Effect of Continued Cardiac Resynchronization Therapy on Ventricular Arrhythmias After Left Ventricular Assist Device Implantation

Appropriate and inappropriate ICD shocks in patients with LVADs: Prevalence, associated factors, and etiologies

BACKGROUND

Implantable cardioverter-defibrillator (ICD) shocks are a common complication after left ventricular assist device (LVAD) implantation; however, data on their frequency and causes are limited.

OBJECTIVE

The purpose of this study was to define the incidence, programming, patient characteristics, and factors associated with appropriate and inappropriate ICD shocks in persons with LVADs.

METHODS

We performed a retrospective review at Duke University Hospital of all LVAD recipients implanted between January 1, 2013, to June 30, 2019, with a preexisting ICD. ICD shocks were adjudicated by the treating physician and a second reviewer for the purpose of this study.

RESULTS

Among 421 patients with an ICD in situ undergoing LVAD implant, 147 (33.9%) had at least 1 shock after LVAD implantation. Among 134 patients with complete device history, a total of 330 shock episodes occurred: 255 (77.3%) appropriate and 75 (22.7%) inappropriate. Etiologies for inappropriate shocks included supraventricular tachycardia (n = 66 [20.0%]), physiological oversensing (n = 1 [0.3%]), and nonphysiological oversensing (n = 8 [2.4%]) including LVAD electromagnetic interference (n = 1 [0.3%]). ICD programming with shorter detection delay (P <.001) and absence of antitachycardia pacing programming (P = .001) in high-rate zones was seen more commonly in inappropriate shock than appropriate shock.

CONCLUSIONS

The rate of inappropriate shocks in LVAD recipients is very high and most often is due to supraventricular arrhythmias. LVAD electromagnetic interference is a rare cause of ICD shock. Implementation of current consensus American Heart Association recommendations for LVAD programming with long detection delays and high rate cutoffs may help prevent inappropriate ICD shocks.

Impact of Cardiac Resynchronization Therapy on Ventricular Arrhythmias and Survival After Durable Left Ventricular Assist Device Implantation

The impact of cardiac resynchronization therapy (CRT) in patients receiving durable left ventricular assist device (LVAD) implantation remains unclear and there is no consensus regarding postoperative management. We sought to determine the impact of postoperative management of CRT on clinical outcomes following LVAD implantation. A total of 789 patients underwent LVAD implantation at our institution from 2007 to 2022 including 195 patients (24.7%) with preoperative CRT. Patients with preoperative CRT were significantly older and more frequently received an LVAD as destination therapy compared to patients without preoperative CRT. After LVAD implantation, 85 patients had CRT programmed "off" and 74 patients had CRT programmed "on." The risk of mortality was significantly increased amongst patients with preoperative CRT that was turned "on" following LVAD implantation compared to patients with preoperative CRT turned "off" following implant (subdistribution hazard ratio [sdHR] = 1.54; 1.06-2.37 95% confidence interval [CI]; p = 0.036). There was no significant difference between incidence of ventricular arrhythmias in patients with and without postoperative CRT "on" (35.1% vs . 48.2%; p = 0.095). Additional clinical trials are warranted to determine the best CRT programming strategy following LVAD implantation.

Managing ventricular arrhythmias and implantable cardiac defibrillator shocks after left ventricular assist device implantation

Continuous flow left ventricular assist devices (CF-LVADs) have been shown to reduce mortality and morbidity in patients with advanced heart failure with reduced ejection fraction. However, ventricular arrhythmias (VA) are common, are mostly secondary to underlying myocardial scar, and have a higher incidence in patients with pre-LVAD VA. Sustained VA is well tolerated in the LVAD patient but can result in implantable defibrillator (ICD) shocks, right ventricular failure, hospitalizations, and reduced quality of life. There is limited data regarding best practices for the medical management of VA as well as the role for procedural interventions in patients with uncontrolled VA and/or ICD shocks. Vast majority of CF-LVAD patients have a preexisting cardiovascular implantable electronic device (CIED) and ICD and/or cardiac resynchronization therapies are continued in many. Several questions, however, remain regarding the efficacy of ICD and CRT following CF-LVAD. Moreover, optimal CIED programming after CF-LVAD implantation. Therefore, the primary objective of this review article is to provide the most up-to-date evidence and to provide guidance on the clinical significance, pathogenesis, predictors, and management strategies for VA and ICD therapies in the CF-LVAD population. We also discuss knowledge gaps as well as areas for future research.

