Supraventricular tachycardia after orthotopic cardiac transplantation

Dissociated rhythms between donor and recipient hearts after heart transplantation using the modified bicaval technique

The modified bicaval anastomosis technique is an orthotopic heart transplantation technique that preserves the posterior wall of the right atrium as a bridging tissue, creating a dual structure of the recipient and donor hearts between the superior and inferior venae cavae. In this report, we present a case with unique electrophysiological findings following heart transplantation using this technique. The patient, who had persistent atrial fibrillation before the procedure, achieved a maintained sinus rhythm afterward. During an episode of cavotricuspid isthmus-dependent atrial flutter in the donor heart, an irregular rhythm suggestive of atrial fibrillation was identified in limited areas of the superior and inferior venae cavae. Atrial flutter ceased after cavotricuspid isthmus ablation; however, atrial fibrillation in the superior and inferior venae cavae persisted. The dissociated rhythms were observed probably because atrial fibrillation may have persisted entirely in the recipient's atrium, and could only be visualized through the superior and inferior venae cavae, which were accessible through the endocardium.

Learning objective

When two different atrial arrhythmias occur in the donor and recipient hearts in a patient after heart transplantation using the modified bicaval anastomosis technique, the recipient heart's arrhythmia may persist concurrently with the donor heart's, resulting in a "duplex arrhythmia." Dissociated rhythms could be observed in the separated areas of the right atrium and the superior and inferior venae cavae, which are accessible through the endocardium.

Late onset of two concurrent and dissociated arrhythmias in a transplanted heart

A 53-year-old patient with a history of heart transplant is referred for atrial tachycardia ablation. Two dissociated concomitant rhythms are observed: a focal atrial tachycardia in the donor atrium and atrial fibrillation in the remaining recipient atrium.

Prevention and rehabilitation after heart transplantation: A clinical consensus statement of the European Association of Preventive Cardiology, Heart Failure Association of the ESC, and the European Cardio Thoracic Transplant Association, a section of ESOT

Little is known either about either physical activity patterns, or other lifestyle-related prevention measures in heart transplantation (HTx) recipients. The history of HTx started more than 50 years ago but there are still no guidelines or position papers highlighting the features of prevention and rehabilitation after HTx. The aims of this scientific statement are (i) to explain the importance of prevention and rehabilitation after HTx, and (ii) to promote the factors (modifiable/non-modifiable) that should be addressed after HTx to improve patients' physical capacity, quality of life and survival. All HTx team members have their role to play in the care of these patients and multidisciplinary prevention and rehabilitation programmes designed for transplant recipients. HTx recipients are clearly not healthy disease-free subjects yet they also significantly differ from heart failure patients or those who are supported with mechanical circulatory support. Therefore, prevention and rehabilitation after HTx both need to be specifically tailored to this patient population and be multidisciplinary in nature. Prevention and rehabilitation programmes should be initiated early after HTx and continued during the entire post-transplant journey. This clinical consensus.

Prevention and Rehabilitation After Heart Transplantation: A Clinical Consensus Statement of the European Association of Preventive Cardiology, Heart Failure Association of the ESC, and the European Cardio Thoracic Transplant Association, a Section of ESOT

Little is known either about either physical activity patterns, or other lifestyle-related prevention measures in heart transplantation (HTx) recipients. The history of HTx started more than 50 years ago but there are still no guidelines or position papers highlighting the features of prevention and rehabilitation after HTx. The aims of this scientific statement are (i) to explain the importance of prevention and rehabilitation after HTx, and (ii) to promote the factors (modifiable/non-modifiable) that should be addressed after HTx to improve patients' physical capacity, quality of life and survival. All HTx team members have their role to play in the care of these patients and multidisciplinary prevention and rehabilitation programmes designed for transplant recipients. HTx recipients are clearly not healthy disease-free subjects yet they also significantly differ from heart failure patients or those who are supported with mechanical circulatory support. Therefore, prevention and rehabilitation after HTx both need to be specifically tailored to this patient population and be multidisciplinary in nature. Prevention and rehabilitation programmes should be initiated early after HTx and continued during the entire post-transplant journey. This clinical consensus statement focuses on the importance and the characteristics of prevention and rehabilitation designed for HTx recipients.

