Cardiac resynchronization therapy in patients with a history of atrial fibrillation: insights from five major clinical trials

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): National Heart, Lung, and Blood Institute

Background

Many patients with heart failure who are considered for cardiac resynchronization therapy (CRT) have a history of (h/o) atrial fibrillation (AF) but there are doubts about the efficacy of CRT in patients with AF.

Purpose

To investigate the association of CRT on morbidity and mortality among patients with and without a h/o AF.

Methods

Original, patient-level data from five clinical trials of CRT that permitted enrolment of patients with a h/o AF were included: COMPANION, MADIT-CRT, BLOCK HF, REVERSE, and MIRACLE trial. Patients with permanent or persistent AF were excluded from these trials, and therefore from this analysis. The outcomes of interest were the composite endpoint of time to heart failure hospitalization (HFH) or all-cause mortality or all-cause mortality alone. The association of CRT (versus no CRT) with outcomes for patients with and without a h/o AF was assessed using a Bayesian-Weibull survival regression model with random terms for the trial-specific treatment effects and the trial-specific baseline hazard functions including an interaction between history of paroxysmal AF and CRT. All results are presented as hazard ratios (HRs) with 95% posterior credible intervals (CIs) and posterior probabilities of no association, adjusting for baseline characteristics.

Results

A total of 4062 patients were included, 661 (16.3%) of whom had a h/o AF. Patients with a h/o AF were older (mean [SD] age 68 [10] years versus 64 [11] years) and had a higher proportion of ischemic cardiomyopathy (67% versus 53%, p<0.001), a higher baseline serum creatinine (1.3 mg/dl versus 1.2 mg/dl, p<0.001), and a lower left ventricular ejection fraction (25% versus 26%, p<0.001). The HRs for all outcomes and the interaction term are shown in Table 1. For the overall population, CRT delayed the time to HFH or all-cause mortality (HR: 0.74, 95% CI: 0.62 – 0.87, p=0.005); for patients with a h/o AF, it did not (HR: 0.87, 95% CI: 0.64 to 1.19, p=0.37). In this patient-level meta-analysis, CRT was not associated with a reduction in mortality, overall or by h/o AF. Howevber, the interaction (estimate shown as a ratio of HRs) between those with or without a h/o AF and the effects of CRT was not significant for either outcome (Table 1).

Conclusion

In the largest post hoc analysis to date, we confirm the benefits of CRT in patients without a h/o AF in reducing HFH or mortality. There was no statistically significant interaction between CRT and h/o AF for any analysed outcome.

Intraoperative defibrillation testing during replacements of implantable cardioverter-defibrillators: The Simpler trial

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): Maurice Kahn Foundation via the Mayo- Sheba Collaboration Fund.

Background

The need for intraoperative defibrillation testing (DFT) during implant and/or replacement of implantable cardioverter-defibrillators (ICDs) has been a matter of debate for many years. This debate was put to rest by the Simple and the Nordic ICD trials, and the practice of testing during new implantations has practically been nearly abandoned.

Nevertheless, induction of VF for testing purposes (VFT) may still have an important role in selective populations at risk for defibrillation failure, who were not included in the SIMPLE and Nordic trials. One such population includes those who undergo device replacements. Old registries demonstrated an increased incidence of significant findings in VFT during replacements. In the present study, we sought to test this observation.

Objectives

Evaluate frequency of significant findings and the safety of VFT in subjects undergoing device replacement.

Methods

A prospective observational multi-center study of VFT included consecutive patients undergoing ICD generator replacement in 5 centers in Israel, Europe, and the US. All centers followed the same VFT protocol. The primary outcome was defined as failure to terminate induced VF with a single shock at 10 Joules below the maximal capacity of the device. Secondary outcomes included complications of VFT. Patients were followed-up at 1 month and 6 months post-procedure. Data collection included documentation of any peri-operative complications and clinical endpoints (occurrence of appropriate shock, inappropriate shocks, lead failure, need for re-intervention, and infection).

