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Background Nonfluoroscopic intracardiac navigation systems reduce the dose of radiation in most ablation procedures. However, they have not been sufficiently studied as a sole guidance tool for electrode catheter handling. Objective The purpose of our study was to assess the feasibility and safety of catheter ablation for atrioventricular nodal re-entrant tachycardia (AVNRT) without the use of fluoroscopy. Methods We prospectively enrolled all of the patients with AVNRT (Group A) treated by catheter ablation guided only by a nonfluoroscopic intracardiac navigation system. These patients were compared with a matched control group of patients (Group B) who had undergone an ablation procedure for AVNRT guided only by fluoroscopy in the preceding months. We compared the success rate and the rate of complications and recurrences. We also compared the procedure and radiofrequency times. Results Fifty patients were enrolled in each group. The procedure was successful in 100% in Group A versus 96% in Group B (P = .15). One patient in Group A and 4 patients in Group B suffered nonserious complications (P = NS). The mean fluoroscopy time in Group B was 18 ± 16 min (range 3.5 to 77, total 924). In 1 case in Group A (2%), the use of fluoroscopy was required. Procedure and radiofrequency times did not differ between the 2 groups. A recurrence developed in 2 patients in each group (P = NS). Conclusions Catheter ablation for AVNRT without fluoroscopic guidance is feasible and safe, and does not prolong procedure time. The reduction in radiation dose is considerable for patients and professionals.

A 10-year-old boy was admitted for a sudden exertional syncope. The ECG showed a regular narrow-QRS tachycardia with RP >PR and negative P waves in inferior leads, suggestive of atrial tachycardia ( Panel A ). The echocardiogram was normal, and the treadmill test provoked high-density monomorphic ventricular extrasystolia. A 24 h Holter documented …

This article contains a review of some of the most significant advances in cardiac arrhythmias that have taken place in the last year, particularly those concerning the most common clinical conditions associated with the risk of arrhythmia, such as sudden cardiac death, atrial fibrillation and syncope, and genetically determined and hereditary heart disease, as well as advances concerning the principal nonpharmacologic treatments, such as catheter ablation, and the use of implantable defibrillators and cardiac resynchronization therapy.

The epsilon wave, which reflects a delayed conduction of the right ventricle and is chiefly found in the right-sided precordial leads, is a major criterion in the diagnosis of arrhythmogenic right ventricle dysplasia because of being considered highly specific. It is estimated to appear …

A 43-year-old man was evaluated in our arrhythmia and sudden arrhythmic death clinic because of his brother’s sudden cardiac death (SCD) at the age of 41 years. The deceased had not presented syncopal attacks nor chest pain before, and died suddenly while resting after a whole day of driving a truck. Postmortem examination was unrevealing for anatomical pathology, suggesting sudden arrhythmic death syndrome. A 12-lead ECG was recovered from the dead proband, which was unremarkable with a QTc interval of 430 ms. No DNA was available for genetic purposes. Our patient was …

Double-chambered right ventricle (DCRV) is a congenital anomaly characterized by the division of the ventricular cavity into two chambers separated by an abnormal hypertrophied muscular band or by severe hypertrophy of the muscle wall. Two adult patients with a diagnosis of DCRV presented sustained monomorphic ventricular tachycardia. In both cases, the clinical tachycardia was induced with programmed stimulation. After surgically resecting, the muscular band tachycardia could no longer be induced in the patient who underwent follow-up electrophysiological study. The outcome was favourable; there was no clinical recurrence of ventricular tachycardia in the two patients at 48 and 36 months, respectively.