Posttransplant atrial fibrillation: Evidence of early posttransplant recipient-to-donor atrioatrial connections

INTRODUCTION

Atrial fibrillation and atrial flutter originating from the donor s heart is a commonly reported complication post heart transplant. Atrial tachyarrhythmia originating from the recipient s heart, propagated through recipient-to-donor connections, is rare with only few cases reported in the literature; most reported cases from our review occur years post-transplant.

CASE

A 47-year-old male presented with atrial tachycardia 6 months post heart transplant. Electrophysiologic study demonstrated atrial fibrillation originating from native heart and propagated through atrio-atrial connections to the donor heart. This arrhythmia was successfully terminated with radiofrequency ablation.

CONCLUSION

Atrio-atrial connection between recipient and donor can form as early as a few months post heart transplant. Radiofrequency ablation appears to be an effective treatment for atrial fibrillation propagated through donor-to-recipient connections.

Observational Study of the Association between Atrial Fibrillation and In-Hospital Mortality during Hospitalization for Solid Organ Transplants in Spain from 2004 to 2021

(1) Background: We analyzed the association between atrial fibrillation or atrial flutter (AF) and in-hospital mortality (IHM) among patients who underwent solid organ transplants in Spain from 2004 to 2021. (2) Methods: We gathered information from all hospital admissions for lung, liver, kidney, and heart transplants. (3) Results: A total of 71,827 transplants were analyzed (4598 lung transplants; 18,127 liver transplants; 45,262 kidney transplants; and 4734 heart transplants). One third of these were for women. Overall, the prevalence of AF was 6.8% and increased from 5.3% in 2004-2009 to 8.6% in 2016-2021. The highest prevalence of AF was found for heart transplants (24.0%), followed by lung transplants (14.7%). The rates for kidney and liver transplants were 5.3% and 4.1%, respectively. The AF code increased over time for all of the transplants analyzed (p < 0.001). The patients' IHM decreased significantly from 2004-2009 to 2016-2021 for all types of transplants. AF was associated with a higher IHM for all of the types of transplants analyzed, except for heart transplants. (4) Conclusions: The prevalence of AF among patients admitted for solid organ transplants was highest for those who underwent heart transplants. The mortality rate during the patients' admission for lung, liver, kidney, or heart transplants decreased over time. AF was independently associated with a higher risk of dying in the hospital for those who underwent lung, liver, or kidney transplants.

Perioperative Management of Heart Transplantation: A Clinical Review

In this clinical review, the authors summarize the perioperative management of heart transplant patients with a focus on hemodynamics, immunosuppressive strategies, hemostasis and hemorrage, and the prevention and treatment of infectious complications.

Excitation and contraction of cardiac muscle and coronary arteries of brain-dead pigs

Excitability and contraction of cardiac muscle from brain-dead donors critically influence the success of heart transplantation. Membrane physiology, Ca2+-handling, and force production of cardiac muscle and the contractile properties of coronary arteries were studied in hearts of brain-dead pigs. Cardiac muscle and vascular function after 12 h brain death (decapitation between C2 and C3) were compared with properties of fresh tissue. In both isolated cardiomyocytes (whole-cell patch clamp) and trabecular muscle (conventional microelectrodes), action potential duration was shorter in brain dead, compared to controls. Cellular shortening and Ca2+ transients were attenuated in the brain dead, and linked to lower mRNA expression of L-type calcium channels and a slightly lower ICa,L, current, as well as to a lower expression of phospholamban. The current-voltage relationship and the current above the equilibrium potential of the inward K+ (IK1) channel were altered in the brain-dead group, associated with lower mRNA expression of the Kir2.2 channel. Delayed K+ currents were detected (IKr, IKs) and were not different between groups. The transient outward K+ current (Ito) was not observed in the pig heart. Coronary arteries exhibited increased contractility and sensitivity to the thromboxane analogue (U46619), and unaltered endothelial relaxation. In conclusion, brain death involves changes in cardiac cellular excitation which might lower contractility after transplantation. Changes in the inward rectifier K+ channel can be associated with an increased risk for arrhythmia. Increased reactivity of coronary arteries may lead to increased risk of vascular spasm, although endothelial relaxant function was well preserved.