Results

A total of 92 patients were eligible, and consented for the study, of which 84 underwent DFT during battery replacement. The median age was 68 years and 79.8% were male subjects. Induction of VF was successful in all 84 patients as well as VFT with a successful conversion on first attempt. During follow up one patient had two appropriate ICD shock events. In four patients, the ICD programming was changed. None suffered an inappropriate shock. There was no evidence of lead malfunction. A total of two deaths occurred, none of which were related to the device.

Conclusion

The present study found VFT was not associated with complications in patients undergoing ICD/CRTD generator replacement but produced no clinically important information.

Utility of device-derived daily activity, a novel digital biomarker, to predict ventricular arrhythmias – data from the CERTITUDE registry

Background

While there have been prior studies showing an association between activity and outcomes, there have been no studies examining the temporal relationship between device-derived daily activity, a novel digital biomarker, and ventricular tachyarrhythmias (VT).

Purpose

In a big dataset with over 55,000 pacemaker, ICD, and CRT devices, we aimed to identify whether changes in activity predict VT, or else VT predict changes in activity.

Methods

The CERTITUDE registry comprises a de-identified database of over 55,000 U.S. BIOTRONIK pacemaker, ICD, CRT devices, and loop recorders active on Home Monitoring®. Daily data on leads, arrhythmias, and physiological parameters such as activity are captured. Patient activity is reported daily as percentage active during the day, assessed by a one-axis accelerometer at ∼0.4 Hz frequency. Analysis to ascertain temporal changes in device-derived activity associated with treated VT was performed using the first event per device and 7-day activity windows (baseline, pre- and post-event). Baseline period was defined as 31–38 days prior to VT. VT events were categorized by heart rate (≤200 bpm,>200 bpm) and treatment (shock with or without ATP, ATP alone). Differences in activity between baseline, and pre- and post-VT were analyzed using the binomial proportion test.

Results

A total of 16,475 devices (9732 ICDs, 6743 CRT-Ds) had activity data available for analysis. The cumulative follow-up duration was 18,355 years (5.6 million days with transmission). Of the 2636 VT events analyzed, 1409 had a heart rate >200 bpm, and 593 were treated with shock. Patients with VT events >200 bpm treated with shock had a significant reduction in activity post-VT with a median −8.7% reduction (IQR −24.6%; 7.3%, p<0.001). However, there was no reduction in activity before the VT>200 bpm (p=0.690) (Figure). VT events >200 bpm treated with ATP alone were not associated with reduction in activity before or after the episode. Similarly, VT events ≤200 bpm treated with shock were also associated with a reduction in activity following the event (−5.8%, IQR −29.5, 12.3%, p=0.003), but not prior to the VT event.

Conclusions

In this report from the CERTITUDE registry, we have shown a temporal decline in device-derived activity following ventricular arrhythmias>200 bpm and ≤200 bpm treated with a shock, but not in patients treated with ATP. Monitoring device-derived activity post-VT events with a shock could provide relevant clinical information and potentially warrant intensified treatment.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Biotronik

Lateral left ventricular lead position is superior to posterior position in long-term outcome of patients underwent cardiac resynchronization therapy

Background

Preferring side branch of coronary sinus during cardiac resynchronization therapy (CRT) implantation is empirical due to the limited data on the association of left ventricular (LV) lead position and long-term clinical outcome.

Purpose

We evaluated the long-term all-cause mortality by LV lead non-apical positions and further characterized them by interlead electrical delay (IED).

Methods

In our retrospective database 2087 patients were registered between 2000 and 2018. Those with non-apical LV lead locations were classified into anterior (n=108), posterior (n=643), and lateral (n=1336) groups. All-cause mortality was assessed by Kaplan-Meier and Cox analyses. Echocardiographic response was measured 6 months after CRT implantation.

Results

During the median follow-up time of 3.7 years, 1150 (55.1%) patients died, 710 (53.1%) with lateral, 78 (72.2%) with anterior and 362 (56.3%) with posterior positions. Patients with lateral position had significantly better outcome in all-cause mortality compared to others (HR 0.80; 95% CI: 0.71–0.90; p<0.0001), which was also confirmed by multivariate analysis after adjusting for relevant clinical covariates (HR 0.81; 95% CI: 0.72–0.91; p<0.0001). When echocardiographic response was evaluated in the lateral group, patients with an IED longer than 110 ms (ROC AUC 0.63; 95% CI: 0.53–0.73; p=0.012) showed 2.1 times higher odds of improvement in echocardiographic response 6 months after the implantation.