Short-term study of atrial shunt and improvement of functional mitral regurgitation

BACKGROUND

This study used an atrial septal shunt to compare the treatment progress and prognosis for patients with heart failure (HF) who have different ejection fractions.

METHODS

Twenty HF patients with pulmonary hypertension, who required atrial septal shunt therapy, were included in this study. The patients underwent surgery between December 2012 and December 2020. They were divided into two groups based on their ejection fraction: a group with reduced ejection fraction (HFrEF) and a group with preserved ejection fraction(HFpEF) + mid-range ejection fraction (HfmrEF). Echocardiography was utilized to evaluate parameters such as left ventricular dimension (LVD), left ventricular ejection fraction (LVEF), and left ventricular end-diastolic volume (LVEDV). Hemodynamic parameters were measured using cardiac catheterization. The patient's cardiac function was assessed using the six-minute walking test (6MWT), KCCQ score, NYHA classification, and the degree of functional mitral regurgitation (FMR). Followed-up visits were conducted at 1, 3, and 6 months, and any adverse effects were recorded.

RESULTS

The LVEF values were consistently higher in the HFpEF+HFmrEF group than HFrEF group at all periods (P < 0.05). Differences in LVD were observed between the two groups before the surgery. Statistically, significant differences were found at the preoperative stage, 1 month, and 3 months (P < 0.05, respectively). However, the LVEDV showed a significant difference between the two groups only at 3 months (P = 0.049). Notably, there were notable variations in LAPm, LAPs, and the pressure gradient between the LA-RA gradient at baeline, after implantation, and during the 6 months follow-up (all P < 0.05).

CONCLUSION

Following treatment, the HFpEF+HFmrEF group exhibited more significant improvements in echocardiographic and cardiac catheterization indices than the HFrEF group. However, there was no statistically significant difference between the two groups regarding the 6MWT and KCCQ scores. It is important to note that the findings of this study still require further investigation in a large sample size of patients.

2023 HRS/APHRS/LAHRS guideline on cardiac physiologic pacing for the avoidance and mitigation of heart failure

Cardiac physiologic pacing (CPP), encompassing cardiac resynchronization therapy (CRT) and conduction system pacing (CSP), has emerged as a pacing therapy strategy that may mitigate or prevent the development of heart failure (HF) in patients with ventricular dyssynchrony or pacing-induced cardiomyopathy. This clinical practice guideline is intended to provide guidance on indications for CRT for HF therapy and CPP in patients with pacemaker indications or HF, patient selection, pre-procedure evaluation and preparation, implant procedure management, follow-up evaluation and optimization of CPP response, and use in pediatric populations. Gaps in knowledge, pointing to new directions for future research, are also identified.

2023 HRS/APHRS/LAHRS guideline on cardiac physiologic pacing for the avoidance and mitigation of heart failure

Cardiac physiologic pacing (CPP), encompassing cardiac resynchronization therapy (CRT) and conduction system pacing (CSP), has emerged as a pacing therapy strategy that may mitigate or prevent the development of heart failure (HF) in patients with ventricular dyssynchrony or pacing-induced cardiomyopathy. This clinical practice guideline is intended to provide guidance on indications for CRT for HF therapy and CPP in patients with pacemaker indications or HF, patient selection, pre-procedure evaluation and preparation, implant procedure management, follow-up evaluation and optimization of CPP response, and use in pediatric populations. Gaps in knowledge, pointing to new directions for future research, are also identified.

Clinical characteristics and outcomes of patients with ventricular arrhythmias after continous-flow left ventricular assist device implant

Background

Ventricular arrhythmias (VAs) are observed in 25%–50% of continuous‐flow left ventricular assist device (CF‐LVAD) recipients, but their role on mortality is debated.

Methods

Sixty‐nine consecutive patients with a CF‐LVAD were retrospectively analyzed. Study endpoints were death and occurrence of first episode of VAs post CF‐LVAD implantation. Early VAs were defined as VAs in the first month after CF‐LVAD implantation.