Temporary Epicardial Pacing After Cardiac Surgery

Temporary epicardial pacing frequently is employed after cardiac surgery, and can have a significant impact on a patient's hemodynamics, arrhythmias, and valvulopathies. Given that anesthesiologists often are involved intimately in the initial programming and subsequent management of epicardial pacing in the operating room and intensive care unit, it is important for practitioners to have a detailed understanding of the modes, modifiable intervals, and potential complications that can occur after cardiac surgery. Because this topic has not been reviewed recently in anesthesia literature, the authors attempted to review relevant epicardial pacemaker specifics, discuss modes and parameters that apply to the perioperative period, present an algorithm for mode selection, describe the potential effects of epicardial pacing on valvulopathies and hemodynamics, and, finally, discuss some postoperative considerations.

Frequency, Risk Factors, and Clinical Outcomes of Late-Onset Atrial Flutter in Patients after Heart Transplantation

Aims: Atrial flutter (AFL) is a common late-onset complication after heart transplantation (HTX) and is associated with worse clinical outcomes. Methods: This study investigated the frequency, risk factors, and outcomes of late-onset post-transplant AFL. We analyzed 639 adult patients undergoing HTX at the Heidelberg Heart Center between 1989 and 2019. Patients were stratified by diagnosis and type of late-onset post-transplant AFL (>90 days after HTX). Results: A total of 55 patients (8.6%) were diagnosed with late-onset post-transplant AFL, 30 had typical AFL (54.5%) and 25 had atypical AFL (45.5%). Patients with AFL were younger at HTX (p = 0.028), received more biatrial anastomosis (p = 0.001), and presented with moderate or severe tricuspid regurgitation (56.4%). Typical AFL was associated with graft rejection (p = 0.016), whereas atypical AFL was associated with coronary artery disease (p = 0.028) and stent implantation (p = 0.042). Patients with atypical AFL showed a higher all-cause 1-year mortality (p = 0.010) along with a higher rate of graft failure after diagnosis of AFL (p = 0.023). Recurrence of AFL was high (83.6%). Patients with catheter ablation after AFL recurrence had a higher 1-year freedom from AFL (p = 0.003). Conclusions: Patients with late-onset post-transplant AFL were younger at HTX, received more biatrial anastomosis, and showed a higher rate of moderate or severe tricuspid regurgitation. Typical AFL was associated with graft rejection, whereas atypical AFL was associated with myocardial ischemia, graft failure, and mortality. Catheter ablation represents a viable option to avoid further episodes of late-onset AFL after HTX.

Atrial Flutter in Particular Patient Populations

"Despite being one of the best understood cardiac arrhythmias, the clinical meaning of atrial flutter varies according to the specific context, and its optimal treatment may be limited by both the suboptimal response to rate/rhythm control drugs and by the complexity of the underlying substrate. In this article, we present a state-of-the-art overview of mechanisms, prognostic impact, and medical/interventional management options for atrial flutter in several specific patient populations, including heart failure, cardiomyopathies, muscular dystrophies, posttransplant patients, patients with respiratory disorders, athletes, and subjects with preexcitation, aiming to stimulate further research in this challenging field and facilitate appropriate patient care."

Preserved electrical conduction between donor and recipient right atria as the cause of macroreentrant atrial tachycardia after heart transplantation

Atrial arrhythmias after heart transplantation are common and usually originate from reentrant circuits inside the donor and recipient atria. A case is presented of macroreentrant atrial tachycardia with a reentry circuit incorporating preserved electrical conduction from the donor and recipient right atria. An invasive electrophysiological study including high-density electroanatomical mapping with a multipolar catheter was performed during tachycardia. A reentry circuit with an area of slow conduction at the supero-lateral aspect of the surgical anastomosis could be demonstrated. Catheter ablation at the site of slow conduction successfully terminated and permanently suppressed the tachycardia.

