Targeted Ganglionated Plexi Ablation With Nanoformulated Calcium Suppresses Postoperative AF Via Vagosympatholytic and Anti-Inflammatory Effects.

Background: The mechanisms underlying postoperative atrial fibrillation (POAF) remain unclear.

Objectives: The aim of this study was to test the hypothesis that targeted chemical ganglionated plexi (GP) modulation of all major left atrial-pulmonary vein GP using novel nanoformulated calcium chloride (nCaCl) can reverse postoperative neuroelectrical remodeling by suppressing vagosympathetic nerve activity and the localized inflammatory process, both critical substrates of POAF.

Methods: In a novel canine model of POAF with serial thoracopericardiotomies, sympathetic nerve activity (SNA), vagal nerve activity (VNA) and GP nerve activity (GPNA) were recorded; spontaneous and in vivo AF vulnerability were assessed; and atrial and circulating inflammatory markers and norepinephrine (NE) were measured to determine the neuroelectrical remodeling that promotes POAF and its subsequent modulation with nCaCl GP treatment (n = 6) vs saline sham controls (n = 6).

Functional-Molecular Mechanisms of Sympathetic-Parasympathetic Dysfunction in PVC-Induced Cardiomyopathy Revealed by Dual Stressor PVC-Exercise Challenge.

Background: The significance of autonomic dysfunction in premature ventricular contraction-induced cardiomyopathy (PVC-CM) remain unknown.

Objectives: Utilizing a novel "dual stressor" provocative challenge combining exercise with premature ventricular contraction (PVCs), the authors characterized the functional and molecular mechanisms of cardiac autonomic (cardiac autonomic nervous system) remodeling in a PVC-CM animal model.

Methods: In 15 canines (8 experimental, 7 sham), we implanted pacemakers and neurotelemetry devices and subjected animals to 12 weeks of bigeminal PVCs to induce PVC-CM.

Arrhythmia-Induced Cardiomyopathy: JACC State-of-the-Art Review.

Arrhythmias frequently accompany heart failure and left ventricular dysfunction. Tachycardias, atrial fibrillation, and premature ventricular contractions can induce a reversible form of dilated cardiomyopathy (CM) known as arrhythmia-induced CM (AiCM). The intriguing question is why certain individuals are more susceptible to AiCM, despite similar arrhythmia burdens.

Left ventricular remodeling in premature ventricular contraction-induced cardiomyopathy: Effect of coupling intervals and atrioventricular dissociation.

Background: Left ventricular dyssynchrony (LVD) and postextrasystolic potentiation (PESP) associated with premature ventricular contractions (PVCs) may play a role in the development of premature ventricular contraction-induced cardiomyopathy (PVC-CM). Long-coupled (LC) PVCs have a greater LVD than short-coupled (SC) PVCs, whereas SC-PVCs have a stronger PESP than LC-PVCs.

Objective: The purpose of this study was to compare SC-PVCs and LC-PVCs to evaluate the roles of LVD, PESP, and atrioventricular dissociation (AVD) in the development of PVC-CM.

Mechanisms of adaptive hypertrophic cardiac remodeling in a large animal model of premature ventricular contraction-induced cardiomyopathy.

Frequent premature ventricular contractions (PVCs) promoted eccentric cardiac hypertrophy and reduced ejection fraction (EF) in a large animal model of PVC-induced cardiomyopathy (PVC-CM), but the molecular mechanisms and markers of this hypertrophic remodeling remain unexplored. Healthy mongrel canines were implanted with pacemakers to deliver bigeminal PVCs (50% burden with 200-220 ms coupling interval). After 12 weeks, left ventricular (LV) free wall samples were studied from PVC-CM and Sham groups.

Abnormal Conduction-Induced Cardiomyopathy: JACC Review Topic of the Week.

