Neurocardiology has mostly been a specialty of medicine led by anatomists and physiologists. The characterization of the cardiac autonomic nervous system has resulted in a new understanding and appreciation of neurocardiology, leading to potential novel neuromodulation therapies in clinical cardiology and cardiac electrophysiology. Sympathectomy or spinal cord stimulation for the treatment of angina pectoris, as well as cardiac sympathetic denervation for the treatment of long QT syndrome associated with malignant ventricular arrhythmias, have been available and performed for more than half a century. However, a new neuromodulation has emerged, based on contemporary research findings, assisted by state-of-the art imaging and ablation techniques. Patients with structural heart disease and malignant ventricular arrhythmias, as well as symptomatic ventricular ectopy, can potentially benefit from techniques to reduce autonomic tone, such as stellate ganglionic block, epidural anesthesia and cardiac sympathetic denervation. Renal sympathetic denervation not only has been shown to ameliorate the treatment of patients with hypertension, but may also reduce atrial and ventricular arrhythmias. Patients with heart failure may be improved clinically by potentiating parasympathetic tone. Cardiac mapping of ganglia and nerves can be performed to delineate regions of ablation that can suppress atrial fibrillation, and potentially treat symptomatic bradyarrhythmias and cardio-inhibitory syncope.

The contemporary history of the cardiac autonomic nervous system includes early descriptions of neuroanatomy in the 19th century, followed by an understanding of the physiologic determinants of neurocardiology in the 20th century. Neurology and cardiology preceded the arrival of clinical cardiac electrophysiology, a specialized field in medicine devoted to the diagnosis and treatment of cardiac arrhythmias. The rapid growth in pharmacology, ablation, pacing and defibrillation, associated with significant technological breakthroughs, have resulted in new opportunities for neuromodulation in the 21st century. Small changes in autonomic tone can potentially provide important therapeutic benefits for patients with cardiac and arrhythmia disorders.

Following new concepts by Bichat in the early 19th century, of organic and animal life centered around the ganglionic nervous system, over 100 years of anatomic studies and physiologic experimentation eventually resulted in Gaskell's 1916 book entitled "The Involuntary Nervous System" and Langley's 1921 book entitled "The Autonomic Nervous System." Neurology and cardiology emerged as specialties of medicine in the early 20th century. Although neurology made several prominent discoveries in neurophysiology during the first half of the 20th century, cardiology developed coronary care units and cardiac catheterization in the 1960s. Programmed electrical stimulation of the heart and noninvasive ambulatory monitoring provided new methodologies to study clinical cardiac arrhythmias. Experimentally, direct cardiac nerve stimulation of sympathetic nerve endings, as well as parasympathetic control of the atrioventricular node, provided the background to new detailed autonomic studies of the heart. Neurocardiology, perhaps initially more directed towards our understanding of sudden cardiac death, ultimately embraced an even significantly more complex scheme of local circuit neurons and near-endless loops of interconnecting neurons in the heart. Intrathoracic extracardiac and intracardiac ganglia have been recharacterized, both anatomically and physiologically, laying the groundwork for potential new therapies of cardiac neuromodulation.

Following the development of permanent transvenous cardiac pacing in the 1960s, the costs of pacemakers quickly led to their reuse in both developed countries and in low‐and middle‐income countries (LMIC). Legal, ethical, and industrial factors gradually resulted in the termination of reuse in developed countries. Without health care budgets to pay for costly pacemaker technologies, nongovernmental organizations (NGOs), and other groups have provided support to physicians and hospitals treating patients with heart block in LMICs. Multiple other academic and private groups have also assisted such patients in LMICs. Pacemaker companies have provided physicians and hospitals with new devices (that have an expired package date or through charitable donations). Greater care of preparing and cleaning refurbished devices have demonstrated overwhelmingly the safety and effectiveness of reused devices. More recently, cardiac resynchronization therapy and implantable cardioverter‐defibrillators have also been reused in patients in LMICs. While the globalization of noncommunicable diseases continues, patients with rhythm disorders in LMICs can no longer be left behind. While patients in developed countries only receive new devices to treat rhythm disorders, the practice of reused cardiac implantable electronic devices will expand in LMICs, until equal access to device technologies be made available to all.