Results

During a median follow‐up of 29.0 months, 19 patients (27.5%) died and 18 patients (26.1%) experienced VAs. Three patients experienced early VAs, and one of them died. Patients with cardiac resynchronization therapy (CRT‐D) showed a trend toward more VAs (p = 0.076), compared to patients without CRT‐D; no significant difference in mortality was found between patients with and without CRT‐D (p = 0.63). Patients with biventricular (BiV) pacing ≥98% experienced more frequently VAs (p = 0.046), with no difference in mortality (p = 0.56), compared to patients experiencing BiV pacing <98%. There was no difference in mortality among patients with or without VAs after CF‐LVAD [5 patients (27.8%) vs. 14 patients (27.5%), p = 0.18)], and patients with or without previous history of VAs (p = 0.95). Also, there was no difference in mortality among patients with a different timing of implant of implantable cardioverter‐defibrillator (ICD), before and after CF‐LVAD (p = 0.11).

Conclusions

VAs in CF‐LVAD are a common clinical problem, but they do not impact mortality. Timing of ICD implantation does not have a significant impact on patients' survival. Patients with BiV pacing ≥98% experienced more frequently VAs.

Another Strike Against Continuing Cardiac Resynchronization Therapy in Left Ventricular Assist Device recipients?

Continuous flow left ventricular assist devices (LVAD) are an important therapeutic strategy, either as a bridge to transplant, bridge to recovery or as destination therapy, in patients with end-stage heart failure. This article is protected by copyright. All rights reserved.

Association Between Biventricular Pacing and Incidence of Ventricular Arrhythmias in the Early Post-Operative Period after Left Ventricular Assist Device Implantation

INTRODUCTION

Cardiac resynchronization therapy (CRT) and left ventricular assist devices (LVAD) improve outcomes in heart failure patients. Early ventricular arrhythmias (VA) are common after LVAD and are associated with increased mortality. The association between left ventricular pacing (LVP) with CRT and VAs in the early post-LVAD period remains unclear.

METHODS

This was a retrospective study of all patients undergoing LVAD implantation from 1/2016 - 12/2019. Patients were divided into those with CRT and active LVP (CRT-LVP) immediately post-LVAD implant versus those without CRT-LVP. ICD electrograms were reviewed and early VAs were defined as sustained VT/VF occurring within 30 days of LVAD implantation.

RESULTS

Of 186 included patients (mean age 53 years, 75% male, mean BMI 28), 72 had CRT devices, 63 of whom had LV pacing enabled after LVAD implant (CRT-LVP group). Patients with CRT-LVP were more likely to have VA in the early post-operative period (21% vs 4%; p=0.0001). All 9 patients with CRT in whom LVP was disabled had no early VA. Among those with early VA, patients with CRT-LVP were more likely to have monomorphic VT (77% vs 40%; p=0.07). In multiple logistic regression, CRT-LVP pacing remained an independent predictor of early VA after adjustment for history of VA and AF.

CONCLUSIONS

Patients with CRT-LVP after LVAD implant had a higher incidence of early VA (specifically monomorphic VT). Epicardial LV pacing may be proarrhythmic in the early post-operative period after LVAD. This article is protected by copyright. All rights reserved.

Implantable cardioverter-defibrillator-related procedures and associated complications in continuous flow left ventricular assist device recipients: A multicenter experience

Background

Limited data exist regarding complication rates of implantable cardioverter-defibrillators (ICD) and cardiac resynchronization therapy devices (CRT-D) in patients with left ventricular assist devices (LVAD).

Objective

We describe the incidence and characteristics of ICD- and CRT-D-related procedures and complications in a multicenter LVAD cohort.

Methods

A total of 537 LVAD patients with a pre-existing ICD or CRT-D from 5 centers were included. Details on device type, device therapies, procedural complications, and long-term survival were analyzed.

Results

Of 537 patients, 280 had a CRT-D and 257 had ICD only. During a median follow-up of 538 days, 126 patients underwent generator replacement with significantly higher rate in the CRT group (79 [28.2%] vs 47 [18.3%], P = .0006). Device-related complications occurred in 36 (13%) CRT-D and 20 (8%) ICD patients (P = .06). Incidence of pocket hematoma (3.2% vs 2.7%), infection (4.3% vs 1.6%), and lead malfunction (3.1% vs 2.8%) was similar in both groups, with no effect of device complication on long-term survival (log-rank P = .7). There was a higher incidence of post-LVAD antitachycardia pacing for ventricular arrhythmias in the CRT-D group compared to the ICD group (35% vs 26%, P = .03).

