Long-term outcome of transvenous bipolar atrial leads implanted in children and young adults with congenital heart disease

Department of Polymer Technology, Faculty of Chemistry, Gdansk University of Technology, 11/12 Narutowicza St., 80-233 Gdansk, Poland, Cemka Z, Szarlej P, Department of Polymer Technology, Faculty of Chemistry, Gdansk University of Technology, 11/12 Narutowicza St., 80-233 Gdansk, Poland, Piłat E, Department of Polymer Technology, Faculty of Chemistry, Gdansk University of Technology, 11/12 Narutowicza St., 80-233 Gdansk, Poland, Gnatowski P, Department of Polymer Technology, Faculty of Chemistry, Gdansk University of Technology, 11/12 Narutowicza St., 80-233 Gdansk, Poland, Sienkiewicz M, Department of Polymer Technology, Faculty of Chemistry, Gdansk University of Technology, 11/12 Narutowicza St., 80-233 Gdansk, Poland, Kucińska-Lipka J, Department of Polymer Technology, Faculty of Chemistry, Gdansk University of Technology, 11/12 Narutowicza St., 80-233 Gdansk, Poland. Hydrogels Based on Natural Polymers for Cardiac Applications

In this work agar- and borax-based hydrogels with and without the addition of poly(vinyl alcohol) (PVA) at different concentrations were synthesized. Hydrogels were modified by the same amount of acetylsalicylic acid (ASA) which exhibits antithrombotic properties. The effect of modification by ASA on the properties of hydrogels was analyzed.

Effects of long-term right ventricular apex pacing on left ventricular dyssynchrony, morphology and systolic function

BACKGROUND

Right ventricular apex (RVA) is still the most common implanted site in the world. There are a large number of RVA pacing population who have been carrying dual-chamber permanent pacemaker (PPM) over decades. Comparison of left ventricular dyssynchrony, morphology and systolic function between RVA pacing population and healthy population is unknown.

METHOD

This case-control study enrolled 61 patients suffered from complete atrioventricular block (III°AVB) for replacement of dual-chamber PPM. Then, 61 healthy controls matched with PPM patients in gender, age, follow-up duration and complications were included. The lead impedance, pacing threshold and sensing were compared between at implantation and long-term follow-up. Left ventricular (LV) dyssynchrony, morphology and systolic function were compared between RVA pacing population (RVA group) and healthy population (healthy group) at implantation (baseline) and follow-up. And clarify the predictors of LV systolic function in RVA group at follow-up.

RESULTS

After 112.44 ± 34.94 months of follow-up, comparing with parameters at implantation, atrial lead impedance decreased significantly (690 ± 2397 Ω vs 613 ± 2257 Ω， p = 0.048); atrial pacing threshold has a increased trend and P-wave amplitude has a decreased trend, but there was no statistical differences; while, RVA ventricular lead threshold increased significantly (0.50 ± 0.23 V vs 0.91 ± 0.47 V， p < 0.001), impedance (902 ± 397 Ω vs 680 ± 257 Ω，p < 0.001) and R-wave amplitude (11.71 ± 9.40mv vs 7.00 ± 6.91 mv， p < 0.001) decreased significantly. Compared with healthy group, long-term RVA pacing significantly increased ventricular dyssynchrony (mean QRS duration, 156.21 ± 29.80 ms vs 97.08 ± 15.70 ms， p < 0.001), left atrium diameter (LAD, 40.61 ± 6.15 mm vs 37.49 ± 4.80 mm，p = 0.002), left ventricular end-diastolic diameter (LVEDD, 49.15 ± 5.93 mm vs 46.41 ± 3.80 mm，p = 0.003), left ventricular hypertrophy (LVMI, 121.86 ± 41.52 g/m2 vs 98.41 ± 25.29 g/m2，p < 0.001), significantly deteriorated degree of tricuspid regurgitation (p < 0.001), and significantly decreased left ventricular ejection fraction (LVEF, 61.38 ± 8.10% vs 64.64 ± 5.85%, p = 0.012), but after long-term RVA pacing, the mean LVEF was still more than 50%. Long-term RVA group LVEF was negatively correlated with preimplantation LVMI (B = -0.055，t = -2.244，p = 0.029), LVMI at follow-up (B = -0.081，t = -3.864，p = 0.000) and tricuspid regurgitation at follow-up (B = -3.797，t = -3.599，p = 0.001).

