Long-Term Outcomes With Cardiac Resynchronization Therapy in Patients With Mild Heart Failure With Moderate Renal Dysfunction

Background—

We aimed to determine the impact of renal function on long-term outcomes with cardiac resynchronization therapy with defibrillator among patients with mild heart failure (HF).

Methods and Results—

We stratified 1820 Multicenter Automatic Defibrillator Implantation Trial–Cardiac Resynchronization Therapy patients by QRS morphology into those with and without left bundle-branch block. Subgroups within each QRS morphology category were created based on glomerular filtration rate (GFR): GFR <60 and ≥60 mL/min per 1.73 m 2 . Primary end point was death; secondary end points were HF/death and HF events alone during long-term follow-up. Among 1274 left bundle-branch block patients, 413 (32%) presented with GFR <60 (mean, 48.1±8.3) mL/min per 1.73 m 2 . Relative to the 861 (68%) patients with GFR ≥60 (mean, 79.6±16.0) mL/min per 1.73 m 2 , low-GFR patients experienced higher risk of death (hazard ratio [HR], 2.09; 95% confidence interval [CI], 1.53–2.86; P <0.01) and HF/death (HR, 1.46; 95% CI, 1.17–1.82; P <0.01). In both GFR groups, cardiac resynchronization therapy with defibrillator was associated with reduction in death (GFR <60: HR, 0.66; 95% CI, 0.44–1.00; P =0.05 and GFR ≥60: HR, 0.68; 95% CI, 0.44–1.05; P =0.08) and HF/death (GFR <60: HR, 0.49; 95% CI, 0.36–0.67; P <0.01 and GFR ≥60: HR, 0.50; 95% CI, 0.38–0.66; P <0.01). In the low-GFR group, there was greater absolute reduction in risk of death (GFR <60: 14% and GFR ≥60: 6%) and HF/death (GFR <60: 25 and GFR ≥60: 15%). Among non–left bundle-branch block patients, low GFR predicted outcomes; however, no benefit from cardiac resynchronization therapy with defibrillator was observed.

Conclusions—

In patients with mild HF, moderate renal dysfunction is associated with higher risk of death and HF during long-term follow-up. Patients with left bundle-branch block, regardless of baseline renal function, derive long-term benefit from cardiac resynchronization therapy with defibrillator, with greater absolute risk reduction in death and HF among those with moderate renal dysfunction.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifiers: NCT00180271, NCT01294449, and NCT02060110.

Sex Differences in Long-Term Outcomes With Cardiac Resynchronization Therapy in Mild Heart Failure Patients With Left Bundle Branch Block

Background

Previous studies have shown conflicting results regarding the benefit of cardiac resynchronization therapy (CRT) by sex and QRS duration.

Methods and Results

In the Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy (MADIT-CRT), we evaluated long-term clinical outcome of heart failure (HF) or death, death, and HF alone by sex and QRS duration (dichotomized at 150 ms) in left bundle-branch block patients with CRT with defibrillator backup (CRT-D) versus implantable cardioverter-defibrillator (ICD) only. There were 394 women (31%) and 887 men with left bundle-branch block. During the median follow-up of 5.6 years, women derived greater clinical benefit from CRT-D compared with implantable cardioverter-defibrillator only, with a significant 71% reduction in HF or death (hazard ratio [HR] 0.29, P<0.001) and a 77% reduction in HF alone (HR 0.23, P<0.001) compared with men, who had a 41% reduction in HF or death (HR 0.59, P<0.001) and a 50% reduction in HF alone (HR 0.50, P<0.001) (all sex-by-treatment interaction P<0.05). Men and women had similar reduction in long-term mortality with CRT-D versus implantable cardioverter-defibrillator only (men: HR 0.70, P=0.03; women: HR 0.59, P=0.04). The incremental benefit of CRT-D in women for HF or death and HF alone was consistent with QRS <150 or >150 ms.

Conclusions

During long-term follow-up of mild HF patients with left ventricular dysfunction and wide QRS, both women and men with left bundle-branch block derived sustained benefit from CRT-D versus implantable cardioverter-defibrillator only, with significant reduction in HF or death, HF alone, and all-cause mortality regardless of QRS duration. There is an incremental benefit with CRT-D in women for the end points of HF or death and HF alone.

Clinical Trial Registration

URL: https://clinicaltrials.gov/. Unique identifiers: NCT00180271, NCT01294449, and NCT02060110.

Longer right to left ventricular activation delay at cardiac resynchronization therapy implantation is associated with improved clinical outcome in left bundle branch block patients

Aims

Data on longer right to left ventricular activation delay (RV-LV AD) predicting clinical outcome after cardiac resynchronization therapy (CRT) by left bundle branch block (LBBB) are limited. We aimed to evaluate the impact of RV-LV AD on N-terminal pro–B-type natriuretic peptide (NT-proBNP), ejection fraction (EF), and clinical outcome in patients implanted with CRT, stratified by LBBB at baseline.

