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The anatomical features of right atrial cavo-tricuspid isthmus can impact radiofrequency catheter ablation in term of success rate and complications
Full text linkBackground: Radiofrequency (RF) catheter ablation targeting the isthmus between the tricuspid annulus and the inferior vena cava (IVC) is the established treatment for typical atrial flutter (AFL) due to its high efficacy. Despite this high success rate, ablation of the cavo-tricuspid isthmus (CTI) can be extremely difficult, due to its highly variable anatomy. The aim of this study is to analyze how and why the great inter-individual variability can influence ablation procedure. Primary endpoint was to evaluate the impact of the underlying CTI anatomy on acute and long-term success rate. Secondary endpoint was to determine any ablation related complication and procedure time.
Methods: Over a period of 54 months, 337 consecutive patients underwent CTI ablation. One 5F decapolar catheter was placed within the coronary sinus (CS) and another 7F multipolar catheter was placed anterior to the crista terminalis at the right free wall close to the tricuspid annulus. CTI anatomy was classified into: (A) simple (flat) CTI, (B) complex (pouch-like recess or concave shape) CTI. Vital parameters, such as arterial blood pressure and oxygen saturation were monitored throughout the entire procedure. All procedures were performed under conscious sedation using boluses of midazolam and fentanyl. Termination ablation was decided when bidirectional block was demonstrated. Ablation was performed using 8 mm-tip catheter with a power limit of 70 W and a target temperature of 60°C. The CTI length was measured as the shortest linear distance between the lower hinge point of the tricuspid annulus and the IVC in the frontal fluoroscopic projection. Outpatient follow-up included 12-lead ECG, and Holter ECG monitoring, scheduled at months 3, 6, and 12.
We also examined 104 formalin-fixed hearts from patients who underwent routine clinical autopsy performed at the Cardiovascular Pathology Unit, University of Padua. Every heart was examined by two independent expert cardiovascular pathologists. The following features were assessed: 1. the length of the central isthmus; 2. the presence of pouch-like recesses; 3. the number of the recesses; 4. the position of the recesses. The histological analysis was performed.
Results:
Ablation: Mean age of all patients was 62.8 ± 10.6 years (range 28 – 84), male was 236 (70%). Deep recesses were found in 37 patients (10.9%) and were not related to aging, gender, left atrial size, and left ventricle ejection fraction (p = NS). Total mean CTI length was 23.3 ± 3.9 mm (range 10 – 35 mm). CTI length was shorter in type A anatomy as compared to type B (22.9 ± 3.2 vs 25.6 ± 6; p = 0.01). The primary endpoint of efficacy, proved by the bidirectional block, was achieved in 99.4% (335/337). Acute ablation failure (n = 2 patients) was associated with a CTI type B anatomy.
Regard to the secondary endpoints, complication occurred in 1 patient (0.29%) with the CTI type B anatomy: a “pop” immediately followed by cardiac tamponade required urgent pericardiocentesis. Total mean procedure time of was 51.6 ± 14.4 minutes, no difference between two groups (p= NS), but CTI bidirectional block was obtained with a significantly longer RF application time in CTI type B anatomy as compared to the type A (8.3 min vs 10.7 min, p = 0.025); that demonstrates ablation is more difficult in case of complex anatomy. During a mean follow-up period of 36.7 ± 17.2 months, 99.7% (334/335) of the patients were free of AFL recurrences. AFL recurred in 1 symptomatic patient with CTI type B anatomy. The patient underwent second ablation procedure. Conduction across the ablation line was demonstrated. Successful ablation was performed. No new recurrences have occurred until this time.
Anatomy: The mean age of the individuals was 67 ± 17 years, with a male prevalence (65%). The mean heart weight was 457 ± 102 g. The length of the central isthmus was 24 ± 4.1 mm (range 15 - 38 mm) without differences between groups (24.1 vs 23.6, p = NS), respectively. The central isthmus in the patients affected by atrial flutter was significantly longer compared to the other cardiac specimens (p < 0.01). In 10 of our cases (9.6%), a sub-Eustachian recess was present. As in the clinical series of patients undergoing ablation, the presence of recesses was not related to aging and gender. The recess was single in the majority of cases (60%) and the most frequent location was the central isthmus (60%). In the 4 cases diagnoses with atrial flutter, no recess was found in the CTI.
The highest number of recesses found in one specimen was 3. The regions with the thinnest muscular wall resulted to be the anterior and middle paraseptal and middle central.
Conclusions: Our investigation with both electrophysiological and anatomical study provides relevant information to clinical practice. Catheter ablation of typical AFL involving the CTI has been confirmed to be a safe, effective, and well-established ablation procedure. Nevertheless, the CTI anatomy impacts ablation parameters, such as RF energy application. Moreover, difficult procedure is also associated with longer length of isthmus. Recesses can complicate ablation, and knowing where they might be present is useful to avoid them. Therefore, success rate and ablation complications can be optimized by a deep knowledge of anatomy and centre experience
Transesophageal echocardiographic follow-up of pulmonary veins in patients undergoing ostial radiofrequency catheter ablation for atrial fibrillation
No full textOstial radiofrequency catheter ablation (RFCA) of pulmonary veins (PVs) is a promising invasive approach for the non-pharmacologic treatment of atrial fibrillation, but PV stenosis has been reported as a possible complication of this intervention. The aim of this study was to assess PV anatomy and stenosis (i.e. number and progression) by means of transesophageal echocardiography (TEE) during the follow-up of patients undergoing RFCA
ICD Implantation Practice Within Europe: How To Explain The Differences Beyond Economy?
No full textImplantable cardioverter defibrillators (ICD) offer the potential to prevent sudden cardiac death and demonstrated a survival benefit in high risk cardiac patients. ICD implantation rates vary significantly throughout the countries all over Europe although there are no major differences in cardiovascular morbidity among countries. ICD implantation rates in each European country may be influenced by economic factors, including the gross domestic product, its percentage devoted to public health, and organization of the health system. However, ICD implantation rates vary substantially also among countries with a high gross domestic product. Beyond economy, other important factors that may influence ICD implantation rates are lack of guidelines awareness and poor guidelines adherence especially when treating specific subgroup of patients (such as elderly and those with non ischemic cardiomyopathies)
Haemodynamic effects of coffee and purified caffeine in normal volunteers: a placebo-controlled clinical study.
No full textIn order to evaluate the effects of 'espresso' Italian coffee on resting flow, blood pressure, and peripheral resistance, 15 non-coffee drinking healthy volunteers received 2 cups of regular coffee, 200 mg purified caffeine or placebo in a latin square double-blind crossover protocol. Before and 30, 60, 90 and 120 min after ingestion, segmental resting flow and BP were measured and peripheral resistance was calculated. An echocardiogram was also performed before and 60 and 120 min after caffeine intake. Both regular coffee and caffeine produced a significant decrease in resting flow and a significant increase in resistance; both systolic and diastolic BP also increased, although not significantly. No variation was observed in heart rate and in cardiac contractility. Placebo (highly decaffeinated coffee for regular coffee and china bitter extract for caffeine) did not produce any haemodynamic effect. In five other healthy volunteers used to drinking more than 5 cups of coffee a day, coffee administration had no effect. These data demonstrate that the caffeine contained in espresso Italian coffee is a vasoconstrictor agent whose effects however are completely blunted in usual coffee drinkers as a consequence of adaptation
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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