Cavotricuspid Isthmus-Dependent Atrial Flutter. Beyond Simple Linear Ablation.

The demonstration of a peritricuspid circular movement with a zone of slow conduction in the cavotricuspid isthmus, together with the high efficacy of linear ablation and widely accepted acute endpoints, has established typical flutter as a disease with a well-defined physiopathology and treatment. However, certain aspects regarding its deeper physiopathology, ablation targets, and methods for verifying the results remain to be clarified. While current research efforts have primarily been focused on the advancement of effective ablation techniques, it is crucial to continue exploring the intricate electrophysiological, ultrastructural, and pharmacological pathways that underlie the development of atrial flutter. This ongoing investigation is essential for the development of targeted preventive strategies that can act upon the specific mechanisms responsible for the initiation and maintenance of this arrhythmia. In this work, we will discuss less ascertained aspects alongside the most widely recognized general data, as well as the most recent or less commonly used contributions regarding the electrophysiological evaluation and ablation of typical atrial flutter. Regarding electrophysiological characteristics, one of the most intriguing findings is the presence of low voltage zones in some of these patients together with the presence of a functional, unidirectional line of block between the two vena cava. It is theorized that episodes of paroxysmal atrial fibrillation can trigger this line of block, which may then allow the onset of stable atrial flutter. Without this, the patient will either remain in atrial fibrillation or return to sinus rhythm. Another of the most important pending tasks is identifying patients at risk of developing post-ablation atrial fibrillation. Discriminating between individuals who will experience a complete arrhythmia cure and those who will develop atrial fibrillation after flutter ablation, remains essential given the important prognostic and therapeutic implications. From the initial X-ray guided linear cavotricuspid ablation, several alternatives have arisen in the last decade: electrophysiological criteria-directed point applications based on entrainment mapping, applications directed by maximum voltage criteria or by wavefront speed and maximum voltage criteria (omnipolar mapping). Electro-anatomical navigation systems offer substantial support in all three strategies. Finally, the electrophysiological techniques to confirm the success of the procedure are reviewed.

Long-term hyperuricemia impact on atrial fibrillation outcomes.

BACKGROUND: No studies have been conducted to analyze the impact of serum uric acid (UA) levels on the outcome of atrial fibrillation (AF) patients. We aimed to evaluate the effect of hyperuricemia (HU) on the prognosis of AF. METHODS AND RESULTS: Consecutive patients who consulted our emergency room for an episode of AF, already known or newly diagnosed, between January 1, 2010, and December 31, 2015 (n=2017) were enrolled. After applying exclusion criteria, 1772 patients were included. Serum UA levels in the 6 months before or after the date of the episode were recorded and classified into quartiles: Q1 (n=443) serum UA levels <4.6 mg/dL; Q2 (n=430) 4.6-5.6 mg/dL; Q3 (n=435) 5.7-6.9 mg/dL; and Q4 (n=464) ≥7 mg/dL. Two groups were differentiated: patients without HU (Q1-Q3) and those with HU (Q4). The mean follow-up was 3.7 ± 1.4 years. The primary endpoint was all-cause mortality during follow-up. Mortality during follow-up in the bivariate analysis was higher (p < 0.001) in patients with HU (52.1 %) compared to those without it (35.3 %), confirming multivariate Cox analysis of HU as an independent risk factor for death [hazard ratio 1.89 (1.59-2.25)]. Kaplan-Meier survival analysis showed a shorter survival time in patients with HU (log-rank test, p<0.001). Cox analysis confirmed significant differences in the risk of heart failure (30 % vs. 22 %) in patients with HU. CONCLUSIONS: HU is independently associated with an increased risk for all-cause mortality and hospitalization for heart failure in patients with AF.

Gender-Based Clinical, Therapeutic Strategies and Prognosis Differences in Atrial Fibrillation.

