The Convergent Procedure: A Unique Multidisciplinary Hybrid Treatment of Atrial Fibrillation.

The convergent procedure is a hybrid ablation treatment for atrial fibrillation. It is increasingly considered as a management option for patients with persistent and long-standing atrial fibrillation. It consists of surgical ablation of the posterior left atrium through a minimally invasive closed-chest approach followed by endocardial catheter ablation. It is increasingly performed with concurrent epicardial occlusion of the left atrial appendage with a video-assisted thoracoscopic technique to physically and electrically isolate the left atrial appendage. This article provides an overview of a multidisciplinary approach to the convergent procedure, with concurrent thoracoscopic closure of the left atrial appendage, with an emphasis on perioperative management at a single institution. It provides a literature review of procedural outcomes, current data limitations, and future considerations.

Nationwide Trends in Hospitalizations for Atrial Fibrillation and Flutter in the United States before and during the Outbreak of the COVID-19 Pandemic.

Background/Objectives: Atrial fibrillation (AF) and flutter (AFL) are the most common cardiac arrhythmias worldwide. Cardiovascular complications are a common manifestation of acute and post-acute COVID-19 infection. We aimed to analyze the nationwide trends in clinical characteristics and outcomes of patients hospitalized for AF/AFL before and during the COVID-19 outbreak in the U.S. Methods: This study is a retrospective analysis of patients, aged 18 and older, hospitalized for AF/AFL in the U.S. between 2016 and 2020. We drew data from the National Inpatient Sample (NIS) database. Baseline sociodemographic and clinical data, as well as outcomes including stroke, acute coronary syndrome (ACS), and mortality, were analyzed. Multivariable analysis was performed to identify independent associations between the different clinical and demographic characteristics and the composite endpoint of Mortality/ACS/Stroke. Results: An estimated total of 2,163,699 hospitalizations for AF/AFL were identified. The hospitalization volume between 2016 and 2019 was stable, averaging 465,176 a year, followed by a significant drop to 302,995 in 2020. Patients' median age was 72 years (IQR 62-80), 50.9% were male, and 81.5% were white. The composite endpoint steadily increased from 6.5% in 2016 to 11.8% in 2020 (Ptrend < 0.001). In a multivariable regression analysis, age > 75 (OR: 1.35; 95% CI 1.304-1.399, p < 0.001), ischemic heart disease (OR: 1.466; 95% CI: 1.451-1.481; p < 0.001), and chronic kidney disease (OR: 1.635; 95% CI: 1.616-1.653; p < 0.001) were associated with the composite endpoint. COVID-19 was associated with the composite endpoint outcome in the year 2020 (OR: 1.147; 95% CI: 1.037-1.265; p = 0.007). Conclusions: Hospitalization for AF/AFL dropped significantly during the first year of the COVID-19 pandemic outbreak, possibly due to patients' avoidance of hospital visits. The composite endpoint of Mortality/ACS/Stroke uptrended significantly during the study period. COVID-19 was shown to be independently associated with the adverse composite outcome Mortality/ACS/Stroke.

Single- Versus Dual-Chamber Implantable Cardioverter-Defibrillator for Primary Prevention of Sudden Cardiac Death in the United States.

Background Routine addition of an atrial lead during an implantable cardioverter-defibrillator (ICD) implantation for primary prevention of sudden cardiac death, in patients without pacing indications, was not shown beneficial in contemporary studies. We aimed to investigate the use and safety of single- versus dual-chamber ICD implantations in these patients. Methods and Results Using the National Inpatient Sample database, we identified patients with no pacing indications who underwent primary-prevention ICD implantation in the United States between 2015 and 2019. Sociodemographic and clinical characteristics, as well as in-hospital complications, were analyzed. Multivariable logistic regression was used to identify predictors of in-hospital complications. An estimated total of 15 940 patients, underwent ICD implantation for primary prevention of sudden cardiac death during the study period, 8860 (55.6%) received a dual-chamber ICD. The mean age was 64 years, and 66% were men. In-hospital complication rates in the dual-chamber ICD and single-chamber ICD group were 12.8% and 10.7%, respectively (P<0.001), driven by increased rates of pneumothorax/hemothorax (4.6% versus 3.4%; P<0.001) and lead dislodgement (3.6% versus 2.3%; P<0.001) in the dual-chamber ICD group. Multivariable analyses confirmed atrial lead addition as an independent predictor for "any complications" (odds ratio [OR], 1.1 [95% CI, 1.0-1.2]), for pneumo/hemothorax (odds ratio, 1.1 [95% CI, 1.0-1.4]), and for lead dislodgement (odds ratio, 1.3 [95% CI, 1.1-1.6]). Conclusions Despite lack of evidence for clinical benefit, dual-chamber ICDs are implanted for primary prevention of sudden cardiac death in a majority of patients who do not have pacing indication. This practice is associated with increased risk of periprocedural complications. Avoidance of routine implantation of atrial leads will likely improve safety outcomes.