Left ventricular systolic dysfunction related to ventricular arrhythmias is a relatively poorly understood entity. To increase our knowledge base, we describe 5 patients in whom the link between ventricular dysfunction and ventricular arrhythmia was unequivocally established. All patients had repetitive monomorphic ventricular arrhythmias and left ventricular systolic dysfunction (ejection fractionor =40% and end-diastolic sizeor =55 mm). The arrhythmogenic source was identified by electrophysiological study (right ventricle in 2 patients, left ventricle in 2, and left sinus of Valsalva in one), and was eliminated in all patients by radiofrequency catheter ablation. At 7+/-2 months post-ablation, large improvements were seen in left ventricular function and remodeling (ejection fraction/=50% and end-diastolic sizeor =51 mm in all cases), with no recurrence of arrhythmia during follow-up (10-69 months). This finding confirms that recurring ventricular arrhythmias can induce left ventricular dysfunction which may be reversible after ablation.

Atrial fibrillation (AF) is the most prevalent arrhythmia in hospital emergency departments and is a serious disease associated with a twofold increase in morbidity and a high mortality rate. However, the management of AF in this scenario is variable and frequently inadequate. This is probably a consequence of the diverse clinical aspects and therapeutic options to consider in the management of patients with AF. Therefore, implementation of specific, coordinated management strategies by the different care providers involved is needed to improve the quality of care and optimize the use of human and material resources. This document presents the guidelines recommended by the Spanish Society of Cardiology (SEC) and the Spanish Society of Emergency Medicine (SEMES) for the management of AF in hospital emergency departments. These guidelines are based on published scientific evidence and are applicable to most emergency departments in Spain. Specific management strategies are proposed for the conversion and maintenance of sinus rhythm, heart rate control during AF, prophylaxis for thrombi and emboli, and hospital admission and discharge protocols.

We report the results of the first Catheter Ablation Registry of the Arrhythmia Working Group of the Andalusian Society of Cardiology (AWGASC) for 2000.The register includes information about the ablation procedures performed in 2000, which was collected retrospectively and submitted voluntarily by four out of six cardiac electrophysiology laboratories of the AWGASC. A total of 424 patients (mean age 45 18 years; 50% men) were included. Twelve patients underwent two different ablation procedures, bringing the total number of procedures to 436. The overall success rate (based on current criteria), success rate by procedure, in-hospital mortality, and major complications are reported.The type and distribution of the ablation procedures were atrioventricular nodal re-entry tachycardia ablation, 34%; accessory pathway ablation, 39%; ventricular tachycardia ablation, 8%; atrial tachycardia ablation, 3%; atrioventricular junctional ablation, 9%, and cavo-tricuspid isthmus ablation, 9%. The overall success rate was 94% (range 97.8% to 87.4% in different laboratories), rate of major complications 1.1% (range 0% to 3.7%), and overall mortality 0.23% (1 patient).These findings summarize the indications and results of catheter ablation procedures performed in 2000 at four cardiac electrophysiology laboratories in Andalusia. This is the first multicenter registry in Spain.

Little information is available on the evolution of pediatric patients with vasovagal syncope. We therefore aimed to assess the medium-term clinical outcome of children evaluated by tilt testing for syncope of unknown origin.Fifty-one children under 17 years of age who had undergone tilt testing were identified from a data base and studied prospectively. Kaplan-Meier and Cox regression analyses were performed to estimate syncope-free survival, its predictors, and the relative risks of several patient subgroups.Forty-seven (92%) of the children were followed for a mean 21 9 months. The rate of recurrence of syncope was considerably lower than that estimated during history taking before the tilt test (19% vs 47%; p0.01). Although the low rate made it difficult to identify predictors, several potential predictors emerged from the multivariate analysis. Only the history of more than one syncope before the tilt test (vs. isolated syncope) was found to have independent predictive value (p = 0.04). The cumulative probability of recurrence projected for a period of 38 months was 66.2% (SEM = 16.5%) for children with more than one syncope before testing vs. 0% for those who had experienced only one. No other events occurred.The medium-term prognosis seems to be good for children with vasovagal syncope of unknown origin, given the low rate of recurrence, regardless of the results of tilt testing. The only predictor of recurrent syncope was pretest history, such that children with only one syncope before testing experience no recurrence and those with one or more episodes are estimated to have an increasingly higher likelihood of recurrence. These data may be useful for the recommending tilt testing and for planning therapy for children with vasovagal syncope.