Methods and results

Heart failure (HF) patients undergoing CRT implantation with EF ≤ 35% and QRS ≥ 120 ms were evaluated based on their RV-LV AD at implantation. Baseline and 6-month clinical parameters, EF, and NT-proBNP values were assessed. The primary endpoint was HF or death, the secondary endpoint was all-cause mortality. A total of 125 patients with CRT were studied, 62% had LBBB. During the median follow-up of 2.2 years, 44 (35%) patients had HF/death, 36 (29%) patients died. Patients with RV-LV AD ≥ 86 ms (lower quartile) had significantly lower risk of HF/death [hazard ratio (HR): 0.44; 95% confidence interval (95% CI): 0.23–0.82; P = 0.001] and all-cause mortality (HR: 0.48; 95% CI: 0.23–1.00; P = 0.05), compared with those with RV-LV AD < 86 ms. Patients with RV-LV AD ≥ 86 ms and LBBB showed the greatest improvement in EF (28–36%; P<0.001), NT-proBNP (2771–1216 ng/mL; P < 0.001), and they had better HF-free survival (HR: 0.23, 95% CI: 0.11–0.49, P < 0.001) and overall survival (HR: 0.35, 95% CI: 0.16–0.75; P = 0.007). There was no difference in outcome by RV-LV AD in non-LBBB patients.

Conclusion

Left bundle branch block patients with longer RV-LV activation delay at CRT implantation had greater improvement in NT-proBNP, EF, and significantly better clinical outcome.

Treatment for pulmonary arterial hypertension-associated right ventricular dysfunction

Pulmonary arterial hypertension (PAH) includes a heterogeneous group of diseases characterized by pulmonary vasoconstriction and remodeling of the lung circulation. Although PAH is a disease of the lungs, patients with PAH frequently die of right heart failure. Indeed, survival of patients with PAH depends on the adaptive response of the right ventricle (RV) to the changes in the lung circulation. PAH-specific drugs affect the function of the RV through afterload reduction and perhaps also through direct effects on the myocardium. Prostacyclins, type 5 phosphodiesterase inhibitors, and guanylyl cyclase stimulators may directly enhance myocardial contractility through increased cyclic adenosine and guanosine monophosphate availability. Although this may initially improve cardiac performance, the long-term effects on myocardial oxygen consumption and function are unclear. Cardiac effects of endothelin receptor antagonists may be opposite, as endothelin-1 is known to suppress cardiac contractility. Because PAH is increasingly considered as a disease with quasimalignant growth of cells in the pulmonary vascular wall, therapies are being developed that inhibit hypertrophy and angiogenesis, and promote apoptosis. The inherent danger of these therapies is a further compromise to the already ischemic, fibrotic, and dysfunctional RV. More recently, the right heart has been identified as a direct treatment target in PAH. The effects of well established therapies for left heart failure, such as β-adrenergic receptor blockers, inhibitors of the renin-angiotensin system, exercise training, and assist devices, are currently being investigated in PAH. Future treatment of patients with PAH will likely consist of a multifaceted approaches aiming to reduce the pressure in the lung circulation and improving right heart adaptation simultaneously.

Risk factors and the effect of cardiac resynchronization therapy on cardiac and non-cardiac mortality in MADIT-CRT

AIMS

To understand modes of death and factors associated with the risk for cardiac and non-cardiac deaths in patients with cardiac resynchronization therapy with implantable cardioverter-defibrillator (CRT-D) vs. implantable cardioverter-defibrillator (ICD) therapy, which may help clarify the action and limitations of cardiac resynchronization therapy (CRT) in relieving myocardial dysfunction.

METHODS AND RESULTS

In Multicenter Automatic Defibrillator Implantation Trial-Cardiac Resynchronization Therapy (MADIT-CRT), during 4 years of follow-up, 169 (9.3%) of 1820 patients died of known causes, 108 (63.9%) deemed cardiac, and 61 (36.1%) non-cardiac. In multivariate analysis, increased baseline creatinine was significantly associated with both cardiac and non-cardiac deaths [hazard ratio (HR) 2.97, P < 0.001; HR 1.80, P = 0.035, respectively], as was diabetes (HR 1.79, P = 0.006; HR 1.73, P = 0.038, respectively), and the worst New York Heart Association Class > II more than 3 months prior to enrolment (HR 1.90, P = 0.012; HR 2.46, P = 0.010, respectively). Baseline left atrial volume index was significantly associated only with cardiac mortality (HR 1.28 per 5 unit increase, P < 0.001). Ischaemic cardiomyopathy was associated only with non-cardiac death (HR 3.54, P = 0.001). CRT-D vs. an ICD-only was associated with a reduced risk for cardiac death in patients with left bundle branch block (LBBB) (HR 0.56, P = 0.029) but was associated with an increased risk for non-cardiac death in non-LBBB patients (HR 3.48, P = 0.048).

CONCLUSIONS

In MADIT-CRT, two-thirds of the deaths were cardiac and one-third non-cardiac. Many of the same risk factors were associated with both cardiac and non-cardiac mortalities. CRT-D was associated with a reduced risk for cardiac death in LBBB but an increased risk for non-cardiac death in non-LBBB.

CLINICAL TRIAL REGISTRATION

Information for the MADIT-CRT main study http://www.clinicaltrials.gov, NCT00180271.

A Mobile Health Intervention Supporting Heart Failure Patients and Their Informal Caregivers: A Randomized Comparative Effectiveness Trial

Background

Mobile health (mHealth) interventions may improve heart failure (HF) self-care, but standard models do not address informal caregivers’ needs for information about the patient’s status or how the caregiver can help.

Objective

We evaluated mHealth support for caregivers of HF patients over and above the impact of a standard mHealth approach.

Methods

We identified 331 HF patients from Department of Veterans Affairs outpatient clinics. All patients identified a “CarePartner” outside their household. Patients randomized to “standard mHealth” (n=165) received 12 months of weekly interactive voice response (IVR) calls including questions about their health and self-management. Based on patients’ responses, they received tailored self-management advice, and their clinical team received structured fax alerts regarding serious health concerns. Patients randomized to “mHealth+CP” (n=166) received an identical intervention, but with automated emails sent to their CarePartner after each IVR call, including feedback about the patient’s status and suggestions for how the CarePartner could support disease care. Self-care and symptoms were measured via 6- and 12-month telephone surveys with a research associate. Self-care and symptom data also were collected through the weekly IVR assessments.

