Antiarrhythmic therapy for narrow QRS supraventricular tachyarrhythmias in newborns and infants in the first year of life: Potent tools to be handled with care.

Supraventricular tachyarrhythmias pose a significant challenge in neonates and infants, particularly within the first year of life, where prompt and effective management is crucial. By synthesizing available evidence and clinical experience, this review aims to provide a comprehensive overview of antiarrhythmic therapy in this vulnerable population, with a focus on narrow QRS supraventricular tachyarrhythmias. This review examines the current understanding of supraventricular tachyarrhythmia management and discusses the challenges associated with antiarrhythmic therapy in newborns and infants during the critical first year of life, evaluating the efficacy and safety of various antiarrhythmic agents commonly utilized in this population, including dosing considerations, adverse effects, and strategies for acute management and prophylactic long-term antiarrhythmic treatment.

A Refractory Electrical Storm after Acute Myocardial Infarction: The Role of Temporary Ventricular Overdrive Pacing as a Bridge to ICD Implantation.

An electrical storm (ES) is defined as the presence of at least three episodes of sustained ventricular tachycardia or ventricular fibrillation within 24 h. This patient had a previously known arterial hypertension, type II diabetes mellitus, and chronic kidney disease and has presented to the Emergency Department (ED) with symptoms of retrosternal chest pain lasting for several hours prior. The initial 12-lead electrocardiogram revealed ST segment elevation in the anterior leads (V1-V6). Emergent coronary angiography revealed an acute occlusion of the proximal left anterior descending artery (pLAD) and percutaneous coronary intervention was performed with successful implantation of one drug-eluting stent in the pLAD. On day 8 of hospitalization, the patient developed a refractory ES for which he received 50 DC shocks and did not respond to multiple lines of antiarrhythmic medications. Due to a failure of medical therapy, we decided to implant a temporary pacemaker and initiate ventricular overdrive pacing (VOP) that was successful in terminating ES. Following electrical stabilization, the patient underwent a successful ICD implantation. This case demonstrates that VOP can contribute to hemodynamic and electrical stabilization of a patient that suffers from refractory ES and this treatment modality might serve as a temporary bridge to ICD implantation.

Two decades of SVT ablation in Denmark: a trend towards higher age, more comorbidity, and less prior use of antiarrhythmic and rate-limiting pharmacotherapy-a nationwide registry-based Danish study.

BACKGROUND AND AIMS: Trends in patient selection and use of pharmacotherapy prior to catheter ablation (CA) for supraventricular tachycardia (SVT) are not well described. This study examined temporal trends in patients undergoing first-time CA for regular SVT, including atrioventricular nodal re-entry tachycardia (AVNRT), accessory pathways (APs), and ectopic atrial tachycardia (EAT) on a nationwide scale in Denmark in the period 2001-2018. METHODS AND RESULTS: Using Danish Nationwide registers, 9959 patients treated with first-time CA for SVT between 2001 and 2018 were identified, of which 6023 (61%) received CA for AVNRT, 2829 (28%) for AP, and 1107 (11%) for EAT. Median age was 55, 42, and 55 in the AVNRT, APs, and EAT group, respectively. The number of patients receiving CA increased from 1195 between 2001 and 2003 to 1914 between 2016 and 2018. The percentage of patients with a CHA2DS2-VASc score ≥ 2 increased in all patient groups. The number of patients who underwent CA with no prior use of antiarrhythmic- or rate limiting medicine increased significantly, though prior use of beta-blockers increased for AVNRT patients. Use of verapamil decreased in all three SVT groups (P < 0.05). Use of amiodarone and class 1C antiarrhythmics remained low, with the highest usage among EAT patients. CONCLUSION: Between 2001 and 2018, CA was increasingly performed in patients with SVT, primarily AVNRT- and EAT patients. The burden of comorbidities increased. Patients undergoing CA without prior antiarrhythmic- or rate-limiting drug therapy increased significantly. Use of beta-blockers increased and remained the most widely used drug.

Vascular Endothelial Barrier Protection Prevents Atrial Fibrillation by Preserving Cardiac Nanostructure.

