Relevance of subclinical right ventricular dysfunction measured by feature-tracking cardiac magnetic resonance in non-ischemic dilated cardiomyopathy.

BACKGROUND: Right ventricular (RV) dysfunction in patients with non-ischemic dilated cardiomyopathy (NICM) is associated with cardiovascular events. To analyze the feasibility of assessing RV myocardial deformation by feature tracking (FT)-cardiac magnetic resonance (CMR), and its usefulness as a prognostic marker. METHODS: Retrospective study of NICM patients undergoing CMR. Longitudinal FT-RV free wall (LFT-RVFW) and fractional area change (FAC) were obtained. Correlation with standard RV parameters was studied. An association with combined event (heart failure (HF), ICD implantation or cardiovascular death) was assessed using a logistic regression model. RESULTS: 98 patients (64 ± 13 years) were included. Left ventricular (LV) systolic function (LVEF 29.5 ± 9.6%, 47% with LVEF ≥ 30%) and RV (RVEF 52.2 ± 14.6%, 72% with RVEF ≥ 45%). Follow-up of 38 ± 17 months, 26.5% presented at least one admission for HF. An excellent correlation of LFT-RVFW (r = 0.82) and FAC (r = 0.83) with RVEF was evident. No association of RV-FT parameters with prognosis entire study population was found. However, in patients with LVEF ≥ 30%, admissions for HF were associated with lower LFT-RVFW (-21.6 ± 6.6% vs -31.3 ± 10%; p = 0.006) and FAC (36.6 ± 9.6% vs 50.5 ± 13.4%; p < 0.001) values. Similar differences were observed when only patients with RVEF ≥ 45% were considered. An LFT-RVFW cut-off point of -19.5% and FAC of 36.5% showed good prognostic performance. Decreased LFT-RVFW or FAC represented an independent predictor of combined event in patients with LVEF ≥ 30%. CONCLUSIONS: In NICM patients without severe LV dysfunction, decreased values of LFT-RVFW and/or FAC were associated with HF admissions, independently of RVEF.

Public healthcare expenditure and COVID-19 mortality in Spain and in Europe.

OBJECTIVE: To analyze the association between public health expenditure per capita and the mortality rate due to COVID-19 in Europe and Spain. MATERIAL AND METHODS: Pearson's correlation coefficient was used to compare and contrast the mortality rate due to COVID-19 between countries and autonomous communities with higher and lower public health expenditure per capita than the mean. RESULTS: No correlation between the public health expenditure per capita and the mortality rate due to COVID-19 (r: 0.3; p = 0.14) was found among European countries or Spain's Autonomous Communities (r: 0.03; p = 0.91). No significant differences were found when comparing the mortality rate due to COVID-19 among the public health expenditure per capita groups. CONCLUSIONS: The available evidence does not support association between «low¼ public healthcare expenditure and the poor outcomes observed in Spain during the COVID-19 pandemic. Increased funding for the Spanish National Health System should be earmarked for structural reforms to increase its social efficiency.

[Public healthcare expenditure and COVID-19 mortality in Spain and in Europe]. / Gasto sanitario público y mortalidad por COVID-19 en España y en Europa.

OBJECTIVE: To analyze the association between public health expenditure per capita and the mortality rate due to COVID-19 in Europe and Spain. MATERIAL AND METHODS: Pearson's correlation coefficient was used to compare and contrast the mortality rate due to COVID-19 between countries and autonomous communities with higher and lower public health expenditure per capita than the mean. RESULTS: No correlation between the public health expenditure per capita and the mortality rate due to COVID-19 (r: 0.3; p = 0.14) was found among European countries or Spain's Autonomous Communities (r: 0.03; p = 0.91). No significant differences were found when comparing the mortality rate due to COVID-19 among the public health expenditure per capita groups. CONCLUSIONS: The available evidence does not support association between «low¼ public healthcare expenditure and the poor outcomes observed in Spain during the COVID-19 pandemic. Increased funding for the Spanish National Health System should be earmarked for structural reforms to increase its social efficiency.

Quantification of anaesthetic effects on atrial fibrillation rate by partial least-squares.

