Atrial arrhythmias and heart failure: A "modern view" of an old paradox.

BACKGROUND: Heart failure (HF) and atrial arrhythmias (AAs) are two clinical conditions that characterize the daily clinical practice of cardiologists. In this perspective review, we analyze the shared etiopathogenetic pathways of atrial arrhythmias, which are the most common cause of atrial arrhythmias-induced cardiomyopathy (AACM) and HF. HYPOTHESIS: The aim is to explore the pathophysiology of these two conditions considering them as a "unicum", allowing the definition of a cardiovascular continuum where it is possible to predict the factors and to identify the patient phenotype most at risk to develop HF due to atrial arrhythmias. METHODS: Potentially eligible articles, identified from the Electronic database (PubMed), and related references were used for a literature search that was conducted between January 2022 and January 2023. Search strategies were designed to identify articles that reported atrial arrhythmias in association with heart failure and vice versa. For the search we used the following keywords: atrial arrhythmias, atrial fibrillation, heart failure, arrhythmia-induced cardiomyopathy, tachycardiomyopathy. We identified 620 articles through the electronic database search. Out of the 620 total articles we removed 320 duplicates, thus selecting 300 eligible articles. About 150 titles/abstracts were excluded for the following reasons: no original available data, no mention of atrial arrhythmias and heart failure crosstalk, very low quality analysis or evidence. We excluded also non-English articles. When multiple articles were published on the same topic, the articles with the most complete set of data were considered. We preferentially included all papers that could provide the best evidence in the field. As a result, the present review article is based on a final number of 104 references. RESULTS: While the pathophysiology of AACM and Heart Failure with reduced ejection fraction (HFrEF) has been studied in detail over the years, the causal link between atrial arrhythmias and heart failure with Preserved Ejection Fraction (HFpEF) has been often subject of interest. HFpEF is strictly related to AAs, which has always been considered significant risk factor. In this review we described the pathophysiological links between atrial fibrillation and heart failure. Furthermore, we illustrated and discussed the preclinical and clinical predicting factors of AF and HFpEF, and the corresponding targets of the available therapeutic agents. Finally, we outlined the patient phenotype at risk of developing AF and HFpEF (Central Illustration). CONCLUSIONS: In this review, we underline how these two clinical conditions (AF and HFpEF) represent a "unicum" and, therefore, should be considered as a single disease that can manifest itself in the same phenotype of patients but at different times. Furthermore, considering that today we have few therapeutic strategies to treat these patients, it would be good to make an early diagnosis in the initial stages of the disease or intervene even before the development of signs and symptoms of HF. This is possible only by paying greater attention to patients with predisposing factors and carrying out a targeted screening with the correct diagnostic methods. A systemic approach aimed at improving the immuno-metabolic profile of these patients by lowering the body mass index, threatening the predisposing factors, lowering the mean heart rate and reducing the sympathetic nervous system activation is the key strategy to reduce the clinical impact of this disease.

The functional substrate in patients with atrial fibrillation is predictive of recurrences following catheter ablation.

BACKGROUND: Enhanced characterization of the atrial electrical substrate may lead to better comprehension of atrial fibrillation (AF) pathophysiology. OBJECTIVE: With the use of high-density substrate mapping, we sought to investigate the occurrence of functional electrophysiological phenomena in the left atrium and to assess potential association with arrhythmia recurrences following catheter ablation. METHODS: Sixty-three consecutive patients with AF referred for ablation were enrolled. Conduction abnormalities analysis relied on two acquired left atrial electro-anatomical maps (sinus and atrial paced rhythm). We classified conduction abnormalities as fixed (if these were present in both rhythms), or functional rhythm-dependent (if unmasked in one of the two rhythms). Esophagus and aorta locations were recorded to check the correspondence with abnormal conduction sites. RESULTS: 234 conduction abnormalities were detected, of which 125 (53.4%) were functional rhythm-dependent. In sinus rhythm the most frequent anatomical site of functional phenomena was the anterior wall followed by the posterior wall and in paced rhythm, the pulmonary venous antra. Sites of functional phenomena in 82.6% of cases corresponded with extra-cardiac structures such as sinus of Valsalva of ascending aorta anteriorly and the esophagus posteriorly. The vast majority (88%) of areas with functional phenomena had normal bipolar voltage. After pulmonary vein ablation, the number of residual functional phenomena is an indipendent predictor of AF recurrence (HR 2.539 [1.458 - 4.420], p-value = 0.001) with a risk of recurrences at multivariable Cox analysis. CONCLUSIONS: Dual high-density mapping (during sinus and paced rhythms) is able to unmask functional, rhythm-dependent, phenomena which are predictive of AF recurrences during the follow-up.