BACKGROUND: There are limited data on gender-based differences in atrial fibrillation (AF) treatment and prognosis. We aimed to examine gender-related differences in medical attention in an emergency department (ED) and follow-up (FU) among patients diagnosed with an AF episode and to determine whether there are gender-related differences in clinical characteristics, therapeutic strategies, and long-term adverse events in this population. METHODS: We performed a retrospective observational study of patients who presented to a tertiary hospital ER for AF from 2010 to 2015, with a minimum FU of one year. Data on medical attention received, mortality, and other adverse outcomes were collected and analyzed. RESULTS: Among the 2013 patients selected, 1232 (60%) were female. Women were less likely than men to be evaluated by a cardiologist during the ED visit (11.5% vs. 16.6%, p = 0.001) and were less likely to be admitted (5.9% vs. 9.5%, p < 0.05). Electrical cardioversion was performed more frequently in men, both during the first episode (3.4% vs. 1.2%, p = 0.001) and during FU (15.9% vs. 10.6%, p < 0.001), despite a lower AF recurrence rate in women (9.9% vs. 18.1%). During FU, women had more hospitalizations for heart failure (26.2% vs. 16.1%, p < 0.001). CONCLUSIONS: In patients with AF, although there were no gender differences in mortality, there were significant differences in clinical outcomes, medical attention received, and therapeutic strategies. Women underwent fewer attempts at cardioversion, had a lower probability of being evaluated by cardiologists, and showed a higher probability of hospitalization for heart failure. Being alert to these inequities should facilitate the adoption of measures to correct them.

Prognostic value of troponin I in atrial fibrillation.

OBJECTIVE: To evaluate whether circulating cardiac troponin I (cTnI) levels are associated with worst outcomes in patients with atrial fibrillation (AF). METHODS: Consecutive patients visiting the emergency room (ER) with a new episode of a previously diagnosed AF or a new diagnosis of AF during ER admission between January 1st, 2010 and December 31st, 2015, were enrolled in the study (n = 2617). After applying exclusion criteria and eliminating repeated episodes, 2013 patients were finally included. Of these, 1080 patients with at least one cTnI measurement in the ER were selected and classified into 4 groups according to cTnI quartiles: Q1 (n = 147) cTnI <10 ng/L (Group 1); Q2 (n = 254): 10-19 ng/L (Group 2); Q3 (n = 409): 20-40 ng/L (Group 3); and Q4 (n = 270): cTnI >40 ng/L (Group 4). The median follow-up period was 47.8 ± 32.8 months. The primary endpoint was all-cause death during the follow-up. RESULTS: A higher mortality was found in group 4 compared with the other groups (58.9% vs. 28.5%, respectively, p < 0.001), along with, hospitalizations (40.4% vs. 30.7%, p = 0.004), and readmissions due to decompensated heart failure (26.7% vs. 2.5%, p = 0.002). The probability of survival without AF recurrences was lower in the Q4 (p = 0.045). Moreover, cTnI levels >40 ng/L (Q4) were an independent risk factor of death (HR, 2.03; 95% CI, 1.64-2.51; p < 0.001). CONCLUSION: The assessment of cTnI at ER admission could be a useful strategy for risk stratification of patients diagnosed with AF by identifying a subgroup with medium-term to long-term increased risk of adverse events and mortality.

Sex-Specific Ventricular Arrhythmias and Mortality in Cardiac Resynchronization Therapy Recipients.

OBJECTIVES: The study goal was to examine whether there are sex-related differences in the incidence of ventricular arrhythmias and mortality in CRT-defibrillator (CRT-D) recipients. BACKGROUND: Few studies have evaluated sex-related benefits of cardiac resynchronization therapy (CRT). Moreover, data on sex-related differences in the occurrence of ventricular tachyarrhythmias in this population are limited. METHODS: A multicenter retrospective study was conducted in 460 patients (355 male subjects and 105 female subjects) from the UMBRELLA (Incidence of Arrhythmia in Spanish Population With a Medtronic Implantable Cardiac Defibrillator Implant) national registry. Patients were followed up through remote monitoring after the first implantation of a CRT-D during a median follow-up of 2.2 ± 1.0 years. Sex differences were analyzed in terms of ventricular arrhythmia-treated incidence and death during the follow-up period, with a particular focus on primary prevention patients. RESULTS: Baseline New York Heart Association functional class was worse in women compared with that in men (67.0% of women in New York Heart Association functional class III vs. 49.7% of men; p = 0.003), whereas women had less ischemic cardiac disease (20.8% vs. 41.7%; p < 0.001). Female sex was an independent predictor of ventricular arrhythmias (hazard ratio: 0.40; 95% confidence interval: 0.19 to 0.86; p = 0.020), as well as left ventricular ejection fraction and nonischemic cardiomyopathy. Mortality in women was one-half that of men, although events were scarce and without significant differences (2.9% vs. 5.6%; p = 0.25). CONCLUSIONS: Women with left bundle branch block and implanted CRT have a lower rate of ventricular tachyarrhythmias than men. All-cause mortality in patients is, at least, similar between female and male subjects.