Results

Participants were on average 67.8 years of age, 99% were male (329/331), 77% where white (255/331), and 59% were married (195/331). During 15,709 call-weeks of attempted IVR assessments, patients completed 90% of their calls with no difference in completion rates between arms. At both endpoints, composite quality of life scores were similar across arms. However, more mHealth+CP patients reported taking medications as prescribed at 6 months (8.8% more, 95% CI 1.2-16.5, P=.02) and 12 months (13.8% more, CI 3.7-23.8, P<.01), and 10.2% more mHealth+CP patients reported talking with their CarePartner at least twice per week at the 6-month follow-up (P=.048). mHealth+CP patients were less likely to report negative emotions during those interactions at both endpoints (both P<.05), were consistently more likely to report taking medications as prescribed during weekly IVR assessments, and also were less likely to report breathing problems or weight gains (all P<.05). Among patients with more depressive symptoms at enrollment, those randomized to mHealth+CP were more likely than standard mHealth patients to report excellent or very good general health during weekly IVR calls.

Conclusions

Compared to a relatively intensive model of IVR monitoring, self-management assistance, and clinician alerts, a model including automated feedback to an informal caregiver outside the household improved HF patients’ medication adherence and caregiver communication. mHealth+CP may also decrease patients’ risk of HF exacerbations related to shortness of breath and sudden weight gains. mHealth+CP may improve quality of life among patients with greater depressive symptoms. Weekly health and self-care monitoring via mHealth tools may identify intervention effects in mHealth trials that go undetected using typical, infrequent retrospective surveys.

Trial Registration

ClinicalTrials.gov NCT00555360; https://clinicaltrials.gov/ct2/show/NCT00555360 (Archived by WebCite at http://www.webcitation.org/6Z4Tsk78B).

Temporal Influence of Heart Failure Hospitalizations Prior to Implantable Cardioverter Defibrillator or Cardiac Resynchronization Therapy With Defibrillator on Subsequent Outcome in Mild Heart Failure Patients (from MADIT-CRT)

The temporal effect of heart failure (HF) hospitalization occurring at different time periods before implantation has not yet been studied in detail. The aim of the present study was to investigate the potential association between time from last HF hospitalization to device implantation and effects on subsequent outcomes and benefit from cardiac resynchronization therapy with a defibrillator (CRT-D). Multivariate Cox models were used to determine the temporal influence of previous HF hospitalization on the end point of HF or death within all left bundle branch block implantable cardioverter-defibrillator (ICD) and CRT-D patients enrolled in the Multicenter Automatic Defibrillator Implantation Trial-Cardiac Resynchronization Therapy (MADIT-CRT) trial (n = 1,250) and to evaluate the clinical benefit of CRT-D implantation, comparing CRT-D patients with ICD patients within each previous HF hospitalization group. The patients with previous HF hospitalization ≤12 months before device implantation had the greatest incidence of HF or death during 4-year follow-up (31%), while those with previous HF hospitalization >12 months and those with no previous HF hospitalization had similar lower rates of HF or death (22% and 24%, respectively). All patients treated with CRT-D derived significant clinical benefit compared with their ICD counterparts, regardless of time of previous hospitalization (hazard ratios 0.38 [no previous hospitalization], 0.49 (≤12 months), and 0.45 (>12 months); p for interaction = 0.67). In conclusion, in the present study of patients with mild HF with prolonged QRS intervals and LBBB, a previous HF hospitalization ≤12 months was associated with increased risk for HF or death compared with >12 months and no previous HF hospitalizations. The clinical benefit of CRT-D was evident in all patients regardless of time from last HF hospitalization to implantation compared with ICD only.

Regenerative Therapy Prevents Heart Failure Progression in Dyssynchronous Nonischemic Narrow QRS Cardiomyopathy

Background

Cardiac resynchronization therapy using bi-ventricular pacing is proven effective in the management of heart failure (HF) with a wide QRS-complex. In the absence of QRS prolongation, however, device-based resynchronization is reported unsuitable. As an alternative, the present study tests a regenerative cell-based approach in the setting of narrow QRS-complex HF.

Methods and Results

Progressive cardiac dyssynchrony was provoked in a chronic transgenic model of stress-triggered dilated cardiomyopathy. In contrast to rampant end-stage disease afflicting untreated cohorts, stem cell intervention early in disease, characterized by mechanical dyssynchrony and a narrow QRS-complex, aborted progressive dyssynchronous HF and prevented QRS widening. Stem cell-treated hearts acquired coordinated ventricular contraction and relaxation supporting systolic and diastolic performance. Rescue of contractile dynamics was underpinned by a halted left ventricular dilatation, limited hypertrophy, and reduced fibrosis. Reverse remodeling reflected a restored cardiomyopathic proteome, enforced at systems level through correction of the pathological molecular landscape and nullified adverse cardiac outcomes. Cell therapy of a dyssynchrony-prone cardiomyopathic cohort translated prospectively into improved exercise capacity and prolonged survivorship.

Conclusions

In narrow QRS HF, a regenerative approach demonstrated functional and structural benefit, introducing the prospect of device-autonomous resynchronization therapy for refractory disease.