Conclusions

In this study we proved that after CRT implantation only the lateral LV lead location was associated with long-term mortality benefit. Moreover, patients with this position showed the greatest echocardiographic response over 110 ms IED.

Survival of total patient cohort

Funding Acknowledgement

Type of funding source: None

40Lateral left ventricular lead position and long interlead electrical delay predict long-term all-cause mortality in cardiac resynchronization therapy patients

Background

There is limited data on the association of left ventricular (LV) lead position and long-term clinical outcome in patients after cardiac resynchronization therapy (CRT).

Purpose

We evaluated the mid-term echocardiographic response and long-term all-cause mortality of patients who underwent CRT implantation by LV lead non-apical positions and further characterized them by right to left ventricular, interlead electrical delay (IED).

Methods

In our retrospective registry patients after CRT implantation between 2000 and 2018 were registered. Those with non-apical LV lead location were classified into anterior (n = 111), posterior (n = 652), and lateral (n = 1373) positions. Primary endpoint was all-cause mortality assessed by univariate- and Cox multivariate analyses. Secondary endpoint was echocardiographic response within 6 months after CRT implantation.

Results

From 2136 patients 1180 (55.2%) reached the primary endpoint during the mean follow up time of 4.5 years. Univariate analysis showed patients with lateral position had significantly better outcome compared to others (HR 0.80; 95% CI: 0.71-0.90; p < 0.01), which was also confirmed by Cox multivariate analysis (HR 0.69; 95% CI: 0.50-0.93; p = 0.02) after adjusting for relevant clinical covariates such as IED and LBBB. The median value of IED was 106 (89/124) ms in the total patient cohort, which was significantly longer in the lateral group [anterior 80 (60/100) ms vs. lateral 110 (91/128) ms vs. posterior 100 (85/120) ms; p< 0.01]. When echocardiographic response was further evaluated in patients with lateral position, those with an IED longer than 110 ms (ROC AUC 0.64, 95% CI: 0.54-0.74; p = 0.01) showed the greatest benefit within 6 months.

Conclusions

After CRT implantation the most beneficial outcome was associated with lateral left ventricular lead location, moreover the greatest echocardiographic response was found when interlead electrical delay was longer than 110 ms in this group.

Abstract Figure. All-cause mortality of total cohort

P3517Failure to achieve adequate heart rate control in women during therapy optimization

Background

Previous studies highlighted the importance of adequate heart rate control in heart failure patients, and suggested under-treatment with beta-blockers especially in women. However, data on women achieving effective heart rate control during beta-blocker therapy optimization are lacking.

Methods

The wearable cardioverter defibrillator (WCD) allows continuous monitoring of heart rate (HR) trends during WCD use. In the current study, we assessed resting HR trends (nighttime: midnight-7am) in women, both at the beginning of WCD use and at the end of WCD use to assess the adequacy of beta-blockade following a typical 3 months of therapy optimization with beta-blockers. An adequate heart rate control was defined as having a nighttime HR <70 bpm at the end of the 3 months.

Results

There were a total of 21,453 women with at least 30 days of WCD use (>140 hours WCD use on the first and last week). The mean age was 67 years (IQR 58–75). The mean nighttime heart rate was 72 bpm (IQR 65–81) at the beginning of WCD use, that decreased to 68 bpm (IQR 61–76) at the end of WCD use with therapy optimization. Women had an insufficient heart rate control with resting heart rate ≥70 bpm in 59% at the beginning of WCD use that decreased to 44% at the end of WCD use, but still remained surprisingly high. Interestingly, there were 21% of the women starting with HR ≥70 bpm at the beginning of use (BOU) who achieved adequate heart rate control by the end of use (EOU). Interestingly, 6% of women with adequate heart rate control at the start of therapy optimization ended up having higher heart rates >70 bpm at the end of the therapy optimization time period (Figure).