BACKGROUND: Atrial fibrillation (AF), the most common cardiac arrhythmia, is widely associated with inflammation, vascular dysfunction, and elevated levels of the vascular leak-inducing cytokine, vascular endothelial growth factor (VEGF). Mechanisms underlying AF are poorly understood and current treatments only manage this progressive disease, rather than arresting the underlying pathology. The authors previously identified edema-induced disruption of sodium channel (NaV1.5)-rich intercalated disk nanodomains as a novel mechanism for AF initiation secondary to acute inflammation. Therefore, we hypothesized that protecting the vascular barrier can prevent vascular leak-induced atrial arrhythmias. OBJECTIVES: In this study the authors tested the hypothesis that protecting the vascular barrier can prevent vascular leak-induced atrial arrhythmias. They identified 2 molecular targets for vascular barrier protection, connexin43 (Cx43) hemichannels and pannexin-1 (Panx1) channels, which have been implicated in cytokine-induced vascular leak. METHODS: The authors undertook in vivo electrocardiography, electron microscopy, and super-resolution light microscopy studies in mice acutely treated with a clinically relevant level of VEGF. RESULTS: AF incidence was increased in untreated mice exposed to VEGF relative to vehicle control subjects. VEGF also increased the average number of AF episodes. VEGF shifted NaV1.5 signal to longer distances from Cx43 gap junctions, measured by a distance transformation-based spatial analysis of 3-dimensional confocal images of intercalated disks. Similar effects were observed with NaV1.5 localized near mechanical junctions composed of neural cadherin. Blocking connexin43 hemichannels (αCT11 peptide) or Panx1 channels (PxIL2P peptide) significantly reduced the duration of AF episodes compared with VEGF alone with no treatment. Concurrently, both peptide therapies preserved NaV1.5 distance from gap junctions to control levels and reduced mechanical junction-adjacent intermembrane distance in these hearts. Notably, similar antiarrhythmic efficacy was also achieved with clinically-relevant small-molecule inhibitors of Cx43 and Panx1. CONCLUSIONS: These results highlight vascular barrier protection as an antiarrhythmic strategy following inflammation-induced vascular leak.

Atrial fibrillation in heart failure: drugs or ablation?

Atrial fibrillation (AF) and heart failure (HF) frequently coexist and mutually exert negative influences with important clinical implications. Although there is evidence that restoring and maintaining sinus rhythm may have favourable clinical effects in patients with HF, there is no evidence of a survival benefit with pharmacological antiarrhythmic intervention compared with a heart rate control strategy. In these patients, transcatheter ablation (CA) of AF represents a procedure with an excellent safety profile in centres with expertise and a high volume of interventions. However, in the absence of definite evidence of benefit on major clinical end-points that can be generalized to the heterogeneous population with AF and HF, the option of CA should be discussed and shared with the patient, and mainly considered in patients with conditions that are associated with a greater prospect of clinical benefit, such as 'young' age (65-70 years), good health conditions and few or no comorbidities, recent onset of HF and AF (especially if with high heart rate), left atrial volume not excessively compromised (<55 mm in diameter), and without evidence of substantial fibrotic remodelling, left ventricular ejection fraction (LVEF) >25%, including HF with preserved EF (HFpEF).

Triple Antiarrhythmic Therapy in Newborns with Refractory Atrioventricular Reentrant Tachycardia.

