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.

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.

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.

Early postoperative effects of kidney transplantation on the cardiovascular system in our clinical practice

Összefoglaló. Bevezetés: Mind a dializált, mind a veseátültetett betegek körében vezető haláloknak számít a cardiovascularis megbetegedés. E mögött főképp bal kamrai hypertrophia, volumenterheltség, következményes szívritmuszavar, szívbillentyű-elégtelenség, fokozott atherosclerosis állhat. Célkitűzés: Célunk a vesetranszplantáció hatásának vizsgálata a bal kamra pumpafunkciójára, a szívritmuszavarokat kiváltó és meghatározó tényezőkre és a vitiumokra nézve. Módszerek: A 2014. december 20. és 2018. június 21. közti időintervallumban, a Debreceni Egyetem Szervtranszplantációs Tanszékén felnőtt betegeken végzett veseátültetéseket vizsgáltuk retrospektív analízissel (n = 184). Vesetranszplantációt megelőzően, illetve azt követően 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 előtt 34,67 mm volt, míg a 6 hónapos eredmény 31,82 mm, a 12 hónapos 32,68 mm volt (p = 0,01). Átültetés előtt a stroke prevalenciája 7,87% volt, míg a beavatkozás után nem fordult elő szélütés (p<0,001). Transzplantáció hatására a bal pitvari átmérő (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. Műtét előtt II. fokú mitralis regurgitatiót észleltünk 10,7%-nál, mely 4,3%-ra, majd 2,1%-ra csökkent (p = 0,03). Transzplantációt megelőzően a billentyűmeszesedés előfordulása 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 átmérő, a végsystolés bal kamrai átmérő regrediál, csökken a pitvari ritmuszavarok kialakulásának gyakorisága. A mitralis regurgitatio közepesen súlyos fokainál szignifikáns javulást, a diabeteses populáción belül szignifikáns emelkedést tapasztaltunk a meszes billentyűk számát tekintve. Orv Hetil. 2021; 162(26): 1052-1062.

SUMMARY

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.

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.

[Treatment for ventricular arrhythmias in the absence of structural heart disease: from guidelines to clinical practice]

AIM

To determine criteria for choosing management tactics in patients with ventricular arrhythmias (VA) in the absence of structural heart disease from the point of view of physicians and patients in clinical practice and to compare the immediate results of antiarrhythmic drug therapy (ADT) and radiofrequency ablation (RFA) with the trends in arrhythmic syndrome in the non-treatment group.

SUBJECTS AND METHODS

Examinations were made in 90 patients (23 men and 67 women) (mean age, 44 (31; 57) years) with VA in the absence of structural heart disease. Preference was given to RFA (n = 32 (36%)), ADT (n = 37 (41%)), and follow-up tactics (n = 21 (23%)). At baseline and 1 month, Holter ECG monitoring was done; quality of life (QOL) was assessed; and anxiety and depression levels were detected using the SF-36 and HADS questionnaires. In addition, 71 physicians were surveyed about their preferences to the treatment of VA in individuals without structural heart disease.

RESULTS

In the total group of patients, VA was unambiguously accompanied by the symptoms only in 47%. The signs of anxiety and depression were identified in 41 and 14% of cases, respectively. The efficiency of RFA was comparable to that of ADT (p > 0.1): a positive antiarrhythmic effect was observed in 71.9% of the patients in the RFA group and in 67.6% in the ADT group. During one month, 38.1% of the patients in the follow-up group showed a spontaneous substantial reduction in the number of ventricular premature beats (VPBs) or disappearance of unstable ventricular tachycardia (UVT), which met the criteria for a positive effect. At baseline, the QOL indicators on a social functioning scale in the RFA group were worse than those in the ADT group. At the same time, most QOL indicators in the patients who have chosen a wait-and-see tactic were significantly higher than those in the RFA and ADT subgroups. The patients treated with ethacyzin in the ADT group more frequently achieved a positive effect. In the interviewed physicians' opinion, the choice of a tactic depended on the impact of arrhythmia on health status (68%), the number of VPBs per day (61%), and the presence of UVT (56%). RFA or ADT was most often recommended when there were 10,000-15,000 or more VPBs per day ((49 and 35% of the respondents, respectively). 46.5% of the respondents stated that β-blockers were the drug of choice for idiopathic frequent VPBs. Only 30% of the respondents considered it appropriate to restrict to a follow-up in the presence of asymptomatic VPBs.