Nonischemic cardiomyopathies are a frequent occurrence. The understanding of the mechanism(s) and triggers of these cardiomyopathies have led to improvement and even recovery of left ventricular function. Although chronic right ventricular pacing-induced cardiomyopathy has been recognized for many years, left bundle branch block and pre-excitation have been recently identified as potential reversible causes of cardiomyopathy.

Efficacy and Safety of Pulsed Field Ablation in Atrial Fibrillation: A Systematic Review.

Background: Atrial fibrillation (AF) is the most common cardiac arrhythmia associated with high morbidity and mortality. AF treatment is guided by a patient-provider risk-benefit discussion regarding drug versus ablation or combination. Thermal ablation has a high rate of adverse events compared to pulsed field ablation (PFA).

Alterations of sarcoplasmic reticulum-mediated Ca uptake in a model of premature ventricular contraction (PVC)-induced cardiomyopathy.

Premature ventricular contractions (PVCs) are the most frequent ventricular arrhythmias in the overall population. PVCs are known to acutely enhance contractility by the post-extrasystolic potentiation phenomenon, but over time persistent PVCs promote PVC-induced cardiomyopathy (PVC-CM), characterized by a reduction of the left ventricular (LV) ejection fraction. Ca cycling in myocytes commands muscle contraction and in this process, SERCA2 leads the Ca reuptake into the sarcoplasmic reticulum (SR) shaping cytosolic Ca signal decay and muscle relaxation.

Left ventricular dyssynchrony as marker of early dysfunction in premature ventricular contraction-induced cardiomyopathy.

Background: Strain imaging has been suggested as a tool to detect early left ventricular (LV) dysfunction due to frequent premature ventricular contractions (PVCs) in patients with preserved LV ejection fraction (EF). However, the progression of intraventricular dyssynchrony (IVD), radial, and circumferential strain (RS, CS) in PVC-cardiomyopathy (CM) are unknown. The aim of this study was to elucidate the progression patterns of CS, IVD, and electro-mechanical latency (EML) in PVC-CM.

Eccentric hypertrophy in an animal model of mid- and long-term premature ventricular contraction-induced cardiomyopathy.

Background: Tachycardia and heart rate irregularity are proposed triggers of premature ventricular contraction-induced cardiomyopathy (PVC-cardiomyopathy). Bigeminal premature atrial and ventricular contractions (PACs and PVCs) increase heart rate and result in rhythm irregularities but differ in their effects on ventricular synchrony. Comparing chronic bigeminal PACs with PVCs would provide insights into mechanisms of PVC-cardiomyopathy.

Clinical and translational insights on premature ventricular contractions and PVC-induced cardiomyopathy.

The medical community's understanding of the consequences of premature ventricular contractions (PVCs) and PVC-induced cardiomyopathy has been derived mostly from observational and large population-based studies. Due to the difficulty of predicting the development of PVC-cardiomyopathy, the acute and chronic cardiac effects of PVCs and the mechanism of PVC-cardiomyopathy have been derived from pre-clinical studies with large animal models. Recently, these studies have described myocardial substrates that could potentially increase morbidity and mortality in patients with frequent PVCs and PVC-cardiomyopathy.

Outcomes of Premature Ventricular Contraction-Cardiomyopathy in the Veteran Population: A Secondary Analysis of the CHF-STAT Study.

Objectives: This study sought to assess the rate and outcomes of premature ventricular contractions (PVC)-cardiomyopathy from the CHF-STAT (Survival Trial of Antiarrhythmic Therapy in Congestive Heart Failure) trial, a population with cardiomyopathy (left ventricular [LV] ejection fraction of <40%) and frequent PVCs (>10 PVCs per hour).

Background: PVCs are associated with heart failure and PVC-cardiomyopathy. The prevalence of PVC-cardiomyopathy and outcome benefits of PVC suppression are not clear.

Intermediate-term performance and safety of His-bundle pacing leads: A single-center experience.