Atrioventricular reentrant tachycardia (AVRT) is the most common form of supraventricular tachycardia in newborns. AVRT is sometimes refractory to conventional antiarrhythmic therapy. We describe our experience about the use of the triple combination of flecainide + propranolol + amiodarone as third-line regimen for refractory and recurrent AVRT in newborns. We considered a series of 14 patients who had failed both first-line and second-line therapy and were treated using the combination of flecainide + propranolol + amiodarone. Transoesophageal electrophysiologic study (TES) was performed to test the effectiveness of medical therapy during hospitalization and to try to reduce the amount of therapy, after amiodarone wash-out, before 1 year of age. TES was repeated at 1 year of age to test the spontaneous resolution of the arrhythmia after treatment discontinuation. Rhythm control was achieved in all 14 patients. At a mean age of 9.3 ± 2 months, AVRT was not inducible by TES in 11/12 amiodarone-free patients. At a mean age of 14.1 ± 3 months, AVRT was still inducible in 7/12 patients after interrupting the entire antiarrhythmic therapy (58.3%). Triple combination was effective as third-line option to suppress AVRT refractory to single and double antiarrhythmic therapy, with no significant adverse events. Our experience suggests that triple therapy could be maintained for a short-term treatment, discontinuing amiodarone before 1 year of age to avoid long-term side effects. Newborns who needed triple therapy appear to have a lower chance of accessory pathway disappearance at 1 year of age. TES could be useful for risk stratification of recurrences at the time of drug discontinuation in infants considered to be at higher risk of recurrent AVRT.

Atrial Fibrillation can adversely impact Heart Failure with Preserved Ejection Fraction by its association with Heart Failure Progression and Mortality: A Post-Hoc Propensity Score-Matched Analysis of the TOPCAT Americas Trial.

AIMS: Prevalent atrial fibrillation (AF) is associated with excess cardiovascular (CV) death (D) and hospitalizations (H) in heart failure (HF) with preserved ejection fraction (pEF). We evaluated if it had an independent role in excess CVD in HFpEF and studied its impact on cause-specific mortality and HF morbidity. METHODS AND RESULTS: We used propensity score-matched (PSM) cohorts from the TOPCAT Americas trial to account for confounding by other co-morbidities. Two prevalent AF presentations at study entry were compared: (i) subjects with Any AF event by history or on electrocardiogram (ECG) with PSM subjects without an AF event and (ii) subjects in AF on ECG with PSM subjects in sinus rhythm. We analyzed cause-specific modes of death and HF morbidity during a mean follow-up period of 2.9 years. A total of 584 subjects with Any AF event and 418 subjects in AF on ECG were matched. Any AF was associated with increased CVH [hazard ratio (HR) 1.33, 95% confidence interval (CI) 1.11-1.61, P = 0.003], HFH (HR 1.44, 95% CI 1.12-1.86, P = 0.004), pump failure death (PFD) (HR 1.95, 95% CI 1.05-3.62, P = 0.035), and HF progression from New York Heart Association (NYHA) classes I/II to III/IV (HR 1.30, 95% CI 1.04-1.62, P = 0.02). Atrial fibrillation on ECG was associated with increased risk of CVD (HR 1.46, 95% CI 1.02-2.09, P = 0.039), PFD (HR 2.21, 95% CI 1.11-4.40, P = 0.024), and CVH and HFH (HR 1.37, 95% CI 1.09-1.72, P = 0.006 and HR 1.65, 95% CI 1.22-2.23, P = 0.001, respectively). Atrial fibrillation was not associated with risk of sudden death. Both Any AF and AF on ECG cohorts were associated with PFD in NYHA class III/IV HF. CONCLUSION: Prevalent AF can be an independent risk factor for adverse CV outcomes by its selective association with worsening HF, HFH, and PFD in HFpEF. Prevalent AF was not associated with excess sudden death risk in HFpEF. Atrial fibrillation was also associated with HF progression in early symptomatic HFpEF and PFD in advanced HFpEF. TRIAL REGISTRATION: TOPCAT trial is registered at www.clinicaltrials.gov:identifier NCT00094302.

Incidence and Determinants of Spontaneous Cardioversion of Early Onset Symptomatic Atrial Fibrillation.