Lessons learned from the Multicenter Automatic Defibrillator Implantation Trial-Cardiac Resynchronization Therapy (MADIT-CRT)

Cardiac resynchronization therapy (CRT) has evolved as a Class I treatment indication with Level of Evidence A, in patients with mild heart failure, depressed left ventricular ejection fraction, and wide QRS. In this review article, we will discuss the major findings of sub-studies published from the Multicenter Automatic Defibrillator Implantation Trial-Cardiac Resynchronization Therapy (MADIT-CRT).

ECG Patterns In Cardiac Resynchronization Therapy

Cardiac resynchronization therapy is an established treatment modality in heart failure. Though non-response is a serious issue. To address this issue, a good understanding of the electrical activation during underlying intrinsic ventricular activation, biventricular as well as right- and left ventricular pacing is needed. By interpreting the 12-lead electrocardiogram, possible reasons for suboptimal treatment can be identified and addressed. This article reviews the literature on QRS morphology in cardiac resynchronization therapy and its role in optimization of therapy.

Early intervention and long-term outcome with cardiac resynchronization therapy in patients without a history of advanced heart failure symptoms

AIMS

MADIT-CRT showed that cardiac resynchronization therapy with a defibrillator (CRT-D) improves long-term outcomes in currently mildly symptomatic heart failure (HF) patients with LBBB regardless of the presence of prior advanced HF symptoms. We aimed to evaluate the long-term benefit of CRT-D in patients who never experienced advanced HF symptoms prior to device implantation.

METHODS AND RESULTS

Interaction term analysis was used to compare the clinical and echocardiographic benefit of CRT-D vs. implantable cardioverter defibrillator (ICD)-only therapy during long-term follow-up (median 5.6 years) between LBBB patients with or without a history of advanced HF [defined as NYHA class ≥ III or past hospitalization for worsening HF >3 months prior to enrolment in MADIT-CRT (n = 529 and 752, respectively)]. Multivariable analysis showed that treatment with CRT-D was associated with a significant reduction in the risk of HF or death during long-term follow-up regardless of the presence of prior advanced HF symptoms [hazard ratio 0.53 (P < 0.001) and 0.47 (P < 0.001) in the respective groups of patients with and without prior advanced HF; interaction P for the difference = 0.58]. Echocardiographic response to CRT at 1 year was also similar between the two groups (P > 0.10 for all comparisons).

CONCLUSION

Our findings suggest that treatment with CRT-D is associated with pronounced echocardiographic and long-term clinical benefit in patients with LV dysfunction and LBBB who never experienced advanced HF symptoms. These data further emphasize the benefit of early intervention with CRT in this population.

[Implantable cardioverter-defibrillator: Is remote monitoring obligatory?]

BACKGROUND

The possibilities of telemonitoring (TM) of patients with implantable cardioverter-defibrillators (ICD) have been rapidly improving over the last few years. Numerous studies have examined the effects of this development on the follow-up care of ICD patients.

OBJECTIVES

Technical implementation and safety of ICD telemonitoring. Effects on the treatment of cardiac arrhythmias, the management of cardiac insufficiency patients and morbidity as well as mortality. Illustration of patient acceptance and cost-benefit assessment.

MATERIALS AND METHODS

The current research situation regarding TM of ICDs is analyzed and the available evidence for the postulated advantages in the follow-up care of ICD patients are discussed. The current treatment guidelines and recommendations for implementation of TM in daily clinical praxis are presented.

RESULTS AND CONCLUSIONS

TM offers the possibility of faster reaction times to arrhythmias, cardiac decompensation and ICD malfunctions. At the same time, the outpatient follow-ups can be reduced without negatively affecting safety, quality of life or patient acceptance. TM has the potential to cost-neutrally improve the safety of ICD therapy and could lead to optimized management of heart insufficiency patients, while reducing morbidity and mortality. Following the evidence of these benefits as shown in numerous studies, TM has already been included in the current therapy guidelines.

Long-Term Results of Cardiac Resynchronization Therapy: A Comparison between CRT-Pacemakers versus Primary Prophylactic CRT-Defibrillators

BACKGROUND

Cardiac resynchronization therapy (CRT) with or without a defibrillator has a positive effect on mortality and morbidity for patients with heart failure. However, comparisons between CRT-defibrillators (CRT-D) and CRT-pacemakers (CRT-P) are relatively scarce outside the clinical trial setting. This study aimed to assess baseline characteristics in relation to long-term prognosis in patients treated with CRT, and to investigate the potential benefit of CRT-D versus CRT-P.

METHODS

Data were retrospectively collected from the medical records of all consecutive patients treated with CRT-P or primary prophylactic CRT-D at a large tertiary care center between 1999 and 2012. Predictors of mortality were investigated, and time-dependent analysis was performed with all-cause mortality as the primary end point.

RESULTS

A total of 705 patients were included (69.6 ± 10 years, 78% New York Heart Association classes III-IV, left ventricular ejection fraction median 25%, 16% female, 36% CRT-D). The patients were followed for a median of 59 months. Annual mortality differed between CRT-D primary prophylactic and CRT-P groups (5.3% and 11.8%, respectively), but when adjusted for covariates, CRT-D treatment (compared to CRT-P) was not associated with better long-term survival. Independent predictors of survival were: age, use of loop diuretics, hemoglobin levels, and use of renin angiotensin aldosterone system blockers.

CONCLUSIONS

In CRT treatment outside of the clinical trial setting, CRT-D treatment was not an independent predictor of long-term survival. Future research should focus on correct selection of the patients who receive enough benefit of an added defibrillator to justify CRT-D implantation instead of CRT-P treatment only.

