José M. Guerra

Catheter ablation vs. antiarrhythmic drug treatment of persistent atrial fibrillation: a multicentre, randomized, controlled trial (SARA study)

Background Catheter ablation (CA) is a highly effective therapy for the treatment of paroxysmal atrial fibrillation (AF) when compared with antiarrhythmic drug therapy (ADT). No randomized studies have compared the two strategies in persistent AF. The present randomized trial aimed to compare the effectiveness of CA vs. ADT in treating persistent AF. Methods and results Patients with persistent AF were randomly assigned to CA or ADT (excluding patients with long-standing persistent AF). Primary endpoint at 12-month follow-up was defined as any episode of AF or atrial flutter lasting >24 h that occurred after a 3-month blanking period. Secondary endpoints were any atrial tachyarrhythmia lasting >30 s, hospitalization, and electrical cardioversion. In total, 146 patients were included (aged 55 ± 9 years, 77% male). The ADT group received class Ic (43.8%) or class III drugs (56.3%). In an intention-to-treat analysis, 69 of 98 patients (70.4%) in the CA group and 21 of 48 patients (43.7%) in the ADT group were free of the primary endpoint (P = 0.002), implying an absolute risk difference of 26.6% (95% CI 10.0–43.3) in favour of CA. The proportion of patients free of any recurrence (>30 s) was higher in the CA group than in the ADT group (60.2 vs. 29.2%; P < 0.001) and cardioversion was less frequent (34.7 vs. 50%, respectively; P = 0.018). Conclusion Catheter ablation is superior to medical therapy for the maintenance of sinus rhythm in patients with persistent AF at 12-month follow-up. Clinical Trial Registration Information NCT00863213 (http://clinicaltrials.gov/ct2/show/NCT00863213).

Effects of Open-Irrigated Radiofrequency Ablation Catheter Design on Lesion Formation and Complications: In Vitro Comparison of 6 Different Devices

Open‐irrigated radiofrequency ablation catheters with slight differences in tip architecture are widely used, although limited comparative data are available. The purpose of this study was to compare the lesion size and potential complications produced by commercially available open‐irrigated catheters in an in vitro porcine heart model.

A new method of filtering T waves to detect hidden P waves in electrocardiogram signals

AIMSnA correct identification of the P wave is crucial for the diagnosis of narrow QRS tachycardias. This is sometimes difficult because atrial activity is hidden in the T wave. The aim of this study is to evaluate the usefulness of a T wave filtering technique based on wavelet transformation to identify atrial activity.nnnMETHODS AND RESULTSnForty-two patients with narrow QRS tachycardias and regular atrial activity were studied. A surface electrocardiogram (ECG), intra-atrial recording, and the T wave filtering ECG were compared simultaneously to check the accuracy of the filtering system in detecting atrial activity. The sensitivity of the T wave filtering and P wave detection algorithm was 85.8% [95% confidence interval (CI): 81.2-89.4%] and the specificity was 89.4% (95% CI: 87.1-91.4%), with a global accuracy of 88.5% (95% CI: 86.5-90.3%). The expert cardiologists accuracy in distinguishing between atrioventricular nodal reentry tachycardia and atrioventricular reentry tachycardia was 75% in the surface ECG vs. 100% in the ECG with the T wave filtering process (P<0.01).nnnCONCLUSIONSnT wave filtering based on wavelet transformation improves the capacity of the surface ECG to identify atrial activity in cases of regular narrow QRS supraventricular tachycardias.