CONCLUSION

Patient management in clinical practice generally complies with the current guidelines; however, much importance is attached to the severity of arrhythmia (the number of VPBs per day, the presence of UVT) in addition to the presence of symptoms. In the opinion of most physicians, the initiation of treatment is justified when there are 10,000-15,000 and more per day. QOL assessment may be promising in choosing the optimal management tactics for these patients. Treatment should not be initiated immediately in patients with a high level of QOL, especially in those with arrhythmia lasting less than 12 months, by taking into account that there can be a spontaneous improvement in 38% of cases within the next month. The immediate results of ADT and RFA are comparable in patients with VA in the absence of structural heart disease. The Class IC antiarrhythmic drug ethacyzin is the most effective agent that ensures positive changes in arrhythmic syndrome in 66.7% of cases with the rate of side effects being in 17.8%.

Effect of sotalol on heart rate, QT interval, and atrial fibrillation cycle length in horses with atrial fibrillation

Background

Based on its pharmacokinetic profile and electrophysiological effects in healthy horses, sotalol potentially could be used as a long‐term PO antiarrhythmic drug in horses.

Objectives

To evaluate the effect of sotalol on heart rate (HR), QT interval, atrial fibrillatory rate, and success of cardioversion in horses with naturally occurring chronic atrial fibrillation (AF).

Animals

Twenty‐eight horses referred for transvenous electrical cardioversion of AF were treated with 2 mg/kg sotalol PO q12h for 3 days before cardioversion, and 13 horses underwent the same protocol without sotalol administration.

Methods

Retrospective study. Before and after sotalol or no treatment, the HR was measured at rest and during an exercise test. The QT interval and atrial fibrillation cycle length (AFCL) were measured at rest using tissue Doppler velocity imaging.

Results

In the control group, no significant differences were found between the 2 examinations. In the sotalol group, the HR at rest and during exercise was significantly lower after sotalol treatment, whereas the QT interval and AFCL measured by tissue Doppler increased significantly. Cardioversion to sinus rhythm was achieved in 25/28 horses in the sotalol group and all horses in the control group, but the median number of shocks and energy at cardioversion were significantly lower in the sotalol group.

Conclusions and Clinical Importance

In horses with AF, sotalol administration results in class III antiarrhythmic effects and β‐blocking activity, with moderate HR reduction during exercise.

The Use of Continuous Electrocardiographic Holter Monitoring in Pediatric Cardiology

Objective:

To show the place and role of continuous electrocardiographic twenty-four-hour ECG monitoring in daily clinical practice of pediatric cardiologists.

Methods:

According to protocol, 2753 patients underwent dynamic continuous ECG Holter monitoring (data collected from the “Register of ECG Holter monitoring” of Pediatric Clinic, UCC Sarajevo in period April 2003- April 2015).

Results:

There were 50,5% boys and 49,5% girls, aged from birth to 19 years (1,63% - neonates and infants, 2,6% - toddlers, 9,95% - preschool children, 35,5% - gradeschoolers and 50,3% children in puberty and adolescence). In 68,1% of patients Holter was performed for the first time. Indications for conducting Holter were: arrhythmias in 42,2% cases, precordial pain in 23,5%, suspicion of pre-excitation and/or pre-excitation in 10%, crisis of consciousness in 8%, uncorrected congenital/acquired heart defects in 4,2%, operated heart defects in 3,7%, hypertension in 3,1% cases, control of the pacemaker in 1,63% and other causes in 3,5% cases. Discharge diagnosis after ECG Holter monitoring were: insignificant arrhythmias in 47,1% cases, wandering pacemaker in 21,3%, pre-excitation in 16,2%, benign ventricular premature beats in 6,3%, atrioventricular block in 3%, sinus pause in 2.2% cases and other arrhythmias in 3,5%. In mentioned period 57 cases of Wolf Parkinson White syndrome were registered, in 4,5% of patients antiarrhythmic therapy was administered. Radiofrequent ablation was performed in 23 cases.

Conclusion:

The development of pediatric cardiac surgery has initiated development of pediatric arrhythmology as imperative segment of pediatric cardiology. Continuous ECG Holter monitoring has become irreplaceable method in everyday diagnostics and therapy of arrhythmias in children.

Pharmacokinetic and pharmacodynamic profile of dronedarone , a new antiarrhythmic agent for the treatment of atrial fibrillation

INTRODUCTION

Atrial fibrillation (AF) is the most common arrhythmia and is associated with increased morbidity and mortality. Dronedarone is a recent antiarrhythmic drug that has been developed for treatment of AF, with electrophysiological properties similar to amiodarone but with a lower incidence of side effects.

