Leadless cardiac pacing systems: current status and future prospects.

Introduction: Permanent transvenous pacemaker therapy is an essential management option in patients with symptomatic bradyarrhythmias, but harbors a concomitant risk of serious complications. As most complications are lead- or pocket-related, intracardiac leadless pacemaker therapy has the potential to positively impact patient outcome. Since the first leadless pacemaker implant in 2012, many studies have been conducted to evaluate the effectiveness, safety, and applicability of this novel pacing approach.Areas covered: This review will cover the current status of leadless pacemaker technology. Available safety and efficacy outcomes, current area of indication, and end-of-life management will be evaluated. Furthermore, future perspectives for clinical practice and new pacing modalities are discussed.Expert opinion: The first-generation leadless pacemakers are a promising innovation that provide safe and efficient single-chamber pacing therapy without the use of transvenous pacemaker leads. Yet, broad implementation of this technology is hampered by limitations of the current leadless devices, such as end-of-life management and its single-chamber pacing indication. Further innovations such as leadless dual-chamber pacing therapy, leadless cardiac synchronization therapy, energy-harvesting leadless pacemakers, communicating leadless pacemakers with subcutaneous implantable cardiac defibrillators, and minimally invasive completely extracardiac pacemakers are currently being developed that have the potential to become major game changers in pacing therapy.

Impact of Leadless Pacemaker Therapy on Cardiac and Atrioventricular Valve Function Through 12 Months of Follow-Up.

BACKGROUND: Endocardial pacemaker leads and right ventricular (RV) pacing are well-known causes of tricuspid valve, mitral valve, and cardiac dysfunction. Lead-related adverse consequences can potentially be mitigated by leadless pacemaker (LP) therapy by eliminating the presence of a transvalvular lead. This study assessed the impact of LP placement on cardiac and valvular structure and function. METHODS: Echocardiographic studies before and 12±1 months after LP implantation were performed between January 2013 and May 2018 at our center and compared with age- and sex-matched controls of dual-chamber transvenous pacemaker recipients. RESULTS: A total of 53 patients receiving an LP were included, of whom 28 were implanted with a Nanostim and 25 with a Micra LP device. Tricuspid valve regurgitation was graded as being more severe in 23 (43%) patients at 12±1 months compared with baseline ( P<0.001). Compared with an apical position, an RV septal position of the LP was associated with increased tricuspid valve incompetence (odds ratio, 5.20; P=0.03). An increase in mitral valve regurgitation was observed in 38% of patients ( P=0.006). LP implantation resulted in a reduction of RV function, according to a lower tricuspid annular plane systolic excursion ( P=0.003) and RV tricuspid lateral annular systolic velocity ( P=0.02), and a higher RV Tei index ( P=0.04). LP implantation was further associated with a reduction of left ventricular ejection fraction ( P=0.03) and elevated left ventricular Tei index ( P=0.003). The changes in tricuspid valve regurgitation in the LP group were similar to the changes in the dual-chamber transvenous pacemaker control group (43% versus 38%, respectively; P=0.39). CONCLUSIONS: LP therapy is associated with an increase in tricuspid valve dysfunction through 12 months of follow-up; yet it was comparable to dual-chamber transvenous pacemaker systems. Furthermore, LP therapy seems to adversely impact mitral valve and biventricular function.

Leadless pacemaker implantation after explantation of infected conventional pacemaker systems: A viable solution?

BACKGROUND: Conventional cardiac device infections are increasing in incidence, causing significant morbidity and mortality. Leadless pacemaker (LP) therapy may provide new opportunities for the management of pacemaker (PM) infections as it does not require implantation of transvenous leads and a pectoral pocket. OBJECTIVE: We sought to evaluate the effect of early and late LP implantation in patients diagnosed with device infection. METHODS: Patients receiving an LP at our center after conventional PM lead extraction due to infection between December 1, 2013 and November 30, 2017 were included. RESULTS: A total of 17 patients (mean age 77.4 ± 7.77 years) underwent LP implantation (ie, 11 with Nanostim leadless cardiac pacemaker [Abbott, Chicago, IL] and 6 with Micra transcatheter pacing system [Medtronic, Minneapolis, MN]) after successful PM system explantation. In 9 PM-dependent patients, a temporary transvenous pacing system was placed as a bridge to permanent LP implantation. Early LP implantation was performed in 6 patients (<1 week), and in the remaining patients, the LP was placed at a later stage (>1 week). All patients experienced no LP infection during a mean follow-up of 16 ± 12 months, including 7 patients with a history of recurrent device infections with a mean follow-up of 20 ± 14 months. CONCLUSION: Early and late LP placement after infected conventional pacing system explantation was a viable option in our case series. This therapy may provide an alternative strategy in the management of device infection, if confirmed by subsequent prospective randomized trials, particularly for patients who are PM dependent or have a history of recurrent device infections.

Bevacizumab with or after chemotherapy for platinum-resistant recurrent ovarian cancer: exploratory analyses of the AURELIA trial.

BACKGROUND: In the open-label randomized phase III AURELIA trial, adding bevacizumab to chemotherapy for platinum-resistant ovarian cancer (PROC) significantly improved progression-free survival and response rate versus chemotherapy alone, but not overall survival (OS). We explored the effect of bevacizumab use after disease progression (PD) in patients randomized to chemotherapy alone. PATIENTS AND METHODS: In AURELIA, 361 women with PROC were randomized to chemotherapy alone or with bevacizumab. Patients initially randomized to chemotherapy were offered bevacizumab after PD. Post hoc analyses assessed efficacy and safety in three subgroups: chemotherapy alone, chemotherapy followed by bevacizumab after PD, and chemotherapy plus bevacizumab at randomization. RESULTS: Of the 182 patients randomized to chemotherapy alone, 72 (40%) received bevacizumab after PD and 110 (60%) never received bevacizumab. There were no significant differences in patient and disease characteristics between these subgroups at baseline or the time of PD. Compared with patients never receiving bevacizumab, the risk of death was significantly reduced in patients receiving bevacizumab either upfront with chemotherapy [hazard ratio (HR) = 0.68, 95% confidence interval (CI) 0.52-0.90] or after PD (HR = 0.60, 95% CI 0.43-0.86). The tolerability of bevacizumab was similar with administration upfront or after PD. CONCLUSIONS: Post-PD bevacizumab use may have confounded OS results in AURELIA. In these exploratory analyses of non-randomized subgroups, bevacizumab use, either with chemotherapy or after PD on chemotherapy alone, improved OS compared with no bevacizumab. Combining bevacizumab with chemotherapy at first appearance of platinum resistance maximises the likelihood of patients receiving this active treatment for PROC. ClinicalTrials.gov: NCT00976911.