Conclusion

Cardiac implantable electronic device-related procedures are common in LVAD patients. Compared to ICD only, continued CRT-D therapy post-LVAD results in a significantly higher number of generator changes and a trend towards higher device- or lead-related complications. Device-related complications were not associated with reduced survival.

Cardiac Resynchronization Therapy in continuous flow Left Ventricular Assist Device Recipients: A Systematic Review and Meta-analysis from ELECTRAM Investigators

Introduction

Whether cardiac resynchronization therapy (CRT) continues to augment left ventricular remodeling in patients with the continuous-flow left ventricular assist device (cf-LVAD) remains unclear.

Methods

We performed a systematic review and meta-analysis of all clinical studies examining the role of continued CRT in end-stage heart failure patients with cf-LVAD reporting all-cause mortality, ventricular arrhythmias, and ICD shocks. Mantel-Haenszel risk ratio (RR) random-effects model was used to summarize data.

Results

Eight studies (7 retrospective and 1 randomized) with a total of 1,208 unique patients met inclusion criteria. There was no difference in all-cause mortality (RR 1.08, 95% CI 0.86 - 1.35, p = 0.51, I2=0%), all-cause hospitalization (RR 1.01, 95% CI 0.76-1.34, p = 0.95, I²=11%), ventricular arrhythmias (RR 1.08, 95% CI 0.83 - 1.39, p = 0.58, I² =50%) and ICD shocks (RR 0.87, 95% CI 0.57 - 1.33, p = 0.52, I² =65%) comparing CRT versus non-CRT. Subgroup analysis demonstrated significant reduction in ventricular arrhythmias (RR 0.76, 95% CI 0.64 - 0.90, p = 0.001) and ICD shocks (RR 0.65, 95% CI 0.44 - 0.97, p = 0.04) in "CRT on" group versus "CRT off" group.

Conclusions

CRT was not associated with a reduction in all-cause mortality or increased risk of ventricular arrhythmias and ICD shocks compared to non-CRT in cf-LVAD patients. It remains to be determined which subgroup of cf-LVAD patients benefit from CRT. The findings of our study are intriguing, and therefore, larger studies in a randomized prospective manner should be undertaken to address this specifically.

Cardiovascular implantable electronic device therapy in patients with left ventricular assist devices: insights from TRAViATA

BACKGROUND

There is conflicting observational data on the survival benefit cardiac implantable electronic devices (CIED) in patients with LVADs.

METHODS

Patients in whom an LVAD was implanted between January 2008 and April 2017 in the multinational Trans-Atlantic Registry on VAD and Transplant (TRAViATA) registry were separated into four groups based on the presence of CIED prior to LVAD implantation: none (n = 146), implantable cardiac defibrillator (ICD) (n = 239), cardiac resynchronization without defibrillator (CRT-P) (n = 28), and CRT with defibrillator (CRT-D) (n = 111).

RESULTS

A total of 524 patients (age 52 years ±12, 84.4% male) were followed for 354 (interquartile range: 166-701) days. After multivariable adjustment, there were no differences in survival across the groups. In comparison to no device, only CRT-D was associated with late right ventricular failure (RVF) (hazard ratio 2.85, 95% confidence interval [CI] 1.42-5.72, p = 0.003). There was no difference in risk of early RVF across the groups or risk of ICD shocks between those with ICD and CRT-D.

CONCLUSION

In a multinational registry of patients with LVADs, there were no differences in survival with respect to CIED subtype. However, patients with a pre-existing CRT-D had a higher likelihood of late RVF suggesting significant long-term morbidity in those with devices capable of LV‑lead pacing post LVAD implantation.

Biventricular Pacing Versus Right Ventricular Pacing in Patients Supported With LVAD

OBJECTIVES

This study sought to evaluate the effects of right ventricular (RV) pacing versus biventricular (BiV) pacing on quality of life, functional status, and arrhythmias in LVAD patients.

BACKGROUND

Cardiac resynchronization therapy (CRT) and left ventricular assist devices (LVADs) independently improve outcomes in heart failure patients, but the effects of combining these therapies remains unknown. We present the first prospective randomized study evaluating the effects of RV versus BiV pacing on quality of life, functional status, and arrhythmias in LVAD patients.