"Less aggressive" burst stimulation is more effective in terminating spontaneous monomorphic ventricular tachycardia with a lesser acceleration rate. Higher ventricular tachycardia cycle length and use of 91% coupling interval were independent predictors for pacing termination.

Background: Ventricular tachycardia (VT) ablation in patients with arrhythmogenic cardiomyopathy (AC) has a high rate of recurrence. Recent studies suggest that a more extensive epicardial arrhythmogenic substrate could explain these results. We report the results of combined endocardial and epicardial susbtrate VT ablation (using the "scar dechanneling technique") in patients with AC. Methods and results: Thirty-two consecutive patients with AC and VT (mean 14±8 VT episodes/patient) were included in 9 centers. Six patients (19%) had left-dominant AC. A high-density endo (372±152 sites mapped) and epicardial (523±299 sites) electroanatomical voltage map was obtained during sinus rhythm. Electrograms with delayed components (E-DCs) were tagged and classified as entrance or inner conducting channels (CCs) points, depending on the delayed component precocity. The procedural endpoint was the isolation of all identified CCs firstly, by discrete ablation at CC entrance, and the abolition of residual inducible VTs afterwards. The mean procedure and fluoroscopy time were 215±80 min and 18±7 min, respectively. Epicardial maps showed larger scars (94±81 cm2 vs. 18±22 cm2, p

Introduction: The response to entrainment from the right ventricular apex (RVA) is useful to distinguish typical AV node reentrant tachycardia (AVNRT) from atrio-ventricular reentrant tachycardia (AVRT). The purpose of this study was to determine whether this response is useful for differentiating fast-slow AVNRT from the permanent form of junctional reciprocating tachycardia (PJRT). Methods: We studied 33 patients (P) with fast-slow AVNRT or PJRT with successful entrainment from the RVA. All tachycardias had a VA interval which was longer than the AV interval. Diagnoses of fast-slow AVNRT or PJRT were made according to conventional electrophysiological criteria and confirmed by the outcome of the ablation. Fifteen P (mean age 55±24 years, 6 males, tachycardia cycle length -TCL- 446±72 ms) had fast-slow AVNRT, and 18 P (mean age 41±22 years, 10 males, TCL 353±59 ms) had PJRT. The following responses to entrainment were analysed: difference between the postpacing interval after entrainment and TCL (PPI-TCL), difference between the Stimulus-Atrial electrogram interval during entrainment and the VA interval during tachycardia (SA-VA interval), and the A-V response upon cessation of ventricular overdrive pacing (A-V versus pseudo A-A-V response). Optimal cut-off values of continuous variables were determined by ROC curve analyses. Results: Significant differences in mean values for SA-VA interval, PPI-TCL and A-V responses were observed between the two groups (table). The diagnostic yield of the selected cut-off values is also shown. For PPI-TCL: area under ROC curve 0.85; p=0.01. For SA-VA: area under ROC curve: 0.9; p=0.004. View this table: Table 1 Conclusions: The response to tachycardia entrainment from the RVA is useful in order to distinguish fast-slow AVNRT from PJRT. A PPI-TCL lower than 130 ms and an SA-VA interval lower than 100 ms are highly suggestive of PJRT and make fast-slow AVNRT unlikely.