Background: The short-term safety, feasibility, and performance of His-bundle pacing (HBP) leads have been reported; however, their longer-term performance beyond 1 year remains unclear.

Objective: The purpose of this study was to examine the intermediate-term performance and safety of HBP.

Methods: All HBP lead implants at Virginia Commonwealth University between January 2014 and January 2019 were analyzed.

Proarrhythmic effect of automatic threshold testing algorithm in dual chamber devices.

Background: Operation of auto-threshold testing (ATT) algorithm in current dual chamber cardiac devices require temporary shortening of atrio-ventricular (AV) delay to accurately measure evoked potential (capture) after a pacing pulse. Near simultaneous AV pacing causes atrial pressure elevation and may be associated with atrial arrhythmias.

Objective: We evaluated the prevalence of atrial arrhythmias induced by ATT in Abbott devices.

Post-extrasystolic potentiation as a predictor of premature ventricular contraction-cardiomyopathy in an animal model.

Aims: High premature ventricular contractions (PVCs) burden does not always predict the development of PVC-cardiomyopathy (CM). We sought to evaluate post-extrasystolic potentiation (PESP) of left ventricular ejection fraction (LVEF) to predict the severity of PVC-CM in an animal model.

Methods And Results: Right ventricular apical bigeminal PVCs were introduced for 12 weeks in 11 canines to induce PVC-CM.

Persistent Proarrhythmic Neural Remodeling Despite Recovery From Premature Ventricular Contraction-Induced Cardiomyopathy.

Background: The presence and significance of neural remodeling in premature ventricular contraction-induced cardiomyopathy (PVC-CM) remain unknown.

Objectives: This study aimed to characterize cardiac sympathovagal balance and proarrhythmia in a canine model of PVC-CM.

Methods: In 12 canines, the investigators implanted epicardial pacemakers and radiotelemetry units to record cardiac rhythm and nerve activity (NA) from the left stellate ganglion (SNA), left cardiac vagus (VNA), and arterial blood pressure.

Fluoroscopy reduction during device implantation by using three-dimensional navigation. A single-center experience.

Background And Objectives: The use of nonfluoroscopic three-dimensional electroanatomic mapping (3DM) systems reduces radiation exposure during ablation procedures. In this study, we sought to determine the value of 3DM during routine device implant procedures.

Methods: Seventy nonselected patients underwent implantation of a single chamber, dual chamber, or biventricular device guided by Ensite (Abbott Laboratories) to limit fluoroscopy use and compared with 70 consecutive patients, who underwent matching procedures with standard fluoroscopy use (FL) in the period immediately preceding the use of 3DM.

Consequences of chronic frequent premature atrial contractions: Association with cardiac arrhythmias and cardiac structural changes.

Introduction: Frequent premature ventricular contractions (PVCs) can cause cardiomyopathy (CM). Postextrasystolic potentiation (PESP) and irregularity have been in implicated as triggers of PVC-CM. Because both phenomena can also be found in premature atrial contractions (PACs), it is speculated that frequent PACs have similar consequences.

Arrhythmia-Induced Cardiomyopathy: JACC State-of-the-Art Review.

Arrhythmias coexist in patients with heart failure (HF) and left ventricular (LV) dysfunction. Tachycardias, atrial fibrillation, and premature ventricular contractions are known to trigger a reversible dilated cardiomyopathy referred as arrhythmia-induced cardiomyopathy (AiCM). It remains unclear why some patients are more prone to develop AiCM despite similar arrhythmia burdens.

Epicardial injection of nanoformulated calcium into cardiac ganglionic plexi suppresses autonomic nerve activity and postoperative atrial fibrillation.

Background: Imbalanced activation of the cardiac autonomic nervous system triggers postoperative atrial fibrillation (POAF). Neuronal calcium overload induces apoptosis. We hypothesize that epicardial injection of timed-release nanoformulated CaCl (nCaCl) into left atrial ganglionic plexi (GP) modulates autonomic function and suppresses POAF.