A retrospective evaluation of catheter ablation in atrial flutter post cardiac transplantation

BACKGROUND

Atrial flutter is the most common arrhythmia post cardiac transplantation. Observational studies in the non-transplant population have shown prognostic benefit with catheter ablation; however, there are no data in the heart transplant population.

OBJECTIVES

This study evaluated the experience of catheter ablation in atrial flutter post cardiac transplantation.

METHODS

A retrospective review of experience of late onset atrial flutter at the Freeman Hospital, Newcastle-upon-Tyne, UK, between 1985 and January 2020.

RESULTS

Sixty eight of the 722 patients who survived 6 months post cardiac transplantation developed late atrial flutter giving an incidence of 9.4%. Thirty-two patients were managed with ablation with treatment largely determined by time of flutter onset. Kaplan Meier estimates for arrhythmia free survival post first ablation for organized atrial arrhythmias was 83.3% at 1 year. Kaplan-Meier estimates for median survival post onset of atrial arrhythmias treated with ablation was 11.34 years (95% CI 8.00-14.57), compared to 5.79 years in patients managed medically (95%CI 2.26-9.32) (P = .026).

CONCLUSIONS

Atrial flutter is an important late complication of cardiac transplantation. Patients treated with ablation in the modern era had increased survival compared to a historical cohort.

Immuno-Electrophysiological Mechanisms of Functional Electrical Connections Between Recipient and Donor Heart in Patients With Orthotopic Heart Transplantation Presenting With Atrial Arrhythmias

[Figure: see text].

Management of Arrhythmias After Heart Transplant: Current State and Considerations for Future Research

Orthotropic heart transplantation remains the most effective therapy for patients with end-stage heart failure, with a median survival of ≈13 years. Yet, a number of complications are observed after orthotropic heart transplantation, including atrial and ventricular arrhythmias. Several factors contribute to arrhythmias, such as autonomic denervation, effect of the surgical technique, acute and chronic rejection, and transplant vasculopathy among others. To minimize risk of future arrhythmias, the bicaval technique and minimizing ischemic time are current surgical standards. Sinus node dysfunction is the most common indication for early (within 30 days) pacemaker implantation, whereas atrioventricular block incidence increases as time from transplant increases. Atrial fibrillation can occur in the first few weeks following transplantation but is uncommon in the long term unless secondary to a precipitant such as acute rejection. The most common atrial arrhythmias are atrial flutters, which are mainly typical, but atypical circuits can be observed such as those that involve the remnant donor atrium in regions immediately adjacent to the atrioatrial anastomosis suture line. Choosing the appropriate pharmacological therapy requires careful consideration due to the potential interaction with immunosuppressive agents. Despite historical concerns, adenosine is effective and safe at reduced doses if administered under cardiac monitoring. Catheter ablation has emerged as an effective treatment strategy for symptomatic supraventricular tachycardias, including ablation of atypical flutter circuits. Cardiac allograft vasculopathy is an important risk factor for sudden cardiac death, yet the role of prophylactic implantable cardioverter-defibrillator implant for sudden death prevention is unclear. Current indications for implantable cardioverter-defibrillator implantation are as in the nontransplant population. A number of questions for future research are posed.

Atrial fibrillation after orthotopic heart transplantatation: Pathophysiology and clinical impact

BACKGROUND

Atrial fibrillation (AF) is a well-established post-cardiac surgery complication. Orthotopic heart transplantation (OHT) represents a peculiar condition where surgical thoracic veins isolation and autonomic denervation occur. This study aims at investigating AF incidence in OHT in order to define its risk factors and to evaluate its prognostic impact.

METHODS

278 patients affected by OHT were recruited in our Cardiac Surgery Unit and retrospectively analyzed, using clinical, surgical and instrumental data.

RESULTS

The patients cohort showed 45 post-operative (16.5%) and 20 late AF cases (7.2%). Only paroxysmal AF episodes were observed. Elderly donors and acute rejection resulted as risk factors in patients with post-operative AF episodes, who presented higher all-cause mortality at 11 years post-OHT (p < 0.001, Kaplan Meier analysis). The majority of late AF episodes occurred during hospitalization, due to renal failure or infections and more frequently in male patients; no significant correlation was observed with acute or chronic rejection or other characteristics.