A case of complete heart block in a COVID-19 infected patient.

In the midst of the COVID-19 pandemic, we herein report the case of an elderly female with multiple comorbidities coming with typical symptoms of the viral infection in addition to the unusual presentation of bradycardia due to complete heart block requiring pacemaker placement. This may be a rare complication of the disease but one has to keep a high index of suspicion since this virus has an ability to affect multiple organ systems with many ways yet to be uncovered. .

Advances in mechanisms of atrial fibrillation: structural remodeling, high-frequency fractionated electrograms, and reentrant AF drivers.

The mechanisms to explain atrial fibrillation (AF) have been widely debated. Although contemporary experimental techniques have provided more insight, hypotheses regarding AF propagation conceived in the early half of the century remain minimally altered and relevant today. Modern mapping technologies have implicated multiwavelet reentry as the electrophysiologic basis to explain AF propagation within the atrial myocardium; however, reentry has also been observed within pulmonary veins and may behave as a focal trigger. The ability to terminate AF by catheter ablation has provided additional clues to explain AF induction and sustenance. The presence of complex fractionated electrograms (CFAE) and subsequent successful CFAE-directed ablation suggest that diseased atrial myocardium is a necessary substrate for AF maintenance. Atrial remodeling creates differential areas of refractory periods and conduction velocity, which, in turn, creates a suitable environment for AF. This review addresses the complex relationship between remodeled atrial myocardium and reentry and explores the role of CFAEs in AF maintenance.

His bundle pacing.

His bundle pacing (HBP) has recently emerged as a technique to avoid the negative effects of long-term right ventricular apical pacing. In addition to providing physiologic ventricular activation, HBP has been shown to correct underlying conduction abnormalities in certain patients. Although large prospective, randomized clinical trials have not yet been completed, the available observational clinical data support the safety and efficacy of this technique. Here, we review the physiology of the his bundle (HB) as it relates to HBP, describe the current clinical experience, and discuss future directions of this emerging therapy.

Prediction and Prevention of Sudden Cardiac Death.

Sudden death is a major problem, with significant impact on public health. Many conditions predispose to sudden cardiac death and sudden cardiac arrest (SCA), foremost among them coronary artery disease, and an effective therapy exists in the form of the implantable cardioverter defibrillator. Risk stratification for SCA remains imperfect, especially for patients with nonischemic cardiomyopathy. Ongoing trials may make it easier to identify those at high risk, and potentially those at very low risk, in the future.

Cryoablation of the pulmonary veins using a novel balloon catheter.

INTRODUCTION: Pulmonary vein (PV) isolation has emerged as a promising technique for the treatment of patients with drug-refractory atrial fibrillation, however, the achievement of transmural lesions has remained a challenge. We evaluated the ability of a novel balloon-based cryogenic catheter system in achieving transmural lesions for PV isolation. METHODS: Six pulmonary vein ostia from three excised ovine hearts and lungs were used in this study. The balloon catheter was deployed and positioned at the ostia of the PVs and a full 8-minute ablation was then performed, while the heart was bathed in a circulating bath of normal saline at 37 degrees. Thermocouples positioned on the endocardial (balloon surface-tissue interface) and epicardial surfaces of the ostia were used to determine whether transmural freezing was achieved. RESULTS: The mean temperatures measured on the endocardial and epicardial tissue in six PV ablations were -38.8 +/- 6.9 degrees C and -10.0 +/- 7.5 degrees C, respectively. The average pulmonary vein thickness was 3.3 +/- 1.4 mm. CONCLUSIONS: A novel cryoablation balloon catheter is capable of achieving transmural freezing of the pulmonary vein. The catheter has promise for future clinical therapy of atrial fibrillation.

Effectiveness of automated external defibrillators in high schools in greater Boston.