AREAS COVERED

This review evaluates the efficacy, safety, tolerability and side effects of dronedarone in the treatment of AF. In particular, the review includes studies comparing: dronedarone and placebo (ANDROMEDA, ATHENA, DAFNE, ERATO, EURIDIS/ADONIS, HESTIA, PALLAS trials), dronedarone and amiodarone (DIONYSOS trial), ranolazine and dronedarone given alone and in combination (HARMONY trial).

EXPERT OPINION

Dronedarone is an interesting antiarrhythmic agent in well-selected groups of patients. It also has several other pleiotropic effects that may potentially be beneficial in clinical practice, such as the reduction of the risk of stroke and acute coronary syndromes. In addition, combination therapies such as those with dronedarone and ranolazine, currently being investigated in the HARMONY trial, may provide another interesting approach to increase the antiarrhythmic efficacy and further reduce the incidence of side effects. A better understanding of the mechanisms underlying dronedarone's pleiotropic actions is expected to facilitate the selection of patients benefiting from dronedarone, as well as the development of novel antiarrhythmic drugs for AF.

Novel pharmacological targets for the rhythm control management of atrial fibrillation

Atrial fibrillation (AF) is a growing clinical problem associated with increased morbidity and mortality. Development of safe and effective pharmacological treatments for AF is one of the greatest unmet medical needs facing our society. In spite of significant progress in non-pharmacological AF treatments (largely due to the use of catheter ablation techniques), anti-arrhythmic agents (AADs) remain first line therapy for rhythm control management of AF for most AF patients. When considering efficacy, safety and tolerability, currently available AADs for rhythm control of AF are less than optimal. Ion channel inhibition remains the principal strategy for termination of AF and prevention of its recurrence. Practical clinical experience indicates that multi-ion channel blockers are generally more optimal for rhythm control of AF compared to ion channel-selective blockers. Recent studies suggest that atrial-selective sodium channel block can lead to safe and effective suppression of AF and that concurrent inhibition of potassium ion channels may potentiate this effect. An important limitation of the ion channel block approach for AF treatment is that non-electrical factors (largely structural remodeling) may importantly determine the generation of AF, so that "upstream therapy", aimed at preventing or reversing structural remodeling, may be required for effective rhythm control management. This review focuses on novel pharmacological targets for the rhythm control management of AF.

The pathology and treatment of cardiac arrhythmias: focus on atrial fibrillation

Atrial fibrillation (AF) is the most frequently encountered sustained cardiac arrhythmia in clinical practice and a major cause of morbidity and mortality. Effective treatment of AF still remains an unmet medical need. Treatment of AF is based on drug therapy and ablative strategies. Antiarrhythmic drug therapy is limited by a relatively high recurrence rate and proarrhythmic side effects. Catheter ablation suppresses paroxysmal AF in the majority of patients without structural heart disease but is more difficult to achieve in patients with persistent AF or with concomitant cardiac disease. Stroke is a potentially devastating complication of AF, requiring anticoagulation that harbors the risk of bleeding. In search of novel treatment modalities, targeted pharmacological treatment and gene therapy offer the potential for greater selectivity than conventional small-molecule or interventional approaches. This paper summarizes the current understanding of molecular mechanisms underlying AF. Established drug therapy and interventional treatment of AF is reviewed, and emerging clinical and experimental therapeutic approaches are highlighted.

Increased Cell-Cell Coupling Increases Infarct Size and Does not Decrease Incidence of Ventricular Tachycardia in Mice

Increasing connexin43 (Cx43) gap junctional conductance as a means to improve cardiac conduction has been proposed as a novel antiarrhythmic modality. Yet, transmission of molecules via gap junctions may be associated with increased infarct size. To determine whether maintaining open gap junction channels impacts on infarct size and induction of ventricular tachycardia (VT) following coronary occlusion, we expressed the pH- and voltage-independent connexin isoform connexin32 (Cx32) in ventricle and confirmed Cx32 expression. Wild-type (WT) mice injected with adenovirus-Cx32 (Cx32inj) were examined following coronary occlusion to determine infarct size and inducibility of VT. There was an increased infarct size in Cx32inj hearts as compared to WT (WT 22.9 ± 4%; Cx32inj 44.3 ± 5%; p < 0.05). Programmed electrical stimulation showed no difference in VT inducibility in WT and Cx32inj mice (VT was reproducibly inducible in 55% of shams and 50% of Cx32inj mice (p > 0.05). Following coronary occlusion, improving cell–cell communication increased infarct size, and conferred no antiarrhythmic benefit.