METHODS

In this prospective randomized crossover study, LVAD patients with prior CRT devices were alternated on RV and BiV pacing for planned 7-14-day periods. Ambulatory step count, 6-minute walk test distance, Kansas City Cardiomyopathy Questionnaire scores, arrhythmia burden, CRT lead function, and echocardiographic data were collected with each pacing mode.

RESULTS

Thirty patients were enrolled, with a median age of 65 years, 67% male, and mean duration of LVAD support of 309 days. Compared with BiV pacing, RV-only pacing resulted in 29% higher mean daily step count, 11% higher 6-minute walk test distance, and 7% improved KCCQ-12 score (all p < 0.03). LV end-diastolic volume was significantly lower with RV pacing (220 vs. 250 mL; p = 0.03). Fewer patients had ventricular tachyarrhythmia episodes during RV pacing (p = 0.03). RV lead impedance was lower with RV pacing (p = 0.047), but no significant differences were observed in impedance across other CRT leads.

CONCLUSIONS

In the first prospective randomized study comparing variable pacing in LVAD patients, RV pacing was associated with significantly improved functional status, quality of life, fewer ventricular tachyarrhythmias, and stable lead impedance compared with BiV pacing. This study supports turning off LV lead pacing in LVAD patients with CRT.

Acute Hemodynamic Effects of Cardiac Resynchronization Therapy Versus Alternative Pacing Strategies in Patients With Left Ventricular Assist Devices

Background

The hemodynamic effects of cardiac resynchronization therapy in patients with left ventricular assist devices (LVADs) are uncharacterized. We aimed to quantify the hemodynamic effects of different ventricular pacing configurations in patients with LVADs, focusing on short‐term changes in load‐independent right ventricular (RV) contractility.

Methods and Results

Patients with LVADs underwent right heart catheterization during spontaneous respiration without sedation and with pressures recorded at end expiration. Right heart catheterization was performed at different pacemaker configurations (biventricular pacing, left ventricular pacing, RV pacing, and unpaced conduction) in a randomly generated sequence with >3 minutes between configuration change and hemodynamic assessment. The right heart catheterization operator was blinded to the sequence. RV maximal change in pressure over time normalized to instantaneous pressure was calculated from digitized hemodynamic waveforms, consistent with a previously validated protocol. Fifteen patients with LVADs who were in sinus rhythm were included. Load‐independent RV contractility, as assessed by RV maximal change in pressure over time normalized to instantaneous pressure, was higher in biventricular pacing compared with unpaced conduction (15.7±7.6 versus 11.0±4.0 s⁻¹; P=0.003). Thermodilution cardiac output was higher in biventricular pacing compared with unpaced conduction (4.48±0.7 versus 4.38±0.8 L/min; P=0.05). There were no significant differences in heart rate, ventricular filling pressures, or atrioventricular valvular regurgitation across all pacing configurations.

Conclusions

Biventricular pacing acutely improves load‐independent RV contractility in patients with LVADs. Even in these patients with mechanical left ventricular unloading via LVAD who were relative pacing nonresponders (required LVAD support despite cardiac resynchronization therapy), biventricular pacing was acutely beneficial to RV contractility.

Management of ventricular arrhythmias in patients with LVAD

PURPOSE OF REVIEW

Left ventricular assist devices (LVADs) have extended the life expectancy of patients with heart failure. The hemodynamic support afforded by LVADs in this population has also resulted in patients having prolonged ventricular arrhythmias. The purpose of this article is to review the mechanisms of ventricular arrhythmias in LVADs and the available management strategies.

RECENT FINDINGS

Recent evidence suggests that prolonged ventricular arrhythmias may result in increased mortality in patients with LVADs.

SUMMARY

Successful management of ventricular arrhythmias in patients with LVAD requires interdisciplinary collaboration between electrophysiology and heart failure specialists. Medical management, including changes to LVAD changes, heart failure medication management, and antiarrhythmics constitute the initial treatment for ventricular arrhythmias. Surgical or endocardial ablation are reasonable options if VAs are refractory.