The mechanism underlying atrial fibrillation (AF) remains poorly understood. Multiple wandering propagation wavelets drifting through both atria under hierarchical models are not understood. Some pharmacological drugs, known as antiarrhythmics, modify the cardiac ionic currents supporting the fibrillation process within the atria and may modify the AF propagation dynamics terminating the fibrillation process. Other medications, theoretically non-antiarrhythmic, may slightly affect the fibrillation process in non-defined mechanisms. We evaluated whether the most commonly used anaesthetic agent, propofol, affects AF patterns. Partial least-squares (PLS) analysis was performed to reduce significant noise into the main latent variables to find the differences between groups. The final results showed an excellent discrimination between groups with slow atrial activity during the propofol infusion.

Entropy measurements in paroxysmal and persistent atrial fibrillation.

Recent studies on atrial fibrillation (AF) have identified different activation patterns in paroxysmal and persistent AF. In this study, bipolar intra-atrial registers from 28 patients (14 paroxysmal AF and 14 persistent AF) were analyzed in order to find out regional differences in the organization in both types of arrhythmias. The organization of atrial electrical activity was assessed in terms of nonlinear parameters, such as entropy measurements. Results showed differences between the atrial chambers with a higher disorganization in the left atrium in paroxysmal AF patients and a more homogenous behavior along the atria in persistent AF patients.

Ventricular rhythm in atrial fibrillation under anaesthetic infusion with propofol.

Changes in patients' autonomic tone and specific pharmacologic interventions may modify the ventricular response (actual heart rate) during atrial fibrillation (AF). Hypnotic agents such as propofol may modify autonomic balance as they promote a sedative state. It has been shown that propofol slightly slows atrial fibrillatory activity, but the net global effect on the ventricular response remains unknown. We aimed to evaluate in patients in AF the effect of a propofol bolus on the ventricular rate and regularity at ECG. We analysed the possible relation with local atrial fibrillatory activities, as ratios between atrial and ventricular rates (AVRs), analysing atrial activity from intracardiac electrograms at the free wall of the right and left atria and at the interatrial septum. We compared data at the baseline and after complete hypnosis. Propofol was associated with a more homogeneous ventricular response and lower AVR values at the interatrial septum.

Anesthesia with propofol slows atrial fibrillation dominant frequencies.

The mechanisms responsible for the maintenance of atrial fibrillation (AF) are not completely understood yet. It has been demonstrated that AF can be modulated by several cardiac diseases, the autonomic nervous system and even drugs with purportedly no antiarrhythmic properties. We evaluated the effects of a widely used anaesthetic agent (propofol) in the fibrillation patterns. Spectral analysis was performed over atrial electrograms at baseline and immediately after a propofol bolus. Only after performing principal component analysis (PCA), we were able to significantly detect that propofol slows AF.

[The clinical practice guidelines of the Sociedad Española de Cardiología on the automatic implantable defibrillator]. / Guías de práctica clínica de la Sociedad Española de Cardiología sobre el desfibrilador automático implantable.

Since the first implantation in man in 1980 implantable cardioverter defibrillator technology has greatly improved and the number of devices implanted has increased considerably every year. Non thoracotomy lead systems and biphasic shocks are now the approach of choice, offering an almost 100% success rate. This document reviews the recommendations for qualification of personnel and for the centres implanting and carrying out follow-ups on defibrillators. The current indications for the implantation of implantable cardioverter defibrillator are also addressed.

Randomized, prospective comparison of four burst pacing algorithms for spontaneous ventricular tachycardia.

"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.

[Radiofrequency catheter ablation for atrial tachycardia]. / Ablación con catéter mediante radiofrecuencia de taquicardias auriculares.

INTRODUCTION: Radiofrequency catheter ablation of atrial tachycardia guided by bipolar activation mapping has been reported in the last years. This article reports the use of radiofrequency catheter ablation for the treatment of atrial tachycardia using simultaneous bipolar and unipolar activation mapping at our institution. METHODS: Nine patients (7 male and 2 female, mean age 37.2 +/- 24.1 years), were selected for radiofrequency catheter ablation of drug refractory atrial tachycardia. Mapping procedure included an investigation of the local earliest bipolar and unipolar activity and unipolar morphology analysis. RESULTS: Atrial tachycardia was successfully ablated in 7 patients (78%) with an average number of 6.8 +/- 3.1 RF pulses. Procedure related complications and tachycardia follow-up recurrences were not observed in any patient. Bipolar local activation time was significantly shorter at successful than at unsuccessful ablation sites (-30 +/- 21.1 ms vs -18.3 +/- 20.6 ms; p = 0.01). No difference was observed in unipolar local activation time between successful and unsuccessful sites (-22.5 +/- 26.2 ms vs -19.8 +/- 21.5 ms; p = 0.56). Accurate localization of the successful ablation site by unipolar electrogram analysis was not feasible because a "QS" pattern was found at both 21 unsuccessful and 2 successful ablation sites. Finally, a fast slope of the negative deflection of the unipolar electrogram was found at 2 out of 45 unsuccessful and 3 out of 6 successful ablation sites. CONCLUSIONS: Radiofrequency catheter ablation of atrial tachycardia is feasible without complications in most patients. Bipolar activation mapping accurately localizes the successful ablation site. A "QS" pattern is not predictive of successful radiofrequency application.