The clinical course of patients with implantable cardioverter-defibrillators: Extended experience on clinical outcome, device replacements, and device-related complications

BACKGROUND

Large randomized trials demonstrated the beneficial effect of implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy-defibrillator (CRT-D) treatments in selected patients. Data on long-term follow-up of patients outside the setting of clinical trials are scarce.

OBJECTIVE

The aim of this study was to evaluate the long-term outcome of ICD and CRT-D recipients.

METHODS

All patients who underwent ICD (n = 1729 [57%]) or CRT-D (n = 1326 [43%]) implantation at the Leiden University Medical Center since 1996 were evaluated. Follow-up visits were performed every 3-6 months, and events were registered. Cumulative incidence curves of device therapy and device-related complications were adjusted for the competing risk of all-cause mortality.

RESULTS

After a median follow-up of 5.1 years (25th-75th percentile 3.1-7.8 years), 842 patients (28%) died. The cumulative incidence of all-cause mortality was 49% (95% confidence interval [CI] 45%-54%) in ICD recipients after 12 years of follow-up and 55% (95% CI 52%-58%) in CRT-D recipients after 8 years of follow-up. A total of 1081 patients (35%) received appropriate defibrillator therapy. The cumulative incidence of appropriate therapy in ICD patients was 58% (95% CI 54%-62%) after 12 years of follow-up and 39% (95% CI 35%-43%) in CRT-D patients after 8 years of follow-up. Twelve-year cumulative incidences of adverse events were 20% (95% CI 18%-22%) for inappropriate shock, 6% (95% CI 5%-8%) for device-related infection, and 17% (95% CI 14%-21%) for lead failure.

CONCLUSION

After long-term follow-up of ICD (12 years) and CRT-D (8 years) recipients, 49% of ICD recipients and 55% of CRT-D recipients had died. Appropriate ICD therapy was received by the majority (58%) of ICD recipients and by almost 40% of CRT-D recipients.

The postimplantation electrocardiogram predicts clinical response to cardiac resynchronization therapy

BACKGROUND

Biventricular (BiV) pacing for cardiac resynchronization therapy (CRT) is intended to improve left ventricular function by coordinating systolic activity of the septum and free walls. Optimal resynchronization should be manifested by 12-lead electrocardiogram (ECG) patterns consistent with resynchronized activation, a tall (≥4 mm) R wave in V1, and predominant negative deflection in lead I (RV1SI). We investigated whether the presence or absence of RV1SI predicts heart failure outcomes within 1 year of CRT implant.

METHODS

Two independent physicians reviewed the paced ECG of 213 patients post-CRT device implantation with disputes resolved by a third reviewer. The primary end points of all-cause death, unplanned hospitalization, left ventricular assist device implant, or transplant within a 1-year follow-up were blindly adjudicated according to standard definitions. Groups were compared via Kaplan-Meier estimates and Cox proportional hazards models to determine association with event-free survival.

RESULTS

Among CRT patients postimplantation, 56 (26.3%) exhibited the RV1SI pattern on ECG. Patients with the RV1SI pattern were significantly less likely to achieve the primary end point as compared to patients without the RV1SI pattern (33.9% vs 52.2%; Log Rank P = 0.022). This difference was driven by a significantly lower risk for unplanned hospitalization among patients with the RV1SI pattern (hazard ratio = 0.510; confidence interval [0.298, 0.876]). The predictive value remained after adjustment for potential confounders (P = 0.004).

CONCLUSIONS

The 12-lead ECG postimplantation predicts clinical outcomes of BiV pacing. Such prediction may be useful in predicting the need for alternative or advanced heart failure therapies. Further study into ECG patterns may help to prospectively guide CRT.

Update in cardiac arrhythmias and pacing

This article discusses the main advances in cardiac arrhythmias and pacing published between 2013 and 2014. Special attention is given to the interventional treatment of atrial fibrillation and ventricular arrhythmias, and on advances in cardiac pacing and implantable cardioverter defibrillators, with particular reference to the elderly patient.

Personal health technology: A new era in cardiovascular disease prevention

Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality worldwide yet the majority of related risk factors are largely preventable (primary prevention [PP]) and effectively treatable (secondary prevention [SP]) with healthy lifestyle behaviors. The use of information and communication technology (ICT) offers a unique approach to personal health and CVD prevention, as these mediums are relatively affordable, approachable, and accessible. The purpose of this review is to provide an overview of ICT-driven personal health technologies and their potential role in promoting and supporting self-care behaviors for PP and SP of CVD. In this review, we focus on technological interventions that have been successful at supporting positive behavior change in order to determine which tools, resources, and methods are most appropriate for delivering interventions geared towards CVD prevention. We conducted a literature search from a range of sources including scholarly, peer-reviewed journal articles indexed in PubMed and CINAHL, gray literature, and reputable websites and other Internet-based media. A synthesis of existing literature indicates that the overall efficacy of ICT-driven personal health technologies is largely determined by: 1) the educational resources provided and the extent to which the relayed information is customized or individually tailored; and 2) the degree of self-monitoring and levels of personalized feedback or other interactions (e.g. interpersonal communications). We conclude that virtually all the technological tools and resources identified (e.g. Internet-based communications including websites, weblogs and wikis, mobile devices and applications, social media, and wearable monitors) can be strategically leveraged to enhance self-care behaviors for CVD risk reduction and SP but further research is needed to evaluate their efficacy, cost-effectiveness, and long-term maintainability.