CONCLUSION

In conclusion, although long-term RVA pacing has significantly effects on left ventricular dyssynchrony, morphology and systolic function in III°AVB patients, the mean LVEF is still >50%. High preimplantation LVMI can predict the decline of LVEF.

Progress in cardiovascular biomaterials

In 1986, the European Society of Biomaterials Consensus Conference gave a simplified definition of biomaterials as “a non-viable material used in a medical device intended to interact with biological systems”. This seems to be more appropriate when we look into the versatility of applications of biomaterials in the health sector, especially in cardiovascular practice. This field has expanded exponentially in every direction, with multifunctional capability. Heart valves have undergone an evolution in biomaterials and design. Patches and conduits have been developed to correct anatomical deficits, and solutions have been found for narrowing or ballooning of the arteries. Research is ongoing to find replacements for every part of this system by creating replicas made of various materials. To investigate problems pertaining to the cardiovascular system, catheters have undergone an astounding leap in material optimization. In these three sectors, the trends, successes, and failures are worth discussing. This review mainly focuses on the types of biomaterial used for making cardiovascular devices and their advantages and limitations.

Fifteen years' experience of implantable cardioverter defibrillator in children and young adults: Mortality and complications study

BACKGROUND

Young implantable cardioverter defibrillator (ICD) recipients have a high rate of complications, some of which seem to be underestimated. We report our clinical experience with ICD therapy in children and young adults during a 15 year follow up.

METHODS

We reviewed the database of ICD recipients at the present institution and chose 73 consecutive patients who underwent implantation at age 6-21 years. We analyzed intervention rate, mortality, rate and characteristics of complications and treatment options.

RESULTS

A total of 20/73 patients (27.4%) received ≥1 episode of appropriate therapy (AT) for ventricular tachycardia/ventricular fibrillation (anti-tachycardia pacing or shock) and 24/73 patients (32.8%) had one or multiple episodes of inappropriate therapy (IT). Eight patients (11%) had both interventions: AT + IT. A total of 15/73 patients (20.5%) had ventricular lead dysfunction, with 13 re-implantations (17.8%) of a new system. Four of 73 patients (5.5%) had infection: endocarditis or device pocket infection. A total of 2/73 patients (2.7%) died due to ventricular lead dysfunction, while 22/73 patients (30.1%) needed elective device replacement, five of them twice (6.8%).

CONCLUSION

Endocardial ICD implantation in children and young adults is a feasible and life-saving procedure, according to the present 15 year follow up. The rate of complications including IT was high: 72.8% in the young ICD recipients. Re-implantation of a new system was often required due to ventricular lead dysfunction or infection in 25% of the patients.

Physiological pacing in young patients with complex congenital heart defects

AIM

Young patients with operated complex congenital heart defects (CHD) often develop sinus node dysfunction (SND) requiring permanent pacing with rate-responsive function. Activity-driven sensors cannot account for nonmovement stress and cannot modulate heart rate physiologically. Closed Loop Stimulation (CLS, Biotronik, Berlin, Germany) is a physiological rate-responsive pacemaker based on the indirect measure of ventricular contractility. No data are available on the effects of such pacing strategy in young patients.

METHODS

We report a series of nine patients with CHD and SND who underwent single-chamber CLS-atrial pacing with endocardial or epicardial lead. During the first 30 days, the pacemaker was programmed in AAI pacing mode and then was switched to CLS-atrial pacing mode. An in-hospital control was scheduled 1-2 months later to evaluate the CLS response to neurovegetative stresses (i.e., nonmovement stress [Stroop color test, handgrip] and exercise stress test) and Holter monitor. CLS pacing was compared with rate-responsive accelerometer-driven pacing (AAIR).

