RESUMEN
BACKGROUND: Hypertensive heart disease (HHD) is a leading contributor to heart failure with preserved ejection fraction (HFpEF). However, the mechanisms behind the transition to the symptomatic phase remain unclear. OBJECTIVES: We sought to find the association of the exercise response of left atrial (LA) mechanical function with functional capacity, symptoms, and outcome across the heart failure (HF) spectrum in hypertension. METHODS: Echocardiography (including LA reservoir peak atrial longitudinal strain [PALS] and peak atrial contractile strain [PACS] and LA stiffness index) was performed at rest and immediately postexercise in 139 patients with HHD-35 with stage A, 48 with stage B, and 56 with stage C HFpEF. Patients were followed for HF and atrial fibrillation. RESULTS: Exercise capacity was progressively worse from stage A through stage B to stage C and was accompanied by a gradual impairment of changes in PALS and PACS from rest to exercise, whereas LA stiffness reserve remained unchanged until stage C. Peak atrial longitudinal strain and PACS reserves were independently associated with exercise capacity (P = .017 and .008, respectively). Left atrial stiffness reserve and E/e' were the strongest associations of symptomatic HF. Over a median of 25 months, 35 patients developed HF and/or atrial fibrillation. Peak atrial longitudinal strain and PACS reserves were associated with the study end points after adjusting for age, diabetes, N-terminal pro-B type natriuretic peptide, LA volume index, resting E/e', and resting PALS/PACS. CONCLUSIONS: Impaired exercise reserve of LA strain and stiffness are associated with reduced functional capacity in hypertension, and LA strain reserve is independently associated with outcome. These parameters appear to be determinants of progression to overt HF in HHD; however, their contribution may differ depending on HF stage.
Asunto(s)
Función del Atrio Izquierdo , Tolerancia al Ejercicio , Atrios Cardíacos , Insuficiencia Cardíaca , Hipertensión , Humanos , Femenino , Masculino , Tolerancia al Ejercicio/fisiología , Atrios Cardíacos/fisiopatología , Atrios Cardíacos/diagnóstico por imagen , Hipertensión/fisiopatología , Hipertensión/complicaciones , Persona de Mediana Edad , Función del Atrio Izquierdo/fisiología , Anciano , Insuficiencia Cardíaca/fisiopatología , Insuficiencia Cardíaca/complicaciones , Ecocardiografía/métodos , Volumen Sistólico/fisiología , Fibrilación Atrial/fisiopatología , Prueba de Esfuerzo/métodosRESUMEN
AIMS: Weight excess and insulin resistance predispose to heart failure. High sodium consumption may contribute to the development of cardiac impairment in insulin-resistant individuals by promoting inadequate skeletal muscle microvascular perfusion response to insulin. We sought to investigate the association of dietary sodium reduction with muscle perfusion, insulin sensitivity, and cardiac function in overweight/obese insulin-resistant (O-IR) normotensive subjects. METHODS AND RESULTS: Fifty O-IR individuals with higher than recommended sodium intake were randomized to usual or reduced sodium diet for 8 weeks; 25 lean, healthy subjects served as controls for pre-intervention measurements. Echocardiography and muscle perfusion were performed during fasting and under stable euglycaemic-hyperinsulinaemic clamp conditions. O-IR patients demonstrated subclinical cardiac dysfunction as evidenced by lower left ventricular global longitudinal strain (GLS), e' tissue velocity, and left atrial strain and reduced muscle perfusion. The intervention arm showed improvements in insulin resistance [glucose infusion rate (GIR)], GLS, e', atrial strain, and muscle perfusion in fasting conditions, as well as improved responses of GLS and muscle perfusion to insulin during clamp. Significant interactions were found between the allocation to low-salt diet and improvement in muscle perfusion on change in GIR at follow-up (P = 0.030), and between improvement in muscle perfusion and change in GIR on change in GLS response to insulin at follow-up (P = 0.026). Mediation analysis revealed that the relationship between the reduction of sodium intake and improvement in GLS was mediated by improvements in muscle perfusion and GIR (decrease in beta coefficient from -0.29 to -0.16 after the inclusion of mediator variables to the model). CONCLUSIONS: The reduction of dietary sodium in the normotensive O-IR population improves cardiac function, and this effect may be associated with the concomitant improvements in skeletal muscle perfusion and insulin resistance. These findings might contribute to refining heart failure preventive strategies.
Asunto(s)
Resistencia a la Insulina , Sodio en la Dieta , Humanos , Resistencia a la Insulina/fisiología , Músculo Esquelético , Sobrepeso , PerfusiónRESUMEN
OBJECTIVES: This study sought to identify the factors associated with incident atrial fibrillation (AF) in a well-characterized heart failure with preserved ejection fraction (HFpEF) population, with special focus on left atrial (LA) strain. BACKGROUND: AF is associated with HFpEF, with adverse consequences. Effective risk evaluation might allow the initiation of protective strategies. METHODS: Clinical evaluation and echocardiography, including measurements of peak atrial longitudinal strain (PALS), peak atrial contraction strain (PACS), and LA volume index (LAVI), were obtained in 170 patients with symptomatic HFpEF (mean age, 65 ± 8 years), free of baseline AF. AF was identified by standard 12-lead electrocardiogram, review of relevant medical records (including Holter documentation), and surveillance with a portable single-lead electrocardiogram device over 2 weeks. Results were validated in the 103 patients with HFpEF from the Karolinska-Rennes (KaRen) study. RESULTS: Over a median follow-up of 49 months, incident AF was identified in 39 patients (23%). Patients who developed AF were older; had higher clinical risk scores, brain natriuretic peptide, creatinine, LAVI, and LV mass; lower LA strain and exercise capacity; and more impaired LV diastolic function. PACS, PALS, and LAVI were the most predictive parameters for AF (area under receiver-operating characteristic curve: 0.76 for PACS, 0.71 for PALS, and 0.72 for LAVI). Nested Cox regression models showed that the predictive value of PACS and PALS was independent from and incremental to clinical data, LAVI, and E/e' ratio. Classification and regression trees analysis identified PACS ≤12.7%, PALS ≤29.4%, and LAVI >34.3 ml/m2 as discriminatory nodes for AF, with a 33-fold greater hazard of AF (p < 0.001) in patients categorized as high risk. The classification and regression trees algorithm discriminated high and low AF risk in the validation cohort. CONCLUSIONS: PACS and PALS provide incremental predictive information about incident AF in HFpEF. The inclusion of these LA strain components to the diagnostic algorithm may help guide screening and further monitoring for AF risk in this population.