Figure 1

Conclusions

A significant proportion of women with heart failure and low ejection fraction do not reach an adequate heart rate control during the time of beta blocker initiation/titration. The wearble cardioverter defibrillator is a monitoring device that has been demonstrated in this study to appropriately identify patients with inadequate heart rate control at the end of the therapy optimization period. The WCD could be utilized to improve management of beta-blocker therapy in women and improve the achievement of adequate heart rate control in women.

P2277Utility of cardiovascular implantable electronic device (CIED)-derived patient activity, a novel digital biomarker, to predict inappropriate therapy

Background

The role of cardiovascular implantable electronic device (CIED)-derived activity to predict inappropriate implantable cardioverter-defibrillator (ICD) therapy is not known. The Multicenter Automatic Defibrillator Implantation Trial – Reduce Inappropriate Therapy (MADIT-RIT) enrolled 1500 patients with contemporary indication for an ICD or a CRT-D. We aimed to identify whether activity, as a digital biomarker, predicted inappropriate therapy.

Methods

In 1500 patients enrolled in MADIT-RIT, CIED-derived patient activity was acquired daily. CIED-derived activity was averaged for the first 30 days following randomization and utilized in this study to predict inappropriate therapy post- 30-day. Kaplan-Meier survival analysis and multivariate Cox proportional hazards regression models were used to evaluate first inappropriate therapy by 30-day CIED-derived patient activity quintiles, and by 30-day device derived patient activity as a continuous measurement.

Results

There were a total of 1463 patients with activity data available (90%), 135 patients received at least one inappropriate therapy during the post-30 day follow-up period. Patients in the highest quintile (Q5) of CIED-derived activity (more active) were younger, more often males and more likely to have had a prior ablation of an atrial arrhythmia. Patients in the highest quintile of 30-day CIED-derived median activity had the highest risk of receiving inappropriate therapy, 21% at 2 years as compared 7–11% in the other four quintiles (Figure, p<0.001 for the overall duration). Patients with the highest level of 30-day median patient activity (Q5) had 1.75 times higher risk of any inappropriate therapy as compared with lower levels of activity, Q1-Q4 (HR=1.75, 95% CI: 1.23–2.50, p<0.002). Each 10% increase in CIED-derived 30-day median patient activity was associated with a significant, 73% increase in risk of receiving inappropriate therapy (HR=1.73, 95% CI: 1.17–2.54, p=0.005). Patients in the highest quintile for activity had a 68% increase in the risk of SVT excluding atrial fibrillation, atrial flutter or atrial tachycardia (HR=1.69, 95% CI: 1.26–2.25, p=0.004), despite 96% receiving beta-blocker medications.

Inappropriate ICD Therapies by Activity

Conclusions

CIED-derived 30-day median patient activity predicted subsequent inappropriate therapy in ICD and CRT-D patients enrolled in MADIT-RIT. Patients with high levels of 30-day CIED-derived median patient activity were at a significantly higher risk of receiving inappropriate therapy. Activity, as a digital biomarker, may have utility in predicting and managing the risk of inappropriate therapy in this population.

Acknowledgement/Funding

Boston Scientific

P2278Risk of life-threatening ventricular tachyarrhythmia events in diabetes patients with higher ejection fraction in MADIT-CRT

Background

Data on the risk of life-threatening ventricular tachyarrhythmia events in diabetes patients with mild heart failure (HF) and higher ejection fraction (LVEF) are not currently known.

Objective

We aimed to assess the risk of life-threatening ventricular tachyarrhythmia events in mild HF patients with diabetes in patients with baseline LVEF ≤30% or >30%.

Methods

We evaluated the risk of life-threatening VT/VF treated with shock in mild HF patients with diabetes, by those with LVEF ≤30% or >30%, enrolled in MADIT-CRT. Kaplan-Meier analysis and multivariate adjusted Cox regression models were utilized.