Atrial fibrillation (AF) is the most frequent chronic arrhythmia worldwide, and it is associated with significant morbidity and mortality, making it a considerable burden both to patients and the healthcare system. Nowadays, an early attempt to restore sinus rhythm in acute symptomatic AF through electrical or pharmacological cardioversion is the most common approach in the Emergency Department (ED). However, considering the high percentage of spontaneous cardioversion of paroxysmal AF reported by many studies, this approach may not be the ideal choice for all patients. In this manuscript we performed a review of the most relevant studies found in literature with the aim of identifying the main determinants of spontaneous cardioversion, focusing on those easy to detect in the ED. We have found that the most relevant predictors of spontaneous cardioversion are the absence of Heart Failure (HF), a small atrial size, recent-onset AF, rapid Atrial Fibrillatory Rate and the relationship between a previous AF episode and Heart Rate/Blood Pressure. A number of those are utilized, along with other easily determined parameters, in the recently developed "ReSinus" score which predicts the likelihood of AF spontaneous cardioversion. Such identification may help the physician decide whether immediate cardioversion is necessary, or whether to adopt a "watch-and-wait" strategy in the presence of spontaneous cardioversion determinants.

Thyroid Dysfunction under Amiodarone in Patients with and without Congenital Heart Disease: Results of a Nationwide Analysis.

Background: Amiodarone has a profound adverse toxicity profile. Large population-based analyses quantifying the risk of thyroid dysfunction (TD) in adults with and without congenital heart disease (ACHD) are lacking. Methods: All adults registered with a major German health insurer (≈9.2 million members) with amiodarone prescriptions were analyzed. Occurrence of amiodarone-associated TD was assessed. Results: Overall, 48,891 non-ACHD (37% female; median 73 years) and 886 ACHD (34% female; median 66 years) received amiodarone. Over 184,787 patient-years, 10,875 cases of TD occurred. The 10-year risk for TD was 38% in non-ACHD (35% ACHD). Within ACHD, compared to amiodarone-naïve patients, the hazard ratio (HR) for TD was 3.9 at 4 years after any amiodarone exposure. TD was associated with female gender (HR 1.42, p < 0.001) and younger age (HR 0.97 per 10 years, p = 0.009). Patients with congenital heart disease were not at increased risk (HR 0.98, p = 0.80). Diagnosis of complex congenital heart disease, however, was a predictor for TD (HR 1.56, p = 0.02). Amiodarone was continued in 47% of non-ACHD (38% ACHD), and 2.3% of non-ACHD (3.5% ACHD) underwent thyroid surgery/radiotherapy. Conclusions: Amiodarone-associated TD is common and comparable in non-ACHD and ACHD. While female gender and younger age are predictors for TD, congenital heart disease is not necessarily associated with an elevated risk.

Postnatal recurrence and transesophageal inducibility of prenatally treated fetal supraventricular tachycardia.

BACKGROUND: Antiarrhythmic treatment of fetal supraventricular tachycardia (SVT) is used to prevent morbidity and mortality. The postnatal management of survivors is often arbitrary and varied. OBJECTIVE: The purpose of this study was to examine the utility of a risk-based postnatal management strategy. METHODS: Sixty-six prenatally treated newborns with fetal long or short ventriculoatrial tachycardia were reviewed. Postnatal diagnoses included atrioventricular reentrant tachycardia, atrial ectopic tachycardia, and permanent junctional reciprocating tachycardia. Unless SVT persisted to birth, early neonatal observation without treatment was recommended. For newborns without spontaneous arrhythmia after ≥2 days of observation, inducibility was tested by transesophageal pacing study (TEPS). Postnatal therapy was advised for spontaneous or inducible SVT. Characteristics associated with these outcomes were analyzed. RESULTS: Twenty-eight patients (42%) experienced SVT at or early after birth, which was associated with fetal long ventriculoatrial tachycardia (odds ratio [OR] 6.8; 95% confidence interval [CI] 1.88-24.57; P = .0029); delayed in utero cardioversion with treatment (median 11 days vs 5.5 days; P < .0001); prenatal treatment with multiple antiarrhythmics (OR 4.42; 95% CI 1.56-12.55; P = .0059); and postnatal atrial ectopic tachycardia/permanent junctional reciprocating (OR 18.0; 95% CI 2.11-153.9; P = .0013). Of the 38 neonates undergoing TEPS, 19 (50%) had inducible tachyarrhythmias. Recurrence of SVT during infancy or childhood was documented in 4 of 6 patients with SVT at birth (66%), 8 of 22 patients with early neonatal SVT (36%), 4 of 19 patients with inducible SVT (21%), and 0 of 19 untreated patients without inducible SVT (0%) (P = .0032). CONCLUSION: The postnatal risk of SVT is related to the arrhythmia mechanism and prenatal treatment response. In newborns without spontaneous SVT, TEPS may be useful to guide the need for postnatal treatment on the basis of SVT inducibility.

