were similar between women versus men receiving PMs (n=115 076, 55% male; MR 4193 versus MR 4256, respectively; adjusted hazard ratio, 0.87; 95% CI, 0.84–0.90; P<0.001) and implantable cardioverter defibrillators (n=85 014, 74% male; MR 4417 versus MR 4479, respectively; adjusted hazard ratio, 0.98; 95% CI, 0.93–1.02; P=0.244). In contrast, survival was superior in women receiving CRT defibrillators (n=61 475, 72% male; MR 5270 versus male MR 7175; adjusted hazard ratio, 0.73; 95% CI, 0.70–0.76; P<0.001) and also CRT pacemakers (n=7906, 57% male; MR 5383 versus male MR 7625, adjusted hazard ratio, 0.69; 95% CI, 0.61–0.78; P<0.001). This relative difference increased with time. These results were unaffected by age or remote monitoring utilization.

Conclusions

Women accounted for less than 30% of high‐voltage implants and fewer than half of low‐voltage implants in a large, nation‐wide cohort. Survival for women and men receiving implantable cardioverter defibrillators and PMs was similar, but dramatically greater for women receiving both defibrillator‐ and PM‐based CRT.

Computer-aided assessment of the generalizability of clinical trial results

BACKGROUND

The effects of an intervention on patients from populations other than that included in a trial may vary as a result of differences in population features, treatment administration, or general setting. Determining the generalizability of a trial to a target population is important in clinical decision making at both the individual practitioner and policy-making levels. However, awareness to the challenges associated with the assessment of generalizability of trials is low and tools to facilitate such assessment are lacking.

METHODS

We review the main factors affecting the generalizability of a clinical trial results beyond the trial population. We then propose a framework for a standardized evaluation of parameters relevant to determining the external validity of clinical trials to produce a "generalizability score". We then apply this framework to populations of patients with heart failure included in trials, cohorts and registries to demonstrate the use of the generalizability score and its graphic representation along three dimensions: participants' demographics, their clinical profile and intervention setting. We use the generalizability score to compare a single trial to multiple "target" clinical scenarios. Additionally, we present the generalizability score of several studies with regard to a single "target" population.

RESULTS

Similarity indices vary considerably between trials and target population, but inconsistent reporting of participant characteristics limit head-to-head comparisons.

CONCLUSION

We discuss the challenges involved in performing automatic assessment of trial generalizability at scale and propose the adoption of a standard format for reporting the characteristics of trial participants to enable better interpretation of their results.

Geographic and Temporal Variation in Cardiac Implanted Electric Devices to Treat Heart Failure

BACKGROUND

Cardiac implantable electric devices are commonly used to treat heart failure. Little is known about temporal and geographic variation in use of cardiac resynchronization therapy (CRT) devices in usual care settings.

METHODS AND RESULTS

We identified new CRT with pacemaker (CRT-P) or defibrillator generators (CRT-D) implanted between 2008 and 2013 in the United States from a commercial claims database. For each implant, we characterized prior medication use, comorbidities, and geography. Among 17 780 patients with CRT devices (median age 69, 31% women), CRT-Ps were a small and increasing share of CRT devices, growing from 12% to 20% in this study period. Compared to CRT-D recipients, CRT-P recipients were older (median age 76 versus 67), and more likely to be female (40% versus 30%). Pre-implant use of β-blockers and angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers was low in both CRT-D (46%) and CRT-P (31%) patients. The fraction of CRT-P devices among all new implants varied widely across states. Compared to the increasing national trend, the share of CRT-P implants was relatively increasing in Kansas and relatively decreasing in Minnesota and Oregon.

CONCLUSIONS

In this large, contemporary heart failure population, CRT-D use dwarfed CRT-P, though the latter nearly doubled over 6 years. Practice patterns vary substantially across states and over time. Medical therapy appears suboptimal in real-world practice.

Cardiac Resynchronization Therapy in Women

The benefits of cardiac resynchronization therapy (CRT) on the outcomes of patients with heart failure are unquestionable. Women are under-represented in all CRT studies. Most of the available data show that CRT produces a greater clinical benefit in women than men. In several studies, women have left bundle branch block more frequently than men. Women have a remarkably high (90%) CRT response over a wide range of QRS lengths (130-175 milliseconds). Use of a QRS duration of 150 milliseconds as the threshold for CRT prescription may deny a life-saving therapy to many women likely to benefit from CRT.

Sex Differences in Utilisation and Response to Implantable Device Therapy

Multiple studies have demonstrated that implantable cardioverter-defibrillators (ICDs) and cardiac resynchronisation therapy (CRT) provide significant mortality and morbidity benefits to eligible patients irrespective of gender. However, female patients are less likely to receive this life-saving therapy and are significantly under-represented in cardiac device trials. Various performance improvement programmes have proved that this gender disparity can be reduced and these therapies should be offered to all eligible patients regardless of sex. Efforts should be made to enrol more women in clinical trials and sex-specific analysis in medical device clinical studies should be encouraged. In this article we review the data on sex differences in clinical outcomes with ICDs and CRT and explore the reasons for this sex-based disparity.