A program using a strategy of donating a single automatic external defibrillator to 35 schools in the Boston area resulted in compliance with American Heart Association guidelines on automatic external defibrillator placement and training and 2 successful resuscitations from sudden cardiac arrest. Participating schools indicated a high degree of satisfaction with the program.

Cardiovascular toxicities of performance-enhancing substances in sports.

Athletes commonly use drugs and dietary supplements to improve athletic performance or to assist with weight loss. Some of these substances are obtainable by prescription or by illegal means; others are marketed as supplements, vitamins, or minerals. Nutritional supplements are protected from Food and Drug Administration regulation by the 1994 US Dietary Supplement Health and Education Act, and manufacturers are not required to demonstrate proof of efficacy or safety. Furthermore, the Food and Drug Administration lacks a regulatory body to evaluate such products for purity. Existing scientific data, which consist of case reports and clinical observations, describe serious cardiovascular adverse effects from use of performance-enhancing substances, including sudden death. Although mounting evidence led to the recent ban of ephedra (ma huang), other performance-enhancing substances continue to be used frequently at all levels, from elementary school children to professional athletes. Thus, although the potential for cardiovascular injury is great, few appropriately designed studies have been conducted to assess the benefits and risks of using performance-enhancing substances. We performed an exhaustive OVID MEDLINE search to Identify all existing scientific data, review articles, case reports, and clinical observations that address this subject. In this review, we examine the current evidence regarding cardiovascular risk for persons using anabolic-androgenic steroids including 2 synthetic substances, tetrahydrogestrinone and androstenedione (andro), stimulants such as ephedra, and nonsteroidal agents such as recombinant human erythropoietin, human growth hormone, creatine, and beta-hydroxy-beta-methylbutyrate.

Atrioventricular nodal reverse facilitation in connexin40-deficient mice.

BACKGROUND: Facilitation is an important physiologic property of the atrioventricular (AV) node. Previous studies demonstrated abnormal AV conduction in connexin (Cx)40-deficient mice. OBJECTIVES: We hypothesize that Cx40-deficient mice display altered patterns of AV nodal facilitation compared with wild-type mice. METHODS: Sixteen 36-week-old mice (eight Cx40(-/-) mice and eight Cx40(+/+) controls) underwent in vivo closed chest electrophysiologic study. A 2Fr octapolar catheter was advanced into the right ventricle to record a His-bundle electrogram. A special facilitation stimulation protocol was performed in each mouse to evaluate facilitation. Following atrial drive pacing (S1S1) at 150 ms, a facilitating beat S2 was delivered prior to the test beat S3. S3H3 was measured for varying S1S2 values at fixed H2S3 intervals. RESULTS: Progressive shortening of S1S2 (from 150 ms to 130, 110, and 90 ms) resulted in gradual prolongation of S2H2. The prolongation was more pronounced in Cx40(-/-) mice for each S1S2 compared with wild-type mice (P <.001). In each wild-type mouse, for a given H2S3 interval, this gradual increase in S2H2 produced progressive shortening of S3H3, so-called AV nodal facilitation phenomenon. However, in each Cx40(-/-) mouse, facilitation was seen only at S1S2 of 130 ms (P <.001 vs S1S2 of 150 ms). Evidence of reverse facilitation was documented at S1S2 of 110 and 90 ms. CONCLUSION: Facilitation is observed in wild-type mice. With similar S1S2 intervals in Cx40-deficient mice, facilitation is seen only at longer S1S2 intervals, whereas reverse facilitation is seen at shorter S1S2 intervals, suggesting that Cx40 is involved in the generation of AV nodal facilitation.

Device trials in heart failure: a focused summary.

Despite considerable progress in heart failure management with pharmacologic agents, measures to bring about significant improvements in morbidity and mortality are still needed. Cardiac resynchronization therapy (CRT) is a means to enhance myocardial function by stimulating the failing left ventricle at or near the time of right ventricular activation to synchronize ventricular depolarization. Current data from randomized, controlled trials suggest that CRT benefits patients with moderate to severe heart failure and have shown that this therapy significantly reduces mortality and hospital admissions in this group. In addition to CRT, implantable cardioverter-defibrillators have been evaluated in heart failure patients with significantly reduced left ventricular function and have been shown to reduce mortality from sudden cardiac death. This article summarizes recent device trials and discusses how best to apply their results to clinical practice.