CONCLUSION

Pulmonary vein isolation and vagal denervation lead to low AF incidence in OHT recipients. Acute rejection and graft status are the main risk factors for post-operative AF episodes, while other systemic conditions act as late AF triggers. The occurrence of AF episodes is associated with poor outcome and AF should be considered as a marker of clinical frailty.

Radiofrequency ablation of supraventricular arrhythmias after orthotopic heart transplantation: Long-term follow-up of a single-center experience

BACKGROUND

Supraventricular arrhythmias (SVAs), commonly managed with radiofrequency ablation (RFA), may occur after orthotopic heart transplantation (OHT).

METHODS

We retrospectively assessed 514 consecutive patients (pts.) undergoing OHT between January 1990 and July 2016 in a single-center. Patients with SVAs managed with RFA were included. Mechanisms of genesis of SVAs, association with surgical techniques and outcomes, were analyzed.

RESULTS

Of 514 pts undergoing OHT, 53% (272 pts.) were managed with bicaval (BC) technique and 47% (242 pts.) with biatrial (BA) technique. Mean follow-up 10 ± 8.4 years. Nine pts. (1.7%) developed SVA requiring RFA. The BC technique was performed in 4 pts., 3 pts. presented cavotricuspid isthmus-dependent atrial flutter (CTI AFL), and 1 pt. double loop AFL. Five pts. were managed with BA technique, 4 pts. presented CTI AFL, and 1 pt. atrial tachycardia (AT). Mean time between OHT and SVA occurrence was 6.6 ± 5.5 years. The procedure was successful in 89% (8 pts.). Arrhythmia recurrence was seen in 3 pts (37%), all with BA technique.

CONCLUSION

Supraventricular arrhythmias in heart transplantation may be associated with the surgical scar. Identifying the mechanism is vital to choose the appropriate treatment with radiofrequency ablation.

Beta-blocker therapy in heart transplant recipients: A review

Beta-blockers are essential drugs for the treatment of many cardiovascular diseases, such as heart failure, acute and chronic ischemic heart disease, tachyarrhythmias, and hypertension. However, these drugs have not been used in cardiac transplant patients for many years owing to the fear that they could reduce cardiac output and functional capacity. In recent years, however, some evidence has shown that even in cardiac transplanted patients, β-blockers are useful and effective in the treatment of sinus tachycardia, supraventricular and ventricular tachyarrhythmias, left ventricular systolic dysfunction, and arterial hypertension. Furthermore, some data have shown that the use of β-blockers is associated with reduced mortality in heart transplant recipients. In this review, we summarize this evidence with particular emphasis on the practical aspects of the use of β-blockers in post-transplantation patients to promote the use of this important class of drugs in clinical practice.

Cardiac sympathectomy and spinal cord stimulation attenuate reflex-mediated norepinephrine release during ischemia preventing ventricular fibrillation

The purpose of this study was to define the mechanism by which cardiac neuraxial decentralization or spinal cord stimulation (SCS) reduces ischemia-induced ventricular fibrillation (VF). Direct measurements of norepinephrine (NE) levels in the left ventricular interstitial fluid (ISF) by microdialysis, in response to transient (15-minute) coronary artery occlusion (CAO), were performed in anesthetized canines. Responses were studied in animals with intact neuraxes and were compared with those in which the intrathoracic component of the cardiac neuraxes (stellate ganglia) or the intrinsic cardiac neuronal (ICN) system was surgically delinked from the central nervous system and those with intact neuraxes with preemptive SCS (T1-T3). With intact neuraxes, animals with exaggerated NE release due to CAO were at increased risk for VF. During CAO, there was a 152% increase in NE when the neuraxes were intact compared with 114% following stellate decentralization and 16% following ICN decentralization. During SCS, CAO NE levels increased by 59%. Risk for CAO-induced VF was 38% in controls, 8% following decentralization, and 11% following SCS. These data indicate that ischemia-related afferent neuronal transmission differentially engages central and intrathoracic sympathetic reflexes and amplifies sympathoexcitation. Differences in regional ventricular NE release are associated with increased risk for VF. Surgical decentralization or SCS reduced NE release and VF.