Dronedarone: current evidence for its safety and efficacy in the management of atrial fibrillation

Atrial fibrillation (AF) is the most common sustained arrhythmia. Management of AF includes rate control, rhythm control if necessary, prevention of thromboembolic events, and treatment of the underlying disease. Rate control is usually achieved by pharmacological suppression of calcium currents or by applying β-blockers or digitalis compounds. In contrast, the number of compounds available for rhythm control is still limited. Class Ic agents increase mortality in patients with structural heart disease, and amiodarone harbors an extensive side effect profile despite its efficacy in maintaining sinus rhythm. Furthermore, rhythm control by these compounds has not been shown to reduce patient mortality. Dronedarone is a new anti-arrhythmic drug that has been developed to provide rhythm and rate control in AF patients with fewer side effects compared with amiodarone. This review primarily focuses on clinical trials evaluating efficacy and safety of the novel drug. Conclusions from these studies are critically reviewed, and recommendations for clinical practice are discussed. Dronedarone significantly reduced the incidence of hospitalization due to cardiovascular events or death in high-risk patients with atrial fibrillation (ATHENA trial). However, dronedarone was less efficient than amiodarone in maintaining normal sinus rhythm (DIONYSOS trial) and is contraindicated in severe or deteriorating heart failure (ANDROMEDA trial). In summary, dronedarone represents a valuable addition to the limited spectrum of antiarrhythmic drugs and is currently recommended in patients with paroxysmal and persistent AF to achieve rate and rhythm control, excluding cases of severe or unstable congestive heart failure.

The frequency analysis of signal-averaged ECG of P wave as predictor of efficacy of class III antiarrhythmic drugs to maintain sinus rhythm in recurrent idiopathic atrial fibrillation

BACKGROUND

The use of class III antiarrhythmic drugs (ADIII) has been considered a good predictor of sinus rhythm in patients post-cardioversion from atrial fibrillation (AF). Several studies using frequency domain analysis of signal-averaged ECG (FDSAECG) of the P wave were able to identify patients at risk for AF. The aim of this study was to assess the FDSAECG in predicting recurrence of idiopathic persistent AF (IPAF) in patients under ADIII therapy.

METHODS

In 33 patients with two or more previous symptomatic episodes of IPAF, despite classes I and II therapy, the FDSAECG of the P wave was performed during sinus rhythm and free-drug state. The parameters were the mean and standard deviation of the frequency intersegmentar spectral correlation and the standard deviation of the signal frequency edge track. During the follow-up of 30 +/- 18 months, all patients received either amiodarone or sotalol.

RESULTS

During the follow-up, the patients were divided into two groups: Group I-frequent recurrence (>or= three events/year; 16 patients), and Group II-infrequent recurrence (< three events/year; 17 patients). With appropriate cutoff points for each parameter analyzed, intense fragmented electrical activity defined by the presence of at least two abnormal criteria were observed in 13 of 16 patients group I and in 3 of 17 patients group II (P = 0.0003). Sensitivity, specificity, positive and negative predictive values for frequent recurrence were 81.3, 82.4, 81.3, and 82.4, respectively.

CONCLUSIONS

The results suggested that FDSAECG analysis of the P wave accurately predicted patients whose ADIII therapy will be effective in maintaining the sinus rhythm without frequent recurrence of IPAF.

Treatment of resistant ventricular tachycardia with endocavitary fulguration and antiarrhythmic therapy, compared to antiarrhythmic therapy alone: experience in 111 consecutive cases with a mean follow-up of 18 months

Endocavitary fulguration was performed in 31 cases of high-risk ventricular tachycardia (VT) for which antiarrhythmics, including Amiodarone and Class-I antiarrhythmic agents, given alone or in combination, proved ineffective. Permanent VT was incessant in nine patients at the time of fulguration: five of these were moribund, and two were unconscious. Included in the series were ten cases of arrhythmogenic right ventricular dysplasia, 13 cases of chronic VT after myocardial infarction, five cases of idiopathic dilated cardiomyopathy, two cases of idiopathic VT, and one case that involved a congenital anomaly. Combined fulguration and antiarrhythmic therapy succeeded in preventing VT in the 27 patients who survived the initial period of treatment. Thirteen patients needed two or more sessions, however, before their VT was brought under control. Three of the four early deaths were probably related to an imperfect technique. Four late deaths were due to spontaneous evolution of the disease. One patient without cardiac failure died suddenly. The follow-up period ranged from a minimum of 13 to a maximum of 34 months, with an average follow-up of nearly 2 years. The success rate for fulguration alone or for antiarrhythmic drugs is about 90%. This group of patients is compared with a group that involved 73 less severe cases treated with drugs. Fulguration appears to be the better form of treatment.