Reassessment of the electrical connection between the pulmonary veins and the left atrium: A study to determine the different contributions of myocardial fibers along the standard ablation circumference.

Background: Circumferential ablation around the ipsilateral pulmonary veins (PVs) is the standard strategy for atrial fibrillation ablation. The present study seeks to assess which regions of the standard ablation circumference are the main contributors to the venoatrial electrical connection. Methods: A total of 41 patients were included under a specific atrial fibrillation ablation protocol in which the anterior and posterior segments of the standard circumference, between the equatorial line of the superior and the inferior ipsilateral PVs, were ablated first. If PV isolation was not achieved, ablation was extended superiorly or inferiorly, on the basis of the earliest atrial activation recorded during pacing from inside the PV. Complete PV isolation and the length of the areas not requiring ablation (ANRA) at the time of electrical isolation were evaluated. Results: Ablation of the anterior and posterior segments of the standard circumference led to the isolation of 77% left-PV pairs and 51% right-PV pairs (p = 0,015). A superior extension was required in 23% left-PV pairs and in 46% right-PV pairs, while an inferior extension was required only in 10% left-PV pairs and in 11% right-PV pairs. PV isolation was achieved before completing the standard ablation circumference in 97% left-PV pairs and in 94% right-PV pairs, with a median ANRA of 36.9 (IQR: 30.9-42.1) mm in the left PVs [16.0 (IQR: 12.0-19.0) mm superior and 18.8 (IQR: 16.1-24.9) mm inferior, p < 0.01] and 36.9 (IQR: 30.2-41.0) mm in the right PVs [15.1 (IQR: 10.7-19.1) mm superior and 20.6 (IQR: 16.9-23.3) mm inferior, p < 0.01]. Conclusions: The myocardial fibers along the anterior and posterior regions of the standard ablation circumference are the main contributors to the electrical connection between the pulmonary veins and the left atrium. Ablation of these regions results in PV isolation in the majority of patients.

Remote monitoring in a patient with multiple leadless pacemakers.

We describe through a clinical case some of the challenges we can face when remotely monitoring a patient with two devices. The case describes a patient with two leadless pacemaker in which data transmission by remote monitoring has been achieved.

Atrial Fibrillation Originating in the Inferior Vena Cava: A Typical Presentation of an Atypical Location.

Recurrence of atrial fibrillation (AF) despite successful isolation of the pulmonary veins (PVs) represents a great challenge. We present a patient with recurrent episodes of paroxysmal AF despite PV isolation in which a non-PV trigger was identified in the inferior vena cava. (Level of Difficulty: Intermediate.).

From High-Density Mapping to Low-Density Mapping: Outlining the Active Circuit in Complex Atrial Re-Entrant Tachycardias.

OBJECTIVES: The aim of this study was to describe a mapping approach for ablation of complex atrial re-entrant tachycardias (ARTs) in which high-density activation maps are transformed into low-density activation maps displaying only the active part of the tachycardia circuit. BACKGROUND: High-density activation maps during complex ARTs are challenging to interpret because they include the activation patterns of active and passive circuits. Entrainment mapping provides the identification of the active tachycardia circuit. However, current electroanatomic mapping systems are not capable of color-coding the information obtained from entrainment maneuvers. METHODS: Seventeen consecutive patients with atypical atrial flutter were included. A high-density activation map was acquired during index tachycardia. Subsequently, entrainment maneuvers were performed to generate a low-density activation map in which only the activation of the atria directly involved in the flutter circuit was displayed. RESULTS: Of all patients included, 82% were men, and their mean age was 62 ± 7 years. Structural heart disease was present in 59%, and 53% had undergone prior left atrial ablation procedures. Low-density activation maps were successfully generated from an average of 14 ± 3 entrainment points. Twenty circuits (95%) were identified in the left atrium and 1 (5%) in the right atrium. Ablation guided by low-density mapping successfully terminated all ARTs in 267 ± 353 s of radiofrequency application. CONCLUSIONS: Low-density mapping based on entrainment maneuvers provides a precise delineation of the active circuit during complex ARTs and resulted in successful arrhythmia termination. This approach can be easily incorporated into clinical practice.

Performance of the Micra cardiac pacemaker in nonagenarians.

INTRODUCTION AND OBJECTIVES: The Micra transcatheter pacing system has shown high effectiveness and a lower complication rate than conventional transvenous pacemakers. However, the benefit of the device is unknown in the very old population (≥ 90 years). The aim of this study was to evaluate the safety and effectiveness of Micra in patients ≥ 90 years. METHODS: We present a prospective observational study with consecutive patients aged >70 years who underwent implantation of a Micra pacemaker system. Patients were divided into 2 groups: ≥ 90 and<90 years. RESULTS: The Micra system was implanted in 129 patients, of whom 41 were aged ≥ 90 years and 88<90 years. The device was successfully implanted in 40 (97.6%) patients ≥ 90 years and in 87 (98.9%) patients<90 years (P=.58). An adequate position was achieved with need for ≤ 2 repositions in 97.5% and 91.9% of patients, respectively (P=.32). Procedure time (26.1 ±11.6 vs 30.3 ±14.2minutes; P=.11) and fluoroscopy time (6.4 ±4.7 vs 7.2 ±4.9minutes; P=0.41) were similar in the 2 groups. There were 3 major complications (2.3%), all in the group aged<90 years: 1 cardiac perforation, 1 femoral hematoma, and 1 femoral pseudoaneurysm. Thirteen patients aged ≥ 90 years (31.7%) and 16 patients aged <90 years (18.2%) died during a mean follow-up of 230±233 days and 394±285 days, respectively. There were no device-related deaths. No infection, dislocation or migration of Micra were observed. The electrical performance was optimal at follow-up. CONCLUSIONS: The Micra leadless pacing system seems to be safe and effective in patients older than 90 years. It may be considered a reasonable alternative to conventional transvenous pacing in this population.