Taquicardia auricular de vena pulmonar: características clínicas, electrocardiográficas y electrofisiológicas diferenciales

Introduccion y objetivos Las venas pulmonares (VP) son un origen frecuente de taquicardias auriculares (TA) ocasionalmente dificil de reconocer en el ECG. Analizamos las caracteristicas diferenciales clinicas y electrofisiologicas, incluidas la duracion y la presencia de melladura en la onda P sinusal, asociadas a las TA-VP. Metodos Ochenta y siete pacientes sometidos a ablacion de TA fueron incluidos y agrupados: TA-VP (grupo 1, nxa0=xa025), TA-VP asociada a fibrilacion auricular (grupo 2, nxa0=xa018), otras TA izquierdas (grupo 3, nxa0=xa07) y TA derechas (grupo 4, nxa0=xa037). Resultados El grupo 1 presento edad media mas joven (44xa0±xa014 anos) que los grupos 2 a 4 (57xa0±xa09, 58xa0±xa012 y 53xa0±xa016 anos, respectivamente; p Conclusiones Una P sinusal prolongada y mellada en pacientes jovenes con TA rapidas y sin cardiopatia predice un origen en VP.

Atrial Tachycardia Originating From the Pulmonary Vein: Clinical, Electrocardiographic, and Differential Electrophysiologic Characteristics

INTRODUCTION AND OBJECTIVESnAlthough atrial tachycardia (AT) frequently originates in the pulmonary vein, pulmonary vein atrial tachycardia (PV-AT) can be difficult to recognize on an ECG. The aim of this study was to identify clinical and electrophysiologic characteristics specific to PV-AT, including sinus P-wave duration and notching.nnnMETHODSnThe study included 87 patients who underwent AT ablation, divided into four groups: those with PV-AT alone (Group 1, n=25), those with PV-AT associated with atrial fibrillation (Group 2, n=18), and those with other forms of left AT (Group 3, n=7) and right AT (Group 4, n=37).nnnRESULTSnThe mean age of patients in Group 1, at 44 + or - 14 years, was less than in Groups 2, 3 and 4, at 57 + or - 9, 58 + or - 12 and 53 + or - 16 years, respectively (P< .05) and the left atrial diameter, at 38 + or - 4 mm, was less than in the other left AT groups: 48 + or - 7 mm in Group 2 and 49 + or - 5 mm in Group 3 (P< .05). Overall, PV-AT was most frequently due to abnormal automaticity or triggered activity (P< .05) and presented with a short cycle length: 289 + or - 45 ms and 280 + or - 48 ms in Groups 1 and 2, respectively, versus 392 + or - 106 ms and 407 + or - 87 ms in Groups 3 and 4, respectively (P< .05). In patients aged <50 years with AT and no underlying heart disease, PV-AT was significantly (P< .05) associated with a P-wave duration > or = 110 ms (sensitivity 68%, specificity 69%) and P-wave notching (sensitivity 79%, specificity 70%).nnnCONCLUSIONSnSinus P-wave prolongation and notching in young patients with a rapid AT but without heart disease predicted an origin in the pulmonary vein.

Ritmo sinusal normal. Nuevos conceptos anatómicos y fisiológicos del nódulo sinusal. Corriente If

El nodo sinusal es una estructura altamente especializada, cuyas celulas generan despolarizaciones espontaneas repetidas a una frecuencia variable que determina la frecuencia cardiaca. Las celulas nodales se disponen sobre una matriz de tejido conectivo denso formando cordones entrelazados, que en la periferia se mezclan con los miocitos auriculares contractiles. La zona central, encargada de generar los impulsos, se caracteriza por estar relativamente desacoplada del resto de la auricula, mientras que la zona periferica presenta un grado de acoplamiento cada vez mayor. Las celulas nodales presentan una fase diastolica caracterizada por una despolarizacion lenta progresiva que transporta el potencial de reposo al umbral de excitabilidad y genera un nuevo potencial de accion. La activacion de la corriente I f genera esta fase diastolica y esta implicada tambien en el control del ritmo cardiaco mediado por el sistema nervioso autonomo.

Integration of late-enhanced MRI and electroanatomical mapping for substrate ablation of poorly tolerated ventricular tachycardia

We describe the case of a patient with a poorly tolerated ventricular tachycardia (VT) in which a substrate ablation was performed. The ablation was guided by the integrated images of the scar obtained by MRI and electro-anatomical mapping. This combined technique can make substrate ablation more accurate and may have a role in the ablation of unmappable VT.