Results

Out of 542 mild HF patients with diabetes and VT/VF data, 206 (38%) had LVEF >30% and 336 (62%) had LVEF ≤30%. The 5-year cumulative probability of VT/VF treated with shock was 15% in patients with diabetes LVEF >30% as compared to the 15% probability in patients with diabetes and LVEF ≤30% (p=0.342 for the overall difference in event rates during follow-up) (Figure). In Cox models, the risk of VT/VF treated with shock was similar in diabetes patients with LVEF>30% and LVEF ≤30% (HR=0.88, 95% CI= 0.51–1.53, p=0.647) after adjustment for age, ischemic etiology, prior ventricular or atrial arrhythmia, and CRT-D-LBBB interaction. The risk of VT/VF treated with shock was similar regardless of LVEF in both CRT-D patients (HR=1.09, p=0.830) and ICD only patients (HR=0.67, p=0.345).

Conclusion

Diabetes patients with an LVEF >30% are at similarly high risk of life-threatening ventricular tachyarrhythmias to patients with LVEF≤30%. Our findings highlight the need for further investigation and treatment of this uniquely high-risk patient cohort with a higher ejection fraction.

Acknowledgement/Funding

MADIT-CRT was funded by an unrestricted research grant from Boston Scientific to the University of Rochester.

4301Diastolic dysfunction is an independent predictor of adverse events in patients with systolic dysfunction. Insights from the MADIT-CRT trial

Background

Diastolic dysfunction (DD) is common in patients with heart failure with reduced ejection fraction (HFrEF). However, its prognostic relevance in HFrEF, on top of conventional risk factors including natriuretic peptides, is unknown

Purpose

To show the prognostic contribution of DD in HFrEF

Methods

We analyzed 1155 baseline echocardiograms (63% of all available exams) in the MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy) study, comprising HFrEF patients with LVEF≤30%, QRS duration ≥130 ms, and NYHA class I/II. We classified DD according to ASE 2016 classification, based on transmitral Doppler velocities, mitral annular Tissue Doppler velocities, pulmonary venous flow velocities, and left atrial volumes. Using Cox regression and C-statistics we assessed the independent prognostic value of DD for nonfatal HF or death. We also evaluated CART (Classification And Regression Tree) analysis

Results

Patients were 64±11 years-old, 24% females, and mean LVEF was 24±5%. While 45% had impaired relaxation, 33% had pseudo-normal filling, 12% restrictive patter, 6% had indeterminate diastolic function, and 4% were not classifiable due to missing data. During a mean follow-up of 2.1±1.0 years, there were 233 adverse events. After multiple adjustment, compared to patients with impaired relaxation, those with pseudo-normal and restrictive filling had greater risk of HF/death (respectively HR 1.76, 95% CI 1.16–2.66, p=0.007; HR 2.70, 95% CI 1.58–4.60, p<0.001), independently of assigned treatment (p-interaction 0.34). Adding DD to conventional markers of risk improved prediction (C-statistic 0.733, 95% CI 0.689–0.776 versus 0.708, 95% CI 0.663–0.753, p=0.024). Finally, at CART analysis DD was the first parameter to be considered to risk stratify patients (Figure)

Risk stratification tree

Conclusions

DD is a strong independent predictor of death or heart failure in HFrEF patients with mild symptoms and should be considered in assessment of risk in this population

2179Clinical significance of device-derived activity in ICD and CRT-D patients - Data from MADIT-RIT

Background

The Multicenter Automatic Defibrillator Implantation Trial – Reduce Inappropriate Therapy (MADIT-RIT) enrolled 1500 patients and showed that novel ICD programming reduced inappropriate therapy and improved survival. However, the role of device-derived patient activity to predict mortality is not known.

Methods

In 1500 patients enrolled in MADIT-RIT, device-derived patient activity was captured daily. Device-derived activity was averaged for the first 30 days following randomization, and utilized in this study to predict mortality post-30 days. Kaplan-Meier survival analysis and multivariate Cox proportional hazards regression models were used to evaluate all-cause mortality by 30-day device derived patient activity quintiles, and as a 3-level function of 30-day device derived patient activity (Q1, Q2–3, Q4–5).