Ventricular tachycardia characteristics and outcomes with catheter ablation vs. antiarrhythmic therapy: insights from the VANISH trial.

AIMS: Catheter ablation is superior to escalated antiarrhythmic drugs among patients with ventricular tachycardia (VT) and prior myocardial infarction (MI). However, it is uncertain whether clinical VT characteristics, should influence choice of therapy. The purpose of this study was to evaluate whether presentation with electrical storm and the clinical VT cycle length predicted response to ablation vs. escalated antiarrhythmic therapy. METHODS AND RESULTS: All patients enrolled in the Ventricular Tachycardia Ablation vs. Escalated Antiarrhythmic Drug Therapy in Ischaemic Heart Disease (VANISH) trial were included. The association between VT cycle length and presentation with electrical storm and the primary outcome of death, subsequent VT storm or appropriate ICD shock was evaluated. Among the study population of 259 patients, escalated antiarrhythmic drug therapy had worse outcomes for those presenting with a VT cycle length >400 ms [<150 b.p.m., 89/259, hazard ratio (HR) 1.7 (1.02-3.13)]. This effect was more pronounced among those taking amiodarone at baseline [HR of 2.22 (1.19-4.16)]. Presentation with VT storm (32/259) did not affect the primary outcome between groups. However, those presenting with VT storm on amiodarone had a trend towards worse outcomes with escalated antiarrhythmic therapy [HR 4.31 (0.55-33.93)]. CONCLUSION: The VT cycle length can influence response to either ablation or escalated drug therapy in patients with VT and prior MI. Those with slow VT had improved outcomes with ablation. Patients presenting with electrical storm demonstrated similar outcomes to the overall trial population, with a trend to benefit of catheter ablation, particularly in those on amiodarone.

Cardiac Sympathetic Denervation for Refractory Ventricular Arrhythmia in Continuous-Flow Left Ventricular Assist Device.

Cardiac sympathetic denervation has been shown to reduce sustained ventricular arrhythmias and implantable cardioverter-defibrillator shocks by inhibiting sympathetic outflow to the heart. We describe the first case to our knowledge of cardiac sympathetic denervation in the left ventricular assist device population. (Level of Difficulty: Advanced.).

[Atrial fibrillation]. / Vorhofflimmern.

Atrial fibrillation is frequent and has severe sequelae, such as stroke, cardiovascular death and cardiac insufficiency. These sequelae can be effectively reduced by anticoagulants, a meticulous recognition and treatment of cardiovascular comorbidities and an early rhythm-preserving treatment. Catheter ablation leads to a better preservation of the sinus rhythm and in symptomatic patients to a better quality of life in comparison to treatment with antiarrhythmic agents. This should be included in the planning of early rhythm-maintaining treatment.

Early postoperative effects of kidney transplantation on the cardiovascular system in our clinical practice / A vesetranszplantáció korai posztoperatív hatásai a szív- és érrendszeri betegségekre klinikai gyakorlatunkban.