Identification of new biophysical markers for pathological ventricular remodelling in tachycardia-induced dilated cardiomyopathy

Our aim was to identify biophysical biomarkers of ventricular remodelling in tachycardia‐induced dilated cardiomyopathy (DCM). Our study includes healthy controls (N = 7) and DCM pigs (N = 10). Molecular analysis showed global myocardial metabolic abnormalities, some of them related to myocardial hibernation in failing hearts, supporting the translationality of our model to study cardiac remodelling in dilated cardiomyopathy. Histological analysis showed unorganized and agglomerated collagen accumulation in the dilated ventricles and a higher percentage of fibrosis in the right (RV) than in the left (LV) ventricle (P = .016). The Fourier Transform Infrared Spectroscopy (FTIR) 1st and 2nd indicators, which are markers of the myofiber/collagen ratio, were reduced in dilated hearts, with the 1st indicator reduced by 45% and 53% in the RV and LV, respectively, and the 2nd indicator reduced by 25% in the RV. The 3rd FTIR indicator, a marker of the carbohydrate/lipid ratio, was up‐regulated in the right and left dilated ventricles but to a greater extent in the RV (2.60‐fold vs 1.61‐fold, P = .049). Differential scanning calorimetry (DSC) showed a depression of the freezable water melting point in DCM ventricles – indicating structural changes in the tissue architecture – and lower protein stability. Our results suggest that the 1st, 2nd and 3rd FTIR indicators are useful markers of cardiac remodelling. Moreover, the 2nd and 3rd FITR indicators, which are altered to a greater extent in the right ventricle, are associated with greater fibrosis.

Comparison between endocardial and epicardial cardiac resynchronization in an experimental model of non-ischaemic cardiomyopathy

AimsnPacing from the left ventricular (LV) endocardium might increase the likelihood of response to cardiac resynchronization therapy. However, experimental and clinical data supporting this assumption are limited and controversial. The aim of this study was to compare the acute response of biventricular pacing from the LV epicardium and endocardium in a swine non-ischaemic cardiomyopathy (NICM) model of dyssynchrony.nnnMethods and resultsnA NICM was induced in six swine by 3u2009weeks of rapid ventricular pacing. Biventricular stimulation was performed from 16 paired locations in the LV (8 epicardial and 8 endocardial) with two different atrioventricular (80 and 110u2009ms) intervals and three interventricular (0, +30, -30u2009ms) delays. The acute response of the aortic blood flow, LV and right ventricular (RV) pressures, LVdP/dtmax and LVdP/dtmin and QRS complex width and QT duration induced by biventricular stimulation were analysed. The haemodynamic and electrical beneficial responses to either LV endocardial or epicardial biventricular pacing were similar (ΔLVdP/dtmax:u2009+7.8u2009±u20092.2% ENDO vs.u2009+7.3u2009±u20091.5% EPI, and ΔQRS width: -16.8u2009±u20091.3% ENDO vs. -17.1u2009±u20091.9% EPI; Pu2009=u2009ns). Pacing from LV basal regions either from the epicardium or endocardium produced better haemodynamic responses as compared with mid or apical LV regions (Pu2009<u20090.05). The LV regions producing the maximum QRS complex shortening did not correspond to those inducing the best haemodynamic responses (EPI: r2 = 0.013, Pu2009=u2009ns; ENDO: r2 = 0.002, Pu2009=u2009ns).nnnConclusionnEndocardial LV pacing induced similar haemodynamic changes than pacing from the epicardium. The response to endocardial LV pacing is region dependent as observed in epicardial pacing.

High-Density Mapping of Counterclockwise to Clockwise Typical Atrial Flutter: Visualization of the Conduction Gap.

A 57-year-old man without prior history of cardiovascular disease was referred to our arrhythmia unit for ablation of recurrent episodes of typical atrial flutter. An echocardiogram ruled out structural heart disease. After informed consent was obtained the procedure was performed under conscious sedation. A decapolar catheter was introduced into the coronary sinus and a tetrapolar catheter was positioned at the His bundle region. This article is protected by copyright. All rights reserved.