Results

There were a total of 1463 patients with data available (98%), 66 of them died during the follow-up post-30 days. Patients in the lowest quintile (Q1: 4%∼1 hour daily activity) of device-derived activity were older, they were more often female, and they more often had diabetes and NYHA class III HF symptoms. Patients in the lowest quintile of 30-day device derived median activity (1 hour daily activity) had the highest risk of mortality, 15% in 2 years as compared to Q2–3 (1–2 hours daily activity, 8–7% 2-year mortality), and Q4–5 (>2 hours daily activity, 2–3% 2-year mortality) (Figure, p<0.001 for the overall duration). Each quintile decrease in device-derived 30-day median patient activity was associated with a significant, 41% increase in mortality (HR=1.41, 95% CI: 1.15–1.71, p=0.001). Patients with the lowest level of 30-day median patient activity (Q1) had 4.13-times higher risk of mortality as compared to the highest level of activity patients, Q4–5 (HR=4.13, 95% CI: 1.89–9.03, p<0.001). Patients with intermediate levels of activity (Q2–3) still had a 2.8-fold increase in death as compared to the highest activity level cohort of patients (HR=2.79, 95% CI: 1.31–5.91, p=0.008).

Figure 1

Conclusions

Device-derived 30-day median patient activity predicted subsequent all-cause mortality in ICD and CRT-D patients enrolled in MADIT-RIT. Patients with low and moderate levels of 30-day device-derived median patient activity (less than 2 hours daily activity) were at a significantly higher risk of death, and these cohorts warrant further investigation and management to improve outcomes.

Acknowledgement/Funding

MADIT-RIT was funded by an unrestricted research grant from Boston Scientific to the University of Rochester.

P2281Inadequate heart rate control begets sustained ventricular arrhythmias in a large cohort of women

Background

The Wearable Cardioverter Defibrillator (WCD) is an effective therapy for treating ventricular arrhythmias (VT/VF) in at-risk patients, while providing continuous heart rate (HR) monitoring. Because women are under-represented in defibrillator trials, we chose to specifically focus on HR control in women prior to VT/VF events.

Purpose

To evaluate HR profiles preceding sustained VT/VF in women fitted with a WCD.

Methods

Data from women fitted with WCD (≥30 days use) from 2015 to 2018 were obtained from the manufacturer's database. HR is expressed as a weekly resting nighttime median (midnight to 7 am). Men (random sample) with the same inclusion criteria served as a control.

Results

A total of 21,440 women, age 67±15 years, were included for analysis. Over a median WCD use of 90 days (59–116 days), 118 women (0.6%) and 133 men (0.8%) received shocks for VT/VF (p=0.01). Resting HR one-week preceding VT/VF was above the target of 70bpm in 55% of shocked women (65 of 118) versus 44% of non-shocked women (9,272 of 21,322, p=0.01) (figure). HR one week before WCD shock was similar in women and men (71 bpm vs. 72 bpm; p=0.60). Younger women (≤50 years) had higher HR prior to shock than older women (HR 80 bpm vs. 70 bpm p=0.003). Among shocked patients, 24-hour-survival was 89% in women and 88% in men. During three-month follow-up, the same percentage of men and women died after receiving adequate WCD shock therapy (18%).

Heart rate profiles

Conclusions

Women with adequate heart rate control experienced significantly less spontaneous VT/VF than those with higher heart rates. The WCD can be utilized as a diagnostic tool to monitor HR in at-risk women in addition to treating sustained VT/VF.

P1462Return to physical activity among women following newly diagnosed dilated cardiomyopathy or myocardial infarction

Background

Resuming activity following a new diagnosis of dilated cardiomyopathy (DCM) or myocardial infarction (MI) is important for improvements in morbidity and mortality. Activity is also associated with an improved ejection fraction (EF) and lower risk of reinfarction. Patient management could benefit from having normative values and expected gains in activity early following diagnosis of DCM or MI.

Purpose

Assess the change in activity among women for the first 30 days after hospital discharge following a new DCM diagnosis or MI.

Methods

Female adult patients prescribed a wearable cardioverter defibrillator (WCD) for a diagnosis of DCM (n=3550) or MI (n=1422) with low EF were included. Step count was measured by WCD accelerometer. Change in activity over time was analyzed, including weekly percentage gains.