On this year's 25th anniversary of the landmark report 1 Haissaguerre M. Jaïs P. Shah D.C. et al. Spontaneous initiation of atrial fibrillation by ectopic beats originating in the pulmonary veins. N Engl J Med. 1998; 339: 659-666 Crossref PubMed Scopus (6439) Google Scholar on ablation of pulmonary vein ectopy initiating atrial fibrillation (AF), which preceded by 1 year ablation of AF using nonfluoroscopic 3-dimensional mapping, 2 Pappone C. Oreto G. Lamberti F. et al. Catheter ablation of paroxysmal atrial fibrillation using a 3D mapping system. Circulation. 1999; 100: 1203-1208 Crossref PubMed Google Scholar we are reminded how both approaches would forever transform cardiac electrophysiology as a predominant diagnostic discipline, also performing device implantation and ablation of supraventricular tachycardia to become a therapeutic catheter ablation interventional specialty. Clinical cardiac electrophysiologists were somewhat unprepared or caught off guard a few years later when atrioesophageal fistulas, associated with significant morbidity and mortality, were first reported as a complication of ablation of AF. 3 Pappone C. Oral H. Santinelli V. et al. Atrial-esophageal fistula as a complication of percutaneous transcatheter ablation of atrial fibrillation. Circulation. 2004; 109: 2724-2726 Crossref PubMed Scopus (762) Google Scholar During an era of debates on ventricular rate control or maintenance of sinus rhythm strategies to treat patients with AF, complications of ablation of AF significantly influenced the development of mapping and energy delivery technologies. 4 Cappato R. Calkins H. Chen S.A. et al. A worldwide survey on the methods, efficacy, and safety of catheter ablation for human atrial fibrillation. Circulation. 2005; 111: 1100-1105 Crossref PubMed Scopus (1267) Google Scholar ,5 Calkins H. Brugada J. Packer D.L. et al. European Heart Rhythm Association (EHRA); European Cardiac Arrhythmia Society (ECAS); American College of Cardiology (ACC); American Heart Association (AHA); Society of Thoracic Surgeons (STS)HRS/EHRA/ECAS Expert Consensus statement on catheter and surgical ablation of atrial fibrillation: recommendations for personnel, policy, procedures and follow-up. A report of the Heart Rhythm Society (HRS) Task Force on catheter and surgical ablation of atrial fibrillation. Heart Rhythm. 2007; 4: 816-861 Abstract Full Text Full Text PDF PubMed Scopus (1104) Google Scholar Early mortality after inpatient versus outpatient catheter ablation in patients with atrial fibrillationHeart RhythmVol. 20Issue 6PreviewRates of early mortality and complications after catheter ablation (CA) of atrial fibrillation (AF) vary across health care settings. Full-Text PDF

Is the success of pulmonary vein (PV) isolation to treat patients with paroxysmal atrial fibrillation (AF) primarily related to creating permanent ablation lesions preventing PV triggers from initiating or perpetuating AF? Or rather, contemporary strategies of antral isolation inevitably result in ablation of ganglia and nerves, attenuating autonomic tone and playing a decisive role at maintaining sinus rhythm? In this issue of the Journal, Guo, Wang (both authors contributed equally to the study) et al (1) provide new research in an attempt to resolve this crucial dilemma that remains unanswered, now 25 years following the landmark report from Bordeaux on ablation of PV triggers to treat patients with paroxysmal AF (2).

In this issue of Heart Rhythm Journal, Kim et al 1 Kim M.Y. Coyle C. Tomlinson D.R. et al. Ectopy-triggering ganglionated plexus ablation to prevent atrial fibrillation: GANGLIA-AF study. Heart Rhythm. 2022; 19: 516-524 Abstract Full Text Full Text PDF PubMed Scopus (21) Google Scholar report a prospective trial (ClinicalTrials.gov identifier NCT02487654) of patients with paroxysmal atrial fibrillation (AF) undergoing catheter ablation. The 102 patients were randomized to undergo pulmonary vein isolation (PVI) or map-guided left atrial (LA) denervation without PVI. Patients undergoing PVI required significantly more ablation time as compared with patients undergoing map-guided LA denervation (38 ± 14 minutes vs 23 ± 10 minutes; P < .0001). The procedure duration was significantly longer in patients undergoing map-guided LA denervation (181 ± 33 minutes vs 127 ± 33 minutes; P < .0001). Overall, there was no significant difference in patient outcomes between both groups. At 12 months, the freedom from ≥30 seconds of atrial tachyarrhythmias was 64% in the PVI group as compared with 50% in patients undergoing map-guided LA denervation (log-rank, P = .09). The reduction of use of antiarrhythmic agents postablation was significantly greater in patients undergoing map-guided LA denervation (P = .05). Interestingly, a history of hypertension predicted a favorable outcome after map-guided LA denervation. Ectopy-triggering ganglionated plexuses ablation to prevent atrial fibrillation: GANGLIA-AF studyHeart RhythmVol. 19Issue 4PreviewThe ganglionated plexuses (GPs) of the intrinsic cardiac autonomic system may play a role in atrial fibrillation (AF). Full-Text PDF Open Access

