Arrhythmias in patients with ventricular assist devices

Impact of Diabetes Mellitus on Outcomes in Patients with Left Ventricular Assist Devices

Heart failure (HF) represents a significant health burden in the United States, resulting in substantial mortality and healthcare costs. Through the array of treatment options available, including lifestyle modifications, medications, and implantable devices, HF management has evolved. Left ventricular assist devices (LVADs) have emerged as a crucial intervention, particularly in patients with advanced HF. However, the prevalence of comorbidities such as diabetes mellitus (DM) complicates treatment outcomes. By elucidating the impact of DM on LVAD outcomes, this review aims to inform clinical practice and enhance patient care strategies for individuals undergoing LVAD therapy. Patients with DM have higher rates of hypertension, dyslipidemia, peripheral vascular disease, and renal dysfunction, posing challenges to LVAD management. The macro/microvascular changes that occur in DM can lead to cardiomyopathy and HF. Glycemic control post LVAD implantation is a critical factor affecting patient outcomes. The recent literature has shown significant decreases in hemoglobin A1c following LVAD implantation, representing a possible bidirectional relationship between DM and LVADs; however, the clinical significance of this decrease is unclear. Furthermore, while some studies show increased short- and long-term mortality in patients with DM after LVAD implantation, there still is no literature consensus regarding either mortality or major adverse outcomes in DM patients.

Meta-Analysis of the Effect of Preoperative Atrial Fibrillation on Outcomes After Left Ventricular Assist Device Implantation

The effect of preoperative atrial fibrillation (AF) on clinical outcomes after left ventricular assist device (LVAD) implantation remains uncertain. We sought to conduct a meta-analysis to assess the safety and efficacy of LVAD implantation in AF patients. Medline and Scopus were searched for studies that assessed the effect of preoperative AF on clinical outcomes in patients who underwent LVAD implantation. Outcomes of interest included all-cause mortality, thromboembolic events, and bleeding. Estimates were combined using random effects model to calculate risk ratios (RRs) with 95% confidence intervals. In this meta-analysis of 7 studies including 5,658 patients, preoperative AF was not associated with increased risk of all-cause mortality at 30 days (RR = 0.84 [0.51, 1.37]; p = 0.49; I² = 0%), 6 months (RR = 1.17 [0.96, 1.14]; p = 0.11; I² = 21%), 1 year (RR = 1.16 [0.84, 1.60]; p = 0.37; I² = 53%) and 2 years (RR = 1.14 [0.96, 1.36]; p = 0.12; I² = 23%). Preoperative AF did not increase the risk of thromboembolism (RR = 0.86 [0.38, 1.92]; p = 0.71; I² = 26%), pump thrombosis (RR = 1.22 [0.88, 1.68]; p = 0.23; I² = 49%), stroke (RR = 1.02 [0.87, 1.19]; p = 0.79; I² = 11%), or major bleeding (RR = 0.86 [0.38, 1.92]; p = 0.71; I² = 26%) after LVAD implantation. However, AF was associated with significantly increased risk of gastro-intestinal bleeding in patients receiving LVADs (RR = 1.27 [1.05, 1.55]; p = 0.014; I² = 0%). In conclusion, this meta-analysis reports a significantly increased risk of gastrointestinal (GI) bleeding in LVADs recipients having concomitant AF. However, AF had no significant effect on all-cause mortality, stroke, or thromboembolic events in these patients. Further well-conducted studies are needed to validate these results.

Approach to Complications of Ventricular Assist Devices: A Clinical Review for the Emergency Provider

BACKGROUND

Heart failure is a major public health problem in the United States. Increasingly, patients with advanced heart failure that fail medical therapy are being treated with implanted ventricular assist devices (VADs).

OBJECTIVE

This review provides an evidence-based summary of the current data for the evaluation and management of implanted VAD complications in an emergency department context.

DISCUSSION

With a prevalence of >5.8 million individuals and >550,000 new cases diagnosed each year, heart failure is a major public health problem in the United States. Increasingly, patients with advanced heart failure that fail medical therapy are being treated with implanted VADs. As the prevalence of patients with VADs continues to grow, they will sporadically present to the emergency department, regardless of whether the facility is a designated VAD center. As a result, all emergency physicians must be familiar with the basic principles of VAD function, as well as the diagnosis and initial management of VAD-related complications. In this review, we address these topics, with a focus on contemporary third-generation continuous flow VADs. This review will help supplement the critical care skills of emergency physicians in managing this complex patient population.

CONCLUSIONS

The cornerstone of managing the unstable VAD patient is rapid initiation of high-quality supportive care and recognition of device-related complications, as well as the identification and use of specialist VAD teams and other resources for support. Emergency physicians must understand VADs so that they may optimally manage these complex patients.