Összefoglaló. Bevezetés: Mind a dializált, mind a veseátültetett betegek körében vezeto haláloknak számít a cardiovascularis megbetegedés. E mögött foképp bal kamrai hypertrophia, volumenterheltség, következményes szívritmuszavar, szívbillentyu-elégtelenség, fokozott atherosclerosis állhat. Célkituzés: Célunk a vesetranszplantáció hatásának vizsgálata a bal kamra pumpafunkciójára, a szívritmuszavarokat kiváltó és meghatározó tényezokre és a vitiumokra nézve. Módszerek: A 2014. december 20. és 2018. június 21. közti idointervallumban, a Debreceni Egyetem Szervtranszplantációs Tanszékén felnott betegeken végzett veseátültetéseket vizsgáltuk retrospektív analízissel (n = 184). Vesetranszplantációt megelozoen, illetve azt követoen 6 és 12 hónappal az echokardiográfiás, a laboratóriumi és a gyógyszeres terápiás értékeket tanulmányoztuk. A statisztikai elemzéseket khi-négyzet-próbával, Fisher-féle egzakt teszttel és Kruskal-Wallis-féle varianciaanalízissel (ANOVA) végeztük (szignifikancia: p<0,05). Eredmények: A bal kamra végsystolés tágassága az átültetés elott 34,67 mm volt, míg a 6 hónapos eredmény 31,82 mm, a 12 hónapos 32,68 mm volt (p = 0,01). Átültetés elott a stroke prevalenciája 7,87% volt, míg a beavatkozás után nem fordult elo szélütés (p<0,001). Transzplantáció hatására a bal pitvari átméro (43,68 mm; 41,59 mm; 41,00 mm; p = 0,0417) és a káliumszint (4,98 mmol/l; 4,49 mmol/l; 4,49 mmol/l; p = 0,01) szignifikáns változást igazolt. Mutét elott II. fokú mitralis regurgitatiót észleltünk 10,7%-nál, mely 4,3%-ra, majd 2,1%-ra csökkent (p = 0,03). Transzplantációt megelozoen a billentyumeszesedés elofordulása diabetesesek között 45% (p = 0,20), 6 hónap múlva 46,7% (p = 0,018), 12 hónap múlva 60,0% (p = 0,024) volt. Következtetés: Transzplantáció után a bal pitvari átméro, a végsystolés bal kamrai átméro regrediál, csökken a pitvari ritmuszavarok kialakulásának gyakorisága. A mitralis regurgitatio közepesen súlyos fokainál szignifikáns javulást, a diabeteses populáción belül szignifikáns emelkedést tapasztaltunk a meszes billentyuk számát tekintve. Orv Hetil. 2021; 162(26): 1052-1062. INTRODUCTION: Among the population suffering from end-stage renal failure and the population after kidney transplantation, the leading reason of death is cardiovascular triggered by left ventricular hypertrophy, volume overload, consecutive arrhythmias, valvular insufficiency and increased artherosclerosis. OBJECTIVE: This study was aimed at examining the effect of kidney transplantation on pump function of the left ventricle, arrhythmic substrates and valvular heart diseases. METHODS: At the Division of Organ Transplantation, University of Debrecen, we carried out a retrospective data analysis of adult patients (n = 184) who had kidney transplantation in the period between December 2014 and June 2018. Preoperatively and, then, postoperatively (at 6 and 12 months) we studied the echocardiographic parameters, the laboratory results. Statistical analyses were performed using the chi-square/Fisher's exact test and Kruskal-Wallis analysis of variance (ANOVA) test. The results were regarded significant if p<0.05 was found. RESULTS: Preoperatively the end-systolic diameter of the left ventricle was 34.67 mm, whereas 6 and 12 months later these values were 31.82 mm and 32.68 mm (p = 0.01). The prevalence of stroke was 7.87% preoperatively; there was no stroke detected postoperatively (p<0.001). The impact of transplantation on the left atrial diameter (43.68 mm; 41.59 mm; 41.00 mm; p = 0.04) and seral potassium level (4.98 mmol/l; 4.49 mmol/l; 4.49 mmol/l; p<0.01) showed significant improvement. Before transplantation, grade 2 mitral regurgitation was observed in 10.7% of the patients, whereas it reduced to 4.3%, then to 2.1% 6 and 12 months postoperatively (p = 0.03). Preoperative valvular calcification was detected in 45% of the diabetic study population (p = 0.20), 6 and 12 months later, in 46.7% (p = 0.018) and 60.0% (p = 0.024). CONCLUSION: After transplantation, the left atrial and the end-systolic diameter of the left ventricle regrediated, decreasing the frequency of arrhythmic episodes. The number of the middle grade mitral valve regurgitation decreased and the calcification among diabetic population increased significantly. Orv Hetil. 2021; 162(26): 1052-1062.