Objectives. This study sought to analyze two new criteria along with other known predictors of success of radiofrequency ablation. Background. Although the overall success rate of radiofrequency ablation of accessory pathways is high, the individual predictive value of each of the established criteria is low. Methods. We prospectively studied the local electrograms obtained before the application of radiofrequency energy in 33 patients with a left-sided concealed accessory pathway successfully ablated. Two new criteria (“pseudodisappearance” during tachycardia of a bipolar atrial electrogram visible during sinus rhythm and the presence of an “atrial notch” in the ascending limb of the unipolar ventricular electrogram during tachycardia) were studied along with other known predictors. Electrograms recorded at a total of 157 sites were analyzed (33 successful applications, 124 failures). Results. Electrogram characteristics that were predictive of success during ablation on the basis of univariate analyses were a pseudodisappearance criterion (p < 0.001), the presence of a Kent potential (p < 0.005) and the presence of an “atrial notch” (p < 0.005). After adjustment for between-patient differences, logistic regression analysis showed that only the “pseudodisappearance” criterion (odds ratio [OR] 7.2, 95% confidence interval [CI] 1.2 to 42.5, p < 0.03) and the presence of a Kent potential (OR 2.4, 95% CI 1.01 to 5.79, p < 0.05) had independent predictive value. Conclusions. The pseudodisappearance during tachycardia or ventricular pacing of a bipolar atrial electrogram present during sinus rhythm is associated with a good outcome during radiofrequency ablation of concealed accessory pathways. These observations may help to ablate accessory pathways and to avoid missing appropriate sites for ablation when the atrial activation is not clearly visible at the local electrogram.

guio su aislamiento, y el paciente paso a ritmo sinu­ sal (RS), como se aprecia en los electrogramas del SC (fig. 2), manteniendo la VP un ritmo fibrilatorio que posteriormente se regularizo en una taquicar­ dia auricular antes de suprimirse espontaneamente (fig. 3). La ablacion de las venas pulmonares hoy es el tratamiento de eleccion de la FA paroxistica re­ belde a tratamiento farmacologico. La conversion a ritmo sinusal durante la aplicacion de radiofre­ cuencia puede observarse al aislar electricamente un tronco venoso pulmonar (lo mas frecuente) o una unica vena pulmonar, como en este caso, puesto que la arritmia localizada en dicha estructura (ge­ neralmente una taquicardia auricular) es la causa de que se mantenga la FA.

and the patient converted to sinus rhythm, as is seen in the CS electrograms (Figure 2). The PV maintained a fibrillatory rhythm that later regulated to atrial tachycardia, and ultimately disappeared spontaneously (Figure 3). Pulmonary vein ablation is currently the treatment of choice for paroxysmal AF resistant to medical treatment. Conversion to sinus rhythm during radiofrequency application is observed when a main pulmonary trunk (the most common) or a single pulmonary vein, as in this case, is electrically isolated, because it is the arrhythmia located in these structures (usually atrial tachycardia) that maintains the AF

Background Some patients with an automatic implantable cardioverter-defibrillator (ICD) suffer multiple appropriate, consecutive, high-energy discharges (MCDs) during follow-up. Such events might represent resistant ventricular arrhythmias and might have prognostic significance. Methods and Results Eighty consecutive patients with an ICD were followed up for up to 82 months (mean, 21±19 months). Thirty-eight patients had survived an out-of-hospital cardiac arrest and 42 had recurrent ventricular tachycardia. During follow-up, 16 patients had MCD (group A), 26 patients had episodes of single appropriate discharges (group B), and 38 patients had no appropriate discharges (group C). Group A patients had worse functional status ( P =.001), lower left ventricular ejection fractions (LVEFs) ( P =.001), and lower survival rates (log rank, P =.003) than the remaining two groups of patients. Cox analysis showed LVEF ( P =.001) to be an independent predictor of MCD. Independent predictors of death or heart transplant were MCD ( P =.001), female sex ( P =.001), age ( P =.001), history of cardiac arrest ( P =.003), and functional status ( P =.003). The only independent predictor of total mortality was female sex ( P =.002). Independent predictors of cardiac death were MCD ( P =.007) and female sex ( P =.018). Independent predictors of arrhythmic death were age ( P =.001), female sex ( P =.02), and MCD ( P =.023). Conclusions In patients with an ICD, the development of MCD is an independent predictor of cardiac and arrhythmic mortality. If this finding is confirmed in larger studies, it may help to identify patients in whom other therapeutic alternatives, ie, heart transplantation, should be considered during follow-up after ICD implantation.