Association Between Heart Transplantation and Subsequent Risk of Stroke Among Patients With Heart Failure

Background and Purpose- It is uncertain whether heart transplantation decreases the risk of stroke. The objective of our study was to determine whether heart transplantation is associated with a decreased risk of subsequent stroke among patients with heart failure awaiting transplantation. Methods- We performed a retrospective cohort study using administrative data from New York, California, and Florida between 2005 and 2015. Individuals with heart failure awaiting heart transplantation were identified using previously validated International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis codes for heart failure in combination with code V49.83 for awaiting organ transplant status. Individuals with prior stroke were excluded. Our primary exposure variable was heart transplantation, modeled as a time-varying covariate and defined by procedure code 37.51. The primary outcome was stroke, defined as the composite of ischemic and hemorrhagic stroke. Survival statistics were used to calculate stroke incidence, and Cox proportional hazards analysis was used to determine the association between heart transplantation and stroke while adjusting for demographics, stroke risk factors, Elixhauser comorbidities, and implantation of a left ventricular assist device. Results- We identified 7848 patients with heart failure awaiting heart transplantation, of whom 1068 (13.6%) underwent heart transplantation. During a mean follow-up of 2.7 years, we identified 428 strokes. The annual incidence of stroke was 0.7% (95% CI, 0.5%-1.0%) after heart transplantation versus 2.4% (95% CI, 2.2%-2.6%) among those awaiting heart transplantation. After adjustment for potential confounders, heart transplantation was associated with a lower risk of stroke (hazard ratio, 0.4; 95% CI, 0.2-0.6). Conclusions- Heart transplantation is associated with a decreased risk of stroke among patients with heart failure awaiting transplantation.

Controversies in the Postoperative Management of the Critically Ill Heart Transplant Patient

Heart transplant recipients are susceptible to a number of complications in the immediate postoperative period. Despite advances in surgical techniques, mechanical circulatory support (MCS), and immunosuppression, evidence supporting optimal management strategies of the critically ill transplant patient is lacking on many fronts. This review identifies some of these controversies with the aim of stimulating further discussion and development into these gray areas.

Neuromodulation Approaches for Cardiac Arrhythmias: Recent Advances

PURPOSE OF REVIEW

This review aims to describe the latest advances in autonomic neuromodulation approaches to treating cardiac arrhythmias, with a focus on ventricular arrhythmias.

RECENT FINDINGS

The increasing understanding of neuronal remodeling in cardiac diseases has led to the development and improvement of novel neuromodulation therapies targeting multiple levels of the autonomic nervous system. Thoracic epidural anesthesia, spinal cord stimulation, stellate ganglion modulatory therapies, vagal stimulation, renal denervation, and interventions on the intracardiac nervous system have all been studied in preclinical models, with encouraging preliminary clinical data. The autonomic nervous system regulates all the electrical processes of the heart and plays an important role in the pathophysiology of cardiac arrhythmias. Despite recent advances in the clinical application of cardiac neuromodulation, our comprehension of the anatomy and function of the cardiac autonomic nervous system is still limited. Hopefully in the near future, more preclinical data combined with larger clinical trials will lead to further improvements in neuromodulatory treatment for heart rhythm disorders.

Regular tachycardia despite Wenckebach atrioventricular conduction

We present a 21-year-old woman status post orthotopic heart transplantation initially presenting with a regular narrow complex tachycardia at 159beats/min. With intravenous diltiazem the rhythm transitioned to a regular tachycardia at 106beats/min, 2/3rd of the initial heart rate. We demonstrate this to be a novel description of 3:2second-degree Mobitz type I atrioventricular block (Wenckebach) with the absence of the hallmark regularly irregular (grouped beating) pattern.

Recipient Atrial Fibrillation Manifesting as an Irregular Monomorphic Atrial Tachycardia in the Donor Heart

A 63-year-old man presented with a 1-year history of atrial tachycardia (AT) 6 years after orthotopic heart transplantation with bicaval anastomosis. Twelve-lead electrocardiogram showed monomorphic AT with isoelectric intervals across all leads and strikingly irregular PP intervals. At electrophysiology study, the native left atrium's rhythm was atrial fibrillation (AF) while the donor atria exhibited centrifugal activation of irregular cycle length originating from a site along the left atrial anastomosis. Ablation at that site terminated AT to sinus rhythm. Recipient AF with recipient-to-donor conduction should be suspected in the presence of irregular monomorphic AT in orthotopic heart transplantation recipients. Catheter ablation of atrio-atrial conduction is safe and effective.