[Radiofrequency catheter ablation of ventricular tachycardias in patients with postinfarction scars]. / Ablación con catéter mediante radiofrecuencia de taquicardias ventriculares en pacientes con cicatriz postinfarto.

Radiofrequency catheter ablation has recently emerged as a therapeutic option for ventricular tachycardia in postinfarction patients. However, the indications for its use and the mapping procedure remain controversial. The most common arrhythmogenic circuit found fits an "8" shape model. This model incorporates a slow conducting central area, separated from the surrounding myocardium by conduction blocking areas and with entrance and exit sites. This circuit has classically been confined in the left ventricle. However, recently successful radiofrequency catheter ablation of ventricular tachycardia has been reported from the right ventricle. Several markers for adequate positioning of the ablation catheter have been reported: local presystolic activity, isolated mid diastolic potential, transient entrainment with concealed fusion, match between electrogram-QRS and stimulus-QRS intervals, match between first postpacing interval and tachycardia cycle length and tachycardia electrocardiographic reproduction by pace-mapping. Procedure related complications are rare and the success rate is around 70%. Nevertheless, currently this technique should be limited to postinfarction patients with ventricular tachycardia meeting certain requisites.

[Comparative study of 3 algorithms to localize the accessory pathway in Wolff-Parkinson-White syndrome]. / Estudio comparativo de tres algoritmos de localización de la vía accesoria en el síndrome de Wolff-Parkinson-White.

BACKGROUND AND OBJECTIVES: Some electrocardiographic algorithms have been developed to predict the location of the accessory pathway in the WPW syndrome. Few studies address the interobserver variability of such algorithms and the possible observer-dependent changes of accuracy. This study analyzes three algorithms to localize accessory pathways recently published, comparing the inter-observer variability, their predictive value and the most frequent problems observed during their application. METHODS: Ninety-six electrocardiograms from patients who underwent successful ablation of a single accessory pathway were reviewed. The location of each pathway was predicted by two independent observers according to three different reported electrocardiographic algorithms. The interobserver agreement, percentage of correct predictions and critical steps of each algorithm were analyzed. RESULTS: The interobserver agreement varied between 64 and 79% and the accuracy between 38 and 67%. The best results were obtained in the left lateral accessory pathways (69 to 89% correctly located). All the algorithms presented critical steps at which more than 20% of pathways were incorrectly classified. CONCLUSIONS: The analyzed algorithms present a high interobserver variability. The accuracy obtained is clearly lower than that reported by the corresponding authors. These facts should be considered when being used them in clinical settings.

[Bradycardia and asystolia secondary to epileptic crisis. Report of a case]. / Bradicardia y asistolia secundarias a crisis epiléptica. A propósito de un caso.

We report the case of a 21 year old man with bradycardia and asystolia after a seizure. No cardiac disease could be demonstrated, but electroencephalography after sleep deprivation showed the presence of a temporal irritative focus. The importance of differential diagnosis between cardiogenic syncope and loss of consciousness due to epilepsy is discussed.

[Mechanism and location of typical atrial flutter. Information drawn from experimental models and clinical electrophysiology]. / Mecanismo y localización del flutter auricular típico. Información obtenida de los modelos experimentales y de la electrofisiología clínica.