Cardiac resynchronization therapy in women versus men: observational comparative effectiveness study from the National Cardiovascular Data Registry

BACKGROUND

Women have been under-represented in trials of cardiac resynchronization therapy-defibrillators (CRT-D). Previous studies suggest that women benefit from CRT-D at shorter QRS duration than men and that there may be no benefit of CRT-D in patients without left bundle branch block (LBBB) regardless of patient sex.

METHODS AND RESULTS

We compared sex-specific death risk in 75 079 patients with New York Heart Association class III or IV heart failure, reduced left ventricular ejection fraction, and prolonged QRS duration (≥120 ms) receiving either CRT-D or implantable cardioverter defibrillator in subgroups according to QRS morphology and 10-ms increments in QRS duration. We applied propensity score weighting to control for differences between treatments. Among patients with LBBB, women receiving CRT-D had a lower relative death risk than those receiving an implantable cardioverter-defibrillator (absolute difference, 11%; hazard ratio=0.74 [95% confidence interval, 0.68-0.81]). In men, the lower mortality with CRT-D versus implantable cardioverter defibrillator was less pronounced (absolute difference, 9%; hazard ratio=0.84 [0.79-0.89]; sex×device interaction P=0.025). In those without LBBB, the mortality difference was modest and did not differ between women and men (absolute difference, 3%; hazard ratio=0.88 [0.79-0.97] in women and absolute difference, 2%; hazard ratio=0.95 [0.91-0.998] in men; interaction P=0.17). In subgroups according to QRS duration, CRT-D was associated with better survival in both sexes with LBBB and QRS ≥130 ms, whereas there was no clear relation between QRS duration and survival in patients without LBBB regardless of patient sex.

CONCLUSIONS

In a large real-world population CRT-D was associated with a lower mortality risk in both sexes with LBBB, although more pronounced among women. Only among those with LBBB, both sexes had better survival with longer QRS duration. The mortality differences in patients without LBBB were attenuated in both sexes.

The mismatch between patient life expectancy and the service life of implantable devices in current cardioverter-defibrillator therapy: a call for larger device batteries

In 2005, Bob Hauser published a paper in the Journal of the American College of Cardiology entitled "The growing mismatch between patient longevity and the service life of Implantable Cardioverter-Defibrillators". Now, nearly a decade later, I would like to perform a second look on the problem of a mismatching between ICD device service life and the survival of ICD recipients. Since 2005, the demographics of the ICD population has changed significantly. Primary prevention has become the dominant indication in defibrillator therapy and device implantation is indicated more and more in earlier stages of cardiac diseases. In former larger scale ICD trials, the patient average 5-year survival probability was in a range of 68-71%; in newer CRT-D trials in a range of 72-88%. Due to a progressively widened ICD indication and implantation preferentially performed in patients with better life expectancy, the problem of inadequate device service life is of growing importance. The early days of defibrillator therapy started with a generator volume of 145 ccm and a device service life <18 months. In this early period, the device miniaturization and extension of service life were similar challenges for the technicians. Today, we have reached a formerly unexpected extent of device miniaturization. However, technologic improvements were often preferentially translated in further device miniaturization and not in prolonging device service life. In his analysis, Bob Hauser reported a prolonged device service life of 2.3 years in ICD models with a larger battery capacity of 0.54 up to 0.69 Ah. Between 2008 and 2014, several studies had been published on the problem of ICD longevity in clinical scenarios. These analyses included "older" and currently used single chamber, dual chamber and CRT devices. The reported average 5-year device service life ranged from 0 to 75%. Assuming today technology, larger battery capacities will only result in minimal increase in device volume. Selected ICD patients may further benefit from device miniaturization-but the vast majority may much more benefit from a significant prolongation in device service life. All published cost-effectiveness analyses in ICD therapy show that device costs and device service life are the dominant determinants of the results. The performed "second look-nearly a decade later" revealed that there are still relevant limitations regarding the device service life in current defibrillator therapy. Technical improvements were preferentially transformed into device miniaturization but not into prolonging device service life. But this optimization is strongly enforced. The most feasible solution might be the use of device batteries with larger capacities. The economic burden, mainly caused by non-adequate device service life, may limit the future realization of ICD therapy in a progressively growing patient population. In the former years, physicians and device manufacturers have ignored the patient perspective in defibrillator therapy. However, it is the patient viewpoint that prolonged device service life is much more important than smaller generator size.

Stratifying patients at the risk of heart failure hospitalization using existing device diagnostic thresholds

Background

Heart failure hospitalizations (HFHs) cost the US health care system ~$20 billion annually. Identifying patients at risk of HFH to enable timely intervention and prevent expensive hospitalization remains a challenge. Implantable cardioverter defibrillators (ICDs) and cardiac resynchronization devices with defibrillation capability (CRT-Ds) collect a host of diagnostic parameters that change with HF status and collectively have the potential to signal an increasing risk of HFH. These device-collected diagnostic parameters include activity, day and night heart rate, atrial tachycardia/atrial fibrillation (AT/AF) burden, mean rate during AT/AF, percent CRT pacing, number of shocks, and intrathoracic impedance. There are thresholds for these parameters that when crossed trigger a notification, referred to as device observation, which gets noted on the device report. We investigated if these existing device observations can stratify patients at varying risk of HFH.

Methods

We analyzed data from 775 patients (age: 69 ± 11 year, 68% male) with CRT-D devices followed for 13 ± 5 months with adjudicated HFHs. HFH rate was computed for increasing number of device observations. Data were analyzed by both excluding and including intrathoracic impedance. HFH risk was assessed at the time of a device interrogation session, and all the data between previous and current follow-up sessions were used to determine the HFH risk for the next 30 days.