Catheter ablation of organized atrial arrhythmias in orthotopic heart transplantation

BACKGROUND

Organized atrial arrhythmias (OAAs) are common after orthotopic heart transplantation (OHT). Some controversies remain about their clinical presentation, relationship with atrial anastomosis and electrophysiologic features. The objectives of this retrospective study were to determine the mechanisms of OAAs after OHT and describe the outcomes of radiofrequency catheter ablation (RFCA).

METHODS

Thirty consecutive transplanted patients (mean age 48 ± 17 years, 86.6% male) underwent 3-dimensional electroanatomic mapping and RFCA of their OAA from 2004 to 2012 at our center.

RESULTS

Twenty-two patients had biatrial anastomosis and 8 had bicaval anastomosis. Macro-reentry was the arrhythmia mechanism for 96% of patients. The electrophysiologic diagnoses were: cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL) in 93% of patients (n = 28); perimitral AFL in 3% (n = 1); and focal atrial tachycardia (FAT) in 3% (n = 1). In 5 patients with biatrial anastomosis, a right FAT was inducible. Primary RFCA success was obtained in 93% of patients. Mean follow-up time was 39 ± 26.8 months. Electrical repermeation between recipient and donor atria, present in 20% of patients (n = 6), did not account for any of the OAAs observed. Survival without OAA relapse at 12, 24 and 60 months was 93%, 89% and 79%, respectively.

CONCLUSIONS

CTI-dependent AFL accounted for most instances of OAA after OHT, regardless of anastomosis type. Time from transplantation to OAA was shorter with bicaval than with biatrial anastomosis. RFCA was safe and provided good long-term results.

Recurrent myocardial infarction: Mechanisms of free-floating adaptation and autonomic derangement in networked cardiac neural control

The cardiac nervous system continuously controls cardiac function whether or not pathology is present. While myocardial infarction typically has a major and catastrophic impact, population studies have shown that longer-term risk for recurrent myocardial infarction and the related potential for sudden cardiac death depends mainly upon standard atherosclerotic variables and autonomic nervous system maladaptations. Investigative neurocardiology has demonstrated that autonomic control of cardiac function includes local circuit neurons for networked control within the peripheral nervous system. The structural and adaptive characteristics of such networked interactions define the dynamics and a new normal for cardiac control that results in the aftermath of recurrent myocardial infarction and/or unstable angina that may or may not precipitate autonomic derangement. These features are explored here via a mathematical model of cardiac regulation. A main observation is that the control environment during pathology is an extrapolation to a setting outside prior experience. Although global bounds guarantee stability, the resulting closed-loop dynamics exhibited while the network adapts during pathology are aptly described as 'free-floating' in order to emphasize their dependence upon details of the network structure. The totality of the results provide a mechanistic reasoning that validates the clinical practice of reducing sympathetic efferent neuronal tone while aggressively targeting autonomic derangement in the treatment of ischemic heart disease.

Electrocardiographic alterations associated with heart transplantation. Triggers, mechanisms and meaning

Introducción. Las alteraciones del ritmo cardíaco están asociadas con un aumento en la morbimortalidad; sin embargo, en pacientes con trasplante cardíaco no son claros sus desencadenantes ni implicaciones.Objetivos. Realizar una búsqueda en la literatura para identificar y explicar los determinantes en la generación de alteraciones de la conducción eléctrica en pacientes con trasplante cardíaco, así como describir las principales arritmias que pueden presentarse, explicando sus implicaciones patológicas.Materiales y métodos. Se realizó una búsqueda en la base de datos PubMed que arrojó un total de 411 resultados. Además, se buscaron las guías de práctica clínica sobre trasplante cardíaco, electrofisiología cardiovascular y endocarditis infecciosa. Se eligieron 60 artículos que lograban responder a los objetivos de este estudio.Resultados. La técnica quirúrgica, la denervación cardíaca, las lesiones del nodo sinusal, el rechazo del injerto, las biopsias endomiocárdicas y las infecciones son los principales factores que comprometen la viabilidad del órgano y la vida del paciente trasplantado, manifestándose como alteraciones del ritmo sinusal.Conclusiones. Ante la detección de alguna arritmia cardíaca, el equipo médico debe proporcionar un manejo que no se limite al control sintomático y del ritmo sinusal, sino que se debe iniciar una búsqueda activa de su etiología, ya que esta puede ser la manifestación de un proceso patológico subyacente.

