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

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.

Implantable Cardioverter-Defibrillators and Cardiovascular Resynchronization Therapy with Left Ventricular Assist Devices: A MOMENTUM 3 Trial Analysis

BACKGROUND

The benefit of implantable cardioverter-defibrillators (ICD) and cardiovascular resynchronization therapy (CRT-D) in patients supported with a HeartMate 3 left ventricular assist device (LVAD) remains uncertain.

METHODS

An analysis of the MOMENTUM 3 randomized clinical trial and the first 1000 patients in the Continued Access Protocol trial. Patients were divided into three groups based on the presence of ICD and/or CRT-D: No device (n=153, 11%), ICD only (n=699, 50.4%), CRT-D (n=535, 38.6%). We assessed the association of ICD or CRT-D with overall mortality, ventricular arrhythmias (VA), rehospitalization rates, quality of life and six-minute walk test distance at 2-years of follow-up.

RESULTS

Patients with ICD or CRT-D had similar survival to those without (HR 1.3, 95% CI 0.8-2.1, p=0.36) with no differences in rehospitalizations, quality-of-life or six-minute walk test distance. VA occurred more frequently in patients with ICD or CRT-D (HR 2.4, 95% CI 1.3-4.3, p=0.006). Compared to ICD alone, patients with CRT-D demonstrated similar survival (HR 1.1, 95% CI 0.9-1.5, p=0.36), however, had increased rates of VA (HR 1.3, 95% CI 1.0-1.7, p=0.03). There were no differences in rate of rehospitalization between those with ICD or CRT-D and those without (p=0.19) or between those with ICD and those with CRT-D (p=0.32). A propensity-matched sensitivity analysis confirmed these findings.

CONCLUSIONS

In this post-hoc analysis of the MOMENTUM 3 trial, the presence of ICD or CRT-D at the time of HM3 LVAD implantation was associated with an increased incidence of VA but was not associated with survival, quality of life or functional capacity.

TRIAL REGISTRATION

Momentum 3 portfolio, NCT02224755 (Pivotal) and NCT02892955 (CAP).

Prediction, prevention, and management of right ventricular failure after left ventricular assist device implantation: A comprehensive review

Left ventricular assist devices (LVADs) are increasingly common across the heart failure population. Right ventricular failure (RVF) is a feared complication that can occur in the early post-operative phase or during the outpatient follow-up. Multiple tools are available to the clinician to carefully estimate the individual risk of developing RVF after LVAD implantation. This review will provide a comprehensive overview of available tools for RVF prognostication, including patient-specific and right ventricle (RV)-specific echocardiographic and hemodynamic parameters, to provide guidance in patient selection during LVAD candidacy. We also offer a multidisciplinary approach to the management of early RVF, including indications and management of right ventricular assist devices in this setting to provide tools that help managing the failing RV.

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.

Physiology of Continuous-Flow Left Ventricular Assist Device Therapy

The expanding use of continuous-flow left ventricular assist devices (CF-LVADs) for end-stage heart failure warrants familiarity with the physiologic interaction of the device with the native circulation. Contemporary devices utilize predominantly centrifugal flow and, to a lesser extent, axial flow rotors that vary with respect to their intrinsic flow characteristics. Flow can be manipulated with adjustments to preload and afterload as in the native heart, and ascertainment of the predicted effects is provided by differential pressure-flow (H-Q) curves or loops. Valvular heart disease, especially aortic regurgitation, may significantly affect adequacy of mechanical support. In contrast, atrioventricular and ventriculoventricular timing is of less certain significance. Although beneficial effects of device therapy are typically seen due to enhanced distal perfusion, unloading of the left ventricle and atrium, and amelioration of secondary pulmonary hypertension, negative effects of CF-LVAD therapy on right ventricular filling and function, through right-sided loading and septal interaction, can make optimization challenging. Additionally, a lack of pulsatile energy provided by CF-LVAD therapy has physiologic consequences for end-organ function and may be responsible for a series of adverse effects. Rheological effects of intravascular pumps, especially shear stress exposure, result in platelet activation and hemolysis, which may result in both thrombotic and hemorrhagic consequences. Development of novel solutions for untoward device-circulatory interactions will facilitate hemodynamic support while mitigating adverse events. © 2021 American Physiological Society. Compr Physiol 12:1-37, 2021.

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.

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.