Results

Women with DCM were significantly younger (64, SD = 13) than women post-MI (67, SD = 12). Median daily step count across the entire 30-day period was 4093 (IQR: 2123–6609). Women with DCM demonstrated a higher step count compared to women post-MI, 4405 (IQR: 2348–6986) and 3352 (IQR: 1644–5709), respectively, even after correcting for the difference in age between the groups. The greatest increases in activity for all occurred from week 1 to week 2. Women with DCM or post-MI had a 15.4% and 19.1% increase, respectively. Incremental increases in activity continued throughout the month.

Conclusion

Physical activity among women with newly diagnosed DCM or MI and a low EF increased within the first 30 days. The most significant increase occurred from week 1 to week 2. This data can be used as a benchmark to develop and assess prescriptive activity programs for women.

2403Experience with the wearable cardioverter-defibrillator by disease etiology: results from the wearit-II registry

Background

The use of the wearable cardioverter-defibrillator (WCD) in patients with non-ischemic cardiomyopathy has been less characterized.

Objective

We aimed to characterize WCD use and outcomes for patients with ischemic or non-ischemic cardiomyopathy, enrolled in the WEARIT-II Registry.

Methods

In WEARIT-II, we stratified 1,732 patients into ischemic (n=805) and non-ischemic etiology (n=927). WCD wear time, arrhythmia events during WCD use, and implantable cardioverter-defibrillator (ICD) implantation rates, or ejection fraction (EF) improvement at the end of WCD were evaluated for etiology subgroups.

Results

The WCD median wear time was higher in patients with non-ischemic cardiomyopathy (93 vs. 87 days, p=0.003), however daily use was similar (22.4 vs. 22.6 hours, p=0.07). There were 24 ischemic patients (3%) with sustained VT/VF events compared to 10 patients (1%) with non-ischemic cardiomyopathy (p=0.013). About 2/3 of these events were treated with WCD shock in ischemic patients, half of them in the non-ischemic group (1.9% vs. 0.4%). Atrial arrhythmias were frequent in both groups (3.1% vs. 3.1%, p=0.06). At the end of WCD use, 36% of the non-ischemic patients were implanted with an ICD compared to 42% in ischemic (p=0.01), likely due to the lower rate of sustained ventricular arrhythmias (Figure).

Figure 1

Conclusions

In WEARIT-II, patients with non-ischemic cardiomyopathy had longer WCD use than ischemic patients with good compliance. The rate of sustained ventricular arrhythmia events was lower in non-ischemic patients avoiding the need for an ICD implantation in more patients compared to ischemic, following a time period of risk stratification.

Acknowledgement/Funding

WEARIT-II was funded by an unrestricted research grant from ZOLL Inc.

3152Right ventricular function and long-term outcomes in cardiac resynchronization therapy patients enrolled in MADIT-CRT

Background

Long-term predictive value of baseline right ventricular (RV) function and CRT-induced changes of RV function for the clinical outcomes, mortality or heart failure are not well understood, especially in mild HF patients implanted with CRT-D.

Methods

MADIT-CRT enrolled 1,820 patients at 110 centers worldwide, with either ischemic cardiomyopathy (New York Heart Association [NYHA] functional class I or II), or non-ischemic cardiomyopathy (NYHA functional class II only), sinus rhythm, ejection fraction of 30% or less, and a QRS duration of 130 ms or more. We assessed right ventricular function (RVF) as RV fractional area change by echocardiography at baseline and after 1 year of therapy in patients with LBBB assigned to CRT arm (n=633). Kaplan-Meier survival analyses and multivariate Cox models were utilized to identify RV parameters predicting long-term outcomes of HF or death events.

Results

During the median follow up of 5.6 years 192 (30.3%) patients had heart failure or death. CRT-D LBBB patients with below or above median RV end-systolic area (RVS) had lower cumulative probabilities of HF/death (p=0.02). Lower, than the median value of both RVS and RVF were associated with higher risk of HF events alone (p=0.004; p=0.01 respectively). In multivariate analysis, after adjustment of relevant clinical covariates more RV reverse remodeling in the terms of RV end-diastolic area (RVD) decrease proved to be an independent predictor for 5-year all-cause mortality (HR: 0.4; p=0.03).

Kaplan-Meier analysis of baseline RVF

Conclusions

Based on our results RV geometry and function before CRT implant and also significant RV reverse remodeling at 12 months follow up are significant predictors of long-term outcomes.