Postoperative management of heart transplantation patients

Heart transplant recipients are at risk for a number of post-transplantation complications such as graft dysfunction, rejection, and infection. The rates of many complications are decreasing over time, and prognosis is improving. However, these patients continue to experience significant morbidity and mortality. This review focuses on the optimal management of heart transplant recipients in the postoperative period, based on current knowledge. More information is needed about the best ways to predict, prevent, and treat primary graft dysfunction, right ventricular failure, and cellular and antibody-mediated rejection.

Atrial electromechanical delay in patients undergoing heart transplantation

Background

We aimed to assess atrial electromechanical delay (AEMD) in patients who had undergone heart transplantation.

Methods

A total of 32 patients who underwent biatrial anastomosis heart transplantation (24 men, 8 women; mean age: 42±11 years) and 30 healthy volunteers (20 men, 10 women; mean age: 36±13 years) were included in the study. Atrial electromechanical coupling (PA), intra-AEMD, and inter-AEMD were measured.

Results

PA lateral (68±7 vs. 51±11 ms, p<0.01), PA septal (50±5 vs. 42±8 ms, p< 0.01) and PA tricuspid (39±6 vs. 36±9 ms, p<0.01), inter-AEMD (PA lateral–PA tricuspid) (27±7 vs. 10±4 ms, p<0.01), left intra-AEMD (PA lateral–PA septal) (18±7 vs. 10±4 ms, p<0.01), right intra-AEMD (PA septal–PA tricuspid) (13±5 vs. 5±3 ms, p<0.01) values were higher in patients who underwent heart transplantation than in a control population.

Conclusion

Inter-AEMD and intra-AEMD were prolonged in patients who underwent heart transplantation as compared to a control population. This may explain the increased atrial fibrillation and other atrial arrhythmia incidences associated with the biatrial anastomosis heart transplantation technique and may contribute to the treatment of atrial fibrillation in this special patient group.

Incidence of late atrial fibrillation in bilateral lung versus heart transplants

BACKGROUND

We compared the incidence of late-onset atrial fibrillation in orthotopic heart transplant recipients and bilateral orthotopic lung transplant recipients.

METHODS

We reviewed the records of all heart and lung transplant operations carried out in our institution between 1995 and 2015. We performed 1:1 propensity-matching based on patient age, sex, body mass index, and hypertension. Our primary outcome, late-onset atrial fibrillation, was defined as atrial fibrillation occurring after discharge following hospitalization for transplantation.

RESULTS

Over the study period, 397 orthotopic heart transplants and 240 bilateral orthotopic lung transplants were performed. Propensity matching resulted in 173 pairs who were matched with respect to age, sex, body mass index, and preoperative hypertension. The median follow-up was 5.3 years for heart transplant patients and 3.1 years for lung transplant patients. Late-onset atrial fibrillation occurred in 11 heart transplant patients (5 of whom had biopsy-proven evidence of rejection) and 19 lung transplant patients (2 of whom had biopsy-proven evidence of rejection). On Kaplan-Meier analysis, the probability of late-onset atrial fibrillation at 5 years was 4.3% for heart transplant patients vs. 13.9% for lung transplant patients (log-rank p = 0.01).

CONCLUSIONS

We documented an increased probability of late-onset atrial fibrillation among bilateral orthotopic lung transplant patients compared to orthotopic heart transplant patients. This was a hypothesis-generating study that suggests a potential role for cardiac autonomic innervation in the genesis of atrial fibrillation.