Continued versus Suspended Cardiac Resynchronization Therapy after Left Ventricular Assist Device Implantation

Cardiac resynchronization therapy (CRT) improves outcomes in heart failure patients with wide QRS complex. However, CRT management following continuous flow Left Ventricular Assist Device (LVAD) implant vary: some centers continue CRT while others turn off the left ventricular (LV) lead at LVAD implant. We sought to study the effect of continued CRT versus turning off CRT pacing following continuous flow LVAD implantation. A comprehensive retrospective multicenter cohort of 295 patients with LVAD and pre-existing CRT was studied. CRT was programmed off after LVAD implant in 44 patients. We compared their outcomes to the rest of the cohort using univariate and multivariate models. Mean age was 60 ± 12 years, 83% were males, 52% had ischemic cardiomyopathy and 54% were destination therapy. Mean follow-up was 2.4 ± 2.0 years, and mean LVAD support time was 1.7 ± 1.4 years. Patients with CRT OFF had a higher Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) mean profile (3.9 vs 3.3, p = 0.01), more secondary prevention indication for a defibrillator (64.9% vs 44.5%, p = 0.023), and more pre-LVAD ventricular arrhythmias (VA) (77% vs 60%, p = 0.048). There were no differences between the CRT OFF and CRT ON groups in overall mortality (Log rank p = 0.32, adjusted HR = 1.14 [0.54-2.22], p = 0.71), heart transplantation, cardiac and noncardiac mortality, all cause hospitalizations, hospitalizations for ICD shocks, and number and frequency of ICD shocks or anti-tachycardia pacing therapy. There were no differences in post LVAD atrial arrhythmias (AA) (Adjusted OR = 0.45 [0.18-1.06], p = 0.31) and ventricular arrhythmias (OR = 0.65 [0.41-1.78], p = 0.41). There was no difference in change in LVEF, LV end diastolic and end systolic diameters between the 2 groups. Our study suggests that turning off CRT pacing after LVAD implantation in patients with previous CRT pacing did not affect mortality, heart transplantation, device therapies or arrhythmia burden. A prospective study is needed to confirm these findings.

Cardiac Implantable Electronic Devices in Patients With Left Ventricular Assist Systems

Recent progress and evolution in device engineering, surgical implantation practices, and periprocedural management have advanced the promise of durable support with left ventricular assist systems (LVAS) in patients with stage D heart failure. With greater uptake of LVAS globally, a growing population of LVAS recipients have pre-existing cardiac implantable electronic devices (CIEDs). Strategies for optimal clinical management of CIEDs in patients with durable LVAS are evolving, and clinicians will increasingly face complex decisions regarding implantation, programming, deactivation, and removal of CIEDs. Traditional decision-making pathways for CIEDs may not apply to LVAS-supported patients, as few patients die of arrhythmic causes and many arrhythmias may be well tolerated. Given limited data, treatment decisions must be individualized and made collaboratively among electrophysiologists, advanced heart failure specialists, and patients and their caregivers. Large, prospective, well-conducted studies are needed to better understand the contemporary utility of CIEDs in patients with newer-generation LVAS.

Device Therapy and Arrhythmia Management in Left Ventricular Assist Device Recipients: A Scientific Statement From the American Heart Association

Left ventricular assist devices (LVADs) are an increasingly used strategy for the management of patients with advanced heart failure with reduced ejection fraction. Although these devices effectively improve survival, atrial and ventricular arrhythmias are common, predispose these patients to additional risk, and complicate patient management. However, there is no consensus on best practices for the medical management of these arrhythmias or on the optimal timing for procedural interventions in patients with refractory arrhythmias. Although the vast majority of these patients have preexisting cardiovascular implantable electronic devices or cardiac resynchronization therapy, given the natural history of heart failure, it is common practice to maintain cardiovascular implantable electronic device detection and therapies after LVAD implantation. Available data, however, are conflicting on the efficacy of and optimal device programming after LVAD implantation. Therefore, the primary objective of this scientific statement is to review the available evidence and to provide guidance on the management of atrial and ventricular arrhythmias in this unique patient population, as well as procedural interventions and cardiovascular implantable electronic device and cardiac resynchronization therapy programming strategies, on the basis of a comprehensive literature review by electrophysiologists, heart failure cardiologists, cardiac surgeons, and cardiovascular nurse specialists with expertise in managing these patients. The structure and design of commercially available LVADs are briefly reviewed, as well as clinical indications for device implantation. The relevant physiological effects of long-term exposure to continuous-flow circulatory support are highlighted, as well as the mechanisms and clinical significance of arrhythmias in the setting of LVAD support.