Pulmonary vein stenosis (PVS) may arise from a variety of conditions and result in major morbidity and mortality. In some patients, pharmacologic therapy may help, but more often in advanced stages, mechanical treatment must be considered. Transcatheter approaches, both balloon angioplasty (BA) and stent implantation, have been applied. Although both are effective, they continue to be limited by restenosis. In this systematic review and meta-analysis, Ovid MEDLINE, Ovid Embase, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, and Scopus were searched for English-language studies in humans published between January 1, 2010, and August 2, 2021. Two independent reviewers screened for studies in which BA or stenting was performed for PVS with reporting of restenosis outcomes, and data were independently extracted. A systematic review was performed, and overall restenosis rates were reported across all 34 included studies. Meta-analysis was then performed using RevMan version 5.4, assessing rates of restenosis and restenosis requiring reintervention in those studies with available data reported. For restenosis rates, 4 studies treated a total of 340 patients with 579 pulmonary vein interventions (225 with BA and 354 with stenting, mean follow-up 13-69 months). Restenosis requiring repeat intervention was reported in 3 studies, including 301 patients with 495 pulmonary vein interventions (157 with BA and 338 with stenting). Compared with BA, stenting was associated with both a lower risk for restenosis (risk ratio: 0.36; 95% CI: 0.18-0.73; P = 0.005) and a lower risk for restenosis requiring reintervention (RR: 0.36; 95% CI: 0.15-0.86; P = 0.02). For PVS intervention, restenosis and reintervention rates may be improved by stent implantation compared with BA.

Investigators in Japan evaluated echocardiographic and hemodynamic findings in patients with paroxysmal atrial fibrillation, comparing the findings of asymptomatic patients with patients who had symptomatic atrial fibrillation. Transseptal measurements of left atrial pressure were obtained. The multivariate analysis showed that patients with asymptomatic atrial fibrillation had significantly lower E/e on echo and lower rates of change of peak LA pressure in sinus rhythm or with high right atrial pacing. Patients with asymptomatic atrial fibrillation have preserved diastolic function and significantly less increase in LA pressure during atrial fibrillation. Although asymptomatic atrial fibrillation has generally been shown to be present in approximately 25% of patients with atrial fibrillation, new technologies of digital monitoring have revealed documentation of an increased number of patients with asymptomatic atrial fibrillation. This article is protected by copyright. All rights reserved.

The pandemic caused by SARS-CoV-2 has affected communities throughout the world. The global nature of health care disparities is exacerbated by COVID-19. Patients in Low-and Middle-Income Countries have limited health care resources and marginal support for the evaluation and treatment of cardiac rhythm disorders. Heart Rhythm Societies and their members need to advocate for increased subsidies and assistance for these patients.

British physiology got off to a slow start. By 1865, Claude Bernard in France had published “Introduction a l’etude de la medecine experimentale,” which would become the standard reference for the methodological approach to physiology. By 1869, Carl Ludwig in Germany had designed and opened

Hein J.J. Wellens was Director of Cardiology at Annadal Hospital and the University of Limburg in Maastricht, Netherlands between 1977 and 2001. Professor Wellens died on June 9, 2020, at 84 years of age. His remarkable legacy in cardiac electrophysiology ranges from his thesis on programmed electrical stimulation of the heart, published at 36 years of age while at the Academic Medical Center in Amsterdam, to his continued and still relevant teaching of electrocardiography. For general cardiologists, Wellens was synonymous with electrocardiography. However, for those who specialized in cardiac electrophysiology, Wellens emphasized repeatedly that electrocardiography was much more than a 12-lead electrocardiogram. Rhythm tracings and the electrocardiogram have been analyzed and interpreted with our understanding of invasive electrophysiology and recordings of atrial and ventricular electrograms. The passion of Wellens for unifying invasive tracings of the heart with a noninvasive tool such as the electrocardiograph was most vividly witnessed by a group of Canadian physicians who had the extraordinary opportunity to study under Wellens in the Netherlands.