Results

2276 follow-up sessions in 775 patients were evaluated with 42 HFHs in 37 patients. Percentage of evaluations that were followed by an HFH within the next 30 days increased with increasing number of device observations. Patients with 3 or more device observations were at 42× HFH risk compared to patients with no device observation. Even after excluding intrathoracic impedance, the remaining device parameters effectively stratified patients at HFH risk.

Conclusion

Available device observations could provide an effective method to stratify patients at varying risk of heart failure hospitalization.

Is mechanical dyssynchrony a therapeutic target in heart failure with preserved ejection fraction?

BACKGROUND

Previous studies have found a high frequency of mechanical dyssynchrony in patients with heart failure (HF) with preserved ejection fraction (HFpEF), hence suggesting that cardiac resynchronization therapy (CRT) may be considered in HFpEF. The present study was designed to compare the amount of mechanical dyssynchrony between HFpEF patients and (1) HF with reduced EF (HFrEF) patients with an indication for CRT (HFrEF-CRT(+)) group, (2) HFrEF patients with QRS duration < 120 ms (HFrEF-QRS < 120 ms) group, and (3) hypertensive controls (HTN).

METHODS

Electrical (ECG) and mechanical dyssynchrony (atrio-ventricular dyssynchrony, interventricular dyssynchrony, intraventricular dyssynchrony) were assessed using conventional, tissue Doppler, and Speckle Tracking strain echocardiography in 40 HFpEF patients, 40 age- and sex-matched HTN controls, 40 HFrEF-QRS < 120 ms patients, and 40 HFrEF-CRT(+) patients.

RESULTS

The frequency of left bundle branch block was low in HFpEF patients (5%) and similar to HTN controls (5%, P = 0.85). Indices of dyssynchrony were similar between HFpEF and HTN patients or HFrEF-QRS < 120 ms patients. In contrast, most indices of dyssynchrony differed between HFpEF and HFrEF-CRT(+) patients. The principal components analysis on the entire cohort of 160 patients yielded 2 homogeneous groups of patients in terms of dyssynchrony, the first comprising HFrEF-CRT(+) patients and the second comprising HTN, HFrEF-QRS < 120 ms and HFpEF patients.

CONCLUSIONS

Mechanical dyssynchrony in HFpEF does not differ from that of patients with HTN or patients with HFrEF and a narrow QRS. This data raises concerns regarding the role of dyssynchrony in the pathophysiology of HFpEF and thereby the potential usage of CRT in HFpEF.

Non-ventricular, Clinical, and Functional Features of the RyR2(R420Q) Mutation Causing Catecholaminergic Polymorphic Ventricular Tachycardia

INTRODUCTION AND OBJECTIVES

Catecholaminergic polymorphic ventricular tachycardia is a malignant disease, due to mutations in proteins controlling Ca(2+) homeostasis. While the phenotype is characterized by polymorphic ventricular arrhythmias under stress, supraventricular arrhythmias may occur and are not fully characterized.

METHODS

Twenty-five relatives from a Spanish family with several sudden deaths were evaluated with electrocardiogram, exercise testing, and optional epinephrine challenge. Selective RyR2 sequencing in an affected individual and cascade screening in the rest of the family was offered. The RyR2(R420Q) mutation was generated in HEK-293 cells using site-directed mutagenesis to conduct in vitro functional studies.

RESULTS

The exercise testing unmasked catecholaminergic polymorphic ventricular tachycardia in 8 relatives (sensitivity = 89%; positive predictive value = 100%; negative predictive value = 93%), all of them carrying the heterozygous RyR2(R420Q) mutation, which was also present in the proband and a young girl without exercise testing, a 91% penetrance at the end of the follow-up. Remarkably, sinus bradycardia, atrial and junctional arrhythmias, and/or giant post-effort U-waves were identified in patients. Upon permeabilization and in intact cells, the RyR2(R420Q) expressing cells showed a smaller peak of Ca(2+) release than RyR2 wild-type cells. However, at physiologic intracellular Ca(2+) concentration, equivalent to the diastolic cytosolic concentration, the RyR2(R420Q) released more Ca(2+) and oscillated faster than RyR2 wild-type cells.

CONCLUSIONS

The missense RyR2(R420Q) mutation was identified in the N-terminus of the RyR2 gene in this highly symptomatic family. Remarkably, this mutation is associated with sinus bradycardia, atrial and junctional arrhythmias, and giant U-waves. Collectively, functional heterologous expression studies suggest that the RyR2(R420Q) behaves as an aberrant channel, as a loss- or gain-of-function mutation depending on cytosolic intracellular Ca(2+) concentration.

Outcome of prolonged QRS interval in dilated cardiomyopathy: role of implantable cardioverter-defibrillators on mortality

AIM

The main objectives of this study were to investigate the relationship between prolonged QRS interval and its prognosis in patients with dilated cardiomyopathy (DCM), and to determine the effects of cardiac pacing with an implantable cardioverter-defibrillator (ICD) on mortality in patients with a QRS width > 150 ms.

METHODS

We retrospectively queried the healthcare enterprise data warehouse and the patient medical records from January 2007 to December 2012 for 1453 cases of DCM at a university- affiliated hospital. Of the 1453 cases, 989 patients were included in the final analyses. Primary outcome variable was all-cause mortality.

RESULTS

Of the 989 patients, 20% (n = 198) of the patients had a QRS width > 150 ms. Compared with patients who had a QRS < 120 ms, patients with a QRS > 150 ms had significantly higher rates of death (p < 0.001). Among the subgroup of 198 patients who had a QRS width > 150 ms, survival (84.3%, n = 75) was significantly higher (p < 0.001) in patients with a pacemaker inserted compared with those (45.0%, n = 49) who had not been paced.