Several experimental models have been proposed to explain the electrocardiographic and electrophysiological characteristics of atrial flutter. In animal models based on anatomical obstacles, intercaval crush or Y like shaped lesion located in the right atrium, it has been possible to induce sustained atrial arrhythmias in which the entrainment criteria could be demonstrated. Additionally these tachycardias presented an atrialwave morphology similar to the F waves of type 1 or typical atrial flutter. Flutter type 2 could better be explained by models based on functional reentry like the leading circle. Typical atrial flutter in human, saw teeth morphology in inferior ECG leads, is though to be a circus movement located in the right atrium, as deduced of the analysis of activation sequence, resetting and entrainment phenomena from right and left atrium. Moreover the successful results of RDF ablation procedures confirm this idea. Nevertheless the delimitation of the anatomical boundaries of the reentry pathway remains inconclusive.

[Radiofrequency catheter ablation of ventricular tachycardia in patients without apparent structural cardiopathy]. / Ablación con catéter mediante radiofrecuencia de taquicardias ventriculares en pacientes sin cardiopatía estructural aparente.

BACKGROUND AND PURPOSE: It has been suggested that the efficacy of radiofrequency ablation of idiopathic ventricular tachycardia (VT) is dependent on the site of VT origin, with the efficacy being greater for VTs originating from right ventricle. The electrophysiologic characteristic and the results of radiofrequency catheter ablation of ventricular tachycardia in patients without structural heart disease are reported. Special emphasis was focused to the differences observed in the pace and activating mapping between VTs originating in the right ventricle and those originating from the left ventricle and its possible implications for radiofrequency efficacy. METHODS AND RESULTS: 14 consecutive patients with idiopathic VT (7 women and 7 men, mean age 35 +/- 16 years), 8 originating in the right ventricle (RV) and 6 in the left ventricle (LTV), underwent catheter ablation using radiofrequency energy. The observation of entrainment with fusion in all LV VT suggested that the electrophysiologic mechanism was a reentry, meanwhile the RV VT were due to focal non-reentrant mechanisms. Sites for radiofrequency energy delivery were selected on the basis of pace and activation mapping in all patients less in two patients with incessant VT in whom only activation mapping was performed. 14 VT were mapped. The activation mapping demonstrated isolated presystolic electrograms in the point of origin in all VT arising from the LV. However in RV tachycardias there was continuous activity between presystolic and systolic electrograms, although the prematurity of these electrograms was similar (31 +/- 16 ms vs 33 +/- 9 ms; p = 0.77). Radiofrequency was successful in eliminating 93% of TV (100% RV TV vs 83% LV TV; p = 0.23). No complications were observed. CONCLUSIONS: The results of this study suggest that radiofrequency ablation is highly successful either in right and left ventricles idiopathic tachycardias when pace and activation mapping are used complementary.

[The surgical treatment of sustained ventricular tachycardias. The short- and midterm results in the era of the implantable defibrillator and the heart transplant]. / Tratamiento quirúrgico de las taquicardias ventriculares sostenidas. Resultados a corto y medio plazo en la "era" del desfibrilador implantable y del transplante cardíaco.

BACKGROUND: The surgical treatment of refractory ventricular tachycardia has been shown to be effective. Its use has been limited by a high perioperative mortality. OBJECTIVE: To study the extent to which the introduction of new therapeutic options, i.e. the implantable defibrillator and cardiac transplantation, improves patient selection and results of direct antiarrhythmic surgery. PATIENTS AND METHODS: We analyzed 24 consecutive patients operated upon for ventricular tachycardia (study population). At the same time, 42 patients were treated with implantable defibrillator and 11 patients, with symptomatic ventricular arrhythmias, underwent cardiac transplantation (reference population). RESULTS: The clinical characteristics of the study population (age, functional class, ejection fraction) were significantly different from those of both reference groups. Nine patients (38%) were operated upon because of electrical instability and/or contraindication for other therapeutic options despite of having criteria of high surgical risk. There was one perioperative death (4.2%) and no other early arrhythmic recurrences. Persistence of inducibility occurred in 5 cases (22%). During follow up (35 +/- 22 months) there was a single arrhythmic recurrence. Three patients died of nonarrhythmic causes. Presently, 16 patients are in I or II NYHA functional class. CONCLUSIONS: 1) Direct surgery remains as a useful tool in the treatment of ventricular tachycardia; 2) clinical differences among groups caused by the individual selection of the three therapeutic options preclude comparison of their results, and 3) the introduction of other therapeutic approaches, although resulting in only partial improvement of patient selection, leads to acceptable short and mid-term results of direct antiarrhythmic surgery.