When Should the Electrophysiologist Be Involved in Managing Patients with Ventricular Assist Devices and Ventricular Arrhythmias?

The successful management of ventricular arrhythmias (VAs) in people with left ventricular assist devices (LVADs) is often complex. The need for and the role of defibrillator therapy is continually evolving in this group. VAs occur frequently and significantly impact the clinical course of patients with LVADs. The management of VAs begins prior to LVAD implantation and typically involves appropriate implantable cardioverter-defibrillator use and programming after the fact. Surgical ablation during LVAD implantation and supplementary catheter ablation performed as needed are attractive options for the management of VAs in this population. The performance of catheter ablation is generally safe and feasible after LVAD implantation with a team approach.

Usefulness of Cardiac Resynchronization Therapy in Patients With Continuous Flow Left Ventricular Assist Devices

The benefit of cardiac resynchronization therapy in patients supported by a left ventricular assist device (LVAD) is unknown. There are currently no guidelines regarding the continuation, discontinuation or pacemaker (PM) settings post-LVAD implant. The aim of the study was to assess the hemodynamic benefit of biventricular (BiV) pacing in LVAD patients. We studied 22 patients supported by LVADs (age 62 ± 9, 21 males) who had received a BiV PM before LVAD implant. A total of 123 complete sets of hemodynamics were obtained during BiV pacing (n = 54), right ventricular (RV) pacing (n = 54), and intrinsic rhythm (n = 15). There were no significant differences in right atrial (RA) pressure, mean pulmonary artery pressure (mPA), PCWP, cardiac output, PA saturation (PASat) and right ventricular stroke work index between BiV and RV pacing. Hemodynamics obtained during intrinsic rhythm in 15 non-PM-dependent patients were not significantly different compared with those obtained during BiV or RV pacing. Furthermore, hemodynamics were similar at different heart rates ranging 50 to 110 beats/min. Right ventricular stroke work index was significantly lower at the highest heart rate compared with baseline and lowest heart rates suggesting decreased RV performance at higher heart rate. In conclusion, BiV pacing does not have any acute hemodynamic benefit compared with RV pacing or intrinsic rhythm in LVAD patients. A lower heart rate may confer better RV performance.

Acute Hemodynamic Effects of Biventricular Pacing After Left Ventricular Assist Device

BACKGROUND

Despite cardiac resynchronization therapy (CRT), some patients with heart failure progress and undergo left ventricular assist device (LVAD) implantation. Management of CRT after LVAD implantation has not been well studied. The purpose of this study was to determine whether RV pacing or biventricular pacing measurably affects acute hemodynamics in patients with an LVAD and a CRT device.

METHODS AND RESULTS

Seven patients with CRT and LVAD underwent right heart catheterization. Pressures and oximetry were measured and LVAD parameters were recorded during 3 different conditions: RV pacing alone, biventricular pacing, and intrinsic atrioventricular conduction. Paired t tests were used to evaluate changes within subjects. There were no significant changes in right atrial pressure, pulmonary arterial pressures, pulmonary capillary wedge pressure, cardiac index, or any LVAD parameter (P > .05).

CONCLUSIONS

Our data suggest that CRT probably has no acute hemodynamic effect in patients with LVADs, but further study is needed.

Cardiac Resynchronization Therapy and Clinical Outcomes in Continuous Flow Left Ventricular Assist Device Recipients

BACKGROUND

Many patients with heart failure continue cardiac resynchronization therapy (CRT) after continuous flow left ventricular assist device (CF-LVAD) implant. We report the first multicenter study to assess the impact of CRT on clinical outcomes in CF-LVAD patients.

METHODS AND RESULTS

Analysis was performed on 488 patients (58±13 years, 81% male) with an implantable cardioverter defibrillator (ICD) (n=223) or CRT-D (n=265) who underwent CF-LVAD implantation at 5 centers from 2007 to 2015. Effects of CRT on mortality, hospitalizations, and ventricular arrhythmia incidence were compared against CF-LVAD patients with an ICD alone. Baseline differences were noted between the 2 groups in age (60±12 versus 55±14, P<0.001) and QRS duration (159±29 versus 126±34, P=0.001). Median biventricular pacing in the CRT group was 96%. During a median follow-up of 478 days, Kaplan-Meier analysis showed no difference in survival between groups (log rank P=0.28). Multivariate Cox regression demonstrated no survival benefit with type of device (ICD versus CRT-D; P=0.16), whereas use of amiodarone was associated with increased mortality (hazard ratio 1.77, 95% confidence interval 1.1-2.8, P=0.01). No differences were noted between CRT and ICD groups in all-cause (P=0.06) and heart failure (P=0.9) hospitalizations, ventricular arrhythmia incidence (43% versus 39%, P=0.3), or ICD shocks (35% versus 29%, P=0.2). During follow-up, 69 (26%) patients underwent pulse generator replacement in the CRT-D group compared with 36 (15.5%) in the ICD group (P=0.003).