Aims There is ongoing controversy about the need for routine transoesophageal echocardiography (TOE) prior to atrial fibrillation (AF) ablation, Recently, the debate was reignited by the publication of a large series of patients showing a prevalence of left atrial appendage thrombus (LAAT) on TOE of 4.4%. We sought to assess the prevalence of LAAT on TOE before AF ablation at our institution. Methods and results Consecutive patients scheduled for AF ablation at our institution between January 2009 and December 2016 were included. All patients were on oral anticoagulation for at least 4 weeks prior to TOE. Transoesophageal echocardiographies were performed 3-5 days prior to scheduled AF ablation. Data were collected utilizing a prospective database. In all, 668 patients and 943 AF ablation procedures were included. Mean age was 64 +/- 11 years, 72% were male, average CHADS(2) score was 1.0 +/- 1.0, and 72% of the patients had paroxysmal AF. At the time of ablation, 496 (53%) were on non-vitamin K antagonist oral anticoagulants (NOACs) and 447 (47%) were on Warfarin. There were three cases with LAAT (3/943, 0.3%), all of whom had persistent AF and were on Warfarin. Two patients underwent surgical ablation and the third patient did not undergo ablation. Conclusion In our experience, the prevalence of LAAT in patients on anticoagulation therapy undergoing TOE before catheter ablation of AF is 0.3%, which was much lower than recently reported. None of the patients with paroxysmal AF or on NOACs were found to have LAAT. Rather than routine use of TOE prior to AF ablation, a risk-based approach should be considered.

Patients with Wolff-Parkinson-White syndrome are generally evaluated for symptomatic supraventricular tachycardia (SVT). Not infrequently, these patients are also at risk of wide complex tachycardia. Although overt pre-excitation in sinus rhythm is most often present in patients with Wolff-Parkinson-White syndrome, the absence of a delta wave on the resting electrocardiogram (ECG) does not preclude antegrade conduction over the accessory pathway. The deductive analysis required in the interpretation of wide complex tachycardia, and its termination by adenosine, in a patient with intermittent pre-excitation is reviewed.

The impact of ablation of ganglionated plexuses (GPs) during ablation of atrial fibrillation (AF) on ventricular myocardial innervation is unknown. Previous animal studies have shown different electrophysiological outcomes of ventricular myocardial denervation after ablation of autonomic ganglia.1,2 A recent animal report demonstrated that the ligament of Marshall could represent a conduit between the left stellate ganglion and the ventricle.2 There have been no reports evaluating detailed GP mapping and ablation in the atria and potential effects on ventricular sympathetic myocardial innervation.

There is perhaps no better popular account of the effects of the cold on our senses than a good ice cream cone causing a severe, intense frontal headache. But just as the brain freeze results from stimuli to the oropharyngeal region, the effects of the cold on the heart can involve many different pathways, from direct infusion of cold crystalloid cardioplegia to drinking ice-cold beverages. In this issue of the Journal, Miyazaki et al 1 Miyazaki S. Nakamura H. Taniguchi H. Hachiya H. Ichihara N. Takagi T. Iwasawa J. Kuroi A. Watanabe T. Hirao K. Iesaka Y. Impact of the order of the targeted pulmonary vein on the vagal response during second-generation cryoballoon ablation. Heart Rhythm. 2016; 13: 1010-1017 Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar describe the effects on cardiac rhythm of cryoballoon (“cryo”) ablation of the pulmonary veins (PV) in patients with paroxysmal atrial fibrillation (AF). The authors provide 3 important findings that relate to cryo stimuli and ablation, anatomic and physiologic pathways associated with autonomic tone, and considerations for the order of energy delivery during cryoballoon ablation of AF. Impact of the order of the targeted pulmonary vein on the vagal response during second-generation cryoballoon ablationHeart RhythmVol. 13Issue 5PreviewRadiofrequency applications around pulmonary vein (PV) ostia often induce vagal reflexes. Full-Text PDF

Percutaneous, ultrasound-guided fetal cardiac intervention (FCI) is increasingly used to alter the prognosis of specific forms of congenital heart disease. Careful patient selection and postnatal management strategy are essential for optimal outcomes. This article discusses the rationale, patient selection criteria, procedural techniques, and contemporary results of FCI. Sources of information included published patient series, the International Fetal Cardiac Intervention Registry, and the Toronto experience as the Canadian referral center.