CONCLUSIONS

Prolonged QRS interval is significantly associated with a higher rate of mortality. However, we believe that cardiac pacing with an ICD in such patients can significantly improve outcomes.

Effects of atrioventricular nodal ablation on permanent atrial fibrillation patients with cardiac resynchronization therapy: a systematic review and meta-analysis

Cardiac resynchronization therapy (CRT) is a well-established therapy for patients with heart failure (HF) and wide QRS configuration, especially for those in sinus rhythm. However, for those with permanent AF, atrioventricular nodal (AVN) ablation use remains under debate. Our objective was to evaluate clinical outcomes and mortality of AVN ablation in HF patients with permanent AF receiving CRT. Electronic publication database and reference lists through October 1, 2013 were searched. Observational cohort studies comparing CRT patients with AF who received either AVN ablation or medical therapy were selected. Outcomes included mortality, CRT nonresponse, changes in left ventricular remodeling, and functional outcomes, such as New York Heart Association (NYHA) functional class, quality of life, and 6-minute hall walk distance. Of 1641 reports identified, 13 studies with 1256 patients were included. Among patients with permanent AF and insufficient biventricular pacing (< 90%), those who had undergone AVN ablation compared to those who did not had numerically lower all-cause mortality (risk ratio [RR]: 0.63, 95% confidence interval [CI]: 0.42 to 0.96, P = 0.03) and significantly lower nonresponse to CRT (RR: 0.41, 95% CI: 0.31 to 0.54, P < 0.00001). Furthermore, AVN ablation was not associated with additional improvements on left ventricular ejection fraction, NYHA functional class, 6-minute hall walking distance, and quality of life. In patients with permanent AF undergoing CRT, AVN ablation tended to reduce mortality potentially and improved clinical response when it was applied to patients with inadequate biventricular pacing (< 90%). Randomized controlled trials are needed to further address the efficacy of AVN ablation among this population.

Hotline update of clinical trials and registries presented at the American College of Cardiology Congress 2014

This article provides information and commentaries on trials which were presented at the Hotline and Clinical Trial Update Sessions during the Late Breaking Clinical Trial Sessions at the 63rd annual meeting of the American College of Cardiology in Washington, USA, from 29th to 31st March 2014. This article gives an overview on a number of novel clinical trials in the field of cardiovascular medicine, which were presented. Comprehensive summaries have been generated from the oral presentation and the webcasts of the American College of Cardiology, similar to as previously reported and should provide the readers with the most comprehensive information of relevant publications. The discussed studies are US CoreValve, Choice, Symplcity-HTN-3, GRS, ZEUS, GIPS-III, HEAT-PPCI, COPR-2, MSC-HF, POISE-2, SIRS. The data were presented by leading experts in the field.

EAARN score, a predictive score for mortality in patients receiving cardiac resynchronization therapy based on pre-implantation risk factors

AIMS

The beneficial effects of CRT in patients with advanced heart failure, wide QRS, and low LVEF have been clearly established. Nevertheless, mortality remains high in some patients. The aims of our study were to identify the predictors of mortality in patients treated with CRT and to design a risk score for mortality.

METHODS AND RESULTS

A cohort of 608 consecutive patients treated with CRT from 2000 to 2011 in our centre was prospectively analysed. Baseline clinical and echocardiography variables were analysed and mortality data were collected. During a mean follow-up of 36.2 ± 29.2 months, 174 patients died: 123/174 (71%) due to cardiovascular causes, 25/174 (14%) non-cardiac causes, and 26/174 (15%) unknown aetiology. In a multivariate analysis the predictors of mortality were NYHA class IV [hazard ratio (HR) 2.54, 95% confidence interval (CI) 1.7-3.7, P < 0.001], glomerular filtration rate (GFR) <60 mL/min/1.73 m2 (HR 1.61, 95% CI 1.14-2.30, P = 0.008), AF (HR 1.67, 95% CI 1.19-2.3, P = 0.01), age ≥70 years (HR 1.44, (95% CI 1.04-2.00, P = 0.02), and LVEF <22% (HR 1.83, 95% CI 1.33-2.52, P ≤ 0.001). The EAARN score (EF, Age, AF, Renal dysfunction, NYHA class IV) summarizes the predictors. Each additional predictor increased the mortality: one predictor, HR 3.28 (95% CI 1.37-7.8, P = 0.008); two, HR 5.23 (95% CI 2.24-12.10, P < 0.001); three, HR 9.63 (95% CI 4.1-22.60, P < 0.001); and four or more, HR 14.38 (95% CI 5.8-35.65, P < 0.001).

CONCLUSION

The predictors of mortality have a significant add-on predictive effect on mortality. The EAARN score could be useful to stratify the prognosis of CRT patients.

Newer algorithms in bradycardia management

Permanent cardiac pacemakers (PPM) are effective in the treatment of bradycardia in a growing number of clinical scenarios. An appreciation of the capacity of PPMs to result in negative hemodynamic and proarrhythmic effects has grown alongside clinical experience with permanent pacing. Such experience has necessitated the development of algorithms aimed at optimizing device functionality across a broad spectrum of physiologic and pathologic conditions. This review highlights recent device-based algorithms used in automated threshold testing, reduction of right ventricular pacing, prevention and treatment of pacemaker-mediated tachycardia, mode switching for atrial tachyarrhythmias, rate-modulated pacing, and advances in arrhythmia storage and remote monitoring.