CONCLUSIONS

In this large, multicenter CF-LVAD cohort, continued CRT was not associated with improved survival, hospitalizations, incidence of ventricular arrhythmia and ICD therapies, and was related to a significantly higher number of pulse generator changes.

Prospective Randomized Evaluation of Implantable Cardioverter-Defibrillator Programming in Patients With a Left Ventricular Assist Device

BACKGROUND

Ventricular arrhythmias are common in patients with left ventricular assist devices (LVADs) but are often hemodynamically tolerated. Optimal implantable cardioverter defibrillator (ICD) tachy-programming strategies in patients with LVAD have not been determined. We sought to determine if an ultra-conservative ICD programming strategy in patients with LVAD affects ICD shocks.

METHODS AND RESULTS

Adult patients with an existing ICD undergoing continuous flow LVAD implantation were randomized to standard ICD programming by their treating physician or an ultra-conservative ICD programming strategy utilizing maximal allowable intervals to detection in the ventricular fibrillation and ventricular tachycardia zones with use of ATP. Patients with cardiac resynchronization therapy (CRT) devices were also randomized to CRT ON or OFF. Patients were followed a minimum of 6 months. The primary outcome was time to first ICD shock. Among the 83 patients studied, we found no statistically significant difference in time to first ICD shock or total ICD shocks between groups. In the ultra-conservative group 16% of patients experienced at least one shock compared with 21% in the control group (P=0.66). There was no difference in mortality, arrhythmic hospitalization, or hospitalization for heart failure. In the 41 patients with CRT ICDs fewer shocks were observed with CRT-ON but this was not statistically significant: 10% of patients with CRT-ON (n=21) versus 38% with CRT-OFF (n=20) received shocks (P=0.08).

CONCLUSIONS

An ultra-conservative programming strategy did not reduce ICD shocks. Programming restrictions on ventricular tachycardia and ventricular fibrillation zone therapy should be reconsidered for the LVAD population. The role of CRT in patients with LVAD warrants further investigation.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT01977703.

Effect of Ventricular Arrhythmia Ablation in Patients With Heart Mate II Left Ventricular Assist Devices: An Evaluation of Ablation Therapy

BACKGROUND

Patients with advanced heart failure (HF) are predisposed to ventricular arrhythmias (VAs), particularly following implantation of a left ventricular assist device (LVAD). There is minimal evidence for appropriate management strategies.

OBJECTIVES

This study aimed to compare the burden of VA and response to ablation performed either before or following LVAD implantation.

METHODS

We created a retrospective cohort of patients who underwent both VA ablation and Heart Mate II (Thoratec, Pleasanton, CA, USA) LVAD implantation at Mayo Clinic (Rochester, MN, USA). Patients were stratified based on whether they underwent VA ablation before (pre-LVAD) or after LVAD (post-LVAD) implantation. Descriptive analyses assessed 6-month arrhythmia burden in relation to LVAD implantation and VA ablation.

RESULTS

A total of 9 patients underwent both LVAD implantation and VA ablation. There were 3 and 6 patients, respectively, in the pre-LVAD and post-LVAD cohorts. Among patients in the pre-LVAD cohort, the median number of VAs tended to increase after ablation (9 vs. 72) and decreased after LVAD implantation (72 vs. 63). Similarly among patients in the post-LVAD cohort, the median burden of VAs increased after LVAD implantation (1 vs. 22) and the median burden decreased after ablation (22 vs. 13). Two of 6 patients had substrate related to the LVAD inflow cannula site, while other substrate was not related directly to the cannula.

CONCLUSIONS

In patients with progressive HF and LVAD implantation, ablation is associated with reduced VA rates. In LVAD patients, most VAs arise from substrate unrelated to the inflow cannula site.