Extracellular macrostructure anisotropy improves cardiac tissue-like construct function and phenotypic cellular maturation.

Regenerative cardiac tissue is a promising field of study with translational potential as a therapeutic option for myocardial repair after injury, however, poor electrical and contractile function has limited translational utility. Emerging research suggests scaffolds that recapitulate the structure of the native myocardium improve physiological function. Engineered cardiac constructs with anisotropic extracellular architecture demonstrate improved tissue contractility, signaling synchronicity, and cellular organization when compared to constructs with reduced architectural order. The complexity of scaffold fabrication, however, limits isolated variation of individual structural and mechanical characteristics. Thus, the isolated impact of scaffold macroarchitecture on tissue function is poorly understood. Here, we produce isotropic and aligned collagen scaffolds seeded with embryonic stem cell derived cardiomyocytes (hESC-CM) while conserving all confounding physio-mechanical features to independently assess the effects of macroarchitecture on tissue function. We quantified spatiotemporal tissue function through calcium signaling and contractile strain. We further examined intercellular organization and intracellular development. Aligned tissue constructs facilitated improved signaling synchronicity and directional contractility as well as dictated uniform cellular alignment. Cells on aligned constructs also displayed phenotypic and genetic markers of increased maturity. Our results isolate the influence of scaffold macrostructure on tissue function and inform the design of optimized cardiac tissue for regenerative and model medical systems.

Efficacy and Safety of Leadless Pacemaker Implantation in Octogenarians.

INTRODUCTION: Long-term complication rates in standard transvenous pacemakers are reported around 4-12% with a higher incidence in the elderly population. We report our experience in octogenarians undergoing leadless pacemaker implantation in two large-volume centers in Switzerland. METHODS: Consecutive patients undergoing leadless pacemaker implantation at two Swiss large volume centers (University Hospital Zurich, Zurich and Cardiocentro Ticino Institute, Lugano) between October 2015 and March 2020 were included in this retrospective analysis. Demographic information, clinical data, and procedural characteristics were recorded at the day of implantation and during follow-up. RESULTS: Two hundred and twenty patients (mean age 80.6 ± 7.7 years, male 66%) were included. The main indication for pacemaker implantation was slow ventricular rate atrial fibrillation (111 of 220 patients, 50.4%). Out of the 220 patients, 124 (56.3%) were ≥80 years. Overall successful implantation rate was 98.6%. In the octogenarian population, the median procedure time (45 ± 20.2 min vs. 40 ± 19.6 min, p = 0.03) and radiation duration (6.1 ± 8.2 min vs. 5.0 ± 7.2 min, p = 0.03) were longer compared to patients <80 years. Major complications (2.7%, n = 6) and device measurements during follow-up were similar between patients ≥80 and <80 years. CONCLUSION: Implantation of a leadless pacemaker device in octogenarians is safe and effective with a similarly low complication rate compared to non-octogenarians.

Feasibility, Efficiency, and Safety of Zero-Fluoroscopy Catheter Interventions for Right-Sided Cardiac Arrhythmias Using Only Electroanatomic Mapping.

INTRODUCTION: Fluoroscopy is traditionally used for catheter interventions in electrophysiology but carries a long-term health risk. Besides additional invasive procedures to achieve zero-fluoroscopy (ZF) interventions, electroanatomic mapping may be an alternative to fluoroscopy without the need of additional procedures. We aimed to investigate the feasibility, safety, and efficiency of a ZF approach using only electroanatomic mapping (ZF) compared to a conventional fluoroscopic (CF) approach for patients with right sided cardiac arrhythmias. METHODS: We performed a single centre retrospective cohort study of consecutive patients undergoing catheter interventions for electrophysiologic procedures from January 2019 to December 2020. Patients with left-sided arrhythmias, focal cryoablation, implanted endocardial devices, or additional interventions requiring fluoroscopy were excluded. RESULTS: 202 patients underwent a ZF and 126 patients underwent a CF approach for right-sided cardiac arrhythmias. Apart from atrial fibrillation (ZF 16% vs. CF 9%, p = 0.044), baseline demographics were similar in both groups. Acute success rate was 100% in the ZF group and 97.9% in the CF group. Mean procedure time was lower in the ZF group (70 ± 36 vs. 87 ± 44 min, p = 0.0001), while ablation time (356 ± 324 vs. 320 ± 294 s, p = 0.157) was similar. Total complication rate was low in general (1.0 % major, 2% minor complications) and without a difference between both groups. CONCLUSION: A ZF approach using only electroanatomic mapping without additional invasive procedures to diagnose and treat right-sided cardiac arrhythmias is feasible, efficient, and safe.

Conservative Treatment of Unicuspid Aortic Valve with Newly Diagnosed Type A Aortic Dissection.

We present a case of a 36-year-old male patient with known arthrogryposis multiplex congenita and an associated unicuspid aortic valve. The patient later developed a significant aneurysm of the ascending aorta, however refused surgical intervention and missed follow-up appointments for 5 years. During an urgent, general practitioner-initiated transthoracic echocardiography follow-up, a chronic type A aortic dissection was diagnosed as a result of progressive aortic dilatation. Due to the stationary pressure gradients and non-progressive leaflet fibrosis, a conservative approach for to the unicuspid aortic valve was chosen, combined with replacement of the ascending aorta and partial replacement of the aortic arch.

Conservative treatment of unicuspid aortic valve with newly diagnosed type a aortic dissection

Abstract We present a case of a 36-year-old male patient with known arthrogryposis multiplex congenita and an associated unicuspid aortic valve. The patient later developed a significant aneurysm of the ascending aorta, however refused surgical intervention and missed follow-up appointments for 5 years. During an urgent, general practitioner-initiated transthoracic echocardiography follow-up, a chronic type A aortic dissection was diagnosed as a result of progressive aortic dilatation. Due to the stationary pressure gradients and non-progressive leaflet fibrosis, a conservative approach for to the unicuspid aortic valve was chosen, combined with replacement of the ascending aorta and partial replacement of the aortic arch.