RESULTS

At telemetric interrogation, CLS pacing showed a more physiological pattern of 24-h heart rate trends than accelerometer sensors. The data obtained during nonmovement/exercise stress demonstrated a physiological increase in the pacing rate with CLS, in synergy with spontaneous events. The accelerometer sensor histogram, during nonmovement stress, showed a "nonresponse" behavior (only lower rate events), and during exercise test showed most events in lower rate range. Holter monitoring showed increase of average and maximum heart rate compared with AAIR.

CONCLUSION

In young CHD patients, endocardial/epicardial CLS-atrial pacing demonstrated a physiological response of heart rate to neurovegetative and physical stresses.

A novel bioactive osteogenesis scaffold delivers ascorbic acid, β-glycerophosphate, and dexamethasone in vivo to promote bone regeneration

Ascorbic acid, β-glycerophosphate, and dexamethasone have been used in osteogenesis differentiation medium for in vitro cell culture, nothing is known for delivering these three bioactive compounds in vivo. In this study, we synthesized a novel bioactive scaffold by combining these three compounds with a lysine diisocyanate-based polyurethane. These bioactive compounds were released from the scaffold during the degradation process. The cell culture showed that the sponge-like structure in the scaffold was critical in providing a large surface area to support cell growth and all degradation products of the polymer were non-toxic. This bioactive scaffold enhanced the bone regeneration as evidenced by increasing the expression of three bone-related genes including collagen type I, Runx-2 and osteocalcin in rabbit bone marrow stem cells (BMSCs) in vitro and in vivo. The osteogenesis differentiation of BMSCs cultured in this bioactive scaffold was similar to that in osteogenesis differentiation medium and more extensive in this bioactive scaffold compared to the scaffold without these three bioactive compounds. These results indicated that the scaffold containing three bioactive compounds was a good osteogenesis differentiation promoter to enhance the osteogenesis differentiation and new bone formation in vivo.

Long-term outcome of transvenous pacemaker implantation in infants: a retrospective cohort study

AIM

Evaluation of long-term outcome of transvenous pacemaker (PM) implantation in infants.

METHODS AND RESULTS

A retrospective analysis of all transvenous PM implantations in infants <10 kg between September 1997 and October 2001 was made. Indications for PM implantation, age at implantation, and determinants of long-term outcome including cardiac function, PM function, and PM (system) complications were noted. Seven patients underwent transvenous VVI(R) PM implantation. Median age at implantation was 3 days (range: 1 day to 14 months), median weight 3.5 kg (range: 2.3-8.7 kg), and median follow-up 14 years (range: 12.3-16.3 years). Pacemaker indications were congenital complete atrioventricular block (n = 4), long QT syndrome with heart block (n = 2), and post-operative complete atrioventricular block with sinus node dysfunction (n = 1). No procedural complications were noted. Today all patients are alive and symptom free with good PM and cardiac function. Two patients underwent PM generator relocation for imminent skin necrosis and skin traction. Two patients suffered from asymptomatic left subclavian vein occlusion and developed thrombosis on the PM electrode. Three patients were converted to an epicardial PM system, due to atrial perforation after upgrading procedure (n = 1), syncope with need for implantable cardioverter defibrillator implantation (n = 1), and systolic dysfunction with development of dilated cardiomyopathy, which normalized under cardiac resynchronization therapy pacing (n = 1). Two patients needed atrioventricular (AV) valve repair for severe insufficiency. Two patients underwent repositioning of dysfunctional PM leads. In five patients, transvenous leads were removed. Indications were elective lead replacement (n = 1), atrial perforation (n = 1), and switch to an epicardial system (n = 3).

CONCLUSION

Transvenous PM implantation in infants (<10 kg) is associated with a high incidence of vascular occlusion, thrombosis, and severe atrioventricular valve regurgitation during long-term follow-up. We advocate an epicardial approach for PM implantation in small children.

