Atrial Fibrillation and Heart Failure with Preserved Ejection Fraction: Two Chronic Troublemakers

The association of cardiac troponin and cardiovascular events in patients with concomitant heart failure preserved ejection fraction and atrial fibrillation

BACKGROUND

Limited data are available for risk stratification in patients with atrial fibrillation (AF) and combined heart failure with preserved ejection fraction (HFpEF). We aimed to explore the prognostic utility of high-sensitivity cardiac troponin I (hs-cTnI) in patients with newly detected AF and concomitant HFpEF.

METHODS

From August 2014 to December 2016, 2,361 patients with newly detected AF were polled in a retrospective single-center registry. Of which, 634 patients were eligible for HFpEF diagnosis (HFA-PEFF score ≥ 5) and 165 patients were excluded with exclusion criteria. Finally, 469 patients are classified into elevated or non-elevated hs-cTnI groups based on the 99th percentile upper reference limit (URL). The primary outcome was the incidence of major adverse cardiac and cerebrovascular events (MACCE) during follow-up.

RESULTS

In 469 patients, 295 were stratified into the non-elevated hs-cTnI group (< 99th percentile URL of hs-cTnI) and 174 were placed in the elevated hs-cTnI group (≥ 99th percentile URL of hs-cTnI). The median follow-up period was 24.2 (interquartile range, 7.5-38.6) months. During the follow-up period, 106 patients (22.6%) in the study population experienced MACCE. In a multivariable Cox regression model, the elevated hs-cTnI group had a higher incidence of MACCE (adjusted hazard ratio [HR], 1.54; 95% confidence interval [CI], 1.08-2.55; p = 0.03) and coronary revascularization-caused readmission (adjusted HR, 3.86; 95% CI, 1.39-15.09; p = 0.02) compared with the non-elevated hs-cTnI group. The incidence of heart failure-caused readmission tended to occur more frequently in the elevated hs-cTnI group (8.5% versus 15.5%; adjusted HR, 1.52; 95% CI, 0.86-2.67; p = 0.08).

CONCLUSIONS

One-fifth of patients with AF and concomitant HFpEF experienced MACCE during follow-up, and elevated hs-cTnI was independently associated with higher risk of MACCE, as driven by heart failure and revascularization-caused readmission. This finding suggested that hs-cTnI may be a useful tool in individualized risk stratification of future cardiovascular events in patients with AF and concomitant HFpEF.

Acute Heart Failure: Diagnostic-Therapeutic Pathways and Preventive Strategies-A Real-World Clinician's Guide

Acute heart failure (AHF) is the most frequent cause of unplanned hospital admission in patients of >65 years of age and it is associated with significantly increased morbidity, mortality, and healthcare costs. Different AHF classification criteria have been proposed, mainly reflecting the clinical heterogeneity of the syndrome. Regardless of the underlying mechanism, peripheral and/or pulmonary congestion is present in the vast majority of cases. Furthermore, a marked reduction in cardiac output with peripheral hypoperfusion may occur in most severe cases. Diagnosis is made on the basis of signs and symptoms, laboratory, and non-invasive tests. After exclusion of reversible causes, AHF therapeutic interventions mainly consist of intravenous (IV) diuretics and/or vasodilators, tailored according to the initial hemodynamic status with the addition of inotropes/vasopressors and mechanical circulatory support if needed. The aim of this review is to discuss current concepts on the diagnosis and management of AHF in order to guide daily clinical practice and to underline the unmet needs. Preventive strategies are also discussed.

Incidence and Determinants of Spontaneous Cardioversion of Early Onset Symptomatic Atrial Fibrillation

Atrial fibrillation (AF) is the most frequent chronic arrhythmia worldwide, and it is associated with significant morbidity and mortality, making it a considerable burden both to patients and the healthcare system. Nowadays, an early attempt to restore sinus rhythm in acute symptomatic AF through electrical or pharmacological cardioversion is the most common approach in the Emergency Department (ED). However, considering the high percentage of spontaneous cardioversion of paroxysmal AF reported by many studies, this approach may not be the ideal choice for all patients. In this manuscript we performed a review of the most relevant studies found in literature with the aim of identifying the main determinants of spontaneous cardioversion, focusing on those easy to detect in the ED. We have found that the most relevant predictors of spontaneous cardioversion are the absence of Heart Failure (HF), a small atrial size, recent-onset AF, rapid Atrial Fibrillatory Rate and the relationship between a previous AF episode and Heart Rate/Blood Pressure. A number of those are utilized, along with other easily determined parameters, in the recently developed "ReSinus" score which predicts the likelihood of AF spontaneous cardioversion. Such identification may help the physician decide whether immediate cardioversion is necessary, or whether to adopt a "watch-and-wait" strategy in the presence of spontaneous cardioversion determinants.

PRRX1 Loss-of-Function Mutations Underlying Familial Atrial Fibrillation

Background

Atrial fibrillation (AF) is the most common form of clinical cardiac dysrhythmia responsible for thromboembolic cerebral stroke, congestive heart failure, and death. Aggregating evidence highlights the strong genetic basis of AF. Nevertheless, AF is of pronounced genetic heterogeneity, and in an overwhelming majority of patients, the genetic determinants underpinning AF remain elusive.

Methods and Results

By genome‐wide screening with polymorphic microsatellite markers and linkage analysis in a 4‐generation Chinese family affected with autosomal‐dominant AF, a novel locus for AF was mapped to chromosome 1q24.2–q25.1, a 3.20‐cM (≈4.19 Mbp) interval between markers D1S2851 and D1S218, with the greatest 2‐point logarithm of odds score of 4.8165 for the marker D1S452 at recombination fraction=0.00. Whole‐exome sequencing and bioinformatics analyses showed that within the mapping region, only the mutation in the paired related homeobox 1 (PRRX1) gene, NM_022716.4:c.319C>T;(p.Gln107*), cosegregated with AF in the family. In addition, sequencing analyses of PRRX1 in another cohort of 225 unrelated patients with AF revealed a new mutation, NM_022716.4:c.437G>T; (p.Arg146Ile), in a patient. The 2 mutations were absent in 908 control subjects. Biological analyses in HeLa cells demonstrated that the 2 mutants had significantly diminished transactivation on the target genes ISL1 and SHOX2 and markedly decreased ability to bind the promoters of ISL1 and SHOX2 (2 genes causally linked to AF), although with normal intracellular distribution.

Conclusions

This study first indicates that PRRX1 loss‐of‐function mutations predispose to AF, which provides novel insight into the molecular pathogenesis underpinning AF, implying potential implications for precisive prophylaxis and management of AF.