Use of Implantable Cardioverter Defibrillators in Heart Failure Patients and Risk of Mortality: A Meta-Analysis

BACKGROUND

The purpose of this study was to evaluate the effect of implantable cardioverter defibrillators (ICD) in heart failure (HF) patients compared to pharmacologic/conventional management.

MATERIAL AND METHODS

We searched PubMed, Embase, and Springer Link Library databases up to February 10th, 2014. Pooled risk ratio (RR) and 95% confidence interval (CI) for the mortality of the patients with HF were collected and calculated in a fixed-effects model or a random-effects model, as appropriate. Summary effect estimates were also stratified by sex and follow-up time. Egger's regression asymmetry tests were utilized for publication bias detection.

RESULTS

A total of 7 separate studies including 15 520 patients (10 801 ICD cases and 4719 controls) with HF were considered in the meta-analysis. The overall estimates showed that ICD could statistically significantly reduce the mortality of male (RR=0.73, 95% CI: 0.66-0.80) and female (RR=0.75, 95% CI: 0.63-0.90) patients. In addition, the further stratification subgroup analysis indicated that ICD presented a significant reduction (male: RR=0.72, 95% CI: 0.64-0.81; female: RR=0.69, 95% CI: 0.56-0.85) of mortality after 2-3 years of ICD therapy. The RR (95% CI) effects of mortality after 4-5 years of ICD therapy for males and females were 0.76 (0.51-1.14) and 0.96 (0.68-1.37), respectively.

CONCLUSIONS

This meta-analysis suggests that ICD could reduce HF patient mortality despite the sex difference.

Thirteen-year nationwide trends in use of implantable cardioverter-defibrillators and subsequent long-term survival

BACKGROUND

Long-term trends in use of implantable cardioverter-defibrillators (ICDs) and outcomes are rare.

OBJECTIVE

We examined 13-year nationwide trends in ICD implantation and survival rates in Denmark.

METHODS

Using medical databases, we identified all first time ICD recipients in Denmark during 2000-2012 (N = 8460) and ascertained all-cause mortality. We computed standardized annual implantation rates and mortality rate ratios according to age, sex, comorbidity level, indication, and device type.

RESULTS

The standardized annual implantation rate increased from 42 per million persons in 2000 to 213 per million persons in 2012 (from 34 to 174 for men and from 8 to 39 for women). The increase was driven by secondary prophylactic ICDs until 2006 and primary prophylactic ICDs thereafter. The increase occurred particularly in older patients and those with a high level of comorbidity. Independent of indication, 76% of all patients with ICD were alive after 5 years. Men had a higher mortality rate compared with women (mortality rate ratio 1.28; 95% confidence interval 1.10-1.49). Compared with low comorbidity level, moderate, severe, and very severe comorbidity levels were associated with 1.6-, 2.5-, and 4.9-fold increased mortality rates, respectively. The most influential individual comorbidities were heart failure, diabetes, liver disease, and renal disease.

CONCLUSION

The annual implantation rate of ICDs increased 5-fold in Denmark between 2000 and 2012. The rate increase occurred for both men and women, but particularly in the elderly and patients with severe comorbidity. Five-year survival probability was high, but severe comorbidity and male sex were associated with shorter survival.

ICD and CRT use in ischemic heart disease in women

Although the role of implantable cardioverter defibrillator (ICD) and cardiac resynchronization therapy (CRT) in improving outcomes in ischemic cardiomyopathy (ICM) has been described, the data regarding gender-based survival outcomes are limited. There is a higher preponderance of non-ischemic cardiomyopathy (NICM) in women, and most of the ICM literature is derived from sub-study analysis. This review summarizes the current body of literature on prognosis, pathophysiology, and the present clinical practice for device implantation in women with ICM.

Women with nonischemic cardiomyopathy have a favorable prognosis and a better left ventricular remodeling than men after cardiac resynchronization therapy

AIMS

Cardiac resynchronization therapy (CRT) is a well established therapy in heart failure patients who are on optimal medical therapy and have reduced left ventricular ejection fraction (LVEF) and wide QRS complexes. Although women and patients with nonischemic cardiomyopathy are under-represented in CRT trials and registries, there is evidence that these two groups of patients can benefit more from CRT. The aim of our analysis was to investigate the impact of female sex on mortality in a population that included a high percentage of patients (61%) with nonischemic cardiomyopathy.

METHODS

We analyzed data on 507 consecutive patients (20% women) who received CRT at two Italian Heart Transplant centers and were followed up for a maximum of 48 months.

RESULTS

After multivariate adjustment, women showed a trend toward better survival with regard to all-cause mortality [hazard ratio (HR) 0.32, confidence interval (CI) 0.10-1.04; P = 0.059]. However, this benefit was limited to nonischemic patients with regard to all-cause mortality (HR 0.20, CI 0.05-0.87, P = 0.032) and cardiovascular mortality (HR 0.14, CI 0.02-1.05, P = 0.056).

CONCLUSION

Female CRT recipients, at mid-term, have a favorable prognosis than male patients and this benefit appears to be more evident in nonischemic patients. Thus, we strongly believe that the apparent under-utilization of CRT in females is an anomaly that should be corrected.