Clinical characteristics of patients with sustained ventricular arrhythmias after sacubitril/valsartan initiation.

Our aim was to describe the clinical profile of patients presenting sustained ventricular arrhythmias after sacubitril/valsartan (SV) initiation. All cases of sustained ventricular arrhythmias in patients receiving SV were consecutively recorded in two centers. Nineteen patients had sustained ventricular arrhythmias after SV. All were men and were previously receiving angiotensin-converting enzyme inhibitors, or angiotensin II receptor blockers before SV initiation. Fifteen patients (78.9%) had electrical stability in the previous 6 months. Nine patients (47.4%) initiated SV at the lowest available dose (24/26 mg). Globally, in all but five patients alive at discharge, SV was discontinued after the event. Six patients presented new arrhythmic events after discontinuation of SV. Two deaths and three heart transplants occurred (one due to heart failure and the other two due to persistent ventricular arrhythmias). All patients had a high arrhythmic risk, and 17 (89.5%) had an implanted cardioverter defibrillator. No specific triggers for the arrhythmic event were found. Male sex and previous episodes of ventricular arrhythmias could be associated with an increased risk of sustained ventricular tachycardia after SV initiation. Discontinuation of the drug might be an additional approach to enable a better control of ventricular arrhythmias in some patients.

Survival in New York Heart Association class IV heart failure patients treated with cardiac resynchronization therapy compared with patients on optimal pharmacological treatment.

AIMS: Although the benefit of cardiac resynchronization therapy (CRT) in selected patients with heart failure is well established, its effect on mortality in New York Heart Association (NYHA) class IV patients remains unclear. Our study evaluated the effect of CRT on urgent transplant-free survival in NYHA class IV patients treated with CRT, compared with medication-only treatment. METHODS AND RESULTS: Forty NYHA class IV patients treated with CRT (80% men, 62.5% ischaemic, mean age of 65) were matched 1:1 by age, gender and aetiology of cardiomyopathy with patients treated with optimal medical therapy (OPT group). No significant differences were found between the groups in left ventricular diastolic diameter (71 +/- 6 vs. 73 +/- 9 mm), left ventricular systolic diameter (58 +/- 7 vs. 61 +/- 11 mm), and left ventricular ejection fraction (23 +/- 5 vs. 22 +/- 6%). Mean follow-up was 13.2 +/- 9.5 months for the CRT group and 17.3 +/- 11.6 months for the OPT group. Time to all-cause death or urgent transplantation [hazard ratios (HR), 1.29; 95% CI: 0.59-2.83; P = 0.52] or to cardiovascular death or urgent transplantation (HR, 1.53; 95% CI: 0.64-3.67; P = 0.34) was not reduced significantly in patients treated with CRT. CONCLUSION: In this study, CRT did not significantly improve survival of NYHA class IV heart failure patients compared with pharmacological therapy.

Detección del polimorfismo G/A en la región -455 del gen ß-fibrinógeno y su relación con el infarto miocárdico agudo / Detection of G/A polymorphism in the -455 region of the ß-fibrinogen and it's relation with the acute myocardial infarction

El fibrinógeno plasmático es un factor de riesgo para la enfermedad aretrial coronaria. Existe evidencia que variaciones genéticas en el gen del ß-fibrinógeno influye en la tasa de síntesis de esta proteína. El presente estudio evaluo la relación entre los niveles de fibrinógeno plasmático y la presencia de IAM, así como la relación del hábito tabáquico y los niveles de fibrinígeno determinó además, si la presencia del polimorfismo genético -455/A de la cadena ß del fibrinógeno se asocia con niveles elevados de fibrinógeno. Se realizó un estudio de casos y controles, en 55 pacientes con IAM y 498 controles libres de eventos coronarios agudos. Se determinaron los niveles de fibrinógeno de acuerdo a la técnica de von Clauss. La detección del polimorfismo -455/A fue determinado posterior al aislamiento de ADN genómico, mediante la técnica de PCR y ensayo de restricción con la enzima HaeIII. El nivel de fibrinógeno plasmático fue significativamente mayor en los pacienes con IAM; también se observaron mayores niveles de fibrinógeno plasmático en hombres, así como en el subgrupo de pacientes no fumadores. La presencia del alelo -455A se encontró en los pacientes con IAM, que tenían niveles elevados de fibrinógeno. Los resultados presentados en este trabajo demuestran que los niveles de fibrinógeno plasmático se encuentran más elevados en los pacientes con IAM y la importancia del polimorfismo -455/A en la región promotora del gen ß-fibrinógeno, ya que se evidenció asociación entre el alelo -455A con niveles elevados de fibrinógeno plasmático en ambos géneros, en los pacientes con IAM estudiados