Dual-Chamber Stimulation with Single-Lead VDD Pacing System in Mustard Surgery

Sinus node disease is a problem encountered in patients after the Mustard surgery, requiring a pacemaker implantation. The knowledge of the complexity anatomy is crucial because of the possible challenges associated with this procedure. We report a case of a 24-year-old woman presented with symptomatic bradycardia, in which a bicameral stimulation using a single-lead VDD pacing system was successfully performed.

A Case of Transvenous Pacemaker Implantation in a 10-year-old Patient

Objective: The aim of this report was to discuss the type, timing, and surgical techniques of permanent pacemaker implantation in a juvenile patient.

Patients: A 17-year-old girl with Down syndrome and congenital heart defects comprised of ventricular septal defects (VSD) and patent ductus arteriosus (PDA) suffered from postoperative complete atrioventricular block (AVB) when she was 7 months old.

Methods and Results: An epicardial pacemaker was implanted just after the occurrence of complete AVB. Due to the pacing threshold of a ventricular lead not being good, the battery showed rapid depletion. Her generator had to be exchanged under general anesthesia every 2–3 years. When she was 10 years old, we implanted a permanent pacemaker transvenously by using cutdown, screw-in and subpectoral pocket techniques. She has shown a satisfactory outcome since then.

Conclusion: Transvenous pacemaker implantation was safe and effective in our young patient without any complications. The timing of surgery and surgical technique are quite important for pacemaker implantation in juvenile patients.

Biomaterial applications in cardiovascular tissue repair and regeneration

Cardiovascular disease physically damages the heart, resulting in loss of cardiac function. Medications can help alleviate symptoms, but it is more beneficial to treat the root cause by repairing injured tissues, which gives patients better outcomes. Besides heart transplants, cardiac surgeons use a variety of methods for repairing different areas of the heart such as the ventricular septal wall and valves. A multitude of biomaterials are used in the repair and replacement of impaired heart tissues. These biomaterials fall into two main categories: synthetic and natural. Synthetic materials used in cardiovascular applications include polymers and metals. Natural materials are derived from biological sources such as human donor or harvested animal tissues. A new class of composite materials has emerged to take advantage of the benefits of the strengths and minimize the weaknesses of both synthetic and natural materials. This article reviews the current and prospective applications of biomaterials in cardiovascular therapies.

Cardiac pacing in paediatric patients with congenital heart defects: transvenous or epicardial?

AIMS

Cardiac pacing is a difficult technique in children, particularly in patients with congenital heart defects (CHDs). Few studies to date have addressed this topic.

METHODS AND RESULTS

We performed a retrospective analysis of the results of a single centre. Between 1982 and 2008, 287 patients with CHD, median age of 5 years (25-75%, 1-11) underwent cardiac pacing for sinus node dysfunction (SND) and atrioventricular block (AVB); 97% of patients underwent at least one heart surgery. Endocardial systems (Endo) were implanted in 117 patients, epicardial systems (Epi) in 170, with 595 leads (228 Endo, 367 Epi). Endocardial systems showed a significantly older age group with more frequent SND; Epi a younger age group, with more frequent AVB, greater number of surgical interventions. Perioperative complications were mortality 0.6% (Epi), pericardial effusion 0.6% (Epi), and haemothorax 3.4% (Endo). The median follow-up is 5 (2-10) years: the pacing system failed in 29% of patients, 13% Endo, and 40% Epi (P < 0.0001). Multivariate analysis showed a significantly higher risk of failure for Epi, a lower implant age, greater the number of leads implanted. The risk of malfunction of the leads increases significantly for Epi and the younger age when implanted. The steroid-eluting leads have a lower risk of malfunction (P = 0.05), steroid-eluting Endo leads provide significantly better outcomes than Epi.

CONCLUSION

Cardiac pacing in paediatric patients with CHD shows satisfactory results in the long term. Endocardial systems show significantly better results than Epi systems. A younger age when implanted is a risk factor for complications at follow-up.