Pulmonary Disease, Pulmonary Hypertension and Atrial Fibrillation.

Atrial fibrillation is associated with aging, obesity, heart disease, diabetes, and/or hypertension. Recent evidence suggests that parenchymal and vascular lung diseases increase atrial fibrillation risk. We review the epidemiology, clinical features, pathophysiologic mechanisms, and treatment implications of atrial fibrillation associated with diseases of the lungs and their vasculature, especially pulmonary hypertension. We also consider other features of pulmonary disease-associated atrial fibrillation. A key mediator of these conditions is right heart disease and right atrial remodeling. We pay particular attention to the pathophysiology and treatment challenges in atrial fibrillation associated with right heart disease induced by pulmonary diseases, including pulmonary hypertension.

Swallowing-induced supraventricular arrhythmia: A different perspective to mechanism.

Atypical presentations of supraventricular arrhythmias constitute a diagnostic challenge which are not frequently reported in literature. Swallowing-induced supraventricular arrhythmia (SI-SVA), which was first described in 1926, is an intriguing presentation of supraventricular tachycardia and occurs during a wet or solid swallow. A 67-year-old man presented to our outpatient clinic complaining from recurrent episodes of sensation of palpitations and short duration pressure on his chest while swallowing since the last 2 weeks. Ambulatory rhythm Holter monitoring was suggestive of atrial fibrillation (AF) or atrial tachycardia attacks during swallowing. In addition, electrocardiography performed during solid food swallowing, showed short duration of AF consistent with the patient's symptoms. The patient was successfully treated with amiodarone. The main cause of SI-SVA is not known. Cross-talk of nerves during the impulse propagation might be the underlying cause of this phenomenon.

Efficacy and safety of dronedarone by atrial fibrillation history duration: Insights from the ATHENA study.

BACKGROUND: Atrial fibrillation/atrial flutter (AF/AFL) burden increases with increasing duration of AF/AFL history. HYPOTHESIS: Outcomes with dronedarone may also be impacted by duration of AF/AFL history. METHODS: In this post hoc analysis of ATHENA, efficacy and safety of dronedarone vs placebo were assessed in groups categorized by time from first known AF/AFL episode to randomization (ie, duration of AF/AFL history): <3 months (short), 3 to <24 months (intermediate), and ≥ 24 months (long). RESULTS: Of 2859 patients with data on duration of AF/AFL history, 45.3%, 29.6%, and 25.1% had short, intermediate, and long histories, respectively. Patients in the long history group had the highest prevalence of structural heart disease and were more likely to be in AF/AFL at baseline. Placebo-treated patients in the long history group also had the highest incidence of AF/AFL recurrence and cardiovascular (CV) hospitalization during the study. The risk of first CV hospitalization/death from any cause was lower with dronedarone vs placebo in patients with short (hazard ratio, 0.79 [95% confidence interval: 0.65-0.96]) and intermediate (0.72 [0.56-0.92]) histories; a trend favoring dronedarone was also observed in patients with long history (0.84 [0.66-1.07]). A similar pattern was observed for first AF/AFL recurrence. No new drug-related safety issues were identified. CONCLUSIONS: Patients with long AF/AFL history had the highest burden of AF/AFL at baseline and during the study. Dronedarone significantly improved efficacy vs placebo in patients with short and intermediate AF/AFL histories. While exploratory, these results support the potential value in initiating rhythm control treatment early in patients with AF/AFL.

Antiarrhythmic Drugs: Risks and Benefits.

The narrow therapeutic window of antiarrhythmic drugs makes their use clinically challenging. A solid understanding of the mechanisms of arrhythmias and how antiarrhythmics affect these mechanisms is only a preliminary step in their appropriate selection. Clinical factors, side-effect profiles, and proarrhythmic risks are more important than the cellular mechanisms of actions in drug selection and monitoring. This article provides a simplified approach to understanding cellular mechanisms and provides a practical approach to the selection and use of this important class of medications.