Ibutilide for the control of refractory ventricular tachycardia and ventricular fibrillation in patients with myocardial ischemia and hemodynamic instability

INTRODUCTION

Recurrent ventricular tachycardia (VT) and ventricular fibrillation (VF) in patients with myocardial ischemia requiring hemodynamic support can be refractory to available antiarrhythmic agents and even to cardioversion and defibrillation. The purpose of this study was to report the effect of intravenous ibutilide in patients with a VT and/or VF storm in the presence of incomplete revascularization requiring hemodynamic support.

METHODS AND RESULTS

Standard continuous telemetry and frequent 12-lead electrocardiograms were obtained to determine the effect of intravenous Ibutilide in these patients. We studied six consecutive patients (age 60 ± 12 years; five males) with incomplete revascularization and mechanical support (extracorporeal membrane of oxygenation = 2; left ventricular assist device = 4) with VT/VF refractory to lidocaine and amiodarone. Intravenous ibutilide was given as a last resort for management of their ventricular arrhythmias. Intravenous ibutilide (1-2 mg) allowed restoration of sinus rhythm in three patients with persistent VF that were refractory to multiple defibrillation shocks. When the 24-hour period before and after ibutilide administration was compared, this drug markedly reduced the number of required cardioversions/defibrillations in all patients from 20 ± 9 to 0.7 ± 0.8 shocks ( P = 0.036).

CONCLUSIONS

In patients with myocardial ischemia requiring hemodynamic support, intravenous Ibutilide demonstrates a potent antiarrhythmic effect and can facilitate defibrillation in patients with refractory VF.

Arrhythmias in children with ventricular assist devices

BACKGROUND

Children with decompensated heart failure are at high risk for arrhythmias, and ventricular assist device placement is becoming a more common treatment strategy. The impact of ventricular assist devices on arrhythmias and how arrhythmias affect the clinical course of this population are not well described.

METHODS AND RESULTS

A single-centre retrospective analysis of children receiving a ventricular assist device between 1998 and 2011 was performed. In all, 45 patients received 56 ventricular assist devices. The median age at initial placement was 13 years (interquartile range 6-15). The median duration of support was 10 days (range 2-260). The aetiology of heart failure included cardiomyopathy, transplant rejection, myocarditis, and congenital heart disease. In all, 32 patients (71%) had an arrhythmia; 19 patients (42%) had an arrhythmia before ventricular assist device and eight patients (18%) developed new arrhythmias on ventricular assist device. Ventricular tachycardia was most common (25/32, 78%). There was no correlation between arrhythmia and risk of death or transplantation (p=0.14). Of the 15 patients who weaned from ventricular assist device, post-ventricular assist device arrhythmias occurred in nine (60%), with five (33%) having their first arrhythmia after weaning. Patients with ventricular dysfunction after ventricular assist device were more likely to have arrhythmias (p<0.02).

CONCLUSIONS

Arrhythmias, especially ventricular, are common in children requiring ventricular assist device. They frequently persist for those able to wean from ventricular assist device.

Mechanical circulatory support

The role for temporary and durable mechanical circulatory support is rapidly expanding. As the use of these technologies continues to grow, the emergency physician has an increasing opportunity to participate in the advancement of these potentially life-saving technologies. This review discusses the current role of the intra-aortic balloon pump in cardiogenic shock, describes the complications and management strategies for the critically ill patient with a left ventricular assist device, and explores the emerging role of ECMO in the emergency department for patients presenting in refractory cardiogenic shock and cardiac arrest.

Durable mechanical circulatory support in advanced heart failure: a critical care cardiology perspective

Though cardiac transplantation for advanced heart disease patients remains definitive therapy for patients with advanced heart failure, it is challenged by inadequate donor supply, causing durable mechanical circulatory support (MCS) to slowly become a new primary standard. Selecting appropriate patients for MCS involves meeting a number of prespecifications as is required in evaluation for cardiac transplant candidacy. As technology evolves to bring forth more durable smaller devices, selection criteria for appropriate MCS recipients will likely expand to encompass a broader, less sick population. The "Holy Grail" for MCS will be a focus on clinical recovery and explantation of devices rather than the currently more narrowly defined indications of bridge to transplantation or lifetime device therapy.

Management of patients with implanted ventricular assist devices for noncardiac surgery: a clinical review

While originally primarily used as bridge to cardiac transplantation and bridge to recovery, more commonly ventricular assist devices (VADs) are being inserted as destination therapy. These patients are being discharged from transplant and mechanical assist centers, living as outpatients, and thus the pool of community-dwelling patients with VADs continues to expand. Not infrequently they present for surgical procedures either directly related to the device itself or more often incidental to the fact that they have a VAD. This scenario may be more common in patients with VADs placed for destination therapy because these patients tend to be older and have more comorbidities and are living longer with their device. Thus, it is important for all anesthesiologists to be aware of the special anesthesia needs of patients with VADs requiring noncardiac surgery.

Continuous monitoring of cardiac rhythms in left ventricular assist device patients

Monitoring of cardiac rhythms is of major importance in the treatment of heart failure patients with left ventricular assist devices (LVADs) implanted. A continuous surveillance of these rhythms could improve out-of-hospital care in these patients. The aim of this study was to investigate cardiac rhythms using available pump data only. Datasets (n = 141) obtained in the normal ward, in the intensive care unit, and during bicycle ergometry were analyzed in 11 recipients of a continuous flow LVAD (59.1 ± 9.7 years; male 82%). Tachograms and arrhythmic patterns derived from the pump flow waveform, and a simultaneously recorded ECG were compared, as well as heart rate variability parameters such as: the average heart beat duration (RR interval), the standard deviation of the beat duration (SDNN), the root-mean-square of the difference of successive beat durations (RMSSD), and the number of pairs of adjacent beat duration differing by >50 ms divided by the number of all beats (pNN50). A very good agreement of cardiac rhythm parameters from the pump flow compared with ECG was found. Tachycardia, atrial fibrillation, and extrasystoles could be accurately identified from the tachograms derived from the pump flow. Also, Bland-Altman analysis comparing pump flow with ECG indicated a very small difference in average RR interval of 0.3 ± 1.0 ms, in SSDN of 0.5 ± 2.7 ms, in RMSSD of 1.0 ± 5.6 ms, and in pNN50 of 0.3 ± 1.0%. Continuous monitoring of cardiac rhythms from available pump data is possible. It has the potential to reduce the out-of-hospital diagnostic burden and to permit a more efficient adjustment of the level of mechanical support.

Prehospital assessment and management of patients with ventricular-assist devices

Advances in the management of heart failure have led to an increasing number of patients living outside the hospital with a variety of ventricular-assist devices (VADs). These implantable pumps may be placed temporarily as a bridge to cardiac transplantation or resolution of a reversible condition, or as destination therapy for the rest of the patient's life. Emergency medical services (EMS) providers may be called to care for such patients experiencing an emergency related to the device itself, the underlying cardiac condition, or a totally unrelated medical or traumatic issue. Providers should have a basic knowledge of how these devices work and what sort of complications VAD patients may experience. In addition, they should know how to troubleshoot the devices if they alarm or malfunction, what emergency interventions can and cannot be performed, and where to turn for guidance if needed. Challenges related to management of patients with VADs include their poor baseline medical status, limitations of traditional prehospital assessment techniques, the relative infrequency with which these patients are encountered, and the rapidity with which device technology is evolving. This article presents a brief history of VADs, with an emphasis on left ventricular-assist devices (LVADs), reviews the relevant anatomy and pathophysiology, and describes the types of devices currently in clinical use. It discusses patient-specific and device-specific complications that may be encountered and concludes with an approach to prehospital patient assessment and care.

Implantation of the continuous flow HeartWare® left ventricular assist device

Recent outstanding clinical advances with new mechanical circulatory systems have led to additional strategies in the treatment of end-stage heart failure. Heart transplantation can be postponed and for certain patients even replaced by smaller implantable left ventricular assist devices (LVADs). Mechanical support of the failing left ventricle enables appropriate haemodynamic stabilization and recovery of secondary organ failure, often seen in these severely ill patients. These new devices may be of great help to bridge patients until a suitable cardiac allograft is available but are also discussed as definitive treatment for patients who do not qualify for transplantation. Main indications for LVAD implantation are bridge to recovery, bridge to transplantation or destination therapy. An LVAD may be an important tool for patients with an expected prolonged period on the waiting list, for instance those with blood group O or B, with high or low body weight and those with potentially reversible secondary organ failure and pulmonary artery hypertension. However, LVAD implantation means an additional heart operation with inherent perioperative risks and complications during the waiting period. Finally, cardiac transplantation in patients with prior implantation of an LVAD represents a surgical challenge. The care of patients after the implantation of miniaturized LVADs, such as the HeartWare® system, seems to be easier than following pulsatile devices. The explantation of such devices at the time of transplantation is technically more comfortable than after HeartMate II implantation.

Use of implantable cardioverter defibrillators in patients with left ventricular assist devices

Patients with left ventricular assist devices (LVADs) are at high risk of sustained ventricular arrhythmias, but these may be remarkably well tolerated and the association with sudden death is unclear. Many patients who receive an LVAD already have an implantable cardioverter defibrillator (ICD). While it is standard practice to reactivate a previously implanted ICD in an LVAD recipient, this should include discussion of the revised risks and benefits of ICD therapy following LVAD implantation. In particular, patients should be warned that they might receive a significant number of ICD shocks that may not be life saving. When ICDs are reactivated, device programming should minimize the risk of repeated shocks for non-sustained or well-tolerated ventricular arrhythmias. Implantation of a primary prevention ICD after implantation of an LVAD is not supported by current evidence, poses potential risks, and should be the subject of a clinical trial before it becomes standard practice.