Adipose Tissue in Cardiovascular Disease: From Basic Science to Clinical Translation.

The perception of adipose tissue as a metabolically quiescent tissue, primarily responsible for lipid storage and energy balance (with some endocrine, thermogenic, and insulation functions), has changed. It is now accepted that adipose tissue is a crucial regulator of metabolic health, maintaining bidirectional communication with other organs including the cardiovascular system. Additionally, adipose tissue depots are functionally and morphologically heterogeneous, acting not only as sources of bioactive molecules that regulate the physiological functioning of the vasculature and myocardium but also as biosensors of the paracrine and endocrine signals arising from these tissues. In this way, adipose tissue undergoes phenotypic switching in response to vascular and/or myocardial signals (proinflammatory, profibrotic, prolipolytic), a process that novel imaging technologies are able to visualize and quantify with implications for clinical prognosis. Furthermore, a range of therapeutic modalities have emerged targeting adipose tissue metabolism and altering its secretome, potentially benefiting those at risk of cardiovascular disease.

Cerebrovascular accidents in Ebstein's anomaly.

INTRODUCTION: Mechanisms and risk factors for cerebrovascular accidents (CVAs) in Ebstein's anomaly (EA) are not well understood; hence, we aimed to clarify these in a large cohort of EA patients. METHODS: Patients with a confirmed diagnosis of EA were retrospectively reviewed. Baseline characteristics were compared between patients with and without a prior history of CVA using logistic regression modeling. Cox regression analysis was used to identify predictors of CVA following initial evaluation. CVA incidence from birth and following tricuspid valve surgery were estimated using the Kaplan-Meier method. RESULTS: Nine hundred sixty-eight patients (median age 21.1 years, 41.5% male) were included, in which, 87 patients (9.0%) had a history of CVA (54 strokes, 33 transient ischemic attacks; 5 associated with brain abscesses) prior to their initial evaluation. The odds of atrial septal defect/patent foramen ovale (odds ratio [OR] 4.91; 95% CI 2.60-21.22; p = .0002) and migraines/headaches (OR 2.38; 95% CI 1.40-4.04; p = .0013) but not atrial arrhythmias (OR 0.75; 95% CI 0.44-1.30; p = .31) were significantly higher among patients with prior CVA following multivariable adjustment. Seventeen patients experienced CVA following initial evaluation; no examined variables including atrial arrhythmias (HR 2.38; 0.91-6.19; p = .076) were predictive of CVA risk. The 10-year, 50-year, and 70-year incidences of CVA were 1.4%, 15.9%, and 23.5%, respectively, with paradoxical embolism heavily implicated. CONCLUSION: Patients with EA are at substantive risk for CVA. Histories of migraines/headaches and interatrial shunts should prompt concern for paradoxical embolic CVAs. This has significant implications for all patients with atrial-level shunting.

Elimination of Purkinje Fibers by Electroporation Reduces Ventricular Fibrillation Vulnerability.

Background The Purkinje network appears to play a pivotal role in the triggering as well as maintenance of ventricular fibrillation. Irreversible electroporation ( IRE ) using direct current has shown promise as a nonthermal ablation modality in the heart, but its ability to target and ablate the Purkinje tissue is undefined. Our aim was to investigate the potential for selective ablation of Purkinje/fascicular fibers using IRE . Methods and Results In an ex vivo Langendorff model of canine heart (n=8), direct current was delivered in a unipolar manner at various dosages from 750 to 2500 V, in 10 pulses with a 90-µs duration at a frequency of 1 Hz. The window of ventricular fibrillation vulnerability was assessed before and after delivery of electroporation energy using a shock on T-wave method. IRE consistently eradicated all Purkinje potentials at voltages between 750 and 2500 V (minimum field strength of 250-833 V/cm). The ventricular electrogram amplitude was only minimally reduced by ablation: 0.6±2.3 mV ( P=0.03). In 4 hearts after IRE delivery, ventricular fibrillation could not be reinduced. At baseline, the lower limit of vulnerability to ventricular fibrillation was 1.8±0.4 J, and the upper limit of vulnerability was 19.5±3.0 J. The window of vulnerability was 17.8±2.9 J. Delivery of electroporation energy significantly reduced the window of vulnerability to 5.7±2.9 J ( P=0.0003), with a postablation lower limit of vulnerability=7.3±2.63 J, and the upper limit of vulnerability=18.8±5.2 J. Conclusions Our study highlights that Purkinje tissue can be ablated